Reduction of ferric green rust by Shewanella putrefaciens

AIMS

To reduce carbonated ferric green rust (GR*) using an iron respiring bacterium and obtain its reduced homologue, the mixed Fe(II)-Fe(III) carbonated green rust (GR).

METHODS AND RESULTS

The GR* was chemically synthesized by oxidation of the GR and was incubated with Shewanella putrefaciens cells at a defined [Fe(III)]/[cell] ratio. Sodium methanoate served as the sole electron donor. The GR* was quickly transformed in GR (iron reducing rate = 8.7 mmol l(-1) h(-1)).

CONCLUSIONS

Ferric green rust is available for S. putrefaciens respiration as an electron acceptor. The reversibility of the GR redox state can be driven by bacterial activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work suggests that GRs would act as an electronic balance in presence of bacteria. It provides also new perspectives for using iron reducing bacterial activity to regenerate the reactive form of GR during soil or water decontamination processes.

Insights into a plasma membrane signature

The plasma membrane (PM) is an organized biological system that serves as a structural barrier and communication interface with the extracellular environment. Many basic questions regarding the PM as a system remain unanswered. In particular, we do not understand the scope of similarity and differences in protein expression at the PM. This study takes an initial step toward addressing these questions by comparing the PM proteomes of fibroblasts and mammary carcinoma cells. Three sets of proteins were revealed by the study. The first set comprises between 9 and 23% of all proteins at the PM and appears to be common to both fibroblasts and mammary carcinoma. A second group of proteins, comprising approximately 40% of the proteins at the PM, is tightly linked to cell lineage. The third set of proteins is unique to each cell line and is independent of cell lineage. It is reasonable to hypothesize then, that this third group of proteins is responsible for unique aspects of cell behavior. In an effort to find proteins linked to the metastatic phenotype, we identified several proteins that are uniquely expressed at the PM of the metastatic MDA-MB-435 cells. These proteins have functions ranging from cell adhesion to the regulation of translation and the control of oxidant stress.

A method for application of samples to matrix-assisted laser desorption ionization time-of-flight targets that enhances peptide detection

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry has become a fundamental tool for the identification and analysis of peptides and proteins. MALDI-TOF is well suited for the analysis of complex biological mixtures because samples are crystallized onto a solid support that can be washed to remove contaminants and salts prior to laser desorption. A number of approaches for immobilizing samples onto MALDI targets have been put forth. These include the use of different chemical matrices and the immobilization of samples onto different solid supports. In large part though, the preparation of MALDI targets has been an empirical exercise that often requires a unique series of conditions for every sample. Here, a simple method for the application of peptide mixtures onto MALDI targets is put forth. This method differs because peptides are added directly to a sample of nitrocellulose dissolved in acetone, allowing them to interact in solution-phase organic solvent. This solution-phase mixture is then spotted to the MALDI target and evaporated, forming a homogenous solid surface for laser desorption. This procedure is robust, highly sensitive, tolerant to detergents, and easily learned. In our hands, the method provides as much as a 10-fold enhancement to the detection of tryptic peptide fragments derived from in-gel digests.

Estradiol activates p60src, p53/56lyn and renatured p50/55 protein tyrosine kinases in the dog prostate

Protein tyrosine kinases (PTKs) are key enzymes implicated in signal transduction pathways regulated by growth factors (GFs). We have previously shown by immunohistochemistry that the level of phosphotyrosine (pY) proteins is increased in prostatic basal epithelial cells following estrogen treatment in castrated dogs. In this study, we investigated if this treatment increases the level and distribution of prostatic PTK activity, and more specifically, if it alters the expression and/or activity of the Src family members p60src and p53/56lyn. Prostates from normal and hyperplastic dog prostates, as well as those from castrated dogs treated with androgens, were also examined. Only the glands obtained from estrogen-treated dogs had a significantly increased total and specific PTK activity, observed uniquely in the particulate extract, as compared to the other types of prostates studied. In addition, this increased activity was correlated upon gel filtration chromatography with the presence of an additional peak of activity with an apparent molecular weight of 130 kDa, which was absent in other prostate fractions presenting only 50 kDa peaks. Using antibodies, we demonstrate that active p60src and pp53/56lyn kinases accounted for 81% of the activity in this 130 kDa peak. On the other hand, in situ renaturation also revealed the presence of still uncharacterized 50/55 kDa PTKs in the 130 kDa peak. Altogether, these findings raise the possibility that these PTKs contribute to the transmission of mitogenic signals originating directly or indirectly from estrogen stimulation of the basal cell layer of the prostate.

Regulation and activation of focal adhesion kinase and paxillin during the adhesion, proliferation, and differentiation of prostatic epithelial cells in vitro and in vivo

Focal adhesion kinase (pp125FAK) is a nonreceptor protein tyrosine kinase transducing signals initiated through integrin activation triggered by cell/extracellular matrix (ECM) interactions. To examine its role in epithelial cell adhesion, proliferation, and differentiation, we have studied pp125FAK expression, activity, and association with paxillin in two canine prostate models in which these functions can be selectively regulated: in vitro by vitronectin (VN) and serum factors, and in vivo by sex steroids. Kinetic studies revealed that the adhesion and spreading of prostatic epithelial cells in primary culture was regulated by serum VN and a natural ECM containing VN produced by prostate cells. While barely detectable in freshly isolated prostate cells, proliferating cells, after 72 h in culture, expressed higher levels of FAK mRNA (8-fold), pp125FAK (50-fold), and paxillin (50-fold). In prostate cells with a reduced growth rate after 2 weeks in culture, we observed a decrease in pp125FAK (4-fold) and its transcript (3-fold), but no change in paxillin. In vivo, both proteins were undetectable in normal and hyperplastic glands composed of a well differentiated epithelium, and in prostates restored by androgen supplementation. In contrast, pp125FAK and paxillin were up-regulated by androgen deprivation (castration) and further increased by estrogen treatment, which yielded metaplastic prostates mostly composed of proliferating basal epithelial cells. Moreover, both proteins were constitutively phosphorylated on tyrosine in the metaplastic prostate, as well as in proliferating cultured cells. Together, these results demonstrate that pp125FAK expression is regulated at the protein and mRNA levels and forms active signaling complexes with paxillin when epithelial cells in contact with ECM proteins are induced to proliferate in vivo and in vitro.

Phosphotyrosine antibodies preferentially react with basal epithelial cells in the dog prostate

PURPOSE

Considering the hypothesis that androgen-independent but growth factor dependent epithelial cell division may be important in the development and progression of prostate cancer and that protein tyrosine kinases and phosphotyrosine protein phosphatases are key enzymes modulating the levels of specific phosphotyrosylated proteins implicated in several growth factor regulated signal transduction pathways, our aim was to study the cellular distribution of phosphotyrosine proteins in normal and hyperplastic dog prostates as well as in those of castrated dogs supplemented with either androgens or estrogens in order to modify the relative proportion of basal versus secretory epithelial cells.

MATERIALS AND METHODS

Following the determination of optimal conditions to specifically detect phosphotyrosine proteins by a rabbit polyclonal antibody directed against phosphotyrosine, immunohistochemistry was performed on prostate tissue sections from these experimental animals. In addition to morphological criteria, an antibody to high molecular weight cytokeratins and antisera against arginine esterase were used to selectively identify basal and secretory cells. Since prostatic acid phosphatase may be involved in the local regulation of phosphotyrosine proteins, its distribution was also evaluated with a human prostatic acid phosphatase antiserum.

RESULTS

In all prostatic tissues examined, basal epithelial cells were preferentially and specifically stained with antiphosphotyrosine. The staining intensity per basal cell was highest in the estrogen-supplemented dogs. In addition, basal cells were numerically increased and all were highly immunoreactive for high molecular weight cytokeratins. In prostates displaying a well-differentiated glandular epithelium, the number of positive basal cells and their staining intensity varied in the following order: normal < hyperplastic < androgen-supplemented dogs. At all times, the levels of phosphotyrosine proteins in prostatic acid phosphatase and arginine esterase positive cells (secretory) remained low. Fibroblasts and smooth muscle cells were unreactive to antiphosphotyrosine, even though estrogen supplementation increased the prostatic stromal volume.

CONCLUSIONS

The preferential localization of phosphotyrosine proteins in basal cells, their increased level per cell and the number of positive cells in the different experimental animals support the concept that basal cells represent the stem cells of the prostate. The sex steroid-mediated up-regulation of protein phosphorylation on tyrosine residues in these cells suggests that their proliferation is likely to involve growth factor regulated signal transduction pathways. In this respect, the lack of maturation of basal cells and the differentiation of secretory cells induced by androgen deprivation, combined with estrogen stimulation, favors the activation of these pathways and cell growth. On the other hand, the activation of glandular cell differentiation and the increase of stromal volume do not alter the threshold level of protein tyrosine kinase and phosphatase activities in secretory cells, fibroblasts and smooth muscle cells.

Blood pressure responses to a progressive step test in normotensive males and females

This study documents the blood pressure responses to a progressive step test adapted from the Canadian Aerobic Fitness Test (CAFT). Subjects were administered the first five stages of the CAFT in a progressive and discontinuous manner. Mean heart rate, SBP, and delta SBP increased linearly with exercise intensity, while mean diastolic blood pressure remained stable. The variables that contributed most to delta SBP (Stage 3) in males were age and degree of participation in physical activity, and in females the variables were body weight and degree of participation. Criteria for the detection of an exaggerated (mean delta SBP + 1 SD) and highly exaggerated (mean delta SBP + 2 SD) SBP response were defined. Resting normotensive individuals who demonstrate an excessive exercise blood pressure response seem to do so at the lowest levels of stepping intensities. This step test protocol appears to be a useful and practical procedure for assessing the exercise blood pressure response in higher risk individuals.

Comparison of novel synthetic peptide-based DETECT-RUBELLA enzyme immunoassays with Enzygnost and IMx for detection of rubella-specific immunoglobulin G

Enzyme immunoassays (EIAs) using synthetic peptides SP-E1 and SP-E1E2 (DETECT-RUBELLA [Bio-Chem]) were compared with two viral lysate-based EIAs (Enzygnost [Behring] and IMx [Abbott]) for the detection of rubella virus-specific immunoglobulin G antibodies. Sensitivities of 94.7, 100, 98.6, and 100% and specificities of 100, 97.4, 100, and 73.7% were found for the SP-E1, SP-E1E2, Enzygnost, and IMx EIAs, respectively.

Electrocardiographic responses to jogging in middle-aged and older men and women

Recent jogging-related sudden deaths rekindled the concern among health professionals as to the hazards of strenuous exercise. The purpose of this study was to evaluate the extent of rhythm disturbances and myocardial ischemia in older men and women during a typical strenuous jogging session. Twenty-two members of a local jogging club (11 men and 11 women) between the ages of 50 and 66 years participated in the study. The CardioData PR3/ST monitor was employed to record heart rate, rhythm disturbances, J point and ST slope during the course of the run. The men ran a 10 km run and the women a 6 km run at a competitive pace. The mean maximal heart rate during the run was 170 +/- 15 beats/min for the males and 176 +/- 14 beats/min for the females. The mean J point during the run was -3.39 +/- 1.21 mV for the males and -2.97 +/- 0.96 mV for the females. Females showed a significantly lower mean ST slope (3.95 +/- 0.91 mV) during the run than the males (5.56 +/- 1.37 mV, p < 0.05). A number of episodes of premature ventricular beats, both uni- and multifocal, were observed. Exercise testing of sufficient intensity is recommended to detect those persons susceptible to developing serious arrhythmias during strenuous exercise.

Reactive hypoglycemic coma due to insulin autoimmune syndrome: case report and literature review

Recurrent episodes of postprandial hypoglycemic symptoms culminated in hypoglycemic coma in a hypertensive but otherwise healthy man while he was taking hydralazine. The patient was found to have an extreme elevation in the immunoreactive insulin level, leading to the discovery of insulin antibodies in the absence of prior exposure to exogenous insulin. Negative results of an anatomic study of the pancreas and an inability to reproduce hypoglycemia during a prolonged fast helped to exclude insulinoma. In contrast, symptomatic hypoglycemia developed in response to oral glucose loading and was associated with an elevation in total and free insulin as well as C-peptide levels. The patient was diagnosed with insulin autoimmune syndrome, which, although a common source of hypoglycemia in Japan, has been well documented in only 15 cases from other countries. HLA typing revealed the patient to be positive for groups Cw4 and DR4, a combination that has been preliminarily associated with insulin autoimmune syndrome in Japan. Unlike the majority of cases previously reported, this patient had no clinical or serologic evidence of an underlying autoimmune disorder and had not been exposed to drugs containing sulfhydryl groups. This case adds to the world literature on insulin autoimmune syndrome, lends support to a postulated HLA association, and documents the presence of insulin autoantibodies in the absence of another underlying autoimmune disorder.

Relation between cardiorespiratory fitness and selected risk factors for coronary heart disease in a population of Canadian men and women

OBJECTIVE

To determine the relation between cardiorespiratory fitness, as determined with the Canadian Aerobic Fitness Test (CAFT), and selected risk factors for coronary heart disease (CHD) in a Canadian population.

DESIGN

Cross-sectional study. On the basis of age-specific and sex-specific national percentile scores, subjects were classified as being in the low-fitness, moderate-fitness or high-fitness category according to maximum oxygen consumption (VO2 max) predicted from performance on the CAFT.

PARTICIPANTS

A total of 4082 male and 1205 female Canadian federal public servants aged 30 to 59 years who participated in a voluntary fitness testing program between 1984 and 1991.

OUTCOME MEASURES

Body composition (body mass index, triceps skinfold thickness, sum of four skinfold measurements, predicted percentage of body fat and waist-hip ratio), blood lipid levels (total cholesterol, triglycerides, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol and ratio of total cholesterol to HDL-C) and hemodynamic measurements (heart rate and blood pressure at rest and during exercise and predicted VO2 max).

MAIN RESULTS

For both men and women the mean anthropometric measurements, blood lipid levels and blood pressure measurements at rest and after exercise were significantly associated with fitness category (p less than 0.05).

CONCLUSIONS

In both men and women a higher level of aerobic fitness, as defined by VO2 max predicted from performance on the CAFT, is associated with a more favourable CHD risk profile. The results support the use of VO2 max predicted from performance on the CAFT as a valid procedure for classifying people according to fitness level.

Randomized 4-week exercise program in patients with impaired left ventricular function

BACKGROUND

This study was designed to determine the controlled effects of a short-term exercise rehabilitation program on patients with moderate-to-severe left ventricular dysfunction after a recent myocardial infarction.

METHODS AND RESULTS

Thirty-nine male patients 51 +/- 8 years old with a large anterior myocardial infarction less than 10 weeks old were recruited for the study. The patients were randomly assigned to either one of two training or control groups on the basis of their resting ejection fraction: training, less than 30%; control, less than 30%; training, 31-50%; or control, 31-50%. Patients were evaluated for filling pressures, radionuclide ventriculography, heart volume, echocardiography, and work capacity. Patients who underwent training participated in an intensive 4-week in-hospital exercise program, whereas the control patients were restricted to a minimal activity program. Results indicated that there were no significant improvements in resting, submaximal, and maximal hemodynamic measurements as a result of the program. Mean work capacity and peak oxygen consumption improved significantly in the less-than-30% training group but was accompanied by a significant increase in mean pulmonary wedge pressure. Resting ejection fraction improved markedly in both less-than-30% training and control patients, but ejection fraction measures were not associated with work capacity. Training did not cause further deterioration in ventricular function.

CONCLUSIONS

It was concluded that in the present study, exercise training had little or no effect on hemodynamic measurements and that the training effects achieved in patients with left ventricular dysfunction are most likely due to corrected impaired vasodilation, not necessarily to cardiac function. The importance of using a control group in this type of study and the wide interindividual variations in training responses are emphasized.

Blood pressure response to the Canadian Aerobic Fitness Test

Persons who are normotensive or borderline hypertensive at rest but who have an exaggerated blood pressure response to exercise incur a higher risk of developing sustained hypertension. Our purpose was to develop provisional norms for immediate post-exercise blood pressure responses to the Canadian Aerobic Fitness Test (CAFT) for men and women 20-69 years and to recommend threshold values for exercise hypertension. We studied 986 males and females. Blood pressure criteria for inclusion were less than 150/100 mmHg for men and less than 160/100 mmHg for women. The blood pressure values for the 3 stages of the CAFT specific to each age group and sex were appropriately summarized for each workload. An exaggerated blood pressure to exercise was defined as the mean + 1 SD while a grossly exaggerated blood pressure was defined as the mean + 2 SD. As such, the following values are recommended as criteria for the first stage of the CAFT regardless of age: Men: exaggerated response greater than or equal to 170 mmHg, grossly exaggerated, greater than or equal to 190 mmHg; women greater than or equal to 160 mmHg and 180 mmHg respectively. The delta SBP (exercise SBP minus resting SBP) at the first stage of the CAFT could also be utilized to identify persons who demonstrate an abnormal pressure response to exercise. An increase of 10 mmHg above resting diastolic pressure at any stage of exercise should also be cause for concern and counselling.

Ambulatory blood pressure and Holter monitoring during tennis play

The effect of tennis play on blood pressure, heart rate response, and rhythm disturbances was evaluated in 21 men 39 to 61 years of age (M = 49.5 +/- 6.7 yrs). A Holter monitor was utilized for continuous ECG recording during tennis play and a portable ambulatory blood pressure recorder (Spacelabs) was used to measure blood pressures and heart rates periodically during tennis matches. The results indicated that blood pressure response to tennis (singles), although an activity of moderate aerobic intensity, can exert significant increases in systolic and diastolic blood pressure even in those persons who are normotensive at rest. Excessive body weight, and particularly abdominal deposition, appears associated with an increase in diastolic blood pressure to exercise. Few heart rhythm disturbances of consequence were uncovered. A simple submaximal step test such as the Canadian Aerobic Fitness Test, with ECG monitoring, could assist in detecting those individuals susceptible to an exaggerated blood pressure response and to heart rhythm disturbances at exercise.

The effect of infused fat emulsions on reticuloendothelial function in the rabbit

The effect of the infusion of different fat emulsions (Intralipid and MCT/LCT mixtures) on the reticuloendothelial function of the rabbit has been investigated. Emulsions containing 20% dispersed triglyceride were administered over 6 h to a total of 3 g/kg body weight. The extent of blockade of the reticuloendothelial system was measured using a labelled probe in the form of technetium-99m labelled albumin microspheres. Scintigraphic and blood and organ level determinations demonstrated that all emulsions caused an impairment of reticuloendoethlial function, but this was small.

Body mass index as a discriminant function among health-related variables and risk factors

A group of 206 subjects (30-55 years) were studied with the objective of quantifying the relationships between fitness indicators (relative body weight (BMI), aerobic power, muscular endurance), health indicators and risk factors, (appraised age, cost of health services consumed, blood pressure (SBP and DBP), blood lipids (CHO and HDL), cigarette smoking). BMI was significantly correlated with the risk indicators in the male sample (.302 less than or equal to r less than or equal to .364) and in the female sample (.217 less than or equal to r less than or equal to .521). All coefficients were in the direction of the established biological assumption as concerns hazards to health. The discriminant analysis revealed that in the total group of men, 77% (p less than or equal to .001) of the subjects could be classified either in high or low BMI (greater than Q75 or less than or equal to Q25) on the basis of the scores in SBP, HDL, HDL/CHO. In the subgroup of women greater than or equal to 40 years, statistically significant classification occurred in 100% of the cases (p less than or equal to .001) on the basis of DBP, CHO, HDL/CHO, NCIG. The results indicate that BMI is a fitness determinant which is valid, convenient and easy to use in the detection of unfavorable health indices and when clinical intervention is justified.

Accuracy of ambulatory blood pressure monitoring in four exercise situations

Although ambulatory blood pressure monitoring (ABPM) is still considered in its investigational stage, the technique has become increasingly popular in recent years. The rationale for its utilization is its ability to continuously monitor blood pressure (BP) response to situational stressors occurring over the course of a 24-hour period which cannot be detected by casual measurements. In addition, ABPM eliminates the so-called white-coat auscultatory BP response. However, the accuracy of ABPM under situations which are at the measurement limits of the technical characteristics and/or capabilities of the ABPM equipment, such as in exercise situations commensurate with daily life activities, has not been fully documented. The purpose of this study was to evaluate the accuracy of the Spacelabs ABPM monitor against auscultatory (AUS) determinations in four exercise situations: walking, stair climbing, cycling and a progressive step test (modified Canadian Aerobic Fitness Test). Analyses of variance (ANOVA) were computed to determine if significant differences occurred between ABPM and AUS measurements for systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) over the resting and four exercise conditions. Results indicate that, particularly at low to moderate levels of exercise intensity, there is no statistically significant difference between ABPM and AUS measurements for SBP and HR. In 20 of the 26 resting and exercise determinations, the difference in SBP was less than 6 mmHg. For HR the variation was no greater than 4 bpm. However, there was no such agreement between ABPM and AUS measurements for DBP. As the intensity of the exercise situations increased, there was a tendency for SBP ABPM measurements to register higher readings than those obtained by AUS. The major drawback in ABPM is its sensitivity to artifacts due to arm movement. It was concluded that ABPM, such as provided by the Spacelabs instrument, can provide reasonably accurate readings of SBP and HR, particularly at low to moderate intensities of exercise while at higher exercise intensities ABPM has a tendency to provide consistently lower SBP values than the AUS measurements. DBP ABPM was totally ineffective under any of the exercise conditions chosen for this study.

Endurance vs. strength training: comparison of cardiac structures using normal predicted values

There are still disagreements concerning the adaptation of cardiac structures in relation to different training stimuli. To eliminate some of the variance due to individual differences in body surface area, we utilized a new approach based on the calculation of the percentages of each individual's normal predicted values (%NPV). We studied 46 strength (S, bodybuilders) and 57 endurance (E, runners) athletes. Left ventricular (LV) mass was 143.8 +/- 21.9 %NPV (mean +/- SD) in E vs. 134.3 +/- 23.4 %NPV in S (P less than 0.05), and LV volume was 131.0 +/- 24.0 %NPV in E vs. 120.0 +/- 25.5 %NPV in S (P less than 0.05). Moreover, the LV wall thickness-to-radius ratio did not differ from normal values in either group. From these data we conclude that 1) cardiac modifications are greater in E than S, 2) the predominant stimulus is a volume overload type in both groups, and 3) concentric LV hypertrophy may not be as prevalent in S as previously suggested.

Silent ischaemia in post-infarction patients: a 21-month follow-up study

The purpose of this study was to determine the prevalence of silent myocardial ischaemia (SMI) in post-infarction patients and to follow its clinical evolution in the course of a 21-month follow-up period. Of the 12,500 patients treated at the Klinik Roderbirken between Jan 1980 and Jun 1983 40% had angina. Three-vessel disease was documented in 61% of the 3150 subjects who had a coronary angiography. SMI identifiable on the exercise ECG was observed in 680 patients (5.4%). Sixth-three subjects (mean age 52 +/- 5.5 years) were selected and followed on the basis of stringent criteria. Prevalence of SMI at an average of 6 weeks after MI was 1/200 or 0.5% in that sample. Prognosis was good with a low mortality rate of 3.2% during the 21-month follow-up period. Factors weighing negatively on the observed SMI prognosis are the prevalence of 3-vessel disease (74%) and of pathological ejection fractions (52%) as well as the presence of ischaemia itself. Conversely, factors weighing positively on the observed SMI prognosis are the reasonably high exercise tolerance level (102 +/- 32 W), the low arrhythmogenic potential (73% less than or equal to Lown II), and the normal chest X-ray in more than 80% of the patients. In this study, 43% of the patients were felt to require angiography and only 10% were considered for bypass surgery. Good prognosis may be seen as a contra-indication for revascularization surgery. Yet, the prevalence of 3-vessel disease and the fact that 2/3 of the SMI subjects became symptomatic during the follow-up period are arguments in favour of early angiography.

Filling pressures in post-myocardial infarction patients: comparison between isometric and dynamic exercise

The purpose of this study was to determine if isometric exercise (handgrip) using a substantial muscle mass and intensity could be substituted for dynamic exercise in the assessment of left ventricular function in myocardial infarct (MI) patients. Forty patients with documented MI were assigned, on the basis of their previous exercise ECG responses, to either an exercise-induced ischaemic group (Group 1) or to a non-exercise ischaemic group (Group 2). Eight apparently healthy males served as controls. Pulmonary capillary pressure (PCP) was measured at rest, during volume loading and during isometric and dynamic exercise. Mean PCP in Group 1 increased progressively from 7.5 +/- 2.9 mmHg at rest, to 11.6 +/- 3.8 mmHg during volume loading, to 18.8 +/- 10.2 mmHg during the isometric exercise and to 25.2 +/- 10.1 mmHg during the dynamic exercises. For Group 2, the respective values were 9.6 +/- 6.3, 13.1 +/- 6.4, 18.7 +/- 13.7 and 18.4 +/- 9.8 and for the controls 8.9 +/- 1.9, 11.3 +/- 1.2, 13.3 +/- 3.3 and 11.8 +/- 3.6 mmHg. The results of this study indicate that isometric exercise of 50% MVC using both hands can adequately replace dynamic exercise in the diagnosis of left ventricular function in post MI patients.

Familial aggregation in physical fitness, coronary heart disease risk factors, and pulmonary function measurements

In order to test for the presence of familial aggregation in physical fitness and coronary heart disease risk factors, body fat, submaximal power output, muscular strength, muscular endurance, blood pressure, pulmonary functions, and several blood biochemical variables were measured in 304 nuclear families living in the Quebec city area. Analysis of variance indicated a larger between-family than within-family variation for all the variables. When all members of nuclear families were considered, intraclass correlations ranged from 0.21 to 0.34 (P less than or equal to 0.01). Interclass correlations computed for various pairs of relatives revealed significant parent-child and sibling correlations for all the variables (0.14 less than or equal to r less than or equal to 0.55; P less than or equal to 0.01). On the other hand, spousal correlations tended to be lower but significant (0.10 less than or equal to r less than or equal to 0.30; P less than or equal to 0.05) for all variables except subcutaneous fat and hemoglobin concentration. These results suggest that heredity and common lifestyle shared by members of nuclear families are responsible for the familial aggregation of physical fitness, coronary heart disease risk factors, and pulmonary functions. The findings also support the notion of considering the nuclear family as a unit of intervention in the application of preventive measures aimed at the reduction of several risk factors.

Exercise hypertension in the perspective of systemic arterial hypertension. An overview

Systemic arterial hypertension is one of the most wide-spread diseases in the world. It is a chronic disease with a very long asymptomatic phase. At an estimated prevalence in the developed countries of 15 to 20%, it can be assumed that approximately 80% of men and 60% of women with hypertension are either unaware of their condition or are not treated adequately. These figures show that reliable diagnostic measures are needed to provide efficient detection of high blood pressure in a given population. In this regard, exercise testing has proven particularly well-suited. Using standardized ergometry, patients with latent, borderline or manifest hypertension can be identified. Exercise hypertension is defined on the basis of an abnormal blood pressure increase during physical exercise in persons with normal blood pressure at rest. Because of marked interindividual fluctuation in blood pressure, values measured at rest may be of only limited usefulness in the diagnosis of hypertension. In contrast, the blood pressure during dynamic exercise may be particularly informative with respect to probability of future development of manifest hypertension and treatment of high blood pressure. Long-term studies have shown that within five years up to one-third of patients with exercise hypertension develop manifest hypertension at rest. Based on the Canada Fitness Survey data indicating that about 2% of the population demonstrate exercise hypertension, it can be estimated that approximately 200,000 Canadians will develop manifest hypertension within five years. Similar statistics are also applicable for most of the developed countries of the world.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise hypertension in healthy normotensive subjects. Implications, evaluation and interpretation

Exercise hypertension, defined as a blood pressure response to a dynamic exercise stressor which is considered excessive to what is normally observed in a healthy population, is currently the subject of much discussion. This interest appears to be related to the recent concerns that are being expressed in the utilization of hypertensive drugs with respect to their long-term benefits and risks. I would seem that the proper selection of patients for drug therapy will become as important as the treatment itself, not only for clinical purposes but to insure the quality of life of a patient in the pursuit of his/her daily activities. Also, a number of retrospective studies have shown that an exaggerated blood pressure response to exercise in resting normotensive persons could be a useful indicator to assist in detecting those persons who may be on the way to developing sustained hypertension. The literature suggests that this is a tenable hypothesis but one that will require testing by prospective research. In this respect, it has been suggested that if the blood pressure response to a dynamic exercise in borderline or labile hypertensives is normal, it is possible to dismiss the diagnosis of hypertension, at least temporarily. However, if the blood pressure response is exaggerated, then the diagnosis of hypertension should be considered. In Canada, the Canadian Aerobic Fitness Test (CAFT) has been utilized to assist in detecting exercise hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

[Personality psychological correlates of blood pressure behavior. Group comparison of hypertensive, exercise hypertensive and normotensive heart patients]

It has been well established that individuals with exercise hypertension are at risk of subsequently developing manifest hypertension at rest. In this regard, there is little data available on psychological aspects which may be related to this transition. Accordingly, this study was undertaken to determine whether persons with exercise hypertension and those with manifest hypertension differ in personality traits. With the aid of a personality inventory (FPI-R), a comparative analysis of personality structure was carried out in 60 patients with coronary artery disease (20 with manifest hypertension, 20 with exercise hypertension and 20 normotensive patients). Three differing personality profiles were found. Hypertensive patients had above average values for inhibition, excitability, suffer from stress, psychosomatic complaints and emotional susceptibility; their values for contentment with life were below the average. Persons with exercise hypertension also had above-average values for excitability while normotensive individuals had higher values for extraversion. With regard to prevention of development of manifest hypertension, it would seem reasonable, in patients with exercise hypertension, to encourage the learning of stress management techniques to suppress excitability.

[Physical fitness improves after mitral valve replacement]

To determine whether women with mitral valve prostheses can improve their physical fitness without suffering cardiac dysfunction or hemolysis, 10 women (mean age 47 years) who had undergone mitral valve replacement (an average of 3.7 years earlier) were enrolled in an 8-week program of exercise on a bicycle ergometer. They exercised three times a week, starting at 60% and increasing to 80% of their maximal heart rate achieved during stress testing. Nine other women with similar clinical characteristics (mean age 48 years) constituted a control group. Exercise produced significant cardiovascular improvement, as evidenced by a mean decrease of 12 beats/min in the heart rate at steady-state work load (p less than or equal to 0.01), a mean increase of 121 kpm in the maximal tolerated work load (p less than or equal to 0.01), and a mean increase of 4 ml/kg X min-1 in the peak oxygen consumption (p less than or equal to 0.01). There was a small increase in the mean plasma hemoglobin level (15 to 29 mg/dl) and the mean reticulocyte count (1.8% to 2.4%) after the program (p less than or equal to 0.05). There were no significant changes in any of the variables studied in the control group. There were no changes in the clinical, electrocardiographic or echocardiographic findings in the experimental group. Although slightly increased hemolysis may occur, women with mitral valve replacement can improve their cardiovascular condition by exercising.

Cardiac dimension changes with endurance training. Indications of a genotype dependency

We studied the sensitivity of cardiac structures to endurance training. To evaluate variability in adaptation, 20 sedentary subjects and ten pairs of monozygotic twins were submitted to a 20-week endurance training program. Maximal oxygen uptake increased significantly in both groups: 11 mL O2/kg/min-1 or 30% in the sedentary group and 6 mL O2/kg/min-1 or 13% in the monozygotic twins. Statistically significant increases in left ventricular diameter, posterior wall and septal thicknesses, as well as left ventricular end-diastolic volume and left ventricular mass were observed in the sedentary subjects, but not in the monozygotic twins. We could demonstrate that after training, twin pairs differed more from each other than at the start. Concomitantly, within-pair resemblance was greater after training than before. Results indicate that cardiac dimensions are amenable to significant modifications under controlled endurance training conditions and furthermore that the extent and variability of the response of cardiac structures to training are perhaps genotype dependent.

Sensitivity of maximal aerobic power to training is genotype-dependent

Ten pairs of monozygotic twins of both sexes were submitted to a 20-wk endurance-training program, four and five times per week, 40 min per session, at an average of 80% of the maximal heart rate reserve. Testing and training were performed on cycle ergometers. Maximal aerobic power (MAP in ml O2 X min-1 X kg-1) and ventilatory aerobic (VAT) and anaerobic (VANT) thresholds (ml O2 X min-1 X kg-1) were measured before and after the training program, as well as during the 7th and 14th week to adjust training to changes in maximal heart rate. Considering the 20 individuals as a group, training significantly (P less than or equal to 0.01) increased MAP (from 44 +/- 6 to 50 +/- 6), VAT (25 +/- 3 to 30 +/- 4), and VANT (36 +/- 5 to 42 +/- 6). Thus, MAP improved by 12% of the pre-test value, while mean changes in VAT and VANT reached 20% and 17%, respectively. There were, however, considerable interindividual differences in training gains as exemplified by a range of about 0% to 41% for MAP. Differences in the MAP response to training were not distributed randomly among the twin pairs. Thus, intraclass correlations computed with the amount of improvement in MAP (ml O2 X min-1 X kg-1) reached 0.74 (P less than 0.01) indicating that members of the same twin-pair yielded approximately the same response to training. The same coefficient reached 0.43 and 0.24 for VAT and VANT, respectively (P greater than 0.05). These results suggest that there are considerable individual differences in the adaptive capacity to short-term endurance training. Moreover, sensitivity of maximal aerobic power to such training is largely genotype-dependent.

Responses of maximal aerobic power and capacity to aerobic training

The purpose of this experiment was to investigate the individual differences and the specificity in the response of maximal aerobic power (MAP) and capacity (MAC) to a 20-week aerobic training program. Twenty-four subjects (25 +/- 4 years), ascertained as sedentary, including 13 women and 11 men, participated in this study. MAP was determined with a progressive maximal ergocycle test, while MAC was computed as the total work output accomplished during a 90-min maximal ergocycle test. A modified bicycle ergometer allowed the exact measurement of the distance and the load for the computation of the work performed during MAC. The aerobic training program enhanced mean MAP/kg and MAC/kg by 33% and 51%, respectively. Although MAP/kg response to training was similar in both sexes, there was a sex difference in the response of MAC/kg, men improving 50% more than women. Individual differences in the response to the standardized training program were considerable with training gains ranging from 5% to 88% for MAP/kg and from 16% to 97% for MAC/kg. Correlations between training increments in MAP/kg with those in MAC/kg were rather low ranging from 0.28 to 0.44. These results indicate that there is a sex difference in the trainability of aerobic capacity, but not of maximal aerobic power, under the same 20-week aerobic training program. Moreover, large individual differences in the response to similar aerobic training are observed in sedentary persons, suggesting that certain genotypes are more sensitive to training than others. Finally, there is a high level of specificity in the response to training of the power and of the capacity of the aerobic energy metabolism.

Vigorous physical training after aortic valve replacement: analysis of 10 patients

Improved prosthetic aortic valves have reduced the incidence of complications to a point where it can be hypothesized that functional class I subjects after aortic valve replacement (AVR) should adapt to a vigorous training program without a significant increase of hemolytic activity or clinical signs of prosthesis malfunction. To test this hypothesis, 10 men (mean age 52 years) who had undergone AVR (7 Björk-Shiley and 3 Lillehei-Kaster) were submitted to an 8-week training program on ergometer, 3 times/week, from 60 to 80% of individual maximal heart rate. Ten other men who had undergone AVR but did not participate in the training program were control subjects. The exercise program produced significant improvements in posttraining maximum tolerated ergometer work load (210 kpm, p less than 0.001), in maximum total body oxygen consumption (5 ml/kg X min-1, p less than or equal to 0.01) and in double product at submaximal work load (-5,126, p less than or equal to 0.01). After training, hemoglobin decreased by about 1 g% (p less than or equal to 0.05) and hematocrit, reticulocyte counts and haptoglobin did not change significantly. Serum LDH and serum AST did not increase. Pre- and post-training echocardiograms did not show detectable alterations. Thus, patients with AVR who are in functional class I can adapt to a physical exercise program without significant adverse effects.

The uptake and acylation of exogenous lysophosphatidylethanolamine by Escherichia coli cells

Escherichia coli envelopes were fractionated to yield inner and outer membrane fractions. Both these fractions were found to convert [14C]lysophosphatidylethanolamine to its diacyl analogue. Intact Escherichia coli cells were capable of absorbing exogenous labelled lysophosphatidylethanolamine and converting it to phosphatidylethanolamine. When the 14C- and 32P-labelled lyso analogue was used, both the absorption process and the conversion to diacyl analogue proceeded without a significant change in isotope ratio either in the presence or in the absence of added inorganic phosphate. The absorption process was not markedly stimulated by Ca2+ in the medium; it proceeded to an amount representing 25--30% of the endogenous membrane lipid and was accompanied by some degradation to water-soluble products which accumulated in the cell mainly, but also in the incubation medium. The absorbed lipid was recovered in both the inner and outer membrane fractions of the cell envelope. The results indicate that Escherichia coli inner and outer membranes are capable of absorbing exogenous lysophosphoglyceride and converting it into structurally useful diacyl analogue.

The formation of phosphatidylethanolamine from diglyceride by extracts of Escherichia coli

Extensively dialyzed cell-free homogenates or washed particulate fractions, of Escherichia coli in the presence of added CTP, Mg2+, serine, and rac-glycerol 3-phosphate, incorporated [32P]phosphatidic acid into phosphatidylglycerol and cardiolipin but not into phosphatidylethanolamine. [14C]Phosphatidic acid could be incorporated by these preparations into phosphatidylethanolamine in the absence of added CTP and Mg2+. CDP-diglyceride did not significantly affect the formation of [14C]phosphatidylethanolamine from [14C]phosphatidic acid. 14C-labeled diglyceride was also readily incorporated into phosphatidylethanolamine in the absence of added cofactors by both homogenate and particulate fraction. Serine stimulated the incorporation somewhat whereas CTP + Mg2+ diminished this conversion slightly because of concurrent [14C]phosphatidic acid and [14C]phosphatidylglycerol formation. CDP-diglyceride did not significantly affect the conversion of 14C-labeled diglyceride to phosphatidylethanolamine. Dialyzed 14C-labeled cytosol fractions of E. coli, obtained from cells grown in medium containing [14C]serine, transferred some of their label to phosphatidylethanolamine in the presence of fresh particulate fraction. This transfer was stimulated by added diglyceride. The results indicate that phosphatidylethanolamine can be synthesized from exogenous diglyceride by a pathway which does not require CDP-diglyceride as an intermediate but which likely makes use of an endogenous cofactor supplying phosphorylethanolamine and (or) phosphorylserine.