Electrocardiographic changes in workers occupationally exposed to lead

BACKGROUND

The significance of heavy metals in pathogenesis of the circulatory system diseases remains unresolved. The aim of the study was to evaluate electrocardiographic changes in workers occupationally exposed to lead without clinical presentation of cardiac involvement.

METHODS

A group of 60 smelters and refiners and 45 healthy men, as a control group, were enrolled. Twelve-lead electrocardiogram (ECG) and 24-hour Holter monitoring were performed. Further analysis included heart rate variability (HRV) in time and frequency domains and heart rate turbulence (HRT).

RESULTS

Analysis of 12-lead ECG recordings revealed various pathologies in 27 out of 60 men occupationally exposed to lead. Twenty-four-hour ECG Holter monitoring showed the higher mean heart rate in copper smelters than in healthy subjects (85.8 ± 14.1 bpm vs 72.6 ± 9.2 bpm; P < 0.05) and more premature supraventricular and ventricular contractions (298 ± 235 vs 27 ± 45; P < 0.05 and 152 ± 138 vs 18 ± 18; P < 0.05, respectively). The majority of time domain and frequency domain HRV parameters were significantly lower, and the LF:HF ratio was higher when compared with the control group. Turbulence onset was abnormal in six copper smelters and turbulence slope in five men exposed to lead.

CONCLUSIONS

Electrocardiographic evaluation showed that various heart rhythm disorders were more frequent in metallurgists, as compared to the control group, and the decreased HRV and abnormal parameters of HRT were observed. Noninvasive electrocardiographic evaluation could be a valuable method of the early prediction of cardiovascular disorders in men occupationally exposed to lead.

Orai1 contributes to the establishment of an apoptosis-resistant phenotype in prostate cancer cells

The molecular nature of calcium (Ca²⁺)-dependent mechanisms and the ion channels having a major role in the apoptosis of cancer cells remain a subject of debate. Here, we show that the recently identified Orai1 protein represents the major molecular component of endogenous store-operated Ca²⁺ entry (SOCE) in human prostate cancer (PCa) cells, and constitutes the principal source of Ca²⁺ influx used by the cell to trigger apoptosis. The downregulation of Orai1, and consequently SOCE, protects the cells from diverse apoptosis-inducing pathways, such as those induced by thapsigargin (Tg), tumor necrosis factor α, and cisplatin/oxaliplatin. The transfection of functional Orai1 mutants, such as R91W, a selectivity mutant, and L273S, a coiled-coil mutant, into the cells significantly decreased both SOCE and the rate of Tg-induced apoptosis. This suggests that the functional coupling of STIM1 to Orai1, as well as Orai1 Ca²⁺-selectivity as a channel, is required for its pro-apoptotic effects. We have also shown that the apoptosis resistance of androgen-independent PCa cells is associated with the downregulation of Orai1 expression as well as SOCE. Orai1 rescue, following Orai1 transfection of steroid-deprived cells, re-established the store-operated channel current and restored the normal rate of apoptosis. Thus, Orai1 has a pivotal role in the triggering of apoptosis, irrespective of apoptosis-inducing stimuli, and in the establishment of an apoptosis-resistant phenotype in PCa cells.

Primate-specific RFPL1 gene controls cell-cycle progression through cyclin B1/Cdc2 degradation

Ret finger protein-like 1 (RFPL1) is a primate-specific target gene of Pax6, a key transcription factor for pancreas, eye and neocortex development. However, its cellular activity remains elusive. In this article, we report that Pax6-elicited expression of the human (h)RFPL1 gene in HeLa cells can be enhanced by in vivo p53 binding to its promoter and therefore investigated the hypothesis that hRFPL1 regulates cell-cycle progression. Upon expression in these cells, hRFPL1 decreased cell number through a kinase-dependent mechanism as PKC activates and Cdc2 inhibits hRFPL1 activity. hRFPL1 antiproliferative activity led to an increased cell population in G(2)/M phase and specific cyclin B1 and Cdc2 downregulations, which were precluded by a proteasome inhibitor. Specifically, cytoplasm-localized hRFPL1 prevented cyclin B1 and Cdc2 accumulation during interphase. Consequently, cells showed a delayed entry into mitosis and cell-cycle lengthening resulting from a threefold increase in G(2) phase duration. Given previous reports that RFPL1 is expressed during cell differentiation, its impact on cell-cycle lengthening therefore provides novel insights into primate-specific development.

Dietary modulation of ghrelin and leptin and gorging behavior after weight loss in the obese Zucker rat

In this study, we measured ghrelin and leptin in obese Zucker rats after weight loss induced by calorie restriction using either a low-fat (LF) or high-energy palatable (HEPa) diet. After weight loss, the animals were refed lab chow and offered one hour-palatable test meals on the second and fifteenth days of refeeding. Both LF and HEPa rats lost 10% of their initial body weight (P<0.0001). Plasma ghrelin increased with calorie restriction in both groups (P<0.002) with a tendency to a higher increase in the HEPa group while plasma leptin decreased only in the LF group (P<0.01). Both groups ate the same quantity of chow during refeeding and both groups gorged on palatable diet during test meals at a very high constant intensity in HEPa rats. After one week of refeeding, ghrelin levels remained elevated in HEPa rats (+33.2%; P<0.001) while returning to baseline in LF rats. Plasma leptin remained low in LF rats. We conclude that weight loss on a palatable diet is possible if total energy intake is controlled. After stopping restriction, when a palatable diet is available, observed gorging might be dependent on specific ghrelin and leptin changes.

[13C2]oxalate absorption in children with idiopathic calcium oxalate urolithiasis or primary hyperoxaluria

Intestinal oxalate absorption is an important part of oxalate metabolism influencing its urinary excretion and its measurement can be a valuable diagnostic tool in hyperoxaluric disorders. In this study, we use [(13)C(2)]oxalate absorption under standardized dietary conditions to assess intestinal oxalate absorption and its impact on urinary oxalate excretion. Tests were conducted in age-matched pediatric patients that included 60 with idiopathic calcium oxalate urolithiasis, 13 with primary hyperoxaluria, and 35 healthy children. In the idiopathic stone formers, median oxalate absorption was significantly higher than that in the controls or in patients with primary disease. From standardized values obtained in control patients, oxalate hyperabsorption was detected in 23 patients with idiopathic disease but not in any patients with primary hyperoxaluria; therefore, a significant correlation between intestinal absorption and urinary excretion was found only in those with the idiopathic disease. We have shown that increased intestinal oxalate absorption is an important risk factor of idiopathic calcium oxalate urolithiasis. In contrast, low intestinal oxalate absorption in patients with primary hyperoxaluria indicates that only foods with excessive oxalate content be restricted from their diet.

Neuropeptide Y in normal eating and in genetic and dietary-induced obesity

Neuropeptide Y (NPY) is one the most potent orexigenic peptides found in the brain. It stimulates food intake with a preferential effect on carbohydrate intake. It decreases latency to eat, increases motivation to eat and delays satiety by augmenting meal size. The effects on feeding are mediated through at least two receptors, the Y1 and Y5 receptors. The NPY system for feeding regulation is mostly located in the hypothalamus. It is formed of the arcuate nucleus (ARC), where the peptide is synthesized, and the paraventricular (PVN), dorsomedial (DMN) and ventromedial (VMN) nuclei and perifornical area where it is active. This activity is modulated by the hindbrain and limbic structures. It is dependent on energy availability, e.g. upregulation with food deprivation or restriction, and return to baseline with refeeding. It is also sensitive to diet composition with variable effects of carbohydrates and fats. Leptin signalling and glucose sensing which are directly linked to diet type are the most important factors involved in its regulation. Absence of leptin signalling in obesity models due to gene mutation either at the receptor level, as in the Zucker rat, the Koletsky rat or the db/db mouse, or at the peptide level, as in ob/ob mouse, is associated with increased mRNA abundance, peptide content and/or release in the ARC or PVN. Other genetic obesity models, such as the Otsuka-Long-Evans-Tokushima Fatty rat, the agouti mouse or the tubby mouse, are characterized by a diminution in NPY expression in the ARC nucleus and by a significant increase in the DMN. Further studies are necessary to determine the exact role of NPY in these latter models. Long-term exposure to high-fat or high-energy palatable diets leads to the development of adiposity and is associated with a decrease in hypothalamic NPY content or expression, consistent with the existence of a counter-regulatory mechanism to diminish energy intake and limit obesity development. On the other hand, an overactive NPY system (increased mRNA expression in the ARC associated with an upregulation of the receptors) is characteristic of rats or rodent strains sensitive to dietary-induced obesity. Finally, NPY appears to play an important role in body weight and feeding regulation, and while it does not constitute the only target for drug treatment of obesity, it may nevertheless provide a useful target in conjunction with others.

Oxalobacter formigenes: a potential tool for the treatment of primary hyperoxaluria type 1

Primary hyperoxaluria is characterized by severe urolithiasis, nephrocalcinosis, and early renal failure. As treatment options are scarce, we aimed for a new therapeutic tool using colonic degradation of endogenous oxalate by Oxalobactor formigenes. Oxalobacter was orally administered for 4 weeks as frozen paste (IxOC-2) or as enteric-coated capsules (IxOC-3). Nine patients (five with normal renal function, one after liver-kidney transplantation, and three with renal failure) completed the IxOC-2 study. Seven patients (six with normal renal function and one after liver-kidney transplantation) completed the IxOC-3 study. Urinary oxalate or plasma oxalate in renal failure was determined at baseline, weekly during treatment and for a 2-week follow-up. The patients who showed >20% reduction both at the end of weeks 3 and 4 were considered as responders. Under IxOC-2, three out of five patients with normal renal function showed a 22-48% reduction of urinary oxalate. In addition, two renal failure patients experienced a significant reduction in plasma oxalate and amelioration of clinical symptoms. Under IxOC-3 treatment, four out of six patients with normal renal function responded with a reduction of urinary oxalate ranging from 38.5 to 92%. Although all subjects under IxOC-2 and 4 patients under IxOC-3 showed detectable levels of O. formigenes in stool during treatment, fecal recovery dropped directly at follow up, indicating only transient gastrointestinal-tract colonization. The preliminary data indicate that O. formigenes is safe, leads to a significant reduction of either urinary or plasma oxalate, and is a potential new treatment option for primary hyperoxaluria.

Angiogenic and coagulation-fibrinolysis factors in non Hodgkin's lymphoma

High serum VEGF and bFGF levels are independent prognostic factors of poor prognosis in NHL patients. There is growing evidence that both angiogenesis and haemostatic aberrancies are integral parts of the pathobiology of cancer growth and dissemination. The purpose of the study was: (a) to analyze relations of VEGF and bFGF serum levels, fibrinogen and D-dimer plasma levels with lymphoma Ann Arbor Staging System (AASS) and International Prognostic Index (IPI) and, (b) to evaluate correlations between serum levels of angiogenic cytokines and plasma levels of coagulation-fibrinolysis factors in 52 previously untreated NHL patients included to the study. The control group consisted of 23 healthy volunteers. Serum VEGF, bFGF and plasma D-dimer levels were measured by enzyme-linked immunosorbent assay (ELISA). Plasma levels of fibrinogen were determined on Behring Coagulation System (BCS) equipment. In lymphoma group serum VEGF and bFGF levels were significantly higher than in the control. Differences in concentrations of VEGF, bFGF between II, III and IV stage of disease acc. AASS were not statistically significant. Plasma levels of fibrinogen and D-dimer were elevated in lymphoma patients when compared with the control. Fibrinogen plasma levels were similar in all stages. The D-dimer level was significantly higher in patients with IV stage in comparison to stage II and III. Statistically significant differences of VEGF and bFGF serum levels were observed only between intermediate/high and high risk groups acc. IPI. Fibrinogen plasma levels were significantly higher in high risk group than in low risk group. D-dimer plasma levels were significantly higher in high risk group than in low risk group and low/intermediate group. We observed positive correlation between serum level of VEGF and plasma level of fibrinogen, and between serum level of bFGF and plasma level of fibrinogen. There was also negative correlation between serum level of VEGF and plasma level of D-dimer, and between serum level of bFGF and plasma level of D- dimer. Our study indicates that D-dimer level, but not VEGF, bFGF and fibrinogen correlates with AASS and IPI in NHL patients. Significant correlations between levels of VEGF/bFGF and fibrinogen/D-dimer suggest specific interactions between angiogenic and coagulation-fibrinolysis system.

[New image of occupational medicine--current problems, future solutions]

Current problems in occupational medicine result mainly from the situation in which existing structures are not appropriately adapted to the changes in economy, work market structures and social and demographic trends, which rapidly appeared within the last decade. The Act of Occupational Medicine Service in force precisely defines the duties of occupational medicine services. However, although the legal powers seem clear and detailed, the possibility of real actions is not put in order and encounters many barriers. The changes in structures of economy, enterprises and work market result in the situation in which despite the obligatory preventive examination system, there is a large group of people that are not subject to them. Care of workers in bigger companies or institutions is also the source of problems concerning mainly the examination range, but also the identification of new threats connected with ergonomics, psychological or biological factors; their limiting, monitoring and prevention. A broad issue of provided service qualities is closely connected with the problems mentioned above. Another question is defining the quality control system, the execution of post-control suggestions and the possibility of applying possible sanctions. A significant task is also to modify the examining and specialisation acquirement system. In the creation of the new image of occupational medicine in Poland the most significant issue is to correct the current legal grounds by introducing new standards of health protection for working people, enable to provide high- quality services, create the conditions for functioning of multidiscipline teams preventively caring of working people, being a guarantee of health and economic benefits for the society.

Diagnosis and metaphylaxis of stone disease. Consensus concept of the National Working Committee on Stone Disease for the upcoming German Urolithiasis Guideline

This review draws the recent state of the art in metabolic diagnosis and metaphylaxis of stone disease. It is the basis for the consensus approval with the other medical societies and institutions in Germany involved in the guideline process of the new "Urolithiasis Guideline". The German Working Committee on Stone Disease reviewed critically the current literature in the field of urolithiasis-including the existing German and EAU-Guidelines as well as the Conference Book of the First International Consultation on Stone Disease. As far as possible the references were rated according to the EBM criteria. On this basis the expert group discussed all pathways and statements regarding the management of stone disease. The present review coincides with the consented guideline draft of the German Working Committee on Stone Disease. Occurrence of stone disease in the western world increases seriously. Modern lifestyle, dietary habits and overweight-problems of the affluent societies-emerge to be the important promoters of the "stone-boom" in the new millennium. This even affects children, whose stone prevalence is otherwise significantly less than that of adults. Criteria for the high risk group of stone formers were clearly defined. A diagnostic standard is formulated for the basic and the elaborate metabolic evaluation of a stone patient. Approximately 75% of all stone patients could anticipate stone recurrence with elementary reorientation of their lifestyle and dietary habits, summarized as general metaphylaxis. About 25% of the stone formers require additional pharmacological intervention to normalize their individual biochemical risk, precisely compiled for each stone type as specific metaphylaxis.

Persistent alterations in neuropeptide Y release in the paraventricular nucleus of rats subjected to dietary manipulation during early life

The aim of the present experiment was to determine the influence of nutritional manipulations during early life on feeding regulatory mechanisms. For this purpose, neuropeptide Y (NPY) release in the hypothalamic paraventricular nucleus was measured in male offspring born to dams fed either on a control (C) diet, on a high-carbohydrate (HC) diet or on a high-fat (HF) diet during gestation and lactation periods. In addition, we examined the development of dietary preferences in these rats. NPY release was measured in vivo through the push-pull technique after a stimulation with 2-deoxy-glucose (2DG), a blocker of carbohydrate metabolism. NPY release was significantly enhanced in the HC rats after 2DG (+89% vs. control and +54% vs. HF rats; P < 0.01). In a two-bottle choice test, a clear preference for carbohydrate (62% vs. 38%; P < 0.01) was present as early as 30 days of age in control rats. The establishment of this preference in HC and HF rats was delayed by 2 and 3 months, respectively. Therefore, each type of dietary manipulation during early life has left a specific imprint in the offspring. The change in reactivity of the NPY system to glucopenia persisted in adulthood. When combined with the early changes in the dietary preferences, this can lead to adverse effects on body weight when abundant and palatable food is offered. These data support the hypothesis of an intrauterine and perinatal programming of the central regulatory mechanisms and reinforce the necessity of a preventive approach for the treatment of obesity and related metabolic disorders.

[Coexistence of pneumoconiosis with myelodysplastic syndrome in a coal miner occupationally exposed to coal dust]

Pneumoconiosis is the most common occupational disease of the respiratory system. The aim of this paper is presentation of case of pneumoconiosis coexisting with myelodysplastic syndrome in a former coal miner occupationally exposed to coal dust. In a mineral coal miner, aged 56 year, with a 15-year duration of work underneath, suffering from pneumoconiosis, pancytopenia was detected. He was admitted to the hospital, where myelodysplastic syndrome was diagnosed. The patient's condition was gradually worsening, even though chemotherapy was applied, he died from thrombocytopenia manifested by bleeding from the digestive tract in a relatively short time since diagnosis. The presented case seems to be interesting not only in view of possible development of pneumoconiosis as a result of occupational exposure to coal dust, typical in this case, but also in view of the occurrence of clonal disease of blood several years after cessation of exposure.