Suppression of the maize phytoglobin ZmPgb1.1 promotes plant tolerance against Clavibacter nebraskensis.

MAIN CONCLUSION: Suppression of the maize phytoglobin ZmPgb1.1 enhances tolerance against Clavibacter nebraskensis by promoting hypersensitive response mechanisms mediated by ethylene and reactive oxygen species. Suppression of the maize phytoglobin, ZmPgb1.1, reduced lesion size and disease severity in leaves following inoculation with Clavibacter nebraskensis, the causal agent of Goss's bacterial wilt disease of corn. These effects were associated with an increase of the transcriptional levels of ethylene biosynthetic and responsive genes, which resulted in the accumulation of reactive oxygen species (ROS) and TUNEL-positive nuclei in the proximity of the inoculation site. An in vitro system, in which maize cells were treated with induced xylem sap, was employed to define the cause-effect relationship of these events. Phytoglobins (Pgbs) are hemoglobins able to scavenge nitric oxide (NO). Suppression of ZmPgb1.1 elevated the level of NO in cells exposed to the induced xylem sap causing a rise in the transcript levels of ethylene biosynthesis and response genes, as well as ethylene. Accumulation of ethylene in the same cells was sufficient to elevate the amount of reactive oxygen species (ROS), through the activation of the respiratory burst oxidase homologs (Rboh) genes, and trigger programmed cell death (PCD). The sequence of these events was demonstrated by manipulating the content of NO and ethylene in culture through pharmacological treatments. Collectively, our results illustrated that suppression of ZmPgb1.1 evokes tolerance against C. nebraskensis culminating in the execution of PCD, a key step of the hypersensitive response.

Relationships between altruistic activity and positive and negative affect among low-income older adult service providers.

Self-reported altruistic activity was examined as a predictor of positive and negative affective states among a sample of 115 low-income older adults who were actively providing services to others within a federally subsidized service delivery program (Foster Grandparents and Senior Companions). Results indicated that altruistic activity was predictive of positive, but not negative affect. It was found that altruistic activity was a significant predictor of positive affect after controlling for relevant demographic variables including social support and income. The theoretical and clinical implications of this research are discussed.

The relationship between signs of cardiovascular deficiency and cognitive performance in old age: a population-based study.

The influence of cardiovascular signs (CVS) on cognitive performance was examined in 227 older adults not suffering from dementia between 75 and 96 years of age who were sampled from the community. Participants received a comprehensive physical examination that included specific evaluation of current CVS, including dyspnea, cardiac murmur, and edema in lower limbs. They were administered tests of digit span, episodic recall and recognition, verbal fluency, and visuospatial skill. CVS were found to predict performance on tests of episodic memory and visuospatial skill, after the effects of age, education, gender, relevant drug use, and mood symptoms were controlled for. Although CVS accounted for relatively little general performance variation, the findings are relevant to the understanding of normal variation in late-life cognitive performance. Finally, CVS increased with age and accounted for a sizable proportion of the age-related cognitive variation.

Nonsymbiotic haemoglobins in plants.

General aspects regarding the presence of nonsymbiotic haemoglobin in plants are presented with the emphasis on those related to its function. As it becomes apparent that the nonsymbiotic haemoglobins are widespread across the plant kingdom and that they represent a more primitive and evolutionary older form of the plant globin genes, the question of their function becomes more attractive. While the physiological functions of the symbiotic haemoglobins in plants are well understood, almost nothing is known about their nonsymbiotic predecessors. Therefore, the known and hypothetical functions of haemoglobins in various systems are described along with information concerning properties and the regulation of expression of the nonsymbiotic haemoglobins. Interestingly, a number of nonsymbiotic haemoglobins have been shown to be hypoxia-inducible. The spatial and temporal pattern of this induction in barley may suggest that it is an integral part of the plants response to limiting oxygen stress.

Measuring patient distress in primary care.

BACKGROUND AND OBJECTIVES: This study examined the psychometric properties of a brief, easily administered mental health screening instrument, the Outcome Questionnaire Short Form (OQ-10), for use in primary care. The OQ-10 provides information to the primary care provider about patient distress and well-being and highlights areas that may require additional exploration and/or intervention. METHODS: The OQ-10 was administered to 292 outpatients in a family practice clinic, along with a standardized measure of functional status and mental health, the Duke Health Profile (DUKE). RESULTS: The patients' mean age was 37.09 years, and 83% were Caucasian. OQ-10 scores were correlated with all subscales of the DUKE. A principal components analysis of the OQ-10 items revealed two factors: psychological well-being and psychological distress. Well-being was positively related to self-reported health, while distress was not. A subsequent specificity and sensitivity analysis was performed on the OQ-10 total score, and this provided preliminary evidence that the OQ-10 may be useful in gauging the psychological state of patients in primary care. CONCLUSIONS: The OQ-10 can be used as a brief screening tool for patient psychological distress in primary care. The OQ-10 items reflect distress and well-being, which may be useful to physicians in treating the range of psychological problems seen in primary care settings.

The British Diabetic Association Cohort Study, I: all-cause mortality in patients with insulin-treated diabetes mellitus.

AIMS: To assess mortality in patients with diabetes incident under the age of 30 years. METHODS: A cohort of 23 752 diabetic patients diagnosed under the age of 30 years from throughout the United Kingdom was identified during 1972-93 and followed up to February 1997. Following notification of deaths during this period, age- and sex-specific mortality rates, attributable risks and standardized mortality rates were calculated. RESULTS: The 23 752 patients contributed a total of 317 522 person-years of follow-up, an average of 13.4 years per subject. During follow-up 949 deaths occurred in patients between the ages of 1 and 84 years, 566 in males and 383 in females. All-cause mortality rates in the patients with diabetes exceeded those in the general population at all ages and within the cohort were higher for males than females at all ages except between 5 and 15 years. The relative risk of death (standardized mortality ratio, SMR), was higher for females than males at all ages, being 4.0 (95% CI 3.6-4.4) for females and 2.7 (2.5-2.9) for males overall, but reaching a peak of 5.7 (4.7-7.0) in females aged 20-29, and of 4.0 (3.1-5.0) in males aged 40-49. Attributable risks, or the excess deaths in persons with diabetes compared with the general population, increased with age in both sexes. CONCLUSIONS: This is the first study from the UK of young patients diagnosed with diabetes that is large enough to calculate detailed age-specific mortality rates. This study provides a baseline for further studies of mortality and change in mortality within the United Kingdom.

The British Diabetic Association Cohort Study, II: cause-specific mortality in patients with insulin-treated diabetes mellitus.

AIMS: To measure cause-specific mortality, by age, in patients with insulin-treated diabetes incident at a young age. METHODS: A cohort of 23 752 patients with insulin-treated diabetes diagnosed under the age of 30 years, from throughout the United Kingdom, was identified during 1972-93 and followed to February 1997. Death certificates have been obtained for deaths during the follow-up period and cause-specific mortality rates and standardized mortality ratios by age and sex are reported. RESULTS: During the follow-up period 949 deaths occurred and at all ages mortality rates were considerably higher than in the general population. Acute metabolic complications of diabetes were the greatest single cause of excess death under the age of 30 years. Cardiovascular disease was responsible for the greatest proportion of the deaths from the age of 30 years onwards. CONCLUSIONS: Deaths in patients with diabetes diagnosed under the age of 30 have been reported and comparisons drawn with mortality in the general population. To reduce these deaths attention must be paid both to the prevention of acute metabolic deaths and the early detection and treatment of cardiovascular disease and associated risk factors.

The heme environment in barley hemoglobin.

To elucidate the environment and ligand structure of the heme in barley hemoglobin (Hb), resonance Raman and electron paramagnetic resonance spectroscopic studies have been carried out. The heme is shown to have bis-imidazole coordination, and neither of the histidines has imidazolate character. Barley Hb has a unique heme environment as judged from the Fe-CO and C-O stretching frequencies in the CO complex. Two Fe-CO stretching modes are observed with frequencies at 534 and 493 cm-1, with relative intensities that are pH sensitive. The 534 cm-1 conformer shows a deuterium shift, indicating that the iron-bound CO is hydrogen-bonded, presumably to the distal histidine. A C-O stretching mode at 1924 cm-1 is assigned as being associated with the 534 cm-1 conformer. Evidence is presented that the high Fe-CO and low C-O stretching frequencies (534 and 1924 cm-1, respectively) arise from a short hydrogen bond between the distal histidine and the CO. The 493 cm-1 conformer arises from an open conformation of the heme pocket and becomes the dominant population under acidic conditions when the distal histidine moves away from the CO. Strong hydrogen bonding between the bound ligand and the distal histidine in the CO complex of barley Hb implies that a similar structure may occur in the oxy derivative, imparting a high stability to the bound oxygen. This stabilization is confirmed by the dramatic decrease in the oxygen dissociation rate compared with sperm whale myoglobin.

Markov chain models and estimation of absolute progression rates: application to cataract progression in diabetic adults.

BACKGROUND: We present a case study in the use of Markov chain models of disease progression, with exponential regression to model the effects of covariates. METHODS: An exponential regression model was developed for a three-state Markov chain to model progression of cataracts in diabetic patients, with a view to estimation of absolute progression rates. Two methods of estimation were applied, a non-linear least squares approximation, and Markov Chain Monte Carlo (MCMC). RESULTS: Both methods gave estimated transition rates which can readily be transformed to absolute progression probabilities. Agreement was reasonable for most but not all of the parameters. CONCLUSIONS: The MCMC estimates had more conservative variance estimates.

Evidence of an increasing prevalence of diagnosed diabetes mellitus in the Poole area from 1983 to 1996.

This study examined the prevalence of diagnosed diabetes mellitus in a defined population over 13 years by undertaking cross-sectional surveys on 3 occasions between 1983 and 1996. The study population consisted of all the people registered with 10 general (primary care) practices at the time of each survey; 90660 in 1983/4; 97122 in 1988/9; and 86287 in 1996. Ascertainment of cases was by a surveillance programme in general practice and the hospital diabetes department. The number of diabetic patients increased significantly over the study period: in 1983/4, there were 917 patients, crude prevalence 1.01% (95% CI 0.95-1.08%); in 1988/9, 1150 patients, crude prevalence 1.17% (1.12-1.25%); and in 1996, 1604 patients, crude prevalence 1.86% (1.77-1.95%). The prevalence adjusted to the age and sex distribution of the UK was 0.97% (95% CI 0.90-1.03%) in 1983/4, 1.05% (0.99-1.11%) in 1988/9 and 1.55% (1.48-1.63%) in 1996. The main increase in prevalence was due to Type 2 diabetes mellitus, crude prevalence 0.75% (95% CI 0.69-0.81%) in 1983/4, 0.92% (0.86-0.98%) in 1988/9 and 1.52% (1.44-1.60%) in 1996 rather than Type 1 diabetes mellitus, crude prevalence 0.25% (0.21-0.28%) in 1983/4, 0.25% (0.22-0.28%) in 1988/9 and 0.34% (0.30-0.38%) in 1996. During the study period, the crude prevalence of diagnosed diabetes was significantly greater in men than women; in 1983/4 men 1.1% (95% CI 1.00-1.20%) versus women 0.93% (0.84-1.02%); in 1988/9, men 1.31% (1.21-1.41%) versus women 1.07% (0.98-1.16%); and in 1996, men 2.13% (2.00-2.27%) versus women 1.60% (1.49-1.72%). This difference was statistically significant in the 1988/9 and 1996 surveys. In conclusion, over 13 years there was a significant increase of 83.6% in the prevalence of diagnosed diabetes mellitus in the Poole area, with the UK age and sex adjusted prevalence increasing by 60.7%.

Altering hemoglobin levels changes energy status in maize cells under hypoxia.

Nonsymbiotic hemoglobins are broadly present across the plant kingdom; however, the function of these proteins is unknown. Cultured maize cells have been transformed to constitutively express a barley hemoglobin gene in either the sense (HB+) or antisense (HB-) orientation. Hemoglobin protein in the transformed cell lines correspondingly was higher or lower than in wild-type cells under normal atmospheric conditions. Limiting oxygen availability, by placing the cells in a nitrogen atmosphere for 12 hr, had little effect on the energy status of cells constitutively expressing hemoglobin, but had a pronounced effect on both wild-type and HB- cells, where ATP levels declined by 27% and 61%, respectively. Total adenylates in these cells were approximately 35% lower than in HB+ cells. Energy charge was relatively unaffected by the treatment in HB+ and wild-type cells, but was reduced from 0.91 to 0.73 in HB- cells, suggesting that the latter were incapable of maintaining their energy status under the low oxygen regime. Treatment of the cells grown in an air atmosphere with antimycin A gave essentially the same results. It is suggested that nonsymbiotic hemoglobins act in plants to maintain the energy status of cells in low oxygen environments and that they accomplish this effect by promoting glycolytic flux through NADH oxidation, resulting in increased substrate-level phosphorylation. Hypoxic acclimation of plants is an example of this effect in nature. Nonsymbiotic hemoglobins are likely ancestors of an early form of hemoglobin that sequestered oxygen in low oxygen environments, providing a source of oxygen to oxidize NADH to provide ATP for cell growth and development.

Preferences of old and young Navaho Indians for Western and indigenous health care providers: an exploratory study.

References for Western versus traditional health care providers were assessed in 27 older (M = 61.5 years) and 21 younger (M = 22.6 years) American Indians living on the Navaho reservation. Participants were read standardized vignettes depicting diagnosable physical and emotional illnesses, and they completed a series of forced-choice questions indicating their preference for traditional or Western health care providers for treating these conditions. Analysis of variance (ANOVA) was used to assess health care provider preference with age, interviewer, and illness type as independent variables. Medical doctors were preferred over all other health care providers for physical problems, and this was particularly true for the younger group. Although it was anticipated that the older participants would favor traditional healers and the younger participants would prefer Western options, there was no main effect for age. This lack of differentiation by age in provider preference was interpreted in terms of informal utilization patterns and the role of the family referral system inherent in this group of indigenous adults.

Expression, purification, and properties of recombinant barley (Hordeum sp.) hemoglobin. Optical spectra and reactions with gaseous ligands.

A cDNA encoding barley hemoglobin (Hb) has been cloned into pUC 19 and expressed in Escherichia coli. The resulting fusion protein has five extra amino acids at the N terminus compared with the native protein, resulting in a protein of 168 amino acids (18.5 kDa). The recombinant Hb is expressed constitutively. Extracts made from the bacteria containing the recombinant fusion construct contain a protein with a subunit molecular mass of approximately 18.5 kDa comprising approximately 5% total soluble protein. Recombinant Hb was purified to homogeneity according to SDS-polyacrylamide gel electrophoresis by sequential polyethylene glycol precipitation and fast protein liquid chromatography. Its native molecular mass as assessed by fast protein liquid chromatography-size exclusion was 40 kDa suggesting that it is a dimer. Ligand binding experiments demonstrate that 1) barley Hb has a very slow oxygen dissociation rate constant (0.0272 s-1) relative to other Hbs, and 2) the heme of ferrous and ferric forms of the barley Hb is low spin six-coordinate. The subunit structure, optical spectrum, and oxygen dissociation rate of native barley hemoglobin are indistinguishable from those obtained for the recombinant protein. The implications of these kinetic data on the in vivo function of barley Hb are discussed.

Effectiveness of the number-consonant mnemonic for retention of numeric material in community-dwelling older adults.

The effectiveness of the number-consonant mnemonic for immediate recall and long-term retention of 4 6-digit lock combinations was examined in 36 volunteers who were 60 years old or more. Participants were randomized into either an experimental condition (n = 17) that received training in the number-consonant mnemonic or a group that received placebo training only (n = 19). There were no differences between groups for number recall at posttest. At 3 days a modest difference appeared, favoring the experimental condition, which became highly significant at the 7-day telephone follow-up. This finding suggests that a distinguishing characteristic of the number-consonant mnemonic may be the extent to which it facilitates the maintenance of learned numeric material in memory over time.

Mitochondrial Respiration and Hemoglobin Gene Expression in Barley Aleurone Tissue.

Previous studies have shown that plant hemoglobin (Hb) mRNA is expressed in barley (Hordeum vulgare L.) aleurone layers during hypoxia. We have examined the effect of a number of respiratory inhibitors on barley aleurone layers to determine the factors that influence Hb gene expression. Respiratory inhibitors that reduce O2 consumption, such as CO, cyanide, and antimycin A, strongly enhanced Hb mRNA levels. Treatment with the oxidative phosphorylation uncoupler 2,4-dinitrophenol markedly increased O2 consumption and had a similar positive effect on Hb gene expression. Hb transcript levels were also stimulated by the ATP synthase inhibitor oligomycin. The results suggest that the expression of Hb is not directly influenced by O2 usage or availability but is influenced by the availability of ATP in the tissue.

Mortality rates in diabetic patients from a community-based population compared to local age/sex matched controls.

Using a population-based cohort from 10 general practices in East Dorset, the mortality rate of diabetic patients compared to non-diabetic controls was investigated during 8 years follow-up. From a total population of 90660, 917 diabetic patients were identified; 693 (75%) with non-insulin-dependent (Type 2) diabetes and 224 (25%) with insulin-dependent (Type 1) diabetes. A control group of 917 non-diabetic subjects were selected, matched by age and sex. After 8 years, significantly more diabetic patients (334 or 36.4%) had died than controls (219 or 24%), (odds ratio (OR) 1.99, 95% CI 1.60-2.47). Compared with the controls, the odds ratio of all causes of mortality for diabetic men was 1.89 (CI 1.4-2.54) and for diabetic women 2.16 (CI 1.57-2.96). Compared with controls, the odds ratio for mortality from circulatory disease was significantly increased for diabetic patients 2.0 (CI 1.5-2.6) but mortality for respiratory disease or neoplasms was not significantly different (OR 0.7, CI 0.4-1.2 and OR 0.7, CI 0.6-1.0, respectively). Control data were lower than would be expected from national database data. The diabetic population had a significantly higher mortality than controls, both from all causes and circulatory diseases. Our data incidentally show the importance of appropriate controls for estimating the impact of a chronic disease.

Cloning and expression pattern of Hor v 9, the group 9 pollen isoallergen from barley.

In this study we report the cloning, sequence, and characterization of Hor v 9 allergen cDNAs from barley (Hordeum vulgare) pollen. Structural homologues of Kentucky bluegrass (Poa pratensis) group 9 pollen allergens were identified in a cDNA library of barley pollen expressed mRNAs. The Hor v 9 cDNA clone (hvp9742) contained an open reading frame encoding 313 amino acids which included a putative 27-residue signal peptide and one asparagine sequon for glycosylation. The mRNA corresponding to clone hvp9742 was produced abundantly in pollen during the late stages of anther development. The protein encoded by clone hvp974 was synthesized as a fusion protein in the E. coli expression vector pMAL. Immunoblots using antibodies to this recombinant allergen, rHor v 9, showed that Hor v 9 protein accumulated during pollen development and was produced maximally at pollen maturity. Using these antibodies, we also provide evidence that Hor v 9 protein localized to the extracellular matrix of mature pollen. Southern blots suggested that Hor v 9 allergens exist as multiple isoforms in barley. Sequence comparisons showed that the Hor v 9 cDNA clones were also homologous to group 5 allergens of Timothy grass (Phleum pratense) pollen and canary grass (Phalaris aquatica) pollen, and the group 9 allergen of ryegrass (Lolium perenne) pollen.

Effects of serum vitamin B12 and folate status on episodic memory performance in very old age: a population-based study.

We examined the relationship between low levels of serum vitamin B12 (< 200 pmol/L) and folic acid (< 11 nmol/L), separately or combined, and episodic memory performance in very old age. Participants with low serum vitamin values were compared with a control group matched for age and educational level. Participants (N = 250) were selected from a group of nondemented, community-dwelling persons ages 75-96. Episodic memory was tested by means of free recall and recognition of slowly and rapidly presented words. Results indicated a deterioration in both free recall and recognition as a function of serum vitamin status. However, no linear effects of vitamin levels on memory were observed, indicating that vitamin B12 and folic acid status may effect memory only among individuals at the low end of the distribution. We speculate that the vitamin-related memory deficit may reflect encoding problems, possibly due to alterations in brain metabolism.

The influence of depressive symptomatology on episodic memory functioning among clinically nondepressed older adults.

The authors examined a community-based sample of 303 clinically nondepressed individuals aged 75 through 96 years on 4 recall tasks: free recall of rapidly presented random words, free recall of slowly presented random words, free recall of organizable words, and cued recall of organizable words. Using a classification taxonomy that identified mood- and motivation-related symptoms of depression, it was found that motivation-related symptoms had a negative effect on performance across all tasks, whereas mood-related symptoms had no effects. In addition, motivation-related symptoms negatively influenced the ability to benefit from more study time but had no effect on the ability to make use of item organization or category cues. An analysis of the specific motivation-related symptoms suggested that symptoms that may affect the ability to focus and sustain attention (e.g., concentration difficulties, lack of interest) were most strongly associated with performance deficits.