Lifestyle modifications in the prevention and treatment of hypertension.

OBJECTIVE: To present an objective, evidence-based review of the current literature on the role of lifestyle factors in hypertension. METHODS: We discuss the reported roles of obesity and overweight, nutritional factors, alcohol, physical activity, and smoking in the prevention and treatment of hypertension. RESULTS: For all age-groups and in both sexes, cross-sectional and prospective studies have shown a direct strong relationship between weight and blood pressure. In general, overweight is associated with a twofold to sixfold increase in the risk of developing hypertension. Clinical trials have proved that weight loss is effective in the primary prevention of hypertension as well as in the reduction of both systolic and diastolic blood pressure in patients with normal or high blood pressure. A decreased intake of dietary sodium has been demonstrated to have a hypotensive effect, both alone and as an adjunctive measure to pharmacologic therapy. Although no consensus currently exists about the role of potassium intake in prevention or control of hypertension, some studies support the protective value of high intake of potassium. A consistent relationship has been noted between consumption of alcohol and increased blood pressure, and reduced intake of alcohol has been shown to decrease blood pressure significantly. An inverse relationship exists between blood pressure and physical activity, independent of overweight or obesity. Moreover, increased physical activity helps lower both systolic and diastolic blood pressure. In a study of the effect of smoking and use of smokeless tobacco in healthy middle-aged men, ambulatory diastolic blood pressures were increased in both smokers and smokeless tobacco users in comparison with nonusers. CONCLUSION: Ample evidence supports the beneficial effects of healthful lifestyle modifications in the prevention and management of hypertension. Therefore, physicians should be motivated to provide guidance to the population relative to lifestyle practices that can help prevent and control hypertension.

Immunoquantitative analysis of artemisinin from Artemisia annua using polyclonal antibodies.

Artemisinin was derivatized to dihydroartemisinin carboxymethylether in three steps, without disturbing the peroxide bridge, and then linked to either thyroglobulin (TGB) or bovine serum albumin (BSA). The artemisinin-TGB and -BSA conjugates were injected in female New Zealand rabbits but only the artemisinin-TGB conjugate generated polyclonal antibodies. An enzyme-linked immunosorbent assay (ELISA) was developed and the specificity of the antibodies was confirmed by comparison with pre-immune serum and by competitive assays using different dilutions of artemisinin standards. Although anti-artemisinin antibodies cross-reacted with artemisitene and dihydroartemisinin at all dilutions used, cross-reaction with deoxyartemisinin, artemisinic acid, and arteannuin B occurred only at high concentrations. ELISA successfully detected artemisinin from crude extracts in concentrations as low as 1.5 ng ml-1; and was epsilon 400-fold more sensitive than the HPLC-EC. The ELISA successfully detected and quantified artemisinin in different organs of greenhouse-grown plants and in eight clones of Artemisia annua grown in tissue culture but artemisinin was overestimated owing to cross-reactivity of the antibodies with artemisinin-related compounds present in the samples. Despite overestimation of artemisinin content, the correlations between ELISA and HPLC-EC were r = 0.92 when samples were diluted 100 times, and r = 0.90 when samples were diluted 500 times, indicating that ELISA is a potential tool for screening large A. annua populations.

Relationship of artemisinin content of tissue-cultured, greenhouse-grown, and field-grown plants of Artemisia annua.

Artemisinin content of Artemisia annua L. plants grown under long days in a greenhouse was highly correlated (r = 0.931** and 0.954**, P = 0.01) with the same clones grown under long days in the field. The correlation of artemisinin content of clones grown in long days in tissue culture and in the greenhouse was r = 0.502*. Correlation of artemisinin content of tissue-cultured clones obtained two years apart was r = 0.61**. Broad-sense heritability estimates for artemisinin production based on vegetatively propagated clones derived from a random-mating population and grown in the greenhouse and field varied from 0.91 (greenhouse, individual basis) to 0.98 (combined greenhouse and field, family basis). These results indicate that genetic progress can be expected from intercrossing high artemisinin clones selected in the greenhouse under long days.

Developmental studies of Artemisia annua: flowering and artemisinin production under greenhouse and field conditions.

Cuttings of a clone of A. annua L. (Asteraceae), grown under 16 h photoperiod for 55 days were transferred to six photoperiod treatments in the greenhouse. Under short photoperiods (8, 10, or 12 h), plants flowered after two weeks; plants under long photoperiods (16, 20, or 24 h) remained vegetative until termination of treatment after 10 weeks. When plants grown under long photoperiod treatments were transferred to 8-h photoperiod, flowering occurred 2 weeks later. Flower induction in plants grown under field conditions occurred when the photoperiod was determined to the 13.3 h. Artemisinin levels in all studies were found to be highest at anthesis. Artemisinin content was 4- to 11-fold higher in inflorescences than in leaves.

Changes in nucleus, nucleolus and cell size accompanying somatic embryogenesis of Theobroma cacao L. I. Relationship between DNA and total protein content and size of nucleus, nucleolus and cell.

There was a linear relation between an increase in DNA content and size of nuclei, nucleoli and cells in callus and proembryos (Theobroma cacao L.). In callus the increase of DNA content was accompanied by proportional increase in nuclear size whereas in proembryos the increase in nuclear size did not match the increasing amount of DNA. The stimulation of embryogenesis by 10(-2) mg/l 2,4-D was associated with increase in nuclear and nucleolar size and with decrease in cell sizes. Inhibition of embryogenesis by 1.0 mg/l 2,4-D+10% coconut water did not change nuclear size, but increased cell size in relation to the control. The process of embryo formation was accompanied by changes in relationship between nuclear, nucleolar and cell size and the total (DNFB-stained) proteins content. In callus as well as in proembryo the increase in total protein content in nucleus was not equivalent to the increasing sizes of nuclei which leads to the decrease in nuclear protein concentration. Similar situation was observed for nucleoli. Differences were found in the concentration of cytoplasmic proteins between the callus and proembryo cells. The stimulation of embryogenesis by low concentration of 2,4-D resulted in decrease in concentration of total proteins in nuclei and nucleoli and the increase in cytoplasm.

Changes in nucleus, nucleolus and cell size accompanying somatic embryogenesis of Theobroma cacao L. II. Relation between basic protein content and size of nucleus, nucleolus and cell.

Embryo formation from callus of Theobroma cacao L. was associated with the changes in relationship between nuclear, nucleolar and cell sizes and the content of basic proteins (FG-FCF-stained). Together with the increase in nuclear size of callus and proembryo cells the increase in the amount of nuclear basic proteins was found. In the callus cells the increase in nucleolar protein content exceeded that in nucleolus size, which led to the rise in basic protein concentration in the nucleolus. However, in the early stage of embryogenesis the increase in protein content was not so marked as that in callus, which indicated that embryogenesis involved a decrease in concentration of nucleolar basic proteins. Differences between callus and proembryo cells were also observed in the concentration of cytoplasmic proteins. The increase in size of callus cells was the same as the increasing amount of cytoplasmic proteins. In proembryos a significant increase in cell size was accompanied by only slight changes in cytoplasmic proteins. The stimulation of embryogenesis by 2,4-D resulted in an increase of nuclear concentration of basic proteins in proembryos. The intensification of embryogenesis involved the decrease of the concentration of nucleolar proteins together with the increase in concentration of basic cytoplasmic proteins.

Energy conversion in bull sperm flagella.

With the use of a specially developed incubation chamber the rates of motility, respiration, and fructolysis were measured simultaneously on semen samples. By inhibiting the respiration with antimycin A, and/or the fructolysis with 2-deoxyglucose, the rates of each of the two ATP-producing pathways could be reduced independently. In this way the ratio of the amount of free energy produced by respiration and by fructolysis could be varied at will from 1 to 0. In uninhibited preparations approximately 75% of the free energy derives from respiration, and 25% from fructolysis. By the use of the absolute rates of respiration, fructolysis, and motility, the efficiency of the conversion of free energy into hydrodynamic work was calculated. After correction for the decay of the preparation during the experiment, this conversion efficiency was found to be 30-45% lower for free energy from respiration than for free energy from fructolysis. The difference in distribution of the enzymes for fructolysis and respiration over the flagellum was ruled out as the cause of the efficiency difference. The respiration could be 70% inhibited by oligomycin. It is concluded that approximately one-third of the free energy from respiration is used for maintenance of the mitochondria.