Comparison of direct and indirect measures of systemic arterial pressure during weightlifting in coronary artery disease.

Based on auscultation measurements after exercise, circuit weight training in cardiac patients has been reported to provoke minimal increases in systolic pressure. Direct (brachial artery catheter) and indirect (sphygmomanometry) measures of blood pressure were compared at rest, during lifting with the legs (approximately the fourth, ninth and fourteenth repetition) and during 2 minutes of recovery after lifting with the arms and legs. Subjects performed 15 repetitions of single-arm curl, single-arm military press and single- and double-leg press exercises at 40 and 60% of the maximum load that could be lifted once on a multistation weightlifting apparatus. Indirect measures of systolic pressure at rest were 13% less than those recorded directly (130 +/- 7 vs 149 +/- 8 torr; p less than 0.01); diastolic pressures were similar using either method. This pattern was maintained during lifting with the legs at both intensities, and after exercise with both the legs and the arms. The mean systolic pressure recorded indirectly immediately after exercise was 63 torr (31%) and 76 torr (34%) less than the average peak intraarterial value recorded during leg and arm exercises, respectively. The highest intraarterial pressures were generated during the final repetitions of the set; immediately after the last repetition, both systolic and diastolic pressures rapidly decreased. It is concluded that indirect estimates of systolic pressure are significantly less than true arterial values at rest, and during and after lifting. Moreover, indirect measurements after lifting do not allow accurate conclusions to be drawn about the arterial pressures generated during lifting because of the rapid decrease in pressure that occurs after exercise.

Combination neurohormonal blockade with ACE inhibitors, angiotensin II antagonists and beta-blockers in patients with congestive heart failure: design of the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) Pilot Study.

BACKGROUND: The Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) Pilot Study is a trial of combination neurohormonal blockade using an angiotensin II antagonist (candesartan), an angiotensin-converting enzyme inhibitor (enalapril) and a beta-blocker (metoprolol) in patients with congestive heart failure (CHF). OBJECTIVES: Primary objectives of stage I are to determine the efficacy (via the 6 min walk test) and safety of candesartan alone, and in combination with enalapril, versus enalapril alone. Secondary objectives are to determine the effect of the above combinations on neurohormones, ventricular function, quality of life and symptoms. Stage II objectives are similar, evaluating the effect of the addition of metoprolol or placebo to the above medication(s). DESIGN: Randomized, two-stage trial consisting of a three-way comparison (stage I), followed by a 3 x 2 partial factorial design (stage II). SETTING: Sixty out-patient clinics in five countries. PATIENTS: Patients with symptoms of CHF (New York Heart Association functional classes II to IV), ejection fraction less than 40% and 6 min walk distance of 500 m or less. INTERVENTIONS: In stage I, 770 patients are randomized to receive candesartan alone, enalapril alone, or candesartan plus enalapril. After five months (end of stage I), patients are assessed for eligibility to be randomized in stage II. Those who are not candidates for randomization to beta-blocker or placebo are followed on their stage I medications until the end of the study. In stage II, patients are randomized to receive metoprolol or placebo for a further six months in addition to their stage I medications. Endpoints are measured at baseline, end of stage I (week 20) and end of stage II (week 46). STUDY STATUS: The study has recently completed follow-up in both stages. The findings from this study will be used to design a large scale mortality study that will help further define the role of neurohormonal blockade in patients with CHF.

[Problems associated with setting maximum allowable concentrations (MAC) of harmful substances present in the work environment]. / Problemy zwiazane z ustalaniem najwyzszych dopuszczalnych stezen (NDS) substancji szkodliwych dla zdrowia wystepujacych w srodowisku pracy.

The major aim of setting MAC values is to reduce the risk of occupational exposure to harmful substances to the acceptable level. In the process of setting MAC values, a critical analysis of the toxicological and medical literature, used by teams of experts who try to estimate the probability of health effects with different concentrations and different duration of exposures, is most essential. This process is usually very difficult since the epidemiological data and the results of animal experiments are often incomplete, and extrapolation of experimental results from animals to humans entails a lot of doubts. Moreover, one never knows which level of the risk can be considered as acceptable. That is why MAC values set by groups of experts cannot be treated as absolutely safe to the human health. They should be verified if new data on biological effect of substances harmful to health and new criteria for occupational risk assessment become available.

[Strategies in measuring air pollution in the work environment]. / Strategia pomiarów zapylenia powietrza w srodowisku pracy.

The procedures of measuring the dustiness in the work environment have been discussed, involving short- and long-lasting stationary measurements taken continually during the 8-hour working day with individual samplers. Examples of a statistic treatment of the results and interpretation based on mandatory hygienic standards for industrial dusts have been presented.

[Measurement and evaluation of air contamination by dust in the Federal Republic of Germany]. / Pomiary i ocena pylowych zanieczyszczen powietrza w RFN.

The paper presents hygienic standards, either currently valid in the GFR or planned to be introduced in 1982, for industrial dusts containing free crystalline silica and asbestos. In addition, methods and apparatus for measuring dust respirable fraction concentrations at workplaces are discussed, as well as principles of work conditions evaluation and hygienic interpretation of measurements results. The basis of this interpretation is an assumption that the MAK (Maximale Arbeits-platzkonzentrationen) values for the dusts containing crystalline forms of silica and TRK (technische Richtkonzentrationen) for the dusts containing asbestos are average values for 1 year. Dustiness at workplaces is also evaluated for 1 year.

[Identification of crystalline phases and various metal content of fibrous minerals (Polish asbestos) found in nickel ore deposits]. / Identyfikacja faz krystalicznych i zawartosc niektórych metali w mineralach wlóknistych ("azbest polski") towarzyszacych zlozom rud niklu.

Nickel ore deposits near Szklary in Lower Silesia are accompanied by minerals of clearly fibrous structure ("Polish asbestos"). The pulverization process of those minerals yields particles resembling fibres. Basing on the diffractometric characteristics and absorptive spectra analysis in infrared, crystalline phases were identified in five dust samples of those minerals. The major crystalline phases were found to be: anthophyllite (samples 1, 2, 3), quartz (samples 2, 3, 5) and antigorite (samples 4 and 5). Tests on X-ray spectrometer SPARK-1 indicated that all the samples contained ferrum (1-2%), nickel (0,08-0,15%), copper (below 0,005%), in one sample the content of zinc amounted to 0.006%, in the other the content of zinc and chromium was lower than their detectability limit. Air dustiness in the nickel ore mine and nickel ore processing plant may result in serious diseases in those inhaling the dust. The pollution of air, water and soil in the mine environs cannot be neglected, either.

[Specific surface factor of dust particles and preliminary selection of silica dusts]. / Charakterystyczny wspólczynnik powierzchni czastek i wstepna selekcja plynów krzemionkowych.

The results of particles analysis of three kinds of silica dust by means of miscroscopy and sedimentation in Andreasen's pipette served as a base for the determination of factor phi specific for particle surface. This factor is expressed as a ratio of the mean projected diameter (dp) to the aerodynamic diameter (d). The formula of the factor is: (formula: see text). The value of factor phi for tested silica dusts ranges from 2.0 to 2.6 (mean value--2.3), while the variability coefficient is 13.5%. Taking into account the value of factor phi determined by experiment and the value of dispersion of silica dust particles, the expected permeability of the selector (elutriator) and the deposition of dust in lungs were calculated.

The effect of asbestos-cement, cement and asbestos dusts on the lungs of rats.

Experimental coniosis was induced by intratracheal administration to rats of 25 mg or 50 mg of Portland cement, asbestos-cement, as well as chrysotile and crocidolite asbestos. The rats were sacrificed 90, 165 and 180 days after dust administration. The weight of wet lungs and hydroxyproline content in lungs were determined. Statistically significant lower values of fibrogenic effects indices following cement dust administration, as compared to those indices for the other dusts, were found. On the other hand, no significant differences were found between fibrogenic effects indices for asbestos-cement containing approx. 13% of asbestos and pure asbestos dusts (chrysotile or crocidolite). Furthermore, it seems that the duration of dust action is more important than the dust dose in the development of fibrogenic asbestosis.

[Biological effect of fibrous mineral dust. I. Fibrogenic properties of the products of the thermal degradation of chrysotile]. / Biologiczne dzialanie wlóknistych pylów mineralnych. I. Wlasciwosci zwlókniajace produktów termicznej degradacji chryzotylu.

Chrysotile asbestos samples, on comminution, were exposed to temperatures typical for asbestos products exploitation. Subsequently, in an experiment on white rats the effects of temperature upon asbestos fibrous effects were evaluated. The highest aggressiveness was that of the sample heated at 600 degrees C. All the animals died as soon as 50 or 25 mg of dust had been administered intratracheally. Only 3 samples could be administered intratracheally at a dose of 50 mg: non-heated. heated at 400 degrees C and heated at 800 degrees C samples. The doses heated at 400 and 800 degrees C had be reduced by half. Samples heated at 150 to 800 degrees C induced higher hydroxyproline increases than the non-heated sample. The fibrogenic activity of the dust heated at 1200 degrees C was very similar to the fibrogenic activity of the non-heated dust.

[Polish asbestos and its fibrogenic effect. II. Identification and fibrogenic effect of fibrous minerals occurring in road stone deposits]. / Azbest polski i jego dzialanie zwlókniajace. II. Identyfikacja i dzialanie zwlókniajace mineralów wlóknistych wystepujacych w zlozach kamienia drogowego

Fibrogenic properties of a fibrous mineral occurring in road stone deposits mined at Naslawice at the Lower Silesia have been tested. Diffractometric and infrared absorption spectra tests identified this mineral as antigorite. The content of free crystalline silica was 1.3%. The dust (50 mg) obtained from the test mineral when intratracheally administered to experimental animals as a suspension in physiological NaC1 solution yielded statistically significant increases of the lung weight and hydroxyproline content, as compared to controls. The mean weight of experimental animals' lungs after 3 months was 1898.4 mg, after 6 months--2116.8 mg, after 9 months--2878.4 mg. The control animals' lung weight was 1409.6 mg after 3 months, 1634.4 mg after 6 months and 1939.9 mg after 9 months. Hydroxyproline content in experimental animals' lungs was 5.1 after 3 months, 5.8 mg after 6 months and 8.6 mg after 9 months. In controls, hydroxyproline content in lungs was, respectively: 3.5; 3.9 and 4.0 mg after 3, 6, and 9 months of the experiment. However, the process of lung fibrosis when affected by antigorite from Naslawice was slower than under effects of antigorite from Szklary, which may result from almost 10 times fewer numbers of fibrous particles in the dust obtained from antigorite from Naslawice.

[Maximum permissible levels of asbestos and other natural minerals with fibrous structure--necessity of verification]. / Najwyzsze dopuszczalne stezenia dla azbestu i innych naturalnych mineralów o strukturze wlóknistej--koniecznosc weryfikacji.

MACs of asbestos are from 2 to 20 times higher in Poland than in other Western Europe countries. The analysis of occupational diseases reported between 1983 and 1988 among workers of asbestos-cement plants has showed that Polish MAC values do not protect people from work-related asbestosis. Asbestosis was frequently diagnosed in workers employed at mining and processing of nickel ore containing admixtures of fibrous antigorite. The risk of asbestosis in workers of a nickel++ metallurgical plant was 8 times higher that in those employed at an asbestos-cement plant. In an animal study, fibrogenic, carcinogenic and mutagenic activity of antigorite was similar to the biological aggressiveness of crocidolite. Based on own studies and literature data, the following MACs for asbestos and other natural fibrous minerals were established: a) for dusts containing asbestos and other fibrous minerals except crocidolite and fibrous antigorite, total dust concentration equals 1 mg/m3 and concentration of fibres longer than 5 microns = 0.5 fibre/cm3 b) for dusts containing crocidolite and fibrous antigorite total dust concentration = 0.5 mg/m3 and concentration of fibres longer than 5 microns = 0.2 fibre/cm3.

[Amorphous silica. Types, health effects of exposure, NDS]. / Krzemionki bezpostaciowe. Rodzaje, skutki zdrowotne ekspozycji, NDS.

Maximum allowable concentration (MAC) values for amorphous silica dust have not been identified in the Polish legal regulations up-to-date. In this work the authors review values of allowable (recommended) amorphous silica dust concentrations in other countries. Data on other types of amorphous silica (natural and synthetic) used in industry as well as data on health effects of exposure to these types of dust are presented. The work encompasses 42 entries in the references and one Table which includes the following proposed MAC values: Non-calcinate diatomaceous earth (diatomite) and synthetic silica: Total dust--10 mg/m3 Respirable dust--2 mg/m3 Calcinate diatomaceous earth (diatomite) and fused silica (vitreous silica): Total dust--2 mg/m3 Respirable dust--1 mg/m3.

[Refractory ceramic fibers, kinds, health effects after exposure, TLVs]. / Ogniotrwale wlókna ceramiczne, rodzaje, skutki zdrowotne ekspozycji, NDS.

Ceramic fibres are amorphous or crystalline synthetic mineral fibres which are characterised by refractory properties (i.c. stability in temperature above 1000 degrees C). In general, ceramic fibres are produced from aluminium oxide, silicon oxide and other metal oxides and less frequently from non-oxide materials such as silicon carbide, silicon nitride and boron nitride. In Poland, the production of ceramic fibres was begun in the Refractory Materials Plant, Skawina, during mid-eighties. The production capacity accounts for about 600 tons annually. It is estimated that approximately 3000 persons are exposed to the effect of ceramic fibres in Poland. During the production of ceramic fibres, concentrations of respiral fibres in the air at work places range from 0.07 to 0.27 f/cm3; during the manufacture of ceramic fibre products from 0.23 to 0.71 f/cm3 and during the application of ceramic fibre products from 0.07 to 1.67 f/cm3. As published data depict, fibres longer than 5 microns are most common in the work environment, and the proportion of fibres with diameters below 1 micron accounts for 40-50%. Bearing in mind the present situation in Poland, namely combined exposure to asbestos (during removal of worn out heat-insulating materials) and ceramic fibres (during installation of new insulation), as well as in view of own investigations and literature data which evidence a strong carcinogenic effect of certain fibres, the following MAC values have been adopted: Dusts of refractory ceramic fibres: total dust-2 mg/m3; respirable fibres-1 f/cm3 (L > 5 microns; D < 3 microns; L: D < 3:1) Dusts of reflactory ceramic fibres mixed with asbestos: total dust-1 mg/m3; respirable fibres-1 f/m3. Dusts of refractory ceramic fibres mixed with other man-made mineral fibres (MMMF): total dust-2 mg/m3; respirable fibres-1 f/m3. According to the IARC, ceramic fibres have been included into group 2B-suspected human carcinogen.

[Chrysotile asbestos: biological effects, the work environment highest allowable concentration and neoplasm risk]. / Azbest chryzotylowy--dzialanie biologiczne, najwyzsze dopuszczalne stezenia w srodowisku pracy I ryzyko nowotworowe.

The authors present the most essential data on physical and chemical properties of chrysotile, sources of its emission, the extent of occupational exposure, and biological effect, used in setting MAC values for chrysotile-containing dusts. Exploitable asbestos deposits do not exist in Poland, but admixtures of asbestos minerals have been found in some deposits of mineral raw materials located in the area of Lower Silesia (melafir, gabbro, dolomite. ore, nickel, magnesite, serpentinite). In the 1970s, about 100,000 tonnes of asbestos, containing 90% of chrysotile, were used annually in Poland. This figure decreased to 30,000 tonnes in 1991. In 1985 the use of crocidolite asbestos was stopped, and in 1999, the use of asbestos-containing products was banned by the virtue of the legal act. At present, the Minister of Economy in agreement with the Minister of Environmental Protection sets regularly the list of asbestos-containing products permitted for the production or in the customs area. Nowadays, the range of dust concentrations in plants which use asbestos products amounts to 0.1-0.6 mg/m3 for total dust and 0.002-0.07 f/cm3 for respirable mineral fibres; and during exploitation of rock raw material deposits 0.7-280 mg/m3, and 0.01-3.3 f/cm3, respectively. During the years 1976-96, 1520 cases of asbestos-related occupational diseases were diagnosed. This figure included 1314 cases of asbestosis, 154 cases of lung cancer and 52 cases of pleura mesothelioma. MAC values for chrysotile and chrysotile-containing dusts are: 0.2 f/cm3 and 1 mg/m3.

[Evaluation of the work environment in factories producing artificial mineral fibers (MMMF)]. / Ocena srodowiska pracy w zakladach produkujacych sztuczne wlókna mineralne (MMMF).

In seven MMMF producing plants, workplaces have been evaluated through measurements of the concentrations of the total dust and respirable fibers of over 5 micron length and below 3 micron diameter, using personal dosimeters of Cassella firm. Only in one of the plants the time weighted average concentration of total dust was 4.11 mg/m3, exceeding the TLV value (4.0 mg/m3). Respirable fibers concentrations ranged from 0.005 to 1.44 fibres/cm3, so in none of the plants the TLV value of 2 fibres/cm3 was reached. The greatest air dustiness was found at mineral wool spreading and breaking workplaces. However, such workplaces occur only in two plants using the oldest technology of MMMF production. Analyses of fibres sizes made with the use of optical and electron microscopy indicated that the contribution of respirable fibres to the total dust weight is slight, up to a dozen per cent.

[Experimental silicosis. I. Fibrogenic activity of quartz material used in the ceramic industry]. / Doswiadczalna pylica krzemowa. I. Dzialanie zwlókniajace surowców kwarcowych stosowanych w przemysle ceramicznym.

A high concentration of silica dust in the air many workstands in ceramic plants is a serious risk for the health of exposed workers. It can cause the development of silicosis. The aim of this paper is to evaluate a fibrogenic activity of dusts containing 98% crystalline silica. The ceramic masses have about 25% of Quartz. The samples of 2 lode quartz and 4 sand quartz originated from different mines in Poland were used for the experiment. Their physical properties were analysed by X-ray diffraction and SiO2 content was determined by colorimetry. Their biological aggresiveness was characterised by wet weight, hydroxyproline content, lipid level in the lungs and wet weight of mediastinal lymph nodes of rats which were intratracheally given of the dusts. The results show that the tested dusts have a moderated fibrogenic activity. At short time (3 months) after their administration the fibrogenic changes in lungs were different depending on the kind of dusts, but at the 6th month of the experiment they did not differ at all. The exposition of workers to silica dusts is a great occupational hazard.

[Determination of free crystalline silica in the dust containing silicates]. / Oznaczanie zawartosci wolnej krystalicznej krzemionki w pylach zawierajacych krzemiany.

The content of free crystalline silica in dusts containing silicates was investigated using Polezajew's method, the HBF4 method and X-ray diffraction. Polezajew's method was found to give highly increased results (133.4% on the average), and with 5% of quartz in mixture with kaolin--252%. Solution of silicates, when heated, in fluoroboric acid considerably reduces the error of determination. The mean value of SiO2 recovery in mixtures of quartz with kaolin is 102.9% and with 5% of quartz--116. This method is highly precise. The results of determination of crystalline silica content in some mineral raw materials used in ceramic industry approximated the results obtained using X-ray diffraction.

[Air concentration of asbestos fibers at work sites]. / Oznaczanie stezenia wlókien azbestu w powietrzu stanowisk pracy.

The paper presents a method for measuring the concentration of asbestos fibres at workplaces. This method consists in sampling the dusted air onto membrane filters, making the filters transparent and counting asbestos fibres under an optical microscope with a positive phase contrast. Errors in counting asbestos fibres, sampling and precision of the method were discussed (total error of the method). Measurements of the concentration of asbestos fibres in the air at workplaces were made at plants producing asbestos textile products, seal plates, packings and frictional goods. 0.1 fibre/cm3 was the lowest concentration (sensitiveness of the method).

[Fly ash and its biological effects. I. Production, utilization and physico-chemical properties of fly ash]. / Popioly lotne i ich dzialanie biologiczne. I. Produkcja, wykorzystanie i wlasciwosci fizyczno-chemiczne popiolów lotnych.

The paper includes the results of Part I of the studies designed to evaluate occupational risk of power engineering workers, i.e. people employed in plants producing fly-ashes, as well as those working in lightweight concrete plants where fly-ashes are applied as raw materials. The authors have found out that fly-ashes included mainly quartz, orthoclase and mullite. In dust samples, particles of fibrous structure have been found (probably--mullite). The content of free crystalline silica came to 31.6% in total dust and 8.9% in respirable dust. Fly-ashes contained:--naturally radioactive elements K40, Ra226, Th228 (maximum values were, respectively: 1070 Bq/kg, 222 Bq/kg, 142 Bq/kg of dust),--aromatic hydrocarbons (benzene-soluble fraction) in the amount of 0.001 to 0.003 microgram/mg, as well as admixtures of heavy metals in amounts varying largely. The dust concentrations at workplaces ranged from 1 mg/m3 to 200 mg/m3, depending on the type of work (inspection, repair of boilers). The results demonstrate that in the working environment of power engineering and lightweight concrete plants there occur agents of potentially fibrogenic and cancerogenic properties.

[Retention of radioactive aerosols (products of radon-222 decay) by various types of anti-dust masks]. / Wyniki badan skutecznosci zatrzymywania aerozoli promieniotwórczych (produktów rozpadu radonu 222Rn) przez niektóre typy masek przeciwpylowych.

The paper presents results of measurements of the efficiency of retention of radon decay products, occurring as radioactive aerosols, by anti-dust masks. The efficiency of three types of masks: PM-1, PM-3, PP-2 "Delta" was studied under various conditions of equilibrium between radon and products of its decay in the air. It was concluded that the efficiency of retention of radon decay products, occurring as radioactive aerosols, by the mentioned types of masks, comes to 75--87%. Anti-dust PM-1 (F-14 filter) and PM-3 (F-13 filter) masks are recommended as most efficient.