Biomedical subjects

A Haas

Publications and source records attributed to A Haas.

At least 73 records · Page 4Linked to original sources

PubMed1997

Postmortem analysis of invasive aspergillosis in a tertiary care hospital.

To estimate the incidence of fatal invasive aspergillosis in a 1500-bed tertiary-care hospital and to investigate the utility of laboratory diagnostic approaches, necropsy protocols and microbiological data from 1994 and 1995 were reviewed. Among 694 necropsies from 1693 patients who died in these two years, 27 (4%) cases of invasive aspergillosis were identified. Twelve cases of invasive aspergillosis were found after transplantation of solid organs, three after bone marrow transplantation, four in patients with haematological malignancies, and five in patients with solid tumours. In 15 cases (56%) invasive aspergillosis was not suspected before death. In patients in whom serum sampling was performed seven days antemortem, the Aspergillus latex agglutination test had a sensitivity of 53% (9/17). Culture of tracheal secretions or bronchoalveolar lavage fluid from patients with pulmonary aspergillosis yielded Aspergillus fumigatus in 88% (14/16).

Adult↗

PubMed1997

[New blindness incidents in Württemberg-Hohenzollern].

UNLABELLED: Blindness causes human suffering and high social costs. Preventive measures are necessary. Virtually all blind people are registered with the social services. Data from these institutions may help in (long-term) planning for blindness prevention. MATERIAL AND METHODS: The present investigation analysed data from the social services of the region Württemberg-Hohenzollern. The files contained information on ocular status, year of birth, district, and sex of newly blind subjects of the year 1994. RESULTS: Two thirds (66.8%) of newly blind subjects are women. About half (47.8%) of all subjects are over 80 years of age. The most frequent causes of blindness are: macular degeneration, 33.7%; diabetic retinopathy, 17.3%; glaucoma, 13.8%; and high myopia, 6.6%. CONCLUSIONS: Blindness is increasingly a problem of high age. Diabetic retinopathy and glaucoma are still major causes of blindness. For these diseases blindness prevention is conceivable. Thus co-ordinated blindness prevention activities should focus on diabetic retinopathy and glaucoma.

Adolescent↗

PubMed1997

Typing of Candida albicans by use of a combined PCR/hybridization assay.

A modified genotyping assay for Candida albicans based on the RAPD-PCR (random amplification of polymorphic DNA) is described. Following capillary blot of RAPD-PCR products onto a nylon membrane, hybridization with a PCR-generated gene probe resulted in heterogeneous band patterns. By this method the discriminatory power of RAPD-PCR is enhanced with satisfactory reproducibility and reduced interference.

Candida albicans↗

PubMed1997

Heparin-induced extracorporeal fibrinogen/LDL precipitation (HELP): a promising regimen for the treatment of vascular diseases.

Current management of atherosclerotic diseases consists primarily of medical therapy designed to increase oxygen supply to the heart, the brain, retinal vessels, or lower limbs. The development of these diseases is based on atherosclerotic changes induced by risk factors such as elevated levels of fibrinogen and lipoproteins. These risk factors are related to a dramatic deterioration of the hemorrheologic pattern, which reduces perfusion. Consequently, attempts are now being made to treat ischemia via hemorrheological intervention. A new treatment modality utilizing the heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP), offers the possibility of obtaining therapeutic success not only in cases of severe hypercholesterolemia but also in the field of hemorheology. With HELP a safe and rapid reduction of fibrinogen and lipid fractions has become feasible, thus providing acute improvements of red cell aggregation, of the filterability of blood cells, of whole-blood and plasma viscosity, and thereby of microcirculation. Because cerebrovascular diseases are known to be related to disturbances of the hemorrheological situation, the HELP system is used in the Department of Electrobiology of Graz for the treatment of acute stroke, cerebral multi-infarct disease, and occlusions of retinal arteries.

Acute Disease↗

PubMed1996

Homotypic vacuole fusion requires Sec17p (yeast alpha-SNAP) and Sec18p (yeast NSF).

In Saccharomyces cerevisiae, vacuoles are inherited by the formation of tubular and vesicular structures from the mother vacuole, the directed projection of these structures into the bud and the homotypic fusion of these vesicles. We have previously exploited a cell-free inheritance assay to show that the fusion step of vacuole inheritance requires cytosol, ATP and the GTPase Ypt7p. Here we demonstrate, using affinity-purified antibodies and purified recombinant proteins, a requirement for Sec17p (yeast alpha-SNAP) and Sec18p (yeast NSF) in homotypic vacuole fusion in vitro. Thus, Sec17p and Sec18p, which are typically involved in heterotypic transport steps, can also be involved in homotypic organelle fusion. We further show that vacuole-to-vacuole fusion is stimulated by certain fatty acyl-coenzyme A compounds in a Sec18p-dependent fashion. Finally, our data suggest the presence of a cytosolic factor which activates vacuole membrane-bound Sec18p.

Acyl Coenzyme A↗

PubMed1996

Reduction of traumatic brain injury-induced cerebral oedema by a free radical scavenger.

Oxygen derived free radicals have been proposed to be in part responsible for the cerebral oedema resulting from head injury. In the present study the effects of free radical suppression with MDL 74,180 (2,3-dihydro-2,2,4,6,7-pentamethyl-3-(4-methylpiperazino)-methyl-1 - benzofuran-5-ol dihydrochloride), an alpha-tocopherol analogue free radical scavenger, on the development of cerebral oedema resulting from head injury has been assessed. Fluid percussion head injury in rats caused a regional oedema 48 h after injury. Infusion of MDL 74,180 for 2 h after the injury significantly attenuated oedema development in a dose-related manner. Using magnetic resonance imaging, cerebral oedema development was monitored in head injured mice. Oedema was apparent 4 h after head injury and was greatest in the vicinity of the olfactory bulb and surrounding the ventricles. Treatment with MDL 74,180 (1-10 micrograms/kg intravenously, administered 3-5 min after the injury) significantly reduced the oedema development. MDL 74,180 is a potential treatment for the oedema caused as a result of head injury.

Animals↗

PubMed1996

Sec18p (NSF)-driven release of Sec17p (alpha-SNAP) can precede docking and fusion of yeast vacuoles.

S. cerevisiae inherits its vacuole by projecting vacuole-derived membrane vesicles and tubules into the bud, where they fuse to establish the daughter vacuole. This homotypic fusion event can be assayed in vitro. It requires Sec17p and Sec18p, the homologs of the mammalian alpha-SNAP and NSF, which cooperate in multiple steps of membrane trafficking. We now report that Sec17p, Sec18p, and ATP are only needed for an early stage of the reaction that results in Sec17p release. Sec17p and Sec18p actions precede, and are needed for, the step employing the Ras-like GTPase Ypt7p. Sec18p-driven release of Sec17p can even precede vacuole docking, as it can occur prior to mixing of vacuoles and is insensitive to vacuole concentration. Sec17p and Sec18p thus may function in a predocking stage of the reaction, rather than in bilayer fusion per se.

Adenosine Triphosphatases↗

PubMed1996

Central serous chorioretinopathy in younger and older adults.

PURPOSE: The purpose of the study is to investigate the demographic characteristics and clinical findings of central serous chorioretinopathy (CSC). METHODS: This study examined a consecutive series of 130 patients with CSC seen over an 18-month period. RESULTS: The mean age of the patients when examined was 51 years, and the male-to-female ratio was 2.6:1.0. A total of 62 patients were older than 50 years of age when first examined. Although the patients shared some clinical and angiographic similarities, the older patients had a lower mean visual acuity and were more likely to have diffuse retinal pigment epitheliopathy, bilateral involvement, and secondary choroidal neovascularization than were the younger patients. With ophthalmoscopic and angiographic examination results, it was possible to differentiate CSC in older adults from choroidal neovascularization. CONCLUSION: This study expands the clinical concept of CSC. The male-to-female ratio was much lower, and the range of ages of the patients was much greater than in previous studies. Disease manifestations in older adults differed somewhat from those seen in younger adults. In older patients, CSC can be distinguished from other exudative maculopathies, particularly that of choroidal neovascularization secondary to age-related macular degeneration.

Adult↗

PubMed1996

Indocyanine green videoangiography of older patients with central serous chorioretinopathy.

PURPOSE: The authors studied the indocyanine green (ICG) videoangiography findings of central serous chorioretinopathy (CSC) in older adults. BACKGROUND: Central serous chorioretinopathy in older adults may be confused with the exudative forms of age-related macular degeneration (AMD) because the two entities may have similar ophthalmoscopic and fluorescein angiographic findings. Because of its enhanced ability to image the choroidal circulation, ICG videoangiography has been used to describe certain choroidal vascular abnormalities in young adults with CSC, as well as older patients with choroidal neovascularization (CNV). The ICG videoangiography findings in CSC in older adults is largely unknown. METHODS: The authors performed ICG videoangiography on 36 patients aged 50 years or older with CSC to characterize their findings. RESULTS: The ICG videoangiography findings of the patients were consistent, revealing choroidal vascular hyperpermeability manifested by areas of hyperfluorescence that were first seen in the midphase of the angiogram. In the later phases of the angiogram, there were dispersion of the hyperfluorescence and a distinctive silhouetting of the larger choroidal vessels. CONCLUSIONS: Older patients with CSC have a unique temporal and topographic pattern of hyperpermeability that can help establish the proper diagnosis.

Aged↗

PubMed1996

Influence of a single HELP application on hemorheology and retinal hemodynamics.

The heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) eliminates selectively fibrinogen, total cholesterol, low-density lipoproteins (LDL) and triglycerides and improves hemorheology. We investigated the hemodynamic changes in 10 patients without ocular diseases performing a video fluorescein angiography after a single HELP procedure measuring the arm-retina time (ART) and the arteriovenous passage time (AVP). Laboratory parameters such as fibrinogen, cholesterol, LDL, triglycerides, red cell transit time, plasma and whole-blood viscosity were determined and retinal circulation was measured immediately before and after the HELP application. All of the laboratory parameters were lowered significantly. The ART was unaffected by the HELP procedure; however, there was a significant AVP reduction from 2.41 +/- 0.49 to 1.97 +/- 0.47 (p < 0.005). These results support the hemorheological and hemodynamic efficiency of the HELP system in microcirculatory diseases.

Adult↗

PubMed1996

Profile of exercising women.

Responses to a questionnaire by 497 women on their exercise, nutrition, and health habits were studied. Analysis showed respondents were well educated and represented a wide age range. The majority exercised at least 3 times a week for at least half an hour per session. Slightly more than half had been engaging in exercise for more than 5 years, with about 1 in 4 beginning for health goals and 1 in 4 motivated by weight control. Health was ranked in the top three most important reasons for continuing to exercise by more than half the women, but so were weight control, pleasure, and tension reduction. Lack of time limited regularity.

Adolescent↗

PubMed1995

The GTPase Ypt7p of Saccharomyces cerevisiae is required on both partner vacuoles for the homotypic fusion step of vacuole inheritance.

In the budding yeast Saccharomyces cerevisiae, vacuoles are inherited by the projection of vesicles and tubules from the mother-cell vacuole into the growing daughter cell during the S phase. These vesicles then fuse and form the daughter-cell organelle. We have described previously in vitro reactions of the formation of vacuole-derived segregation structures and of vacuole-vacuole fusion. Homotypic vacuole fusion requires cytosol, ATP and a physiological temperature, and is sensitive to GTPase inhibitors. These reactions are divisible into early stages which require ATP and cytosol, and late stages which require neither. Here, we report that Ypt7p, a ras-like GTPase implicated previously in endocytosis in yeast, is largely localized to the vacuole and is required on both partners during the in vitro vacuole fusion reaction. The in vitro fusion reaction is inhibited either by Gdi1p, which extracts the GDP-bound form of ras-like GTPases from membranes, or by antibodies specific for Ypt7p. The presence of anti-Ypt7p during the early stages of the reaction inhibits the development of cytosol- and ATP-independent intermediates. Although cytosol and ATP are no longer needed for the late stage of vacuole inheritance in vitro, the inhibition of this late stage by anti-Ypt7p or Gdi1p requires the continued presence of ATP and cytosol. Ypt7p is the first GTPase for which a direct role in organelle inheritance has been established.

Base Sequence↗

PubMed1995

Cranial features of dendrobatid larvae (Amphibia: Anura: Dendrobatidae).

The larval neurocranium and visceral arches of seven dendrobatid species representing four genera are described, based on cleared-and-stained and serially sectioned specimens. A variety of characters is shared by all seven species. Larval features do not substantiate the assumption of close ranoid affinities of the Dendrobatidae. Instead dendrobatid larvae share features such as the special quadripartite cartilago suprarostralis, the lack of the larval processus oticus, the presence of three foramina acustica, and the lack of a foramen perilymphaticum accessorius with many bufonoid larvae. The first of these characters is unique to bufonids, hylids, dendrobatids, and some New World leptodactylids; the other characters also occur in pelobatids and are presumably plesiomorphic for the Neobatrachia. The free proximal ends of Ceratobranchialia II and III are an autapomorphy of the Dendrobatidae supporting the monophyly of the family. Some features of the cranium are paedomorphic: low cartilago orbitalis, lack of connection between cartilage orbitalis and otic capsule (most species), and vestigal taeniae tecti. New anatomical terms are introduced.

Animals↗

PubMed1995

Risk factors for systemic fungal infections in liver transplant recipients.

The risk factors for systemic fungal infections were analysed retrospectively in 186 orthotopic liver transplant procedures performed in 152 patients between June 1985 and January 1993. The total incidence of systemic fungal infections was 16.5% (25/152). The incidence of disseminated candidiasis, aspergillosis, and combined candidiasis and aspergillosis was 6.5% (n = 10), 7.2% (n = 11) and 2.6% (n = 4), respectively. Mortality associated with systemic fungal infections was 80% (20 of 25 patients). There were ten cases of disseminated candidiasis, with 4 patients surviving, and 11 cases of invasive aspergillosis, with 1 patient surviving. All patients with combined systemic fungal infection died. To identify perioperative risk factors, 39 variables were used to compare patients with systemic fungal infections versus those without fungal infections. Fourteen variables were significantly associated with systemic fungal infections by univariate analysis. A consecutive logistic regression analysis revealed that the amount of fresh frozen plasma transfused due to poor initial function of the allograft and acute renal failure requiring hemofiltration were independently significant risk factors for systemic fungal infections. There was no statistical correlation between systemic fungal infections and the underlying liver disease, previous long-term corticosteroids and the postoperative immunosuppressive therapy. Risk factors identified in this study should be considered in the postoperative care of the individual liver transplant recipient. In our study a poor initial function of the hepatic allograft substantially increased the risk of systemic fungal infection.

Adult↗

PubMed1995

[Effect of calcium dobesilate on progression of diabetic retinopathy].

BACKGROUND: The increase of platelet aggregation, plasma and whole blood viscosity and the decrease of red cell deformability in patients with diabetes mellitus may be causative in the development of retinopathy. A therapy influencing these factors maybe prevents retinopathy or slows progression. MATERIAL AND METHODS: In a clinical and prospective study over 2 years 74 patients aged 20 to 69 years with a mild background retinopathy were randomly assigned to take oral 3 x 500 mg calcium dobesilate (Doxium) or no therapy. Both groups did neither differ in demographic nor in laboratory data. In fluorescein angiography following characteristics of retinopathy were graded: microaneurysms, size and outline of foveal avascular zone, capillary loss and severity of dye leakage. Additionally in 15 patients contrast sensitivity, visual fields and oscillatory potentials were investigated. RESULTS: The results of the fluorescein angiographical characteristics revealed no statistically significant difference between both groups. In the oscillatory potentials a significant shortening of latency could be found in both groups, but there was no difference between the groups. CONCLUSION: A 2-years application of calcium dobesilate has no statistically significant influence on the progression of diabetic retinopathy.

Adult↗

PubMed1994

[Non-arteritic anterior ischemic optic neuropathy: long-term results after hemodilution therapy].

BACKGROUND: In patients with nonarteritic anterior ischemic optic neuropathy (AION) we investigated the long-term effect of hemodilution on functional results, recurrence rate in the affected and involvement of the second eye. PATIENTS AND METHODS: In a retrospective study we reviewed 24 patients ranging in age from 62 to 92 years (mean 77 years) with AION. The duration of follow-up was between 8-51 months (mean 24.8 months). All patients received iso- (Hct > 40%) or hypervolemic (Hct < or = 40%) hemodilution over 8-10 days with daily infusion of 10% hydroxyethyl-starch 200/0.5. The hematocrit decreased significant (p < 0.001) from 43.4 +/- 3.8% to 37.8 +/- 3.5% after this 10-day hemodilution treatment. RESULTS: After the longterm follow-up 29.1% of the patients had an improvement of the central vision by two or more lines, 16.7% had a deterioration, 54.2% remained unchanged. The resulting visual acuity was between 0.5-1.0 in 37.5%, between 0.4-0.1 in 41.7% and worse than 0.1 in 20.8%. Neither visual fields nor the VECP were significant changed by hemodilution. After the mean follow-up period of 24.8 months no recurrence occurred in the affected eye and the second eye as never involved. CONCLUSION: Hemodilution therapy has no significant longterm effect on visual acuity and visual fields, but it seems to have a beneficial influence on the recurrence rate in the affected and on the involvement of the second eye.

Aged↗

PubMed1994

G-protein ligands inhibit in vitro reactions of vacuole inheritance.

During budding in Saccharomyces cerevisiae, maternal vacuole material is delivered into the growing daughter cell via tubular or vesicular structures. One of the late steps in vacuole inheritance is the fusion in the bud of vesicles derived from the maternal vacuole. This process has been reconstituted in vitro and requires isolated vacuoles, a physiological temperature, cytosolic factors, and ATP (Conradt, B., J. Shaw, T. Vida, S. Emr, and W. Wickner. 1992. J. Cell Biol. 119:1469-1479). We now report a simple and reliable assay to quantify vacuole-to-vacuole fusion in vitro. This assay is based on the maturation and activation of vacuole membrane-bound pro-alkaline phosphatase by vacuolar proteinase A after vacuole-to-vacuole fusion. In vitro fusion allowed maturation of 30 to 60% of pro-alkaline phosphatase. Vacuoles prepared from a mutant defective in vacuole inheritance in vivo (vac2-1) were inactive in this assay. Vacuole fusion in vitro required a vacuole membrane potential. Inhibition by nonhydrolyzable guanosine derivatives, mastoparans, and benzalkonium chloride suggest that GTP-hydrolyzing G proteins may play a key role in the in vitro fusion events.

Amino Acid Sequence↗

PubMed1994

Determination of four biochemically distinct, sequential stages during vacuole inheritance in vitro.

Vacuole inheritance in Saccharomyces cerevisiae can be reconstituted in vitro using isolated organelles, cytosol, and ATP. Using the requirements of the reaction and its susceptibility to inhibitors, we have divided the in vitro reaction into four biochemically distinct, sequential subreactions. Stage I requires exposure of vacuoles to solutions of moderate ionic strength. Stage II requires "stage I" vacuoles and cytosol. In stage III, stage II vacuoles react with ATP. Finally, during stage IV, stage III vacuoles at a certain, minimal concentration complete the fusion reaction without further requirement for any soluble components. Reagents that inhibit the overall vacuole inheritance reaction block distinct stages. Stage III of the reaction is sensitive to the proton ionophore CCCP, to inhibitors of the vacuolar ATPase such as bafilomycin A1, and to the ATP-hydrolyzing enzyme apyrase, suggesting that an electrochemical potential across the vacuolar membrane is required during this stage. Inhibition studies with the amphiphilic peptide mastoparan and GTP gamma S suggest that GTP-hydrolyzing proteins might also be involved during this stage. Microcystin-LR, a specific inhibitor of protein phosphatases of type 1 and 2A, inhibits stage IV of the inheritance reaction, indicating that a protein dephosphorylation event is necessary for fusion. The definition of these four stages may allow the development of specific assays for the factors which catalyze each of the consecutive steps of the in vitro reaction.

Adenosine Triphosphate↗