Resistance or emigration: response of the high-alpine plant Eritrichium nanum (L.) Gaudin to the ice age within the Central Alps

Two main possibilities regarding glacial survival of the mountain flora of the Alps during the Quaternary have been discussed: the tabula rasa and the nunatak hypotheses. Eritrichium nanum (L.) Gaudin (Boraginaceae) is a perennial cushion plant, occurring at high elevations of the Central Alps and having a preference for extreme habitats. It belongs to a group of high-alpine plants, for which in situ glacial survival on nunataks is ecologically possible. By investigating 20 populations of E. nanum of potential nunatak and peripheral refugial regions using amplified fragment length polymorphism, considerable genetic differences between populations from the Central Alps and populations from peripheral refugia were detected; hence, the latter probably did not serve as potential sources for the re-colonization of the Central Alps after glaciation. Genetic variation was hierarchically structured (AMOVA), and three genetically distinct regions could be identified in the Central Alps. Two of these, the Penninic and Rhaetic Alps, correspond to nunatak regions proposed in the biogeographic literature. Populations from the Lepontic Alps formed a third genetic group. Genetic correlation (Mantel statistics) was highest within populations, with a modest decline among populations within specific nunatak regions and a negative correlation outside the genetic influence of specific nunatak regions. In situ glacial survival in E. nanum could be a model for the Quaternary history of other alpine plants, especially those that also occur at high elevations and in similar habitats.

Effects of an onion-olive oil maceration product containing essential ingredients of the Mediterranean diet on blood pressure and blood fluidity

Twenty-four patients with arterial hypertension (WHO class I) received either 4 capsules of an onion-olive oil maceration product, containing essential ingredients of the Mediterranean diet, or placebo daily over a period of one week. In order to investigate the acute effect on arterial blood pressure, measurements were performed before and 5 h after the administration of the first dose of 4 capsules verum or placebo, respectively. For the evaluation of the long term effect further blood pressure measurements were performed after one week's treatment with a daily dose of 4 capsules. After a wash-out phase of 2 weeks followed by a crossover, the second study phase, which was identical in design, was carried out. In addition patients were instructed to measure their blood pressure 4 times daily at home for the whole study period. Haemorheological parameters (platelet aggregation, erythrocyte aggregation, plasma viscosity and haematocrit) were also determined at the measuring points mentioned above. The onion-olive oil maceration product led to a significant decrease in systolic blood pressure. There was also a trend towards a decrease in diastolic blood pressure. The improved blood fluidity observed resulted from a decrease in haematocrit. All effects could be shown immediately and after one week's administration.

[Age-correlation of blood pressure induced myogenic autoregulation of human retinal arterioles in 40 volunteers]

PURPOSE

For the first time noninvasive measurement of the myogenic response of retinal arterioles is possible by the use of the Retinal-Vessel-Analyzer (RVA). This study investigates the influence of age on retinal autoregulation.

PATIENTS AND METHODS

In 40 healthy volunteers continuous measurement of a retinal arteriole over a 9-min period was performed. After a 3-min baseline measurement isometric exercise caused a rise in blood pressure of 15-30 mm Hg. During the last 3 minutes recovery was documented. Volunteers were split into a group of 20 younger (18-34 yrs.) and 20 older subjects (35-57 yrs.). For statistical analysis the Mann-Whitney test was used.

RESULTS

All volunteers showed a rise in blood pressure. Significant differences in the blood-pressure rise were followed by a myogenic response of 1% up to 10% vasoconstriction. An individual autoregulation-curve was defined with negative gradient. Significant differences between the younger and the older volunteers can be identified by this methodology.

CONCLUSION

Age has a significant influence on the myogenic response in human retinal arterioles. Age should be considered as a factor in clinical studies on retinal autoregulation.

Influence of the onion as an essential ingredient of the Mediterranean diet on arterial blood pressure and blood fluidity

Mediterranean diet has got a favourable effect on life expectancy. One of the crucial components of the diet are onions. In an open and a randomized, placebo-controlled, double-blind, cross-over phase-I study a spontaneous pharmacological effect 5 h after administration of an onion-olive-oil maceration capsule formulation on arterial blood pressure could be demonstrated in apparently healthy subjects. In addition to a decrease in arterial blood pressure, a significant reduction in plasma viscosity and haematocrit were observed. These results are indicating a vasodilative effect of the onion-olive-oil-maceration product. The stickiness of the platelets was reduced. The effects were stronger in subjects with reduced blood fluidity compared to those subjects with normal rheological parameters.

A search for diagnostic AFLP markers in Cichorium species with emphasis on endive and chicory cultivar groups

The genus Cichorium consists of two widely cultivated species C. intybus (chicory) and C. endivia (endive) and four wild species, C. bottae, C. spinosum, C. calvum, and C. pumilum. A multivariate and an UPGMA (unweighted pair group method average) analysis based on AFLP (amplified fragment length polymorphism) markers were used to establish the genetic relationships among the species and cultivar groups of C. intybus and C. endivia. At the species level, the results correspond with previously obtained phylogenetic relationships in that C. bottae is the most divergent species, and C. intybus and C. spinosum, as well as C. endivia, C. pumilum, and C. calvum formed clusters. Based on the congruence between phylogenetic and genetic analyses, unique markers were expected for all species, however, hardly any specific marker was found except for C. bottae. The analysis of cultivar groups of C. intybus resembled the species analysis in two respects: (i) grouping of cultivars according to cultivar groups, and (ii) lack of markers unique to cultivar groups. In contrast to C. intybus, the cultivar series of C. endivia do not form distinct groups, which would reflect that crosses have been made among the various cultivar groups. The relationships among Cichorium species and cultivars will be useful for setting up a core collection of Cichorium, and stress the importance of inclusion of the wild species in the collection.

Amplified fragment length polymorphism (AFLP) markers reveal that population structure of triploid dandelions (Taraxacum officinale) exhibits both clonality and recombination

Highly variable amplified fragment length polymorphism (AFLP) fingerprints of triploid apomictic dandelions obtained from three localities in an area where diploids are lacking were analysed to infer the predominant modes of reproduction. The distribution of markers was analysed using character compatibility to infer whether many genotypes agree with a tree-like structure in the data set. The presence of incompatible character state combinations (matrix incompatibility; MI) was used as a measure of genetic exchange. The detection of overrepresented genotypes, of which some were widespread, confirmed asexual reproduction. Not all genotypes were overrepresented; approximately half of the genotypes in the three localities were found only once. Because, in terms of genotype frequencies, only a part of the genetic variation is described, more important aspects of the molecular data such as relationships between markers or genotypes have been studied. The analysis of character compatibility indicated a disagreement of the data with a clonal structure. Nearly all genotypes contributed to MI and this contribution varied considerably among genotypes in each sampled locality. A gradual decrease of matrix incompatibility upon successive deletion of genotypes showing the highest contribution to MI indicated that marker distribution of virtually all genotypes disagreed with a tree-like structure in the data. This result suggested that many genotypes were separated by one or more sexual generations. Consistent with this conclusion was the fact that markers that show a low probability of contributing to MI are different in every sampled locality, which is most easily explained as the result of recombination. Apparently, asexual reproduction has resulted in overrepresented, widespread genotypes but sexual recombination has also substantially contributed to genetic variation in the sites studied.

[Autoregulation of retinal arterioles in patients with diabetes mellitus and normal probands]

BACKGROUND

Measurement of myogenic autoregulation of retinal arterioles was demonstrated by the use of the Retinal-Vessel-Analyzer (Carl Zeiss, Jena). The purpose of the presented study was to find a significant difference of this myogenic response in a group of healthy individuals vs. a group of patients with pathologic conditions.

PATIENTS AND METHODS

As a group of patients with known pathology in microcirculation patients with type 1 diabetes were chosen. By isometric exercise an identical rise in mean arterial blood-pressure was provoked in 20 patients with type-1 diabetes and 20 matched healthy volunteers. The myogenic response of retinal arterioles was measured in both groups by the use of the Retinal-Vessel-Analyzer. The Wilcoxon test was used for statistical analysis within the two groups whereas both groups were compared with each other by the use of the Mann-Whitney test.

RESULTS

Having the same age and same blood-pressure rise (p = 0.624) a significant better myogenic response was found in the healthy subjects vs. the diabetic group (p = 0.008). In the diabetic group no correlation was found between myogenic response and duration of diabetes (p = 0.982) or HbA1c values (p = 0.83).

CONCLUSIONS

In this study significant loss of autoregulation in patients with type 1 diabetes is demonstrated. By the use of the Retinal-Vessel-Analyzer noninvasive testing of the function of autoregulation of retinal arterioles is possible. This method might prove to be of great value in early detection of diabetic vessel pathology.

Molecular evolution of a tandemly repeated trnF(GAA) gene in the chloroplast genomes of Microseris (Asteraceae) and the use of structural mutations in phylogenetic analyses

We sequenced the first ca. 900 bp of the 5'-trnL(UAA)-trnV(UAC)/ndhJ region of the chloroplast DNA of different Microseris accessions in order to resolve homoplasious length variation detected in the trnL(UAA)-trnF(GAA) region. We found two to four tandemly repeated trnF genes in the species of Microseris (Asteraceae, Lactuceae) and two in their sister genus Uropappus. Sequences indicated nonhomologous transitions between two, three, and four trnF genes in different Microseris taxa. Independent origins of similar trnF copy numbers were inferred from a chloroplast phylogeny of Microseris. The taxa involved grow on separate continents, supporting parallel origins of similar length variants. The changes in trnF copy numbers were best explained by interchromosomal recombination with unequal crossing over. The 5' copies of the repeats showed the highest sequence conservation, suggesting that these copies are likely to be functional trnF genes, whereas the other ones probably represent pseudogenes. Our results show that length polymorphisms accumulate once a duplicated sequence has become incorporated. Due to parallel gains of similar trnF copy numbers, homoplasious length variation was introduced into the data matrix. The data demonstrate that length polymorphisms cannot be used as indicators for phylogenetic distance unless they can be analyzed at the sequence level.

Chloroplast DNA evidence for the evolution of Microseris (Asteraceae) in Australia and New Zealand after long-distance dispersal from western North America

Restriction site mutations and trnL(UAA)-trnF(GAA) intergenic spacer length variants in the chloroplast genome were used to investigate the phylogenetic relationships among 53 Australian and New Zealand Microseris populations and to assess their position within their primarily North American genus. The study was performed to enhance understanding of evolutionary processes within this unique example of intercontinental dispersal and subsequent adaptive radiation. A southern blot method using four-base restriction enzymes and fragment separation on polyacryamide gels resulted in 55 mutations of which 30 were potentially phylogenetically informative. Most mutations were small indels of <162 bp, 80% of which were <20 bp. The small indels were useful for phylogenetic reconstruction of Australasian Microseris as judged by the high consistency indexes. The results confirmed the monophyly of the Australian and New Zealand Microseris. The occurrence of "hard" basal polytomies in the most parsimonious trees indicated that rapid radiation has occurred early in the history of the taxon. The monophyly of M. lanceolata, which includes the self-incompatible ecotypes of the Australian mainland, was confirmed. Within this species three clades were found that reflect more geographic distribution than morphological entities, suggesting that migration and possibly introgression between different ecotypes, or parallel evolution of similar adaptations, has occurred. One of the three clades was supported by a 162-bp deletion in the trnL-trnF spacer, while a subgroup of this exhibited also a tandemly repeated trnF exon. The data were inconclusive about the monophyly of the second Australasian species, M. scapigera, which comprises the New Zealand, Tasmanian, and autofertile ecotypes of Australia.

Evolution of the chloroplast genome and polymorphic ITS regions in Allium subg. Melanocrommyum

Relationships based on PCR-RFLPs of non-coding regions of cpDNA indicate that some of the largest subgenera of the genus Allium and five of the largest sections of the Central Asian subg. Melanocrommyum are artificial. Internested synapomorphic mutations without homoplasy were found only in the chloroplast genomes of plants of subg. Melanocrommyum that occur in the border region of Tajikistan, Uzbekistan, Afghanistan, and Kyrgyzstan. Eighteen of 49 plants surveyed were polymorphic for their ITS regions. Even plants that had identical chloroplast genomes were polymorphic for nuclear ribosomal regions. These individuals had markedly different frequencies of ITS variants that were detected with various restriction enzymes. The geographic partitioning of chloroplast haplotypes and the fact that the ITS variants could not be ordered hierarchically can readily be envisioned to result from gene flow. Processes such as concerted evolution and parallel morphological evolution may also be partly responsible for the disconcordance of mutations in the chloroplast and nuclear genome. However, the chimeric nature of the nuclear ribosomal regions indicates that concerted evolution is not the dominating process in Allium subg. Melanocrommyum.

Noninvasive measurement of the Bayliss effect in retinal autoregulation

PURPOSE

The Bayliss effect describes the reaction of smooth muscle cells in the arterial wall to changes in blood pressure. A rise in mean arterial blood pressure (MAP) causes an autoregulatory myogenic vessel constriction by smooth muscle cells in the arterial wall. The responsiveness of retinal vessels to changes in MAP were analyzed using the Retinal Vessel Analyzer (RVA).

METHODS

Continuous measurement of retinal arterial vessels was performed in 40 healthy volunteers (age 18-56 years.) over a 9-min period. After a 3-min baseline measurement (phase I), isometric exercise caused a rise in MAP over the next 3 min (phase II). During the last 3 min (phase III) recovery was observed. Blood pressure and ECG were documented simultaneously throughout the experiment.

RESULTS

Exercise caused a significant rise of 22.8 (+/-6.0) mm Hg in MAP (phase II vs. phase I: P<0.001). Retinal arterioles showed 5.5% (+/-2.8%) vasoconstriction (P<0.001). During phase III vessel diameters returned to normal, with no difference from phase I (P = 0.179).

CONCLUSION

Noninvasive measurement and quantitative analysis of the Bayliss effect in human retinal vessels by means of the RVA is possible. Analysis of retinal arterial autoregulation may provide valuable insight into pathologic conditions such as diabetic or hypertensive retinopathy.

RAPDs and noncoding chloroplast DNA reveal a single origin of the cultivated Allium fistulosum from A. altaicum (Alliaceae)

The origin of the crop species Allium fistulosum (bunching onion) and its relation to its wild relative A. altaicum were surveyed with a restriction fragment length polymorphism (RFLP) analysis of five noncoding cpDNA regions and with a random amplified polymorhic DNA (RAPD) analysis of nuclear DNA. Sixteen accessions of A. altaicum, 14 accessions of A. fistulosum, representing the morphological variability of the species, and five additional outgroup species from Allium section Cepa were included in this study. The RFLP analysis detected 14 phylogenetically informative character transformations, whereas RAPD revealed 126 polymorphic fragments. Generalized parsimony, neighbor-joining analysis of genetic distances, and a principal co-ordinate analysis were able to distinguish the two species, but only RAPD data allowed clarification of the interrelationship of the two taxa. The main results of this investigation were: (1) A. fistulosum is of monophyletic origin, and (2) A. fistulosum originated from an A. altaicum progenitor, making A. altaicum a paraphyletic species. Compared with A. altaicum the cultivated accessions of the bunching onion show less genetic variability, a phenomenon that often occurs in crop species due to the severe genetic bottleneck of domestication. Allium altaicum and A. fistulosum easily hybridize when grown together, and most garden-grown material is of recent hybrid origin.

[Anti-bradycardia ventricle stimulation during the vulnerable phase of the heart cycle in ICD system with DDD cardiac pacemaker function]

We report a case of a 56-year-old white female with an ICD system (Ventak AV, CPI) implanted because of repeated episodes of ventricular fibrillation and preexisting intermittent total AV-block. Several times asynchronic stimulation could be observed in the case of ventricular extrasystole stimulating the ventricle during different times of depolarization. The reason for undersensing of the premature ventricular complexes was a blanking period of 66 ms after atrial stimulation. Therefore, the ICD was not able to sense the ventricular extrasytole and the stimulation of the ventricle occurred during the vulnerable period of the heart cycle. Induction of severe ventricular arrhythmia was not documented. Because of missing programmability of the ventricular blanking period, no possibility of a safety stimulation, and already maximal sensitivity of the ICD, the incidence of these events could only be reduced by increasing the lower rate limit of the pacemaker and suppression of the premature ventricular complexes by medication.

Poststenotic coronary blood flow following percutaneous transluminal coronary angioplasty

Poststenotic intracoronary flow velocity measurements both prior to and following percutaneous transluminal coronary angioplasty (PTCA) by use of a Doppler-tipped guidewire allow estimation of haemodynamic improvement due to interventional procedures. Since poststenotic coronary artery vasoconstriction routinely occurs after PTCA, haemodynamic improvement may be overestimated when measured by flow velocity alone. In 38 patients scheduled for elective PTCA in single vessel disease (left anterior descending = 19; left circumflex = 9; right coronary artery = 10) change of poststenotic coronary blood flow (CBF) was calculated by the combined use of intracoronary flow velocity measurement (average peak velocity: APV) and quantitative coronary angiography (cross sectional area: CSA) both prior to and following PTCA. Poststenotic coronary diameters revealed a small but significant decrease following PTCA (2.9 +/- 0.5 versus 2.7 +/- 0.5 mm, p < 0.001, 33 of 38 analysed vessels, i.e. 86.8%), whereas APV demonstrated a significant increase due to PTCA (17.0 +/- 8 versus 41.5 +/- 16, p < 0.001). Along with the increment in poststenotic flow velocity, poststenotic CBF increased highly significantly following PTCA (33 +/- 25 versus 73 +/- 41 ml min(-1), p < 0.001). In spite of a significant decrease in poststenotic coronary diameter, a highly significant increment of poststenotic flow due to PTCA can be demonstrated paralleling increment of poststenotic coronary Doppler-flow velocity.

[Possibilities and limits of electron beam tomography]

Electron beam CT, which does not require mechanical movement of an X-ray tube, has a temporal resolution which exceeds that of conventional computed tomography by a factor of about ten. Axial images of the heart can be acquired within 50 to 100 ms with a spatial resolution below 0.5 mm2 and permit precise visualization of all cardiac structures. ECG-triggered acquisition of 30 to 40 axial images (3 mm slice thickness) in a short inspiratory breathhold allows one to sample a 3-dimensional volume data set which covers the complete heart. Overall acquisition times are approximately 30 to 50 seconds. While electron beam CT in general permits a complete cardiac investigation, including morphology, function, and perfusion, the method's most important application is non-invasive imaging of the coronary arteries. Without contrast enhancement, coronary calcifications by EBCT currently constitutes the most sensitive non-invasive marker for the presence even of very early forms of coronary atherosclerosis. Intravenous injection of contrast agent during image acquisition additionally permits the selective visualization of the coronary artery lumen and detection of significant stenoses. This method is especially well suited in the follow-up of coronary interventions and coronary bypass grafting. Breathhold and movement artifacts, superposition of coronary arteries and veins, as well as severe coronary calcifications currently constitute the method's main problems. In spite of these limitations, electron beam CT has been shown to permit clinically valuable non-invasive investigations of the coronary arteries, which may be further refined as technology progresses.

Impedance rise, only clue to severe insulation damage in a transvenous single-lead AICD-system

We report a case of severe insulation damage 10 months after implantation of a fourth-generation single-lead implantable cardioverter defibrillator in a 45-year-old patient with dilative cardiomyopathy. The measured impedance was > 2000 Ohm and decreased to < 100 Ohm after slight pressure was applied to the device. All other parameters including intracardiac ECGs and markers were normal. Despite this delicate finding operative exploration revealed severe insulation damage of the pace-sense arm of the plug and insulation loss proximal to the distal coil of the lead.

Assessment of coronary blood flow in humans using phase difference MR imaging. Comparison with intracoronary Doppler flow measurement

Coronary blood flow quantification provides essential information on the hemodynamic significance of coronary artery stenoses. Recently, magnetic resonance (MR) flow mapping has emerged as a new promising method to noninvasively determine flow velocity and flow volume within the coronary arteries. The aim of this study was to compare phase difference (PD) MR flow quantification with intracoronary Doppler flow measurements in 15 patients with suspected or known coronary artery disease. Flow quantification was attempted before and after systemic application of 5mg Isosorbiddinitrate (ISDN) in order to determine possible alterations in coronary flow volume. PD MR flow mapping was performed successfully in 13 of the 15 patients. For flow velocities and flow volume values, a close correlation between PD MR and Doppler flow measurements was found (r = 0.79 and r = 0.90, respectively). However, average flow measured by PD MR was significantly lower than the invasively obtained values (9.0 +/- 4.4 cm/sec vs. 11.7 +/- 4.9 cm/sec; p < 0.001 and 46.3 +/- 28.7 ml/min vs. 53.4 +/- 32.8 ml/min; p < 0.05). Although the mean flow volume remained constant in the entire patient group after ISDN application, individual changes (increase in 6, decrease in 4 cases) could be documented with PD MR imaging and showed a good correlation to the Doppler method (r = 0.82). In conclusion, PD MR flow mapping is a promising method for the noninvasive quantification of coronary blood flow and therefore offers the potential of assessing coronary artery stenoses. However, technical improvements are mandatory in order to increase accuracy of the method.

Microsatellite enrichment in organisms with large genomes (Allium cepa L.)

To exploit the polymorphism of repeat numbers in short tandem repeat (STR) sequences (microsatellites) as molecular markers, STRs must be isolated and PCR primers must be developed in flanking sequences. In species with large genomes such as Allium cepa L. (onion and shallot), an efficient selection procedure for genomic fragments containing STRs is a crucial step. Here we describe a nonradioactive method for microsatellite isolation based on affinity capture of single-stranded restriction fragments annealed to biotinylated microsatellite oligonucleotides (CA)10, (GAA)8 and (AAC)8 followed by adapter-mediated genomic PCR. Cloning of the products in E. coli and plasmid sequencing revealed more than 60% positive clones. Primers were designed in STR-flanking regions, and one or two bands were amplified in 13 diploid onion and five shallot accessions. Allelism of the bands was confirmed by product sequencing.

Effect of montelukast on single-dose theophylline pharmacokinetics

The effect of montelukast (MK-0476), a cysteinyl leukotriene receptor antagonist in development for treatment of asthma, on single-dose theophylline plasma concentrations was studied in three separate clinical trials. Montelukast was evaluated at 10 mg once daily (the clinical dosage), 200 mg once daily, and 600 mg (200 mg three times daily). At the clinical dosage, montelukast did not change single-dose theophylline plasma concentration in a clinically important manner. The geometric mean ratios for theophylline area under the plasma concentration versus time curve (AUC0-->infinity ) (0.92) and maximal plasma concentration (Cmax ) (1.04) were well within the predefined and generally accepted bioequivalence range of 0.80 and 1.25. Montelukast decreased theophylline Cmax by 12% and 10%, AUC0-->infinity by 43% and 44%, and elimination half-time by 44% and 39% at 200 mg/d (oral and intravenous, respectively), and at 600 mg/d, montelukast decreased theophylline Cmax by 25%, AUC0-->infinity by 66%, and elimination half-time by 63%. These results show that montelukast at the clinical dosage did not change theophylline pharmacokinetics in a clinically important manner, but at 20- to 60-fold higher dosages, montelukast significantly reduced the theophylline pharmacokinetics parameters; an apparent dosage dependence is suggested.

Curved multiplanar reconstructions for the evaluation of contrast-enhanced electron beam CT of the coronary arteries

OBJECTIVE

We investigated the applicability of curved multiplanar reconstructions for the evaluation of contrast-enhanced electron beam CT scans of the coronary arteries.

SUBJECTS AND METHODS

Thirty-two patients (43-72 years old; mean age, 58 years old) underwent electron beam CT. After injection of i.v. contrast medium, 40 axial cross sections of the heart were acquired, triggered to the ECG during breath-hold (3-mm slice thickness, 1-mm overlap). Curved multiplanar reconstructions were obtained separately for each coronary artery. The reconstructions were independently evaluated by two investigators for the presence of high-grade stenoses and occlusions. The results were then compared with coronary angiography results, of which the two investigators had been unaware.

RESULTS

Because of degraded image quality, 15 (12%) of the 128 vessels (left main, left anterior descending, left circumflex, and right coronary arteries in 32 patients) were excluded from evaluation. In the remaining 113 vessels, 16 (89%) of 18 high-grade stenoses and occlusions were correctly detected (89% sensitivity). Absence of significant stenosis was correctly detected in 87 (92%) of 95 vessels (92% specificity). The negative and positive predictive values were 98% and 67%, respectively.

CONCLUSION

Curved multiplanar reconstructions are useful in the evaluation of contrast-enhanced electron beam CT scans of coronary arteries.