Genetic and environmental factors in human osteoporosis

Osteoporosis is a common disorder, with prolongation of the average life span it has become a major public health problem. On the formation of osteoporosis genetic factors and environmental influences could play a role then it is considered as multi-factorial. Because a variety of functions to affect susceptibility to the formation of osteoporosis VDR-F, VDR-B, COL1A1, ESR1X, ESR1P and CTR are thought to be candidate genes. In this study, the aim is to investigate the relationship between these genes polymorphism and bone mineral density (BMD) values of lumbar vertebra and femoral neck in 188 Turkish people. Lumbar spine and femoral neck BMD of the individuals included in the study were measured by the dual X-ray absorptiometry method. The genotyped polymorphisms by simultaneous amplification of five regions of the genome, containing six SNPs of interest and detecting the amplified product, using the kit MetaBone Clinical Arrays^?. Statistical analyses indicated that; VDR-B gene polymorphisms major (P?=?0.013), VDR-F polymorphisms have minor (P?=?0.082) effect on femur BMD. None of the other genes has any significant effect on spinal BMD. Patient age, body mass index and diet has significant effect on femoral and spinal BMD. Osteoporosis is a multi-factorial disease and many genetic and non-genetic risk factors contribute to the development of osteoporosis. Early detection of a genetic predisposition to osteoporosis should allow delay and/or limit unfavorable changes in the bone tissue.     

Viruses as environmental mutagenic factors

Injections into Drosophila melanogaster males of 9 DNA- and RNA-containing viruses non-infectious for this insect, proved that all of them are highly mutagenic, inducing numerous gene mutations or microdeletions but no gross chromosome rearrangements. Relatively few specific loci are affected, they vary per virus, and the mutation rate for such a locus is extraordinarily high. These peculiarities of the mutagenic action of viruses closely resemble those of the mutagenic action of exogenous non-viral DNA earlier studied by the author and his co-workers. It was shown that the mutagenic element of a virus is its nucleic acid; viral proteins completely lack mutagenic properties. Virus-induced gene mutations are probably due to insertions of fragments of viral DNA (or cDNA) into the host chromosomes; at least some of these mutations are capable of transpositions and reversions. On the other hand, chromosome aberrations which arise in virus-infected cells are evidently produced secondarily by pathological disturbances of metabolic processes in the infected cells. Our results and literature data lead to the conclusion that a significant share of hereditary defects in man might be caused by viruses, even by those apathogenic for humans, particularly by attenuated live viral vaccines. It is, therefore, important to work on the creation of purely proteinaceous viral vaccines free from nucleic acids and thus genetically safe. The hazards of viral mutagenesis should also be kept in mind when preparing recombinant DNA molecules used in genetic engineering.     

Leaf shape: genetic controls and environmental factors

In recent years, many genes have been identified that are involved in the developmental processes of leaf morphogenesis. Here, I review the mechanisms of leaf shape control in a model plant, Arabidopsis thaliana, focusing on genes that fulfill special roles in leaf development. The lateral, two-dimensional expansion of leaf blades is highly dependent on the determination of the dorsoventrality of the primordia, a defining characteristic of leaves. Having a determinate fate is also a characteristic feature of leaves and is controlled by many factors. Lateral expansion is not only controlled by general regulators of cell cycling, but also by the multi-level regulation of meristematic activities, e.g., specific control of cell proliferation in the leaf-length direction, in leaf margins and in parenchymatous cells. In collaboration with the polarized control of leaf cell elongation, these redundant and specialized regulating systems for cell cycling in leaf lamina may realize the elegantly smooth, flat structure of leaves. The unified, flat shape of leaves is also dependent on the fine integration of cell proliferation and cell enlargement. Interestingly, while a decrease in the number of cells in leaf primordia can trigger a cell volume increase, an increase in the number of cells does not trigger a cell volume decrease. This phenomenon is termed compensation and suggests the existence of some systems for integration between cell cycling and cell enlargement in leaf primordia via cell-cell communication. The environmental adjustment of leaf expansion to light conditions and gravity is also summarized.     

Psoriasis: familial predisposition and environmental factors.

In a survey for coronary risk factors 14 667 adult men and women answered a questionnaire on lifestyle, diet, and health, including whether they had psoriasis. The overall prevalence of psoriasis was 4.79% in men and 4.85% in women. The data showed an increasing incidence of psoriasis. The association with family history, lifestyle, diet, and health was explored by multiple regression analysis. The occurrence of psoriasis in first degree relatives contributed to more than 90% of the explained variance for both sexes. Of the other variables, only the positive association with rheumatoid arthritis was significant in both sexes. It is concluded that the examined environmental factors have only minor effects on the prevalence of psoriasis.     

Nutritional and environmental factors affecting pigmentation inTrichophyton rubrum

Summary 1. Pigmentation inTrichophyton rubrum appears to be dependent upon tyrosine and phenylalanine (as precursors), carbohydrate (primarily as an energy source), and oxygen.2. Cysteine and methionine inhibit the growth ofT. rubrum in a minimal medium. L-sorbose also inhibits the growth of this organism, even in a complete medium.3.T. rubrum apparently synthesizes all of the vitamins required for growth and pigmentation.4. At certain concentrations of ascorbic acid, it is possible to distinguish between the pigmentogenic and growth processes ofT. rubrum.5. Sunlight suppresses growth and pigmentation inT. rubrum.     

Genetic and environmental factors in cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is an interesting example of multifactorial disease, where both genetic and environmental factors are involved and interact. Major risk factors include a personal and familial history of melanoma, cutaneous and pigmentary characteristics, sun exposure and reactions to sun exposure. Phenotypic risk factors are likely to be genetically determined. Two high-risk melanoma susceptibility genes-CDKN2A and CDK4-have been identified to date, with a third gene p14(ARF) also being suspected of playing a role. Other high-risk genes are anticipated by the existence of 9p21-unlinked families. A low-risk melanoma-susceptibility gene-MC1R-has also been identified. Current studies aim to identify other susceptibility genes as well as to determine the respective contributions and interactions of the various genetic and environmental factors of CMM and associated phenotypes.     

Genetic and environmental factors in cancer and neurodegenerative diseases

The aim of this review is to summarise the recent findings in the fields of carcinogenesis and neurodegenerative diseases, the both disorders are characterised by the contribution of different factors including the inheritance of mutated genes, and the exposure to endogenous or exogenous agents during the life. We first analysed the causative genes until now discovered in both processes, then we focused our attention on the role of environmental exposure, susceptibility factors, oxidative stress, apoptosis and aging to the development of such disorders. The genotype at a particular locus may account for an inter-individual susceptibility that can both increase or decrease the risk to develop the pathology especially after the exposure to environmental agents. The mechanism of apoptosis, that is an excellent strategy in order to eliminate damaged cells, seems to be lost during carcinogenesis, while it seems to be involved in the neuronal death in a lot of neurodegenerative disorders. Oxidative stress can both lead to DNA mutations or to the formation of damaged proteins, so being an important risk factor for the initiation and the progression of a disease: in fact it may be one of the causes or can arise as a consequence of a damage caused by other factors increasing then the first damage. It is well established that carcinogenesis is a multi-step process caused by series of successive mutations occurring into a cell and conferring to this cell a growth advantage, so that age is the largest risk factor for cancer in humans. Pathophysiology of neurodegenerative diseases is complex and likely involves multiple overlapping and perhaps redundant pathways of neuronal damage, characterised by the generation of anomalous proteins, often due to mutations in the corresponding gene, and by their subsequent accumulation into or outside specific areas of the brain.     

Postpartum aggression in mice: Experiential and environmental factors

Six experiments were conducted to assess the influence of duration of lactation, the presence of young, and the stimulus characteristics of intruder animals upon postpartum aggression of mice. The first experiment showed that postpartum aggression toward conspecifics was highest between Day 3 and Day 8, declined between Day 9 and Day 14, and was present toward males but absent toward females between Day 15 and Day 21 of the lactation period. Experiment 2 showed that lactating mice rarely attacked conspecifics to which they had been previously exposed but would readily attack strangers. Experiment 3 and 4 demonstrated that lactating animals never attacked intruders when tested 5 hr after pup removal. However, placement of young behind a wire partition in the home-cage for 5 hr or replacement of the offspring for as little as 5 min following 5 hr of separation restored postpartum aggression. The fifth experiment showed that 1- and 10-day old intruders were seldom attacked while intense aggression was directed against 14- and 20-day old intruders. Finally, Experiment 6 demonstrated that 14-day old intruders whose hair was removed were rarely attacked.     

EPT昆虫群落分布与环境因子的相关性

为了研究EPT昆虫与水环境因子的相关性,在2006年6-7月和9-10月分季在丹江口水库两条主水源河流上分设5个采样点,对EPT昆虫和水质采样检测。结果共检测到EPT昆虫780头,为12科16种(或种团),水质理化指标7项。简单相关分析与复相关分析都表明,氮浓度、磷浓度、生化需氧量与EPT昆虫密度呈极显著正相关（P<0.01）,与EPT昆虫的种数呈极显著负相关（P<0.01）。典型相关分析表明,EPT昆虫组与环境因子组有极显著的正相关（P<0.0001）,EPT昆虫组主要目为蜉蝣目和襀翅目,环境因子组主要因子为氮浓度、磷浓度、生化需氧量。由此得出：即使在低污染、低营养程度的水环境下,EPT昆虫与环境因子也表现出群体的显著相关性,环境因子对EPT昆虫分布有重要影响。     

Influence of cultural and environmental factors on breast-feeding.

A study was undertaken at hôpital Sainte-Justine, Montreal, to determine the factors that influence the choice of feeding method for infants and the duration of breast-feeding. The factors that most clearly distinguished the mothers who breast-fed were lifestyle, education and conditioning to the parental role; those who nursed successfully for a long time were well motivated, well educated, supported by their family, especially the husband, and the La Leche League, and were of an economic status such that it was not necessary for them to return to work soon after delivery. Although the breast-fed babies were more fussy, they were healthier and received fewer drugs.     

Genome size and environmental factors in the genus Pinus

Nuclear 1C DNA content in haploid megagametophyte tissue of 18 North American and one exotic Pinus species was determined using scanning microspectrophotometry. The nuclear DNA content in root meristematic cells of Zea mays L. ssp. mays, inbred line Va35 (4C = 10.31 pg) was used as a standard. DNA content measured by microspectrophotometry was verified using laser flow cytometry with two additional standards, Hordeum vulgare cv. Sultan (2C = 11.12 pg) and P. eldarica (2C = 47.30 pg). DNA values obtained by both methods were significantly correlated (r = 0.987). The 1C nuclear DNA content ranged from 21 pg to 31 pg. The ratio of DNA content in embryo tissue of P. eldarica to that in megagametophyte tissue was 1.72 by scanning microspectrophotometry and 1.74 by laser flow cytometry. To date, this is the most comprehensive data set available for North American Pinus species. Relationships between genome size of 18 North American Pinus species and climatic factors and indices of growth were investigated using regression and correlation analyses. Positive correlations were observed between nuclear DNA content and growth indices, minimum seed-bearing age, and seed dimensions. Strong negative correlations were observed between nuclear DNA content and two climatic factors, the lowest mean annual and monthly precipitation (excluding January) and the highest mean monthly spring air temperature. These correlations suggest that the large genome size and its variation in Pinus are adapted responses to the habitats of these species.