DNA content and cytogenetic characteristics of Gymnocalycium quehlianum (Cactaceae) along an altitudinal gradient / Contenido de ADN y características citogenéticas de Gymnocalycium quehlianum (Cactaceae) a lo largo de un gradiente altitudinal

ABSTRACT Important changes in vegetation types occur along elevational gradients. The genus Gymnocalycium is endemic to southern South America, and its species are distributed along elevational gradients. In particular, Gymnocalycium quehlianum is a globular cactus endemic to the Sierras de Córdoba. Studying cytogenetic aspects and DNA content in populations throughout their distribution is key to understanding the species. DNA content and cytogenetic characteristics were analyzed in four populations of G. quehlianum (615, 744, 948 and 1257 masl). The genome size in the four populations varied between 3.55 and 4.30 pg. The populations were diploid (2n = 22). All populations showed the karyotype formula of 10 metacentrics (m) + 1 submetacentric (sm). The species presented symmetrical karyotypes and constitutive heterochromatin CMA+/DAPI- associated with nucleolar organizing regions, always found in the first pair of m chromosomes. The 18-5.8-26S rDNA locus is found in the terminal regions of the first pair of chromosomes m, and the 5S locus is adjacent to the 18-5.8-26S locus. A tendency for DNA content to decrease with increasing altitude was observed.

RESUMEN A lo largo de los gradientes altitudinales se producen cambios importantes en los tipos de vegetación. El género Gymnocalycium es endémico del sur de América del Sur y sus especies se distribuyen en gradientes altitudinales. En particular, Gymnocalycium quehlianum es un cactus globular endémico de las Sierras de Córdoba. Estudiar aspectos citogenéticos y de contenido de ADN en las poblaciones a lo largo de su distribución es clave para comprender a la especie. En cuatro poblaciones de G. quehlianum (615, 744, 948 y 1257 msnm) se analizaron el contenido de ADN y las características citogenéticas. El tamaño del genoma en las cuatro poblaciones varió entre 3,55 y 4,30 pg. Las poblaciones resultaron diploides (2n=22). Todas las poblaciones presentaron la fórmula del cariotipo de 10 metacéntricos (m) + 1 submetacéntrico (sm). La especie presentó cariotipos simétricos y heterocromatina constitutiva CMA+/DAPI- asociados con regiones organizadoras nucleolares, que siempre se encontraban en el primer par de cromosomas m. El locus de ADNr 18-5.8-26S se encuentra en las regiones terminales del primer par de cromosomas m y el locus de 5S está adyacente al locus 18-5.8-26S. Se observó una tendencia del contenido de ADN a disminuir con el aumento de la altitud.

Environmental health collaboration: United States and Russia.

Developed nations share similar challenges to human health from commercial and agricultural chemicals that are released into the environment. Although Russia and the United States are historically distinct and unique, both countries are geographically large and economically dependent on emission-producing surface transportation. This paper describes U.S.-Russian collaborative activities that grew from a 1995 conference in Moscow that brought together environmental health investigators from both countries to discuss common concerns about the human health impact of environmental pollutants. Lead, pesticides, volatile organic compounds, and mercury were identified as contaminants of greatest concern. Collaborative studies were initiated that included collecting blood and hair samples and splitting samples for analyses in both countries, and introducing and sharing new portable blood and environmental sample analyses instruments. The findings demonstrated that hair analysis was not a good predictor of BLL and that Russian children in the first city sampled had a mean BLL of 7.7 microg/dl. Although higher than the U.S. mean, this level was below the 10.0 microg/dl CDC level of concern. This manuscript summarizes additional study results and describes their impacts on Russian policy. On-going collaborative environmental investigations are described.

[The revaccination against diphtheria and tetanus with adsorbed DT-m anatoxin of children having solid tumors in their case histories]. / Revaktsinatsiia protiv difterii i stolbniaka ADS-m anatoksinom detei, imeiushchikh v anamneze solidnye opukholi.

Data on the safety and effect of the vaccination of children with solid tumors are presented. As revealed in this study, the injection of adsorbed DT-m toxoid with reduced antigen content at the period of remission does not induce the relapse of the disease and leads to the production of specific antitoxic antibodies on the protective level. The study has shown that complex antitumor treatment does not essentially affect the formation of specific immune response, though prolonged changes in cell-mediated immunity can be observed.

Childhood Lead Poisoning in Russia: A Site-specific Pediatric Blood Lead Evaluation.

Lead poisoning in children is an international concern. Health effects vary according to a child's blood lead level. Historically, the problem of lead poisoning in Russia had been defined by analysis of hair samples. In Saratov, Russia, during the spring of 1996, the authors conducted the first evaluation of blood lead levels among Russian children. The mean blood lead level of 579 samples analyzed at the Centers for Disease Control and Prevention was 7.7 µg/dL (range 3.0 to 35.7 µg/dL). The sensitivity of hair analysis in identifying blood lead levels above 10 µg/dL was 50%. Most of the environmental samples evaluated (including water, dust, paint, and soil) were within acceptable U.S. remediation standards. Almost one-fourth of the Russian children evaluated during this site-specific investigation had blood lead levels capable of causing adverse health effects in children. Hair analysis is not an adequate method for identifying these children. Additional investigations in other Russian cities are necessary in order to determine the extent of lead poisoning in Russia's children.

[Mortality of geologists in relation to occupational activities]. / Smertnost' geologov v sviazi s osobennostiami professional'noi deiatel'nosti.

The study covered mortality among a cohort of geologists working in North-Western Russia. The cohort included 3911 geologists, geophysicists and drillers, whose life was followed during 1977-1992. The standardized relative mortality risk with all death causes equalled 0.58 in general. Risk of mortality with hypertension in the male geologists was 21.7 times higher and for the female ones-25.4 times higher than for general population. Definite dependence between the stronger effects and the longer length of service was seen. The highest standardized relative mortality risk appeared among the drillers. Occupational risk factors for geologists reliably increase risk of mortality with active rheumatism, diseases involving arteries, veins and lymphatic vessels. The male geophysicists tend to have higher incidence of prostatic cancer, and female ones-higher incidence of uterine carcinoma.

[Mortality of people residing near electric power supply line with voltage of 500 kV]. / Smertnost' naseleniia, prozhivaiushchego vblizi énergoob"ekta élektroperedachi napriazheniem 500 kilovol't.

The epidemiologic study covered causes and levels of mortality in the settlement situated near electric power supply line (voltage is 500 kV). The work used retrospective cohort method adjusted for evaluation of mortality in general population. The study revealed no higher mortality risk with all the causes totally and with leading causal groups under influence of high frequency electromagnetic fields. However, higher relative mortality risk with leukemia and suicide appeared statistically insignificant.

[Regional aspects of health status of the population with regard to chemical pollution of the environment]. / Regional'nye aspekty sostoianiia zdrov'ia naseleniia v sviazi s khimicheskim zagriazneniem okruzhaiushchei sredy.

The article summarises data on regional aspects associated with health state of population in connection with environmental pollution. Changes in health state of population inhabiting polluted territories are assessed through wide variety of parameters, in accordance with special Criteria. Notions are that no adequate investigations cover influence of environmental factors on infants and children mortality, only few works deal with evaluation of toxic chemicals in human biologic material.

[Mortality of personnel operating electric power objects with 500 kV voltage]. / Smertnost' personala, osushchestvliaiushchego ékspluatatsiiu énergoob"ektov napriazheniem 500 kV.

The retrospective cohort study covered causes and mortality levels among the staffers working at 6 objects of power supply line (voltage of 500 kV) in Vladimir, Gorky, Rjazan, Ulyanovsk and Lipetsk regions. The mortality in general and concerning specific causes demonstrated no increase in connection with exposure to industrial electromagnetic fields. The relative risk of mortality with leukemia appeared to be insignificantly higher.

Evaluation of carcinogenic risk in friction product workers.

Mortality rates of two cohorts of asbestos friction product (FP) workers were studied in comparison with the population of the adjoining towns over periods of 20 and 40 years respectively. The second cohort was subdivided into 3 subcohorts exposed to chrysotile asbestos (CA), vulcanization and/or polymerization vapours and gases (VPGV) and asbestos bakelite (AB) or asbestos rubber (AR) dusts. In the first cohort no deaths from lung cancer were recorded, even though the total tumour mortality was higher than in the general population. In the second cohort an excess tumour mortality was observed in the first subcohort for stomach cancer only. In the other two subcohorts the expected rates were higher for all the tumour sites. Following intraperitoneal injection of CA, AB and AR dusts, malignant tumours developed in 31.5% of the rats which received CA, and in about 10% of the rats which were injected with AB and AR dusts. Also, the mean longevity of CA-treated animals was significantly lower than in the other two groups. Thus, the carcinogenic risk was real in the group of FP production workers with significant CA exposure only.

[Concept of risk in epidemiological studies]. / Poniatie riska v épidemiologicheskikh issledovaniiakh.

Risk is defined as probability of disease within the stated period of time. The concepts of relative risk, difference of risks, standardized relative risk and others conventional in epidemiological and hygienic research are given.

[Epidemiology of chronic, precancerous and oncologic diseases in workers of asbestos and cement industry]. / Epidemiologiia khronicheskikh, fonovykh, predopukholevykh i onkologicheskikh zabolevanii v proizvodstve asbestotsementnykh izdelii.

Hygienic, clinical and epidemiologic screening was performed in staff of asbestos and cement goods production enterprise. Various dystrophic processes of pharynx and nasal cavity appeared to prevail among upper respiratory tract diseases. Average exposure to dust during 22 years at the stated production can lead to asbestosis 0-I stage, average exposure during 20.5 years can result in dust bronchitis and occupational allergic dermatosis can result from average exposure to dust during 21 years. Retrospective cohort study of mortality within 1949-1988 failed to find oncologic risk in workers engaged into asbestos and cement goods production higher than in general population.

[Clinical and epidemiologic evaluation of carcinogenic pollution in the wood-processing industry]. / Kliniko-épidemiologicheskaia otsenka kantserogennoi opasnosti derevo obrabatyvaiushchego proizvodstva.

Hygienic, clinical, epidemiologic studies in primary woodworking and chipboard production workers showed that exposure to occupational hazards (wooden dust, formaldehyde and other chemicals of wooden origin) results in frequent allergy and irritation of upper respiratory tract and skin. High oncologic risk among woodworking production employees assigns the industry to a group with oncologic jeopardy. MAC for wooden dust should be corrected taking into account the chemicals (phenol, formaldehyde, furans et al.) content.

[The results and outlook of a clinico-epidemiological study of the problem of the carcinogenic hazard in industry]. / Itogi i perspektivy kliniko-épidemiologicheskogo izucheniia problemy kantserogennoi opasnosti na proizvodstve.

Much attention is paid to clinical and epidemiological aspects of carcinogenic hazards in the production of asbestos textile, asbestos cement, friction, graphite and furniture goods. "Dose-response" relationship in exposure to occupational carcinogens was studied, criteria of occupational malignant neoplasma appurtenance were worked out, role of carcinogenic factors in malignant tumors of rare localisations was shown, signs of carcinogenic aerosols effects described and prophylactic measures suggested.

[The epidemiological assessment of the "dose-response" relationship in the hygienic regulation of asbestos-containing dusts]. / Epidemiologicheskaia otsenka zavisimosti "doza--otvet" pri gigienicheskom reglamentirovanii asbestsoderzhashchikh pylei.

"Dose-response" dependence worked out by American scientists helped to reveal the linear dependence between carcinogenic risk factor, asbestos containing dust, and lung cancer formation, use it for basing the new MAC for asbestos containing dust taking into account the oncologic security.

The age-dependent risk of postvaccination complications in vaccinees with smallpox vaccine.

The use of vaccinia virus in recombinant systems may result in the occurrence of complications observed following smallpox vaccination. The results are presented of a large survey carried out in the USSR between 1968 and 1979. High complication rates are reported, particularly in older primary vaccinees; for example, there were 312.5 cases of neurological complications per million in those aged greater than or equal to 5 years. The author concludes that this factor will limit the use of vaccinia virus in recombinant technology.