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A Haas

Publications and source records attributed to A Haas.

At least 55 records · Page 3Linked to original sources
PubMed2000

Yeast homotypic vacuole fusion: a window on organelle trafficking mechanisms.

Homotypic (self) fusion of yeast vacuoles, which is essential for the low copy number of this organelle, uses catalytic elements similar to those used in heterotypic vesicular trafficking reactions between different organelles throughout nature. The study of vacuole inheritance has benefited from the ease of vacuole isolation, the availability of the yeast genome sequence and numerous mutants, and from a rapid, quantitative in vitro assay of fusion. The soluble proteins and small molecules that support fusion are being defined, conserved membrane proteins that catalyze the reaction have been identified, and the vacuole membrane has been solubilized and reconstituted into fusion-competent proteoliposomes, allowing the eventual purification of all needed factors. Studies of homotypic vacuole fusion have suggested a modified paradigm of membrane fusion in which integral membrane proteins termed "SNAREs" can form stable complexes in cis (when on the same membrane) as well as in trans (when anchored to opposing membranes). Chaperones (NSF/Sec18p, LMA1, and -SNAP/Sec17p) disassemble cis-SNARE complexes to prepare for the docking of organelles rather than to drive fusion. The specificity of organelle docking resides in a cascade of trans-interactions (involving Rab-like GTPases), "tethering factors," and trans-SNARE pairing. Fusion itself, the mixing of the membrane bilayers and the organelle contents, is triggered by calcium signaling.

Animals↗
PubMed2000

Value of Candida polymerase chain reaction and vaginal cytokine analysis for the differential diagnosis of women with recurrent vulvovaginitis.

OBJECTIVES: Recurrent vulvovaginitis remains difficult to diagnose accurately and to treat. The present investigation evaluated the utility of testing vaginal specimens from women with symptomatic recurrent vulvovaginitis for Candida species by polymerase chain reaction (PCR) and for cytokine responses. METHODS: Sixty-one consecutive symptomatic women with pruritus, erythema, and/or a thick white discharge and a history of recurrent vulvovaginitis and 31 asymptomatic women with no such history were studied. Vaginal swabs were tested for Candida species by PCR, for the antiinflammatory cytokine interleukin (IL)-10, and for the proinflammatory cytokine IL-12. RESULTS: C. albicans was detected in 19 (31.1%) of the patients as well as in three (9.7%) controls (P = 0.03). Both IL-10 (31.1% vs. 0%) and IL-12 (42.6% vs. 6.5%) were also more prevalent in the recurrent vulvovaginitis patients (P < 0.001). However, there was no relation between the presence or absence of Candida and either cytokine. Detection of IL-12 in 14 women indicated the stimulation of a vaginal cell-mediated immune response possibly from an infectious agent. The presence of only IL-10 in six patients indicated a suppression of vaginal cell-mediated immunity and was consistent with a possible allergic etiology. The absence of both IL-10 and IL-12 in other patients, similar to that found in healthy controls, suggested a noninfectious, nonallergic etiology of their symptoms. CONCLUSION: Many women with recurrent vulvovaginitis are not infected with Candida. Testing for Candida should be required in this population. Treatment with only anti-Candida medication will clearly be inadequate for the majority of women with this condition.

Candida albicans↗
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1999

A four-year review of fatal Aspergillosis.

To investigate the incidence, underlying diseases, and macropathological and microbiological features of invasive aspergillosis in a university hospital, the protocols of 1187 autopsies performed during the 4-year period 1993-1996 were reviewed. Invasive aspergillosis was diagnosed as the cause of death in 48 (4%) cases, four (8%) of which did not involve severe primary immunosuppression. In seven (15%) cases no pulmonary involvement was found; in six of these cases the portal of infection could not be established, whereas in one case invasive aspergillosis originated from Aspergillus peritonitis. Aspergillus grew in 42% of the samples obtained from the respiratory tracts of 32 patients with pulmonary aspergillosis and submitted within 10 days antemortem; at least one positive culture was obtained from 20 (63%) of these patients. It is concluded that the diagnosis of aspergillosis by means of culture has an appreciable sensitivity. Fatal invasive aspergillosis was rare among patients without severe immunosuppression, whereas invasive aspergillosis without pulmonary involvement was unexpectedly frequent.

Adult↗
PubMed1999

[Serous detection of the neuroretina in Waldenström disease. A case report].

BACKGROUND: Waldenstrom's Macroglobulinemia is a monoclonal gammopathy producing pathologic IgM antibodies with increased blood viscosity, platelet dysfunction and retinal hemorrhages. As a complication a serous detachment of the macula is described. The pathogenesis of the serous detachment is still not fully understood. CASE REPORT: A 73-year-old male patient was presented with Waldenstrom's Macroglobulinemia, a typical hyperviscosity retinopathy and serous detachment of the macula. We performed fluorescein (FA)- and indocyaningreenangiography (ICG) before and three months after chemotherapy. Especially ICG-angiographic findings revealed a serous detachment that was restricted to the posterior pole but showed a fingershaped enlargement to the optic disc. CONCLUSION: FA- and especially ICG-angiographic findings can help to get more information about the pathogenetic mechanism of serous detachment in Waldenstrom's Macroglobulinemia. Besides toxic alteration of the retinal pigmentepithelium, oncotic and hydrostatic pressure, a pathologic communication between the optic disc, the subarachnoid space and the subretinal space is discussed.

Aged↗
PubMed1998

Correlations of cranial morphology, ecology, and evolution in Australian suctorial tadpoles of the genera Litoria and Nyctimystes (Amphibia: Anura: Hylidae: Pelodryadinae).

Suctorial anuran larvae are highly specialized for living in fast-flowing waters, using their oral disks as adhesive organs to attach to the substrate. The cranial musculoskeletal structure of suctorial larvae of Litoria nannotis, L. rheocola, and Nyctimystes dayi (Hylidae: Pelodryadinae) were compared with congenerics with pond-type larvae (L. caerulea, L. genimaculata, L. xanthomera). Data from two other neobatrachian species with suctorial larvae (Boophis sp., Hyla armata) as well as published descriptions were taken into account. Suctorial tadpoles evolved several times independently in the Neobatrachia and share various features, irrespective of their phylogenetic position. These include the following. Cornua trabeculae are expanded anteriorly and sometimes fused. The lower jaws are robust. The greatest width of the skull is at the level of the jaw articulation. The upper jaw cartilages are partially or fully fused. The palatoquadrate is robust and connected to the skull by a wide commissura quadratocranialis anterior, processus oticus, processus basalis (in some species), and processus ascendens (vestigial or absent in some species). A processus ventralis quadrati provides an extended area of origin for the m. orbitohyoideus. The m. rectus abdominis inserts far anterior and acts on the cranium. The insertion of the epaxial musculature is shifted anteriorly to the anterior parts of the otic capsule. The mm. diaphragmatobranchialis and rectus cervicis cross at their origins. The origin of the m. levator mandibulae anterior has shifted posteriorly. The branchial basket is relatively small and the ceratohyal area is large. Multiple convergent evolution of these features suggests that they may be causally associated with the suctorial mode of larval life. Aside from these characters, however, the suctorial and pond-type neobatrachian species are remarkably similar in their jaw musculature and hyobranchial musculoskeletal composition. In some features, Ascaphus truei differs significantly from the neobatrachian suctorial species, indicating the influence of the historically distant separation of the two taxa. A novel modification of the upper jaw abduction mechanism has evolved in L. nannotis, L. rheocola, and N. dayi. It involves an adrostral cartilage as a pushing-rod element. This mechanism and unique structural similarities of the cartilago labialis superior gives support to the preliminary assumption that the nannotis species group is more closely related to the suctorial Nyctimystes dayi than it is to other Litoria species with pond-type larvae. Suctorial larvae presumably were present in the most recent common ancestor of the Litoria nannotis group and Nyctimystes dayi.

Animals↗
PubMed1998

[The photon therapy of subfoveal choroidal neovascularization in age-dependent macular degeneration. The results of a prospective study in 40 patients].

AIM: To determine the effect of external beam radiotherapy on subfoveal choroidal neovascularization in age-related macular degeneration. PATIENTS AND METHODS: Between September 1995 and July 1996, 40 patients (9 males and 31 females; mean age 74 years, range 61 to 83 years) were included in a prospective study. Eight patients had classic, well-defined neovascularisations, 32 patients had occult lesions. Complete ophthalmic investigations included visual acuity contrast sensitivity as well as fluorescein and indocyanine green angiographic examinations prior to treatment and 1, 3, 6, and 12 months after radiotherapy. External beam radiotherapy (8-MV photons) was delivered with a total dose of 14.4 Gy in 8 fractions of 1.8 Gy per day (Figures 1 and 2). The field size averaged 5.5 x 4.5 cm. RESULTS: No treatment related morbidity during or after treatment was obtained. After 6 months follow-up the visual acuity was improved in 2 (5%) patients and maintained at pretreatment level in 17 (42%) patients. However, 12 months post treatment a stable situation was found in 6 (15%) patients and a decrease in visual acuity in 34 (85%) patients (Table 1). The central visual fields deteriorated significantly from 16.5 decibel (dB) to 12.4 dB. The enlargement of exudates and neovascular membranes increased 5- to 7-fold. At 12 months after treatment, 3 (7.5%) patients stated that they had improved vision subjectively, 12 (30%) patients had no change and 25 (62.5%) patients suffered from subjective decrease in visual acuity. CONCLUSIONS: Using a total dose of 14.4 Gy/1.8 Gy no difference concerning visual acuity and exudative changes in comparison to the natural history on age-related macular degeneration was obtained after 12 months. However, the results of multicenter studies are to be awaited.

Aged↗
PubMed1998

External beam radiation therapy for choroidal neovascularization.

OBJECTIVE: This study aimed to determine the effect of external beam radiation therapy on choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). DESIGN: The study design was a nonrandomized clinical trial with an historic control group. PARTICIPANTS: A total of 91 patients were treated with external beam radiation. These patients were compared retrospectively to the 119 patients in a control group. INTERVENTION: Patients with subfoveal CNV who did not meet the criteria for laser treatment defined by published reports from the Macular Photocoagulation Study Group or who did not want laser treatment were considered for radiation therapy in a nonrandomized, prospective clinical trial. Additional entry criteria for this prospective study included visual acuity better than or equal to 20/320 on the Early Treatment Diabetic Retinopathy Study chart and a lesion size less than 12 disc areas. The patients were treated with 5 fractions of 200 cGy 6 MV external beam photons. MAIN OUTCOME MEASURES: The visual acuity measured at baseline was compared to the visual acuity after 1 year of follow-up. RESULTS: The mean baseline visual acuity of the 91 patients entered into the Radiation Study was 20/80. After 1 year, 83 patients (91.2%) completed follow-up, and their mean visual acuity dropped to 20/200. By comparison, the mean baseline visual acuity of the control patients also was 20/80, and after 1 year, the control subjects had a mean visual acuity of 20/125. At 1 year of follow-up, 49.4% of patients treated with radiation and 38.1% of the control subjects lost 3 or more lines of visual acuity (P = 0.16). CONCLUSIONS: This study found that external beam radiation using 1000 cGy in 5 fractions, a dose similar to that used in previous studies, was not effective in the treatment of CNV secondary to AMD. These results suggest that patients should not be treated with this dose of external beam radiation for CNV secondary to AMD.

Aged↗
PubMed1998

Intraocular pressure difference in Goldmann applanation tonometry versus Perkins hand-held applanation tonometry in overweight patients.

OBJECTIVE: To analyze the increase in intraocular pressure (IOP) caused by anatomic and physiologic factors in overweight patients when using Goldmann applanation tonometry. DESIGN: A prospective cohort study. PARTICIPANTS: Seventy average-weight individuals who had no difficulties with IOP measurements at the slit lamp and 12 obese patients with suspected glaucoma who could position the head at the slit lamp only with great effort participated. INTERVENTION: The authors compared IOP values between slit-lamp-mounted Goldmann applanation tonometry and Perkins hand-held tonometry. MAIN OUTCOME MEASURE: The difference in Goldmann and Perkins IOP measurements was examined. RESULTS: In the group of obese patients, the mean IOP was 20.9+/-2.28 mmHg (mean +/- standard deviation; range, 18-26 mmHg) for the right eye and 21.4+/-3.16 mmHg (range, 16-28 mmHg) for the left eye when determined by Goldmann tonometry and 16.3+/-2.39 mmHg (range, 13-20 mmHg) for the right eye and 16.3+/-2.42 (range, 11-19 mmHg) for the left eye when determined by Perkins tonometry. The mean decrease was 4.5+/-1.3 mmHg (range, 3-7 mmHg) for the right eye and 4.9+/-1.9 mmHg (range, 2-9 mmHg) for the left eye. In the control group, the mean difference between the two types of tonometers for the right eye was 0.34+/-0.69 mmHg and for the left eye was 0.33+/-0.82 mmHg. Patients who had a falsely elevated IOP on Goldmann tonometry had an average body mass index of 34+/-3.82 (range, 28.5-41.9); most were female (5:1 ratio). CONCLUSION: The authors believe simultaneous breath-holding and thorax compression, with subsequent increase in venous pressure, may be a causative factor for transitory elevations of IOP. Perkins tonometry in obese patients may help avoid a false diagnosis of glaucoma caused by transitory elevations in IOP.

Adult↗
PubMed1998

NSF--fusion and beyond.

NSF (N-ethylmaleimide-sensitive fusion protein) was the first protein to be isolated as a crucial factor in intracellular membrane-fusion events, such as the fusion of synaptic vesicles with the presynaptic membrane during neurotransmission. Although the activation of membrane SNARE proteins for subsequent fusion is clearly a primary role of NSF, recent studies have provided surprising evidence that NSF also interacts with glutamate receptors at the postsynaptic membrane in a way that does not seem to involve SNAREs. These results suggest that NSF might act as a molecular chaperone not only on SNAREs but also of other proteins.

Animals↗
PubMed1998

[Effect of steam application based on microbiological and parasitologic test procedures].

In the present study steam application was investigated with regard to microbicidal and parasiticidal effects. The cleaning apparatus used (Uninova Company) works at a boiler pressure of about 5 bar and consequently with a temperature up to 155 degrees C inside the boiler. Whereas the ambient atmosphere working temperature of steam is slightly below 100 degrees C. The tests are based on the DVG guidelines for testing chemical disinfectants (2). Different steaming times and distances were used in germ carrier tests with three different germ carriers (tile, wood, carpet) and three different test germs (Staphyloccocus aureus, Pseudomonas aeruginosa, Candida albicans) in order to determine the optimum conditions for biocidal effects of steam-application. These optimum conditions were additionally tested with two test viruses (ECBO- and Reo-virus) and a parasitological resting form (ascarid worm eggs). Swirling of germs caused by steam turbulence was minimized by covering the steam outlet nozzle with cloth. The experiments showed logarithmical reduction factors of at least 5.0 in the germ count at steaming times of 5 seconds and a steaming distance of 2.5 cm for all three test germs on all three germ carriers (mean of 10 repeated tests). The virological tests showed good disinfection results after a steaming time of only 2 seconds using aseptic gauze as germ carrier and also after 5 seconds using wood as a carrier. Finally in testing vitality of undeveloped Ascarid worm eggs only 2 seconds of steam treatment proved to be sufficient for a 100 percent destruction. According to the present results steam treatment is most likely to become a valuable, ecologically compatible method in controlling hygienic problems, with a potential of partly replacing chemical disinfectants. In particular we see applications in keeping pets and companion animals, provided the above mentioned rules are followed (steaming distance 2.5 cm; steaming time 5 seconds; cloth). In farm animal stables steam disinfection seems harder to achieve because of large, rough surfaces and economical reasons as e.g. expenditure of time and energy.

Animals↗
PubMed1997

I2B is a small cytosolic protein that participates in vacuole fusion.

Saccharomyces cerevisiae vacuole inheritance requires two low molecular weight activities, LMA1 and LMA2. LMA1 is a heterodimer of thioredoxin and protease B inhibitor 2 (I2B). Here we show that the second low molecular weight activity (LMA2) is monomeric I2B. Though LMA2/I2B was initially identified as a protease B inhibitor, this protease inhibitor activity is not related to its ability to promote vacuole fusion: (i) Low Mr protease B inhibitors cannot substitute for LMA1 or LMA 2, (ii) LMA1 and LMA2 promote the fusion of vacuoles from a strain that has no protease B, (iii) low concentrations of LMA2 that fully inhibit protease B do not promote vacuole fusion, and (iv) LMA1, in which I2B is complexed with thioredoxin, is far more active than LMA2/I2B in promoting vacuole fusion and far less active in inhibiting protease B. These studies establish a new function for I2B.

Chromatography, Gel↗
PubMed1997

Homotypic vacuolar fusion mediated by t- and v-SNAREs.

Membrane fusion is necessary both in the eukaryotic secretory pathway and for the inheritance of organelles during the cell cycle. In the secretory pathway, heterotypic fusion takes place between small transport vesicles and organelles. It requires N-ethylmaleimide-sensitive fusion protein (NSF/Sec18p), soluble NSF attachment proteins (SNAPs/Sec17p) and SNAP receptors (SNAREs). SNAREs are integral membrane proteins (v-SNAREs on vesicles, t-SNAREs on the target organelles) and are thought to provide specificity to the fusion process. It has been suggested that Sec17p and Sec18p bind to v-SNARE/t-SNARE complexes and mediate the membrane fusion event. Homotypic fusion of yeast vacuoles also requires Sec17p and Sec18p (ref. 6), but in vitro they are needed only to 'prime' the vacuoles, not for subsequent docking or fusion. It has been unclear whether these reactions involve SNAREs that are similar to those previously identified in heterotypic fusion systems and, hence, whether the actions of Sec18p/NSF and Sec17p/alpha SNAP in these systems can be compared. Here we identify typical v- and t-SNAREs on the yeast vacuolar membrane. Although both are normally present, vacuoles containing only the v-SNARE can fuse with those containing only the t-SNARE. Vacuoles containing neither SNARE cannot fuse with those containing both, demonstrating that docking is mediated by cognate SNAREs on the two organelle membranes. Even when t- and v-SNAREs are on separate membranes, Sec17p and Sec18p act at the priming stage. Their action is not required at the point of assembly of the SNARE complex, nor for the fusion event itself.

Adenosine Triphosphatases↗
PubMed1997

Three-dimensional reconstruction of histological sections using modern product-design software.

BACKGROUND: Computer-based, three-dimensional reconstruction of histological sections is necessary for solving a diversity of questions in morphology and anatomy. Programming software for this purpose is difficult and time-consuming. Therefore, we tested if commercially available product-design software is useful for reconstructing anatomical virtual models. METHODS: We used Alias Wavefront Studio software on a Silicon Graphics workstation. Sections were projected with a newly developed microslide projector on a digitizing board and digitized interactively. Alternatively, pictures of sections were digitized on screen. The resulting set of contours was used as scaffold around which a surface was created manually. RESULTS: Repeated creation of the same object and subsequent measurements gave results that will be sufficiently reliable for many purposes. The visual presentation of objects satisfy highest demands. Little time is needed to reconstruct simple objects, and the time used for complex virtual models is acceptable. Manipulation of objects on screen is nearly in real time and rendering speed is high. CONCLUSIONS: Product-design software packages are a readily available and useful option for anatomists who want to do virtual reconstructions quickly without programming software themselves.

Animals↗
PubMed1997

Application of HELP in nonarteritic anterior ischemic optic neuropathy: a prospective, randomized, controlled study.

BACKGROUND: Heparin-induced extracorporeal LDL/fibrinogen precipitation (HELP) eliminates selectively fibrinogen, LDL, cholesterol, triglycerides and LP(a) from blood plasma using extracorporeal circulation. The reduction of fibrinogen and LDL by about 50% after only one procedure immediately improves the hemorheological situation. METHOD: In a prospective, randomized, controlled study over a period of 3 months, 40 patients with nonarteritic ischemic optic neuropathy (NAION) were randomly assigned to either HELP or hemodilution therapy to determine the efficacy of these two treatments on visual acuity and fields. RESULTS: After transformation of the Snellen acuity into logMAR units the statistical analysis did not show a significant difference between the two groups (P = 0.48). An increase of the visual acuity by two or more lines was obtained in 9 patients (47.4%) of the HELP group, 10 (52.6%) remained stable and none got worse. In the hemodilution group, visual acuity increased in patients (33.4%), 9 (42.8%) remained stable and 5 (23.8%) experienced a decrease. The calculated mean sensitivity of visual fields at baseline improved statistically significantly (P < 0.01) in the HELP group from 6.83 +/- 4.52 dB to 8.27 +/- 4.89 dB, but did not change significantly in the hemodilution group (6.25 +/- 4.12 dB to 6.12 +/- 3.92 dB). CONCLUSION: The HELP system seems to be safe and more effective than hemodilution in improving the hemorheological and the functional situation in NAION and could be a promising regimen in the treatment of NAION.

Aged↗
PubMed1997

Surgical complications after preoperative irradiation of Ewing's sarcoma.

The influence of preoperative irradiation on surgical complications in 42 patients with Ewing's sarcoma was analysed. After preoperative irradiation and chemotherapy, 35 of 40 patients showed a good histological response and 25 of 40 patients had no viable tumour cells in the resected specimen. Local relapse alone did not develop, local relapse and metastasis developed in 2 patients and metastasis alone in 15 patients. Surgical complications appeared in 12 of 42 patients: 9 of 19 central tumours (19 pelvic lesions), 1 of 13 proximal and 2 of 10 distal tumours. Surgical complications after preoperative irradiation are distributed as follows: delayed wound healing 8, hematoma 2, thrombosis 2, skin infection 1, and abscess 1. On the other hand, complications appeared in 2 of 28 patients without preoperative irradiation: none in 9 patients having central tumours including 2 pelvic lesions, 1 in 12 patients with proximal tumours, and 1 in 7 patients with distal tumours. The multivariate regression test showed that the tumour site (central) is an influencing factor in the appearance of surgical complications. In central tumours, the surgical complication rate increases after preoperative irradiation; however, it is affected by the increase of the ratio of patients with pelvic tumours.

Adolescent↗