Impact of river dynamics on the genetic variation of Gypsophila repens (Caryophyllaceae): a comparison of heath forest and more dynamic gravel bank populations along an alpine river.

Alpine rivers are, despite anthropogenic water flow regulation, still often highly dynamic ecosystems. Plant species occurring along these rivers are subject to ecological disturbance, mainly caused by seasonal flooding. Gypsophila repens typically grows at higher altitudes in the Alps, but also occurs at lower altitudes on gravel banks directly along the river and in heath forests at larger distances from the river. Populations on gravel banks are considered non-permanent and it is assumed that new individuals originate from seed periodically washed down from higher altitudes. Populations in heath forests are, in contrast, permanent and not regularly provided with seeds from higher altitudes through flooding. If the genetic structure of this plant species is strongly affected by gene flow via seed dispersal, then higher levels of genetic diversity in populations but less differentiation among populations on gravel banks than in heath forests can be expected. In this study, we analysed genetic diversity within and differentiation among 15 populations of G. repens from gravel banks and heath forests along the alpine River Isar using amplified fragment length polymorphisms (AFLP). Genetic diversity was, as assumed, slightly higher in gravel bank than in heath forest populations, but genetic differentiation was, in contrast to our expectations, comparable among populations in both habitat types. Our study provides evidence for increased genetic diversity under conditions of higher ecological disturbance and increased seed dispersal on gravel banks. Similar levels of genetic differentiation among populations in both habitat types can be attributed to the species' long lifetime, a permanent soil seed bank and gene flow by pollinators among different habitats/locations.

Operando UV-Vis spectroscopy of a catalytic solid in a pilot-scale reactor: deactivation of a CrO(x)/Al2O3 propane dehydrogenation catalyst.

A novel operando UV-Vis spectroscopic set-up has been constructed and tested for the investigation of catalyst bodies loaded in a pilot-scale reactor under relevant reaction conditions. Spatiotemporal insight into the formation and burning of coke deposits on an industrial CrO(x)/Al(2)O(3) catalyst during propane dehydrogenation has been obtained.

Classification of perioperative histamine-related reactions.

OBJECTIVE: Histamine release may cause anaphylactoid reactions. However, during anaesthesia and surgery especially cardiovascular effects may not be regarded as histamine-related. Therefore, we adapted the classical concept of histamine release reactions to the perioperative situation and validated the new paradigm. METHODS: Elevated plasma histamine (diagnostic gold standard) was correlated to potentially related intraoperative signs and symptoms. The validity, repeatability and sensitivity of the 'gold standard' was tested by ROC analysis in volunteers, who also received H1-/H2-histamine antagonists. Additionally, a dose-response relationship was determined in dogs using the histamine releaser compound 48/80. RESULTS: The 'gold standard' had a sensitivity of 96% (90%-100%) and a specificity of 93% (85%-100%). The reproducibility was proven by repeated injections of histamine. Skin reactions, tachycardia and hypertension were identified as histamine-related diagnostic variables. A dose-response curve of plasma histamine release was created. CONCLUSIONS: The defined 'gold standard' is valid for the diagnosis of histamine-related reactions during anaesthesia and surgery. It may help to identify patients, who could benefit from pre-anaesthetic antihistamine prophylaxis.

Heart failure management in a community hospital system.

Chronic disease management requires a clear vision, collaboration, and continuing program development to be successful. The patient benefits from an approach that is patient-centered and goal directed. Our challenge in this environment of declining healthcare reimbursement is to stay the course and continue measurement of our outcomes to determine our success in meeting our goals.

Age effects on Wechsler Adult Intelligence Scale-III subtests.

This investigation extended work on the Wechsler Adult Intelligence Scaled-Revised (WAIS-R) to the WAIS-III by determining how allotments of scaled-score points change with age, and to evaluate WAIS-III performance in terms of the Horn-Cattell constructs of crystallized and fluid intelligence. The age norms for the 14 individual WAIS-III subtests indicate that additional scaled-score points are awarded primarily to the Letter-Number Sequencing subtest of the Verbal Scale and to the seven Performance Scale subtests at ages 45 to 89 years for the same performance as individuals in the 20- to 34-year-old reference group. Subtests that measure speed of information processing showed more of a decline than subtests that measure verbal processing. Results are consistent with the view that measures of fluid intelligence show more of a decline with advancing age than do measures of crystallized intelligence. Published by Elsevier Science Ltd

Intracellular metabolism of human apolipoprotein(a) in stably transfected Hep G2 cells.

Lipoprotein(a) [Lp(a)] consists of LDL and the glycoprotein apolipoprotein(a) [apo(a)], which are covalently linked via a single disulfide bridge. The formation of Lp(a) occurs extracellularly, but an intracellular assembly in human liver cells has also been claimed. The human apo(a) gene locus is highly polymorphic due to a variable number of tandemly arranged kringle IV repeats. The size of apo(a) isoforms correlates inversely with Lp(a) plasma concentrations, which is believed to reflect different synthesis rates. To examine this association at the cellular level, we analyzed the subcellular localization and fate of apo(a) in stably transfected HepG2 cells. Our results demonstrate that apo(a) is synthesized as a precursor with a lower molecular mass which is processed into the mature, secreted form. The retention times of the precursor in the ER positively correlated with the sizes of apo(a) isoforms. The mature form was observed intracellularly at low levels and only in the Golgi apparatus. No apo(a) was found to be associated with the plasma membrane. Under temperature-blocking conditions, we did not detect any apo(a)/apoB-100 complexes within cells. This finding was confirmed in HepG2 cells transiently expressing KDEL-tagged apo(a). The precursor and the mature forms of apo(a) were found in the ER and Golgi fractions, respectively, also in human liver tissue. From our data, we conclude that in HepG2 cells the apo(a) precursor, dependent on the apo(a) isoform, is retained in the ER for a prolonged period of time, possibly due to an extensive maturation process of this large protein. The assembly of Lp(a) takes place exclusively extracellularly following the separate secretion of apo(a) and apoB.

Comparative study of procedures for isolation and cultivation of Legionella pneumophila from tap water in hospitals.

For the isolation and cultivation of Legionella pneumophila from tap water in hospitals, we compared different media and selection techniques. A second part of the study compared the L. pneumophila yields from different water samples at identical sites. A total of 210 water samples (500 ml each) were collected from two selected sites in each of 21 hospitals. Warm water samples were collected after flow times of 0, 5, 10, and 15 min; in addition, one cold water sample was collected. Filtration was used to concentrate all samples. Following filtration, 0.1 and 1 ml each of untreated samples, heat-treated samples (3 min, 59 degrees C), and acid-treated samples (pH 2.2, 15 min) were spread onto the selective media MWY (SR 118; Oxoid) and BMPA alpha (SR 111; Oxoid), and samples from 12 hospitals were also spread onto GVPC medium (SR 152; Oxoid). A total of 72 (34%) of the 210 samples from 12 hospitals were positive. With respect to the positive Legionella cultures, there was no significant difference between the selective media MWY, BMPA alpha, and GVPC. With the BMPA alpha supplement, more samples were positive following heat treatment (P < 0.05) or acid treatment (P < 0.05) than without any further treatment. For the maximum yield of Legionella colonies with minimum additional microbial flora, acid treatment was the most effective, and by all methods, the GVPC supplement was the most selective. For routine water tests in hospitals for differentiating between systemic and local contamination, acid treatment of the concentrated samples, the use of different selective media, and the correct selection of sampling sites are recommended.

Elevated plasma histamine concentration as a sensitive real-time parameter for distinct phases of surgical trauma: a tool for technology assessment.

High technology plays an important role in surgery, either to expand surgical procedures or to reduce tissue trauma, which is a main goal of minimum invasive surgery. Due to the tremendous increase of costs the problem of technology assessment will not only be solved by statistical methods, but also by biomedical considerations and laboratory tests. Histamine release could be an indication for tissue trauma, which is caused directly by tissue damage or indirectly by infection or hypoxia. Therefore histamine release was investigated during different phases of operation in two clinically very important and complex situations: resection of liver metastases of colorectal carcinoma and resection of the oesophagus because of an oesophageal carcinoma. To model this situation in animal experiments, two randomized controlled studies were conducted in sheep. Traditional techniques were compared with techniques of minimum invasive surgery. Plasma histamine levels were determined at well-defined phases of the operation. Histamine release was demonstrated at distinct phases of operation indicating considerable specificity of this parameter, if sensitivity is guaranteed by advanced tests. Incision of the liver capsule by thermocauterization, liver ischaemia, tissue trauma in more extended disruption of perioesophageal tissue were causes of more extended histamine release. It is concluded that measurement of plasma histamine is a suitable indicator for discriminating between extended and minimum invasive surgery. The consequence of considering this parameter may be less complications in the post-operative period and a short hospital stay with better quality of life.

Investigations of the cholinergic deficit hypothesis in the hippocampus of the aged rat brain with physostigmine and scopolamine.

Using histochemically demonstrated acetylcholinesterase activity and (14)C-2-deoxyglucose uptake as the respective indices, a study was set up to determine whether cerebral (hippocampal) metabolism was stimulated by a cholinergic agonist and/or inhibited by a cholinergic antagonist. For this 36 12-month-old (adult) and 48 27-month-old (aged) Fischer 344 rats were given intraperitoneal injections of physostigmine 0.05, 0.1 or 0.2 mg/kg or scopolamine 0.01, 0.03 or 0.1 mg/kg for 5 days. In the aged rats there was a slight increase in acetylcholinesterase activity after physostigmine but no convincing evidence of enhanced (14)C-2-deoxyglucose uptake. In neither age group was glucose uptake significantly reduced by scopolamine; it was in fact increased, as was - slightly but significantly - acetylcholinesterase activity. Findings for acetylcholinesterase activity and (14)C-2-deoxyglucose uptake in aged Fischer 344 rats thus do not provide firm corroboration of physostigmine-induced stimulation of mental performance found in behavioural studies, while scopolamine did not adversely affect the hippocampal variables studied. It is concluded that cholinergic agents such as physostigmine and scopolamine have only a marginal effect on the functional and metabolic deficits associated with cerebral aging.

Histamine and the stomach: chemical histamine assays.

Histamine assays in gastroduodenal tissues and body fluids are not an absolute objective of scientific interest but are related to the role of histamine in health and disease. Hence, the reliability of histamine assays has to be assessed in relation to this aim. Sensitivity and specificity of the chemical histamine assays are similar in tissues and body fluids. The modern developments in a fluorometric-fluoroenzymatic assay guarantee the highest sensitivity and specificity, especially by tests that monitor specificity in each single run of histamine determinations. Precision and accuracy of histamine measurement were especially investigated for the fluorometric assay. They included tests on the coefficient of variation over the whole concentration range, long-term precision with double-sample standard control charts, comparison of several methods for histamine assay including bioassay, and long-term accuracy with the use of Cusum charts. Finally, appropriate sample preparation, sample-taking, relevant body fluids and tissues, and the right time for sample-taking were evaluated in extended methodologic studies. Histamine assays are not just methods for a normal routine laboratory. Extended knowledge about histamine release and metabolism will be necessary to analyse data in this particular field with reasonable validity.

Human intestinal diamine oxidase (DAO) activity in Crohn's disease: a new marker for disease assessment?

The key-enzyme for the metabolism of diamines in man is diamine oxidase (DAO). Its highest activities are in the intestinal mucosa, localized in the cytoplasm of the mature enterocytes of the small and large bowel. If the gut is affected by inflammation in Crohn's disease macroscopical changes are observed. This prospective study investigated if these mucosal alterations are also reflected in changes of mucosal diamine oxidase activity and/or mucosal histamine content respectively. Twenty patients (12 female, 8 male; age: means = 31, range 18-49 years) undergoing gut resection because of complications in Crohn's disease (Jan.-Dec. 1988) formed the basis of the study. Tissue samples of the resected material from areas inflamed and histologically not involved in the disease were investigated for diamine oxidase activities and histamine content. Diamine oxidase activities in the mucosa obtained from the macroscopically normal proximal (155.6; (76-393) mU/g (means, range)) and distal (132; (58.5-295) mU/g) resection margins were similar to our previous findings. In all patients, however, samples from the diseased mucosa had significantly (ca. 50%) lower diamine oxidase activities (74.5; (5-262) mU/g) compared to the healthy tissue. Similar differences were found in material obtained either from whole intestinal wall or from the mucosa. The determination of diamine oxidase activity constitutes possibly a more unambiguous and earlier parameter for assessing the extent of the inflamed area than histological disease presentations. Using biopsies the necessary extent of resection could be estimated before operation: this may influence operative strategies and help in the definition of the minimum amount of inflamed gut to be removed.

Intestinal diamine oxidases and enteral-induced histaminosis: studies on three prognostic variables in an epidemiological model.

The danger of luminal histamine administered orally or formed in the intestinal fluid by bacteria has long been neglected. However, the demonstration of blocking intestinal diamine oxidase (DAO) by a variety of common drugs has revived the discussion and has created a new disease concept: enteral-induced histaminosis. In an animal model the three central prognostic variables of this disease concept (large amounts of histamine in food to make the individual ill, blocking of DAO by commonly used drugs, and the relationship between increased plasma histamine levels and disease manifestation by exogenous histamine application) were tested with randomized trials in vivo and biochemical tests in vitro using semipurified enzymes from pig and man. In the first trials authentic histamine in quantities similar to that in normal amounts of food or cheese bought from a supermarket produced life-threatening reactions if the DAO was inhibited by pretreatment with aminoguanidine. In the second series of experiments in vitro a numerous commonly used drugs was shown to inhibit both the porcine and human enzyme. Some of the inhibitors were really strong, such as dihydralazine, chloroquine, pentamidine, cycloserine, clavulanic acid, dobutamine, pancuronium and others. The type of inhibition was sometimes competitive as in the case of dihydralazine and pancuronium, sometimes non competitive (e.g. pentamidine) which may be important for long-term treatment. In the third group of experiments a relationship between the dose of i.v. injected histamine and the elevation in plasma histamine levels and clinical symptoms in pigs was demonstrated. Hence, elevated plasma histamine in pigs acts as a pathogenetic factor for the disease manifestation. It is concluded that after modelling enteral-induced histaminosis in an animal the trias of variables shown in this study should be consequently investigated in man.

Food-induced histaminosis under diamine oxidase (DAO) blockade in pigs: further evidence of the key role of elevated plasma histamine levels as demonstrated by successful prophylaxis with antihistamines.

Using a recently established porcine model, it was clearly shown that oral histamine administration is extremely dangerous in the presence of diamine oxidase (DAO) blockade. Due to the severity of the symptoms (20% death) and the clinical relevance, further interest has been focussed on strategies to prevent or alleviate food induced histaminosis. In a randomized controlled trial, 10 pigs under DAO blockade were challenged with oral histamine (60 mg). Half of these animals received a prophylactic premedication with a combination of H1- and H2-receptor antagonists. As expected, all animals developed a massive increase in plasma histamine levels, with significantly higher values in the control group (median: 123 ng/ml) compared to the antihistamine group (median: 32 ng/ml). In contrast, clinical symptoms were only observed in the control group. The maximum fall in mean arterial pressure (hypotension) was 60 mmHg (median for control group) but only 15 mmHg (median) under antihistamine pretreatment. These results firstly provide further evidence for the causal role of histamine in the new disease concept and secondly enable us to investigate appropriate therapeutic measures for patients at risk.

Potencies of ceftriaxone and cefotaxime in a single chamber pharmacokinetic system simulating their in vivo half-lives.

Ceftriaxone and cefotaxime are third-generation cephalosporins with similar in vitro potencies and spectra. However, previous studies have shown that ceftriaxone had superior in vivo activity (mouse PD50 values greater than or equal to 2-fold lower) compared to cefotaxime in 23 of 46 tested enterobacteriaceae. This superior activity was thought to be due to ceftriaxone's 5- to 8-fold longer half-life. The relationship between half-life (ceftriax-one 6 h, cefotaxime 1 h) and potency was examined by following bacterial kill curves in a single chamber, open-ended perfusion model over an 8-hour period. Both antibiotics were compared for efficacy at both half-lives against four gram-negative bacteria. For two of the bacterial strains antibiotic potency differences in the perfusion model were determined largely by pharmacokinetics. For the other two strains intrinsic bacterial and antibiotic properties were of prime importance.

Food-induced histaminosis as an epidemiological problem: plasma histamine elevation and haemodynamic alterations after oral histamine administration and blockade of diamine oxidase (DAO).

In a randomized controlled trial, 30 pigs were orally treated with histamine (60 mg). In addition, half of the animals underwent a specific blockade of the enzyme diamine oxidase (DAO), which is the main histamine catabolising enzyme in the intestinal tract. Only these DAO-blocked animals exhibited severe clinical symptoms (e.g. hypotension, flush, vomiting) and, in parallel, showed tremendous elevations of plasma histamine levels of up to 160 ng/ml. 3 out of 15 animals in this group died within the experimental period. In contrast, the control animals neither exhibited plasma histamine levels above 5 ng/ml nor had any clinical reactions. These results contradict the current opinion that oral histamine intake in food is not clinically relevant, especially since many commonly used drugs are DAO-inhibitors and approximately 20% of our population take these drugs. Apart from drugs, some other factors (alcohol, spoilt food etc.) can also function via a blockade of DAO as an additional risk. DAO-blockade is therefore a real epidemiological problem. Evidence is presented here for the new disease concept: Food-Induced Histaminosis.