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R Mach

Publications and source records attributed to R Mach.

At least 19 recordsLinked to original sources
PubMed2003

Molecular biological methods (DGGE) as a tool to investigate nitrification inhibition in wastewater treatment.

Incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. Preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (AOM) by process waters of the rendering plant was responsible for the situation. We were able to show a correlation between the existence of specific AOM and nitrification capacity expressed as oxygen uptake rate for maximal nitrification (OURNmax). Only Nitrosospira sp. was found in the activated sludge of the rendering plant and another industrial wastewater treatment plant with problems in nitrification, while reference plants without nitrification problems showed Nitrosomonas spp. as the predominant ammonia oxidising bacteria. By accompanying engineering investigations and experiments (cross-feeding experiments, operation of a two-stage laboratory plant) with molecular biological methods (DGGE--Denaturing Gradient Gel Electrophoresis) we were able to elaborate an applicable solution for the rendering plant. Laboratory experiments with a two-stage process layout finally provided complete nitrification overcoming the inhibiting nature of process waters from the rendering plant. DGGE analysis of the second stage activated sludge from the laboratory plant showed a shift in population structure from Nitrosospira sp. towards Nitrosomonas spp. simultaneous to the increase of nitrification capacity. Nitrification capacities comparable to full-scale municipal wastewater treatment plants could be maintained for more than two months. As the design of wastewater treatment plants for nitrification is linked to the growth characteristics of Nitrosomonas spp., established criteria can be applied for the redesign of the full-scale plant.

Abattoirs↗
PubMed2002

Extremely productive microbial communities in shallow saline pools respond immediately to changing meteorological conditions.

Diel changes in bacterial and cyanobacterial numbers, as well as heterotrophic bacterial production, were examined in two shallow alkaline pools, harbouring dense populations of cyanobacteria (up to 1100 x 109 cells l-1) and bacteria (up to 500 x 109 cells l-1). Together with the recorded bacterial production rates (925 micro gC l-1x h-1), these values are the highest reported for natural aquatic ecosystems. The investigations were performed during a fair-weather situation, and during a rapid change after a long-term fair-weather situation to thunderstorms and heavy rainfall. During fair weather, bacterial growth was significantly correlated to the diurnal light and temperature cycle. Prokaryotic abundances were fairly constant, and loss by grazing and viral lysis must have been of significant importance. During the invasion of rainy weather, the prokaryotic community showed a strong and immediate response. A significant enhancement of bacterial growth followed after rainfall, suggesting that the high salt concentrations had inhibited bacterial activity. Changes in bacterial and cyanobacterial numbers were consistent with this pattern. From comparison with the available literature, we conclude that diel changes of bacterioplankton are regulated by a complex combination of environmental factors specific for each investigated ecosystem. In the soda pools investigated, external abiotic factors were dominant on a diel scale. In larger ecosystems, such factors are much more buffered and internal biotic interactions may prevail.

Ecosystem↗
PubMed2001

The Hypocrea jecorina HAP 2/3/5 protein complex binds to the inverted CCAAT-box (ATTGG) within the cbh2 (cellobiohydrolase II-gene) activating element.

The 5' regulatory region of the chh2 gene, encoding cellobiohydrolase II, of the filamentous fungus Hypocrea jecorina contains the cbh2 activating element (CAE) which is essential for cbh2 expression. The CAE consists of two separate, adjacent motifs, a CCAAT box on the template strand (ATTGG) and a GTAATA box on the coding strand, which co-operate in the induction of the gene by cellulose or sophorose. EMSA supershift experiments using an antibody against Aspergillus nidulans HAPC suggested that the complex which binds to the H. jecorina CCAAT box contains a HAPC homolog. To obtain direct evidence for this, we have cloned the hap2, hap3 and hap5 genes from H. jecorina. They encode proteins whose core regions display great similarity to Aspergillus HAPB, HAPC and HAPE and to known HAP homologs from other organisms. All three genes are transcribed in a carbon source-independent manner. A. nidulans deltahap strains were functionally complemented in vitro by the overexpressed H. jecorina HAP2, HAP3 and HAP5 proteins, and they thus represent subunits of the CCAAT-binding complex. Furthermore, all three proteins (HAP2, HAP3 and HAP5) were needed to bind to the CAE in the H. jecorina cbh2 gene promoter in vitro. We conclude that the CCAAT box on the template strand in CAE is bound by the H. jecorina equivalent of the HAP protein complex.

Amino Acid Sequence↗
PubMed2001

[Intralenticular metal foreign bodies].

OBJECTIVE: The paper is concerned with the problem of extraction of foreign metal bodies, which remained after a perforating injury in the patient's lens. The authors discuss early and late extraction of the opacifying lens. MATERIAL AND METHODS: In three successive accidents of young men (22-34 years) the authors compare the fate of intralenticular metal bodies and the lens. RESULTS: All three metal bodies were extracted, at the same time also surgery of the opacifying lens was performed with implantation of a posterior chamber intraocular lens into the sac after continual curvilinear capsulorrhexy. The postoperative visual acuity was 6/6. CONCLUSION: With regard to contemporary possibilities of careful solution of lenticular surgery, using high standard viscoelastic materials, it is advisable to remove primarily the foreign body from the lens along with the damaged opacified lens and replacement of the latter by a posterior chamber intraocular lens as the quickest possible solution of the posttraumatic state.

Adult↗
PubMed2000

Molecular characterization of a cellulase-negative mutant of Hypocrea jecorina.

The "cbh2 activating element," CAE, consisting of two separate boxes (ATTGG = CCAAT and GTAATA, respectively) is essential for cellobiohydrolase II gene expression in the filamentous fungus Hypcrea jecorina. Here we report that cell-free extracts from a cellulase-negative mutant form CAE-protein complexes with higher mobility and lower binding-strength compared to the wild type. EMSA analysis demonstrated an increased mobility of the GTAATA-binding protein complex and, supported by in vivo footprinting, a lowered binding strength of the HAP2/3/5 proteins. However, the hap2/hap3/hap5 genes of the mutant are unaltered and transcribed normally. A nucleotide fragment of the cbh1 promoter containing a (GG)CTAATA motif without an adjacent CCAAT box is also bound by cell-free extracts of H. jecorina, and the protein-DNA complex of the mutant shows the characteristic increase in mobility. We conclude that this mutant is defective in the functional formation of the CAE-protein complexes but not in their binding to the target sequences itself.

Base Sequence↗
PubMed1999

Cholecystokinin-B/gastrin receptor binding peptides: preclinical development and evaluation of their diagnostic and therapeutic potential.

The high sensitivity of pentagastrin stimulation in detecting primary or metastatic medullary thyroid cancer (MTC) suggests widespread expression of the corresponding receptor type on human MTC. Indeed, autoradiographic studies demonstrated cholecystokinin (CCK)-B/gastrin receptors not only in >90% of MTCs but in a high percentage of small cell lung cancers and potentially a variety of gastrointestinal adenocarcinomas. In a pilot study, we have demonstrated the feasibility of radiolabeled gastrin-I to target CCK-B receptor-expressing tissues in vivo in animals and patients (T. M. Behr et al., Eur. J. Nucl. Med., 25: 424-430, 1998). The aim of the present study was to systematically optimize, in a preclinical model, suitable radioligands for targeting CCK-B receptors in vivo. For this purpose, a variety of CCK/gastrin-related peptides, all having in common the COOH-terminal CCK-receptor binding tetrapeptide sequence Trp-Met-Asp-PheNH2 or derivatives thereof, were studied. They were radioiodinated by the Iodogen or Bolton-Hunter procedures. The peptides tested were members of the gastrin- or cholecystokinin families or possessed characteristics of both, which differ by the intramolecular position of a tyrosyl moiety (occurring in native or sulfated form). Their stability and affinity were studied in vitro and in vivo; their biodistribution and therapeutic efficacy were tested in nude mice bearing s.c. human MTC xenografts. Diethylene-triamine-pentaacetate derivatives of suitable peptides were synthesized, evaluated, and labeled with (111)In. All members of the CCK or gastrin family were stable in serum (with t(1/2)s of several hours at 37 degrees C); nevertheless, the stability of those peptides was highest that bore the NH2-terminal pGlu residues (e.g., big gastrin, gastrin-I, caerulein, and others) or D-amino acids. In accordance to their comparably low affinity, nonsulfated members of the CCK family showed fairly low uptake in the tumor and other CCK-B receptor-expressing tissues (e.g., the stomach). Sulfated CCK derivatives performed significantly better but additionally displayed a high uptake in normal, CCK-A receptor-expressing tissues (such as the liver/gallbladder, pancreas, and bowel). Best tumor uptake and tumor:nontumor ratios were obtained with members of the gastrin family, probably because of their selectivity and affinity for the CCK-B receptor subtype. Pilot therapy experiments in MTC bearing animals showed significant antitumor efficacy as compared with untreated controls. (111)In-Labeled diethylene-triamine-pentaacetate derivatives of minigastrin showed excellent targeting of CCK-B receptor-expressing tissues in animals and a normal human volunteer. These data suggest that CCK/gastrin analogues may be a useful new class of receptor binding peptides for diagnosis and therapy of CCK-B receptor-expressing tumors, such as MTC or small cell lung cancer. Nonsulfated gastrin derivatives may be preferable because of their CCK-B receptor selectivity, and hence, lower accretion in normal CCK-A receptor-expressing organs. Further preclinical as well as clinical studies are ongoing.

Amino Acid Sequence↗
PubMed1997

[Treatment of retinal venous occlusion with hemodilution and laser coagulation. Prevention of secondary glaucoma].

BACKGROUND: Neovascular glaucoma is similarly as other ocular neovascularizations, a complication of retinal venous occlusions. The objective of the present work was to assess whether it is possible to prevent this complication by isovolaemic haemodilution and laser coagulation of the retina. METHODS AND RESULTS: Between 1991 and 1996 we used in 10 patients with occlusion of the central retinal vein and in 25 patients with occlusion of the branch of the central retinal vein repeated haemodilution with reduction of the haematocrit to 0.36. In case of soft retinal exudates the retina was treated by laser coagulation. The whole group comprised 28 men and 7 women. The patients' age was 42 to 76 years, 14% of the patients were under 50 years. The mean follow-up period was 29.5 months. During the investigation period so far none of the patients developed neovascular glaucoma. After treatment venous collaterals developed in the retina in 48.5%, in the disc of the optic nerve in 16% of the patients. Improved visual acuity was recorded in 90% of the patients after occlusion of the trunk and in 44% patients after occlusion of the branch of the central retinal vein. CONCLUSIONS: Adjustment of rheological conditions by haemodilution improved for three months the haemodynamic conditions in the affected retina, promote recanalization of the occluded vessels and the development of a collateral circulation and prevented neovascularization. Based on their experience the authors assume that haemodilution combined with laser coagulation has a positive impact on the visual prognosis, but in particular on prevention of neovascular glaucoma, which so far did not develop in the thus treated patients.

Adult↗
PubMed1997

[Importance of evaluation of edema of the optic nerve disk in sudden increase in intracranial pressure].

The authors examined in 1987-1995 56 patients who had a sudden rise of intracranial pressure. Fifty patients developed oedema of the optic nerve disc, most frequently within 12-24 hours after development of the basic disease. They provided clear evidence of the importance of retinal haemorrhages for the prognosis of the disease. In patients with haemorrhage into the vitreous body (Pearson's syndrome) the mortality was up to 50%. Also the rapid onset of oedema of the optic nerve disc is not a favourable prognostic sign for survival. The authors found also that in the majority of patients, who survived the basic disease there was no marked decline of the central visual acuity.

Adolescent↗
PubMed1996

[Primary intraocular lens implantation after laser therapy in active diabetic retinopathy].

The author presents an account of the results and complications of cataract operations with primary implantation of a posterior chamber intraocular lens in 10 eyes of 8 patients suffering from preproliferative diabetic retinopathy, partly treated by laser. After operation in nine eyes the visual acuity improved during a mean follow-up period of 22.7 months. As to postoperative complications, a late fibrinous reaction was important (4x posterior synechia of the iris, incl. iris capture syndrome in one case with subsequent secondary glaucoma). In three eyes within one year secondary fibrotic cataract developed, in one it was necessary to perform Nd-YAG laser membranotomy. In none of the eyes so far after supplementary laser coagulation progression of diabetic retinopathy was recorded. The authors recommend to carry out maximum laser coagulation of the retina before operation of the cataract, to remove during operation the total mass of the lens, to carry out preventive basal iridectomy and to complete panretinal laser coagulation as quickly as possible after operation.

Adult↗
PubMed1995

[Differences in the progression of myopic correction in patients with corrective eyeglasses in comparison with correction with contact lenses].

The authors compare the increment of values of myopis correction in 100 patients with bilateral myopia above -3 d corrected by glasses with a similar group of 100 myopic patients where for correction mostly sift contact lenses were used. In both groups adults and children and youth were compared separately. The groups were selected at random from the registers of two departments. In the course of five years in the group of patients under 20 years of age who wore glasses there was a more marked increase of values of myopic correction, as compared with the control group which wore contact lenses. On prescription of glasses the weakest correction was recommended which enabled the subjects to read line 1.0 of Snellen's optotypes. Patients with contact lenses were corrected according to the assessed refraction. The mean progression in young patients wearing glasses in five years was -1.66 d, for contact lenses -0.85 d. In both groups of myopic patients above 25 years (glasses and contact lenses) after five years in one third of the patients an average progression of -1.0 d was recorded. The authors conclude that "subcorrection" of myopic patients, still recommended in many departments, does not slow down the progression of myopia. The results of the investigation justify full correction of the defect in particular in younger patients where due to elasticity of the lens accommodation to close objects works perfectly.

Adolescent↗
PubMed1993

Fluorinated and iodinated dopamine agents: D2 imaging agents for PET and SPECT.

A novel series of dual-labeling D2 dopamine agents (labeled with either 18F or 123I for PET or SPECT imaging, respectively) was investigated. Two desired fluorinated and iodinated dopamine agents, FIDA1, (S)-(-)-2-(2-fluoroethoxy)-5-iodo-3-methoxy-N-[(1-ethyl-2- pyrrolidinyl)methyl]-benzamide, and FIDA2, (R)-(+)-2,3-dimethoxy-5-iodo-N-[(1-(4'-fluorobenzyl)-2- pyrrolidinyl)-methyl]benzamide, were synthesized. Both compounds displayed high affinity to the D2 receptor of rat striatal membrane preparations (Kd = 0.13 and 0.02 nM for FIDA1 and FIDA2, respectively). The biodistribution study in rats exhibited high localization in the striata of the brain with the striatum/cerebellum ratio reaching 29.3 and 13.1 at 1 h post iv injection for FIDA1 and FIDA2, respectively. Imaging studies with [18F]- and [123I]FIDA2 in monkeys, with PET and SPECT, respectively, showed comparable high selective striatal uptake. These results suggest that they are potentially useful D2 dopamine receptor imaging agents for PET and SPECT.

Animals↗
PubMed1993

[Isovolemic hemodilution--one of the possibilities in therapy of retinal vein occlusion].

The author submits a review of findings on the basis of which isovolaemic haemodilution is recommended as a therapeutic procedure in occlusion of retinal veins. By modification of the viscosity of blood rheological conditions change and thus the conditions for repair of the affected retina improve. The method of the procedure is described. The author mentions also indications and contraindications of this procedure and specifies the group of patients indicated for this treatment. The author considers the presented review an adequate basis for using haemodilution in other departments, similarly as in the author's, where it has been used now for more than three years.

Female↗
PubMed1992

[Treatment of diabetic retinopathy using panretinal laser coagulation].

The author presents an account of his experience with panretinal photocoagulation by means of greenish-blue light of an argon laser in diabetics. He evaluates the technique of treatment. In a group of 156 eyes of 103 patients 1-18 months after photocoagulation with a mean follow-up period of nine months the author compares the development of visual acuity after treatment. Based on these findings he describes the success and asset of treatment for the patient. After one year in 62% of 63 investigated eyes deterioration of visual acuity was arrested, in 16% improvement was achieved. After one and a half year 64% of 33 followed up patients were stabilized, in 12% the visual acuity was still better than at the onset of treatment. Panretinal photocoagulation by means of an argon laser can be considered at present the most effective treatment of diabetic retinopathy.

Adult↗