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R Dietz

Publications and source records attributed to R Dietz.

At least 73 records · Page 4Linked to original sources
PubMed2000

Geographical differences of zinc, cadmium, mercury and selenium in polar bears (Ursus maritimus) from Greenland.

Muscle, liver, and kidney tissues from 100 polar bears (Ursus maritimus), caught in the Avanersuaq area, north-west Greenland, and Ittoqqortoormiit area, central-east Greenland, were analysed for zinc, cadmium, mercury and selenium. The zinc concentrations in muscle and liver were higher than in kidney. Mean zinc concentrations ranged from 19.7 to 76.0 micrograms/g (all data are presented as geometric means on a wet wt. basis). The presented cadmium concentrations by area and age groups were all low in muscle and in many cases below the detection limit (range: < 0.015-0.048 microgram/g). Cadmium concentrations were intermediate in liver (range: 0.120-1.98 micrograms/g) and highest in kidney tissue (range: 2.16-28.9 micrograms/g). Mercury was likewise lowest in muscle tissue (range: 0.034-0.191 microgram/g). Mercury concentration ranged quite similarly in liver and kidney tissue (liver range: 2.13-22.0 micrograms/g; kidney range: 2.87-32.0 micrograms/g). The selenium concentration increased from muscle (range: < 0.2-0.452 microgram/g) over liver (range: 1.20-9.80 micrograms/g) to kidney (range: 2.34-13.9 micrograms/g). No age accumulation was found for zinc. A weak increase was found for selenium, whereas cadmium and mercury clearly accumulated with age. An exception was mercury concentrations in muscle tissue, where no clear pattern was observed. Polar bears had significantly lower cadmium concentrations than ringed seals from the same area in all three tissues. Likewise mercury was significantly lower in the muscle tissue of polar bears than in ringed seals, whereas liver and kidney concentrations were higher. Biomagnification factors are provided for different tissues and age groups. Tissue ratios are given for different age groups and metals to enable a rough extrapolation from one tissue to another. Tissue ratios for cadmium, selenium and for mercury vary up to a factor of 6 with age. No significant differences could be detected between the elements analysed in bears from two management zones in north-west Greenland. This finding is in agreement with the genetic pattern in the two areas. In central-east Greenland, however, cadmium, selenium, and some of the mercury concentrations in polar bears from the southern area were higher than from the northern area, indicating that the east Greenland area represents two different ecological regions with different polar bear populations. Geographical differences between polar bears from north-west and east Greenland were only found for mercury and cadmium in liver tissue, where the concentrations were highest in bears from north-west Greenland. The geographical trend of increasing cadmium concentrations in polar bear liver tissue from west to east, which has been found previously in Canada, could be extended to cover north-west Greenland as well. East of this region a decrease was found. Mercury concentrations in polar bear liver tissue showed an increase from Svalbard over east and north-west Greenland, peaking in bears from south-west Melville Island. A marked decrease was found west of Melville Island, and the lowest concentrations were found in the Chukchi Sea.

Animals↗
PubMed2000

Temporal trends of cadmium and mercury in Greenland marine biota.

Data for cadmium and mercury in Greenland marine biota (blue mussels, polar cod, shorthorn sculpin, glaucous gull and ringed seals) over a period of 20 years has been analysed in order to assess temporal changes. Most of the comparisons were conducted between tissue samples collected in the mid-1980s and mid-1990s. Cadmium data from a few time series obtained at reference sites during monitoring of mining activities were also included. No overall temporal trends in cadmium or mercury concentrations were found within the 20-year period assessed. However, cadmium concentrations in ringed seals tended to increase in the period from late-1970s to the mid-1980s. From the mid-1980s to the mid-1990s cadmium concentrations in ringed seals decreased again, whilst mercury concentrations showed a tendency to increase in the same period. The observed changes may reflect natural fluctuations caused by factors such as a shift in feeding behaviour, rather than changes in anthropogenic exposure.

Animals↗
PubMed2000

Organochlorines in Greenland marine fish, mussels and sediments.

Shorthorn sculpin (Myoxocephalus scorpius), polar cod (Boreogadus saida), blue mussels (Mytilus edulis) and sediments were sampled in Greenland 1994-1995 at three locations at the west coast and one at the east coast. Fish liver, mussel soft tissue and sediments were analysed for PCBs (10 congeners), DDTs (pp,'), HCHs (alpha, beta, gamma), HCB and trans-nonachlor. The overall geometric mean concentrations found for PCBs were 17 micrograms kg-1 wet wt. in shorthorn sculpin liver, 33 micrograms kg-1 wet wt. in polar cod liver, and 0.86 microgram kg-1 wet wt. in blue mussels. For the three species, the geometric mean concentrations for DDTs were 11, 36, and 0.39 micrograms kg-1 wet wt., respectively; for HCHs: 8.7, 32 and 0.56 micrograms kg-1 wet wt., respectively; for HCB: 4.2, 11 and 0.06 micrograms kg-1 wet wt., respectively; and for trans-nonachlor: 6.3, 19 and 0.16 microgram kg-1 wet wt., respectively. All organochlorines in the sediment samples were below the detection limit of 0.1 microgram kg-1 dry weight. For sculpins and mussels, most organochlorine compounds were found to increase with increasing lipid content. The weight of mussels did not influence organochlorine concentrations, whereas organochlorine content in general increased with fish length of sculpins. The concentrations were found to be comparable to levels in other Arctic regions, but orders of magnitude lower than levels found in the southern part of the North Sea. Organochlorine concentrations in sculpins showed a decreasing trend following the ocean current flowing from north to south at the east coast and from south towards north at the west coast of Greenland. The proportion of higher chlorinated PCBs (Cl atoms > or = 6) in sculpin liver followed the decreasing trend of PCB concentrations.

Animals↗
PubMed2000

Organochlorines in Greenland ringed seals (Phoca hispida).

Twenty-five ringed seals (Phoca hispida) were sampled in 1994 at each of four areas in Greenland, three on the west coast and one on the east coast. Seal blubber samples were analysed for polychlorinated biphenyls (PCBs, IUPAC Nos. 28, 31, 52, 101, 105, 118, 138, 153, 156 and 180), DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT), hexachlorocyclohexanes (alpha-, beta- and gamma-HCH), hexachlorobenzene (HCB) and trans-nonachlor. A number of the seals (n = 56) were also analysed for toxaphene (total toxaphene and single congeners: CHB Nos. 26, 32, 50 and 62). The overall geometric means (and ranges) found in seals were in microgram kg-1 wet wt. for sigma PCBs: 452 (85-4200), sigma DDTs: 607 (97-6040), sigma HCHs: 123 (51-382), HCB: 13 (3-27), trans-nonachlor: 83 (21-1236) and total toxaphene: 263 (71-950). The geometric means for HCB, trans-nonachlor, toxaphenes and the sums of PCBs and DDTs were higher for the east coast samples than for those from the west coast, and a decreasing trend in concentrations followed the east Greenland current. No geographical trend was apparent for HCHs. Differences in concentrations between females and males were only significant for HCB and HCH within certain age classes and sampling areas. A tendency for concentrations to increase with age was observed, but was not statistically significant. Principal component analyses for PCB congeners revealed that the proportion of higher chlorinated PCBs (Cl atoms > or = 6) decreased with decreasing concentrations of PCBs found for the four sampling areas. No differences between the higher and lower chlorinated PCBs were seen in females and males, but a higher proportion of CB-105 and CB-118 compared to CB-52 and CB-101 was seen in male seals compared to female seals.

Animals↗
PubMed2000

Organochlorines in Greenland glaucous gulls (Larus hyperboreus) and Icelandic gulls (Larus glaucoides).

Glaucous gulls (Larus hyperboreus) and Icelandic gulls (Larus glaucoides) were sampled in 1994 from four different areas in Greenland, three on the west coast and one on the east coast. Livers of 93 glaucous gulls and seven Icelandic gulls were analysed for polychlorinated biphenyls (PCBs, IUPAC Nos. 28, 31, 52, 101, 105, 118, 138, 153, 156 and 180), DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT), hexachlorocyclohexanes (alpha-, beta- and gamma-HCH), hexachlorobenzene (HCB) and trans-nonachlor (TNC). The overall geometric means of the concentrations found in glaucous gull liver were for sigma PCBs 388 (range 20-5557), for sigma DDTs 363 (17-8604), sigma HCHs 7.4 (1-53), HCB 47 (4-594) and trans-nonachlor 19 (3-187) micrograms kg-1 wet wt., respectively. The geometric means of concentrations in Icelandic gull liver were for sigma PCBs 112 (24-435), for sigma DDTs 95 (25-298), sigma HCHs 2.9 (1.4-5.2), HCB 22 (8-58) and trans-nonachlor 5.1 (2.4-8.6) micrograms kg-1 wet wt., respectively. Significantly (P = 0.05) higher concentrations of PCBs, DDTs and HCHs were found in glaucous gulls at Ittoqqortoormiit at the east coast than in gulls from Qeqertarsuaq at the west coast of Greenland. This tendency was also seen for HCB and trans-nonachlor, but the differences were not statistically significant (P = 0.05). A decreasing trend in organochlorine concentrations followed the East Greenland Current, flowing from north to south down the east coast and to the north on the west coast. Gulls taken from the most northerly sampling area of the west coast, however, showed slightly higher concentrations than those from the central west coast. There appeared to be a tendency for higher concentrations to be found in males than females, and in adults compared to young glaucous gulls, but the differences were not statistically significant (P = 0.05). The concentration ranges found in gulls from Greenland were similar to those reported previously for gulls from northern Norway and Russia. A principal component analysis revealed no obvious link between the presence of higher chlorinated PCBs and higher PCB concentrations in glaucous gulls. Significantly higher proportions of higher chlorinated PCBs were found in glaucous gulls than in Icelandic gulls, and in adult glaucous gulls compared to young gulls of 1-2 calendar years. As no such difference was found between female and male gulls it seems that PCBs of all degrees of chlorination may be passed equally well from mother to offspring.

Animals↗
PubMed2000

Lead, zinc, cadmium, mercury, selenium and copper in Greenland caribou and reindeer (Rangifer tarandus).

Samples of caribou and reindeer muscle (127 samples) and liver (126 samples) were collected from four locations during two seasons plus 3 years in Greenland. The levels of lead, zinc, cadmium, mercury, selenium, and copper were determined, and analyzed in relation to location, two seasons, age and year of sampling. The lead concentrations (geometric mean) ranged from below the detection limit to 0.007 microgram/g wet weight (wet wt.) in muscle and from 0.027 to 0.926 microgram/g wet wt. in liver. Zinc geometric mean concentrations ranged from 17.5 to 39.6 micrograms/g wet wt. in muscle and from 23.2 to 31.7 micrograms/g wet wt. in liver. For cadmium, the geometric mean concentrations were at, or below the detection limit in muscle, while concentrations in liver ranged from 0.121 to 0.695 microgram/g wet wt. Mercury levels ranged from 0.003 to 0.043 microgram/g wet wt. in muscle and from 0.040 to 0.618 microgram/g wet wt. in liver. Selenium concentration levels in muscle ranged from 0.030 to 0.252 microgram/g wet wt., and from 0.085 to 0.984 microgram/g wet wt. in liver. Copper levels in muscle ranged from 2.09 to 3.60 micrograms/g wet wt., and from 21.8 to 71.0 micrograms/g wet wt. in liver. Mercury concentrations were higher than those found at lower latitudes in Norway and Canada, especially in Isortoq in southern Greenland. Selenium levels were also high compared to other Arctic regions. Concentrations of lead, zinc, cadmium and copper are similar to those reported in caribou from Canada and Norway. Concentrations of elements generally decreased in the following order: Isortoq > Akia > Itinnera > Kangerlussuaq, and there was only found minor variation in the annual levels during 3 years in Itinnera. Late winter levels were generally significantly higher than early winter levels especially in the lichen-rich localities, and it is suggested that the availability of lichens as winter forage is the key determining the level of elements. Accordingly, when using caribou and reindeer as monitoring organism, knowledge of winter forage is very important for interpretation of results.

Animals↗
PubMed2000

Comparison of contaminants from different trophic levels and ecosystems.

The present paper provides an overview of the priority contaminants and media from the Greenland part of the Arctic Monitoring and Assessment Program. Levels and accumulation patterns of heavy metals, POPs and a radionuclide (137Cs) are compared from the terrestrial, freshwater and marine ecosystems. Of the nine compounds presented, seven (Cd, Hg, Se, sigma PCB, sigma DDT, sigma HCH, HCB) increased in concentration towards higher trophic levels. For these contaminants the concentrations in soil and aquatic sediment were in the same order of magnitude, whereas the concentrations in marine biota were higher than found in the freshwater and terrestrial ecosystems probably due to the presence of longer food chains. Pb and 137Cs showed the reverse pattern compared with the other compounds. The concentrations in soil and aquatic sediments decreased in the order terrestrial, freshwater and marine ecosystems, which was reflected in the biota as well. Reindeer had similar or lower levels of Pb and 137Cs than lichens. Levels of Pb and 137Cs in marine biota did not show the same clear increase towards higher trophic as found for the other analysed compounds. Greenland Inuit contains considerably less mercury but higher levels of sigma PCB, sigma DDT and HCB than other Arctic marine top consumers.

Animals↗
PubMed2000

Evaluation of the Greenland AMAP programme 1994-1995, by use of power analysis (illustrated by selected heavy metals and POPs).

The levels of PCBs, HCB, HCHs, DDTs, Cd, Pb, Hg and Se, and especially the variability in biota obtained during Phase 1 of the Greenland AMAP-programme have been used to illustrate the ability of the programme to detect differences in contaminant levels over time. The statistical power of t-tests of contaminant levels are illustrated according to various scenarios of magnitude of change, significance level and sample size. The statistical power of various time series of contaminant levels to detect linear trends in mean log-concentrations, including a random between-year variation component, is illustrated. We conclude that the ability to detect differences is rather poor for many combinations of contaminants and media, and that long time series are needed before temporal trends are likely to be detected.

Animals↗
PubMed2000

Role of nitric oxide in the vasodilator effect of recombinant human growth hormone in patients with dilated cardiomyopathy.

OBJECTIVE: Dilated cardiomyopathy is characterized by elevated arterial vascular resistance and impaired nitric oxide (NO)-dependent vasodilation. Insulin-like growth factor-I (IGF-I) has been shown to stimulate endothelial NO-synthase resulting in endothelium-dependent vasodilation. Growth hormone (GH) substitution therapy leads in GH-deficient patients to significant increases of IGF-I which may alter systemic vascular resistance by stimulating NO production. This study was designed to evaluate the effects of treatment with recombinant human growth hormone (GH) on NO production and NO-dependent vascular effects in patients with dilated cardiomyopathy. METHODS: 50 patients with dilated cardiomyopathy were randomly assigned to double-blind treatment with 2 I.U. of GH or placebo for 3 months. Central hemodynamics were determined by Swan-Ganz catheter and cardiac output was obtained by the thermodilution method. Serum GH and IGF-I levels were measured and systemic NO production was determined from urinary nitrate and cyclic GMP excretion rates in 42 patients. RESULTS: GH treatment caused in comparison to the placebo group a significant increase of IGF-I by 91 ng/ml (P = 0.0001). Urinary excretion rates of nitrate and cyclic GMP increased also significantly by 38 mumol/mmol creatinine (P = 0.027) and 65 nmol/mmol creatinine (P = 0.003), respectively. The parallel increase of both marker molecules indicates increased systemic NO production during GH treatment. CONCLUSION: GH treatment induces a significant, but moderate increase of systemic NO production in patients with dilated cardiomyopathy. This effect may be mediated by IGF-I stimulating endothelial NO synthase.

Cardiomyopathy, Dilated↗
PubMed2000

[Renovascular illness: prevalence and therapy in patients with coronary heart disease].

To explore the relationship between coronary artery disease and renal vascular disease, we performed renal arterial angiography in 609 patients undergoing coronary angiography for suspected coronary artery disease. We defined renal artery stenosis as nonsignificant (< 40%), borderline (40-60%) and significant (> 60%). One-hundred fifty-two patients had renal artery stenosis, while 457 did not. Two-hundred and ten patients had no coronary disease; of these, only 9 had renal artery stenosis. On the other hand, the 143 patients with renal artery stenosis, when subdivided, had similar degrees of coronary disease; three vessel disease was significantly more common than one or two vessel disease in all groups. Renal artery stenosis of all severity degrees was associated with common atherosclerotic risk factors. However, hypertension was not a clue to the presence of renal artery stenosis. To evaluate the effect of percutaneous revascularization on hypertension and renal function all 51 patients with significant renal artery stenosis were treated by primary stent implantation and were followed up for 6 months. Stent implantation showed a marked decrease in systolic and diastolic blood pressure (163 +/- 30 to 145 +/- 17 and 93 +/- 18 to 83 +/- 10 mmHg; p = 0.008) with a decrease in the amount of antihypertensive medication but without beneficial effect on serum creatinine during follow-up (1.46 +/- 0.70 mg/dl to 1.39 +/- 0.58 mg/dl, p = ns). We conclude that renal artery stenosis of any severity is strongly suggestive of three vessel coronary artery disease. The fact that renal stenting lowers blood pressure decreases antihypertensive drugs and increases medication flexibility in patients with coronary artery disease would support the notion of revascularization in patients with significant stenoses.

Aged↗
PubMed2000

The background of the MERIT-HF trial.

In the not so distant past, the idea of using beta-blockers as a primary therapy for congestive heart failure to improve symptoms and prognosis seemed paradoxical. The cardiac community reacted with skepticism when, in 1975, the pioneering report of Waagstein et al. appeared in the British Heart Journal. Since then numerous groups have investigated the effects of beta-adrenoceptor antagonists in patients with congestive heart failure. Unfortunately, the results of these trials have sometimes contradicted one another. Exercise tolerance and left ventricular ejection fraction improved in the trials with a duration of treatment of longer than 3 months, but no benefit was observed when beta-blockers were administered for only 1 month. Now, in the year 2000 we have proof for the concept that beta-blockade improves symptoms and prolongs life in heart failure. Three large placebo-controlled clinical trials with more than 9000 patients have shown that carvedilol, bisoprolol and metoprolol significantly reduce morbidity and mortality in heart failure. These agents, therefore, are clearly indicated in the majority of patients with mild to moderate heart failure.

Adrenergic beta-Antagonists↗
PubMed2000

The Euro Heart Failure Survey of the EUROHEART survey programme. A survey on the quality of care among patients with heart failure in Europe. The Study Group on Diagnosis of the Working Group on Heart Failure of the European Society of Cardiology. The Medicines Evaluation Group Centre for Health Economics University of York.

BACKGROUND: The EUROHEART programme is a rolling programme of cardiovascular surveys among the member nations of the European Society of Cardiology (ESC). These surveys will provide information on the nature of cardiovascular disease and its management. This manuscript describes a survey into the nature and management of heart failure. AIMS: The EuroHeart Failure survey aims to describe the quality of hospital care, diagnostic and therapeutic, for patients with suspected or confirmed heart failure in ESC member countries. Patients will be interviewed subsequent to hospital discharge to assess their understanding of their condition, side effects from and their compliance with therapy and their satisfaction with the management for heart failure. The quality of management will be judged against the recommendations contained in the ESC guidelines on diagnosis and treatment of heart failure. Outcome will be further assessed by repeat interviews in 6-12 months time. A further survey of heart failure in 2001/2002 is also planned. METHODS: A prospective survey of all deaths and discharges from medical (cardiology, internal medicine and geriatric medicine) and cardiac surgical wards to identify patients with heart failure, suspected or confirmed. Approximately 70 hospital clusters, comprising two to six hospitals in each cluster, in 24 member countries of the ESC are conducting the study. At the time of writing, approximately 30000 deaths and discharges have been screened and approximately 4000 patients have been enrolled. CONCLUSIONS: The EuroHeart Survey will allow actual practice to be compared to ESC guidelines on the diagnosis and treatment of heart failure. The surveys and guidelines should prove mutually informative. The main EuroHeart Failure project will be completed by late 2000. However, new centres volunteering to participate in the study (contact corresponding author) may be accepted providing they have the necessary research personnel and provided funding can be agreed for statistical support and administration.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Influence of sustained mechanical stress on Egr-1 mRNA expression in cultured human endothelial cells.

Restenosis after initially successful balloon angioplasty of coronary artery stenosis remains a major problem in clinical cardiology. Previous studies have identified pathogenetic factors which trigger cell proliferation and vascular remodeling ultimately leading to restenosis. Since there is evidence that endothelial cells adjacent to the angioplasty wound area synthesize factors which may initiate this process, we investigated the effects of mechanical stimulation on endothelial gene expression in vitro and focussed on the influence of sustained mechanical stress on expression of immediate early genes which have previously been shown to be induced in the vascular wall in vivo. Primary cultured human umbilical vein endothelial cells (HUVEC) and the human endothelial cell line EA.hy 926 were plated on collagen-coated silicone membranes and subjected to constant longitudinal stress of approximately 20% for 10 min to 6 h. Total RNA was isolated and the expression of the immediate early genes c-Fos and Egr-1 was studied by Northern blot analysis. We found a rapid upregulation c-Fos and Egr-1 mRNA which started at 10 min and reached its maxima at 30 min. HUVEC lost most of their stretch response after the third passage whereas immediate early gene expression was constantly in EA.hy 926 cells. Using specific inhibitors we investigated the contribution of several signal transduction pathways to stretch-activated Egr-1 mRNA expression. We found significant suppression of stretch-induced Egr-1 mRNA expression by protein kinase C (PKC) inhibition (p < 0.05) and by calcium depletion (EA.hy 926, p < 0.05; HUVEC, p = 0.063). No effect on stretch-activated Egr-1 mRNA expression was detected by inhibition of protein kinase A, blockade of stretch-activated cation channels or inhibition of microtubule synthesis. We conclude that sustained mechanical strain induces Egr-1 mRNA expression by PKC- and calcium-dependent mechanisms.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

The somatotrophic system in patients with dilated cardiomyopathy: relation of insulin-like growth factor-1 and its alterations during growth hormone therapy to cardiac function.

OBJECTIVE: Treatment with human recombinant growth hormone has yielded conflicting results in patients with congestive heart failure. In addition, growth hormone resistance has been reported in severe heart failure. Therefore, the purpose of this study was to evaluate the somatotrophic axis and effects of growth hormone on haemodynamics in patients with heart failure due to dilated cardiomyopathy. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Fifty clinically-stable patients with moderate heart failure (mean left ventricular ejection fraction = 26 +/- 2%) due to dilated cardiomyopthy were examined. MEASUREMENTS: Patients were randomly assigned to treatment with placebo or 2 IU/d sc human recombinant growth hormone for a mean of 14 weeks. Cardiac size and function were evaluated by magnetic resonance imaging. Central haemodynamics were obtained by right heart catheterization. Measurements of plasma noradrenaline, serum insulin-like growth factor-1, and insulin-like growth factor binding protein-3 were performed by standard assays at baseline and at the end of the treatment period. RESULTS: The severity of heart failure as determined by stroke volume, left ventricular end diastolic diameter and plasma noradrenaline concentrations correlated significantly to baseline serum insulin-like growth factor-1 levels (each P < 0.05). The growth hormone-induced increase of insulin-like growth factor-1 predicted the changes in ejection fraction (P < 0.05). A significant increase in ejection fraction of 7% was observed in patients whose insulin-like growth factor-1 increased by more than the median increase in comparison to the patients with an increase below the median (+ 4.0 +/- 2.3% vs. - 3.0 +/- 1.8%; P = 0.03). CONCLUSIONS: Serum levels of insulin-like growth factor-1, reflecting growth hormone secretion, are diminished in relation to the severity of heart failure in patients with dilated cardiomyopathy. Growth hormone induced increases of insulin-like growth factor-1 of more than 77 ng/l caused significant improvement of ejection fraction.

Adult↗