Copper resistance of Calluna vulgaris originating from the pollution gradient of a Cu-Ni smelter, in southwest Finland

The copper (Cu) resistance of 1-year-old seedlings of heather (Calluna vulgaris) was tested in a greenhouse experiment. The plant material originated from seeds collected from three peatland sites located 1.2 km to the NW, and 2.5 and 5.5 km to the NE of the Harjavalta Cu-nickel (Ni) smelter, SW Finland. The plants were watered with a nutrient solution containing five different levels of Cu (1, 10, 22, 46 and 100 mg l(-1)). Cu clearly decreased the length growth of shoots, shoot and root biomass of C. vulgaris. More than 50% of the seedlings exposed to the highest Cu treatment died. C. vulgaris accumulated high amounts of Cu, the living old roots containing a maximum of 2200 mg kg(-1) Cu and the living stems 1300 mg kg(-1) Cu. Discolouring leaves contained higher Cu concentrations than green leaves. The results indicate Cu accumulation in roots and root-to-shoot transport. Some differences were found between the responses of the three seed provenances, but none of the populations proved to be more resistant to Cu than the others in all the measured responses.

Long-term effects on clinical outcomes of aggressive lowering of low-density lipoprotein cholesterol levels and low-dose anticoagulation in the post coronary artery bypass graft trial. Post CABG Investigators

BACKGROUND

The Post Coronary Artery Bypass Graft Trial, designed to compare the effects of 2 lipid-lowering regimens and low-dose anticoagulation versus placebo on progression of atherosclerosis in saphenous vein grafts of patients who had had CABG surgery, demonstrated that aggressive lowering of LDL cholesterol (LDL-C) levels to <100 mg/dL compared with a moderate reduction to 132 to 136 mg/dL decreased the progression of atherosclerosis in grafts. Low-dose anticoagulation did not significantly affect progression.

METHODS AND RESULTS

Approximately 3 years after the last trial visit, Clinical Center Coordinators contacted each patient by telephone to ascertain the occurrence of cardiovascular events and procedures. The National Death Index was used to ascertain vital status for patients who could not be contacted. Vital status was established for all but 3 of 1351 patients. Information on nonfatal events was available for 95% of surviving patients. A 30% reduction in revascularization procedures and 24% reduction in a composite clinical end point were observed in patients assigned to aggressive strategy compared with patients assigned to moderate strategy during 7.5 years of follow-up, P=0. 0006 and 0.001, respectively. Reductions of 35% in deaths and 31% in deaths or myocardial infarctions with low-dose anticoagulation compared with placebo were also observed, P=0.008 and 0.003, respectively.

CONCLUSIONS

-The long-term clinical benefit observed during extended follow-up in patients assigned to the aggressive strategy is consistent with the angiographic findings of delayed atherosclerosis progression in grafts observed during the trial. The apparent long-term benefit of low-dose warfarin remains unexplained.

Ca2+ uptake by the sarcoplasmic reticulum decreases the amplitude of depolarization-dependent [Ca2+]i transients in rat gastric myocytes

Gastric myocytes loaded with fura-2 were voltage-clamped at -60 mV. Depolarizations to 0 mV evoked nifedipine-sensitive (5 microM) inward currents and Ca2+ transients. Cyclopiazonic acid (5 microM) elevated steady-state [Ca2+]i and reduced Ca current (ICa), but when divalent cations were omitted from the extracellular solution, cyclopiazonic acid had no effect on either the amplitude or the current-voltage relationship of the nifedipine-sensitive current. This suggests that the reduction in ICa was caused by the rise in steady-state [Ca2+]i. The relationship between the total Ca2+ influx carried by the Ca2+ current (sigmaI(Ca).dt) and the amplitude of the Ca2+ transient (delta[Ca2+]i) was analysed for experiments using physiological Ca2+ solutions by calculating the ratio delta[Ca2+]i/sigmaI(Ca).dt. Cyclopiazonic acid (5 microM) and ryanodine (10 microM) both increased this ratio, indicating a decrease in the buffering power of the cell. Mimicking the increase in steady-state [Ca2+]i produced by these agents by changing the holding potential to -40 mV, however, did not affect delta[Ca2+]i/sigmaI(Ca).dt. It was concluded that up-take by a ryanodine-sensitive store normally limits Ca2+ distribution to the bulk cytoplasm following entry to the cell through dihydropyridine-sensitive channels.

Need for an external proficiency testing program for cytokines, chemokines, and plasma markers of immune activation

An external evaluation program for measuring the performance of laboratories testing for cytokines and immune activation markers in biological fluids was developed. Cytokines, chemokines, soluble cytokine receptors, and other soluble markers of immune activation (CSM) were measured in plasma from a healthy human immunodeficiency virus (HIV)-seronegative reference population and from HIV-seropositive individuals as well as in supernatant fluids from in vitro-stimulated human immune cells. The 14 components measured were tumor necrosis factor (TNF) alpha, gamma interferon, interleukin-1 (IL-1), IL-2, IL-4, IL-6, IL-10, Rantes, MIP-Ia, MIP-Ibeta, soluble TNF receptor II, soluble IL-2 receptor alpha, beta(2)-microglobulin, and neopterin. Twelve laboratories associated with the Adult and Pediatric AIDS Clinical Trial Groups participated in the study. The performance features that were evaluated included intralaboratory variability, interlaboratory variability, comparison of reagent sources, and ability to detect CSM in the plasma of normal subjects as well as the changes occurring in disease. The principal findings were as follows: (i) on initial testing, i.e., before participating in the program, laboratories frequently differed markedly in their analytic results; (ii) the quality of testing of a CSM in individual participating laboratories could be assessed; (iii) most commercial kits allowed distinction between normal and abnormal plasma CSM levels and between supernatants of stimulated and unstimulated cells; (iv) different sources of reagents and reference standards frequently provided different absolute values; (v) inexperienced laboratories can benefit from participating in the program; (vi) laboratory performance improved during active participation in the program; and (vii) comparability between analyses conducted at different sites can be ensured by an external proficiency testing program.

The role of personality in the development and perpetuation of chronic fatigue syndrome

OBJECTIVES

Qualitative evidence suggests that personality may have special relevance to the predisposition, precipitation and perpetuation of chronic fatigue syndrome (CFS). This study compares three dimensions of personality - perfectionism, self-esteem, and emotional control in the personality profiles of CFS patients (N=44) and a control group (N=44) without a history of CFS, matched for age and gender.

METHODS

Participants were assessed on the MPS [Frost RO, Marten P, Lahart C, Rosenblate R. The dimensions of perfectionism. Cognit Ther Res 1990;14:449-468.]; the Rosenberg Self-Esteem Scale [Rosenberg M. Society and the Adolescent Self-image. Princeton, NJ: Princeton Univ Press, 1965.]; the Courtauld Emotional Scale [Watson M, Greer S. Development of a questionnaire measure of emotional control. J Psychosom Res 1983;27:299-305.] and the Marlowe-Crowne Social Desirability Scale [Crowne DP, Marlowe D. A new scale of social desirability independent of psychopathology. J Consult Psychol 1960;24:349-354.].

RESULTS

Analyses revealed that the CFS group reported higher levels than the control group on the Total Perfectionism score and Doubts about Actions and the Concern over Mistakes subscales. Furthermore, the CFS group also reported lower self-esteem than the control group. No difference between the two groups was found on the dimensions of emotional control and social desirability response bias.

CONCLUSION

A developmental model of CFS, which considers the predisposing, precipitating, and perpetuating factors that may account for the course of the disorder irrespective of etiology, is proposed. In the context of the results, recommendations for practice and future research are discussed.

Temporal and small-scale spatial variations of dissolved oxygen in the Rivers Thames, Pang and Kennet, UK

Small-scale spatial dissolved oxygen concentrations were measured on three rivers by taking a number of transects along a river reach. Temporal (diurnal) variations were measured by use of continuous (15-min) monitors located at the mid-transect of the spatial observations. Spatial variation of dissolved oxygen concentrations were found to be relatively small (approx. +/- 10% dissolved oxygen) and biologically insignificant compared to diurnal changes under conditions of high productivity (approx. +/- 60% dissolved oxygen). The diurnal curves were analysed in order to estimate values of reaeration, photosynthesis and respiration on a daily basis for almost 3 months using process-based analytical techniques (the Delta and Hornberger and Kelly methods). The River Kennet was shown to be the most productive river followed by the River Pang and then the River Thames. The patterns of reaeration, photosynthesis and respiration and the behaviour of the three rivers are discussed.

Workforce projections for optometry

BACKGROUND

A 1995 workforce study conducted by RAND estimated a large current surplus of eye care providers in the United States. Due to data limitations of the RAND study and the outdated optometric workforce information available, the American Optometric Association contracted with Abt Associates to conduct a study to project future workforce requirements for optometry.

METHODS

We collected extensive data on both the supply (work hours, retirement rates, new entrants) and demand (patient encounters and associated time requirements) of optometrists. These data were collected from a survey using stratified random sampling of 1,100 practicing optometrists and were used to develop workforce projections for optometry through the year 2030. Projections were calculated using a forecasting tool that can be used to derive workforce and training requirements under a range of future scenarios.

RESULTS

Workforce projections suggest an excess supply of optometrists is likely over the next 20 years. Over the next five years, approximately 550 optometrists are expected to retire each year, while more than 1,100 optometrists enter practice annually. Patient encounter volume is projected to increase steadily, but the effects of this increase are largely offset by an anticipated decrease in optometrist time requirements for routine eye examinations.

DISCUSSION

To reduce the size of the anticipated excess supply, optometry may want to focus on ways that demand can be increased. One way to increase demand is through greater convergence between the actual demand for eye care services and the underlying public health need for eye care.

Interviews with advanced practice nurses: a day in the life. Interview by Sherry L. Child

The role of the advanced practice nurse in nephrology is evolving rapidly. The following questions and role descriptions were posted on the ANNAlink Advanced Practice ListServe. The dialogue is just beginning--stay tuned! Stay informed and connect to advance your practice!

Medical students' self-assessments and their allocations of learning time

PURPOSE

To investigate the impact of self-assessed diagnostic strengths and weaknesses on medical students' allocation of learning time (one indicator of self-directed learning) during a third-year internal medicine clerkship.

METHOD

In 1997-98, 107 students at the University of Michigan Medical School self-assessed their diagnostic skills in 14 clinical areas before and after the clerkship and reported the relative amounts of time spent learning about these topics during the clerkship.

RESULTS

Individual-level analyses indicated that, for the average student, self-assessed strengths and weaknesses did not correlate with allocation of educational time, but that time allocation was positively related to changes in self-assessed skill. Considerable variations in these relationships, however, suggest a need for closer study.

CONCLUSION

Although individual students evidenced different levels of self-directed learning, this study suggests overall that students at this level of training are neophytes in applying both information generated through self-assessment and principles of self-directed learning in their clinical education. Attempts to advance students beyond this level depend on many factors, including the extent to which the learning environment encourages or even permits self-directed learning, the progression and time frame through which students become self-directed practitioners, and the impact of educational interventions to promote this development.

Copper accumulation by sulfate-reducing bacterial biofilms

Sulfate-reducing bacterial biofilms were grown in continuous culture. When exposed to medium containing 20 or 200 microM Cu, biofilms accumulated Cu. Energy-dispersive X-ray analysis (EDXA) showed that accumulation of Cu occurred in the form of sulfides while EDXA mapping of Cu and S in biofilm sections indicated that they were not uniformly distributed but located in the surface of the biofilm. While the polymer content of biofilm exposed to 20 microM Cu did not appear to increase relative to control Cu-free biofilms, biofilms exposed to 200 microM Cu accumulated carbohydrate and smaller amounts of protein throughout the incubation period. The mechanism of uptake, therefore, appeared to be precipitation of Cu sulfides at the biofilm surface or in the liquid phase followed by entrapment of precipitated Cu sulfide by the exopolymer-enhanced biofilm.

Testicular dysfunction in men with primary hypothyroidism; reversal of hypogonadotrophic hypogonadism with replacement thyroxine

OBJECTIVE

Primary hypothyroidism can cause disturbances in normal gonadal function. The aim of this study was to investigate the relationship in men between hypogonadism and primary hypothyroidism and the extent to which free and total testosterone levels rose after introduction of replacement thyroxine.

DESIGN

Paired study of patients in a hypothyroid and thyroxine treated state.

PATIENTS

Ten men with primary hypothyroidism.

MEASUREMENTS

Free and total testosterone, gonadotrophin and prolactin levels before and after thyroxine replacement therapy.

RESULTS

Low free testosterone levels (161 +/- 62 pmol/l) demonstrated at the time the men were hypothyroid rose significantly with the commencement of thyroxine replacement (315 +/- 141 pmol/l; P < 0.001). Gonadotrophin levels were not elevated consistent with hypogonadotrophic hypogonadism. Hyperprolactinaemia, which can occur in primary hypothyroidism and cause hypogonadotrophic hypogonadism, was not present in the majority of these patients. However a reduction in prolactin level was evident with thyroxine replacement and a rise in free testosterone levels.

CONCLUSION

This suggests an effect of hypothyroidism on gonadotrophin secretion at the level of the hypothalamus-pituitary, either directly or through modulation of prolactin secretion. Low free testosterone may also be a contributing factor to some of the symptoms and signs of hypothyroidism in men.

Intra-arterial thrombolysis in a patient presenting with an ischemic stroke due to spontaneous internal carotid artery dissection

We describe a case of a 38-year-old male who presented with acute onset of right-sided hemiplegia and aphasia, who was transferred for emergent percutaneous intervention. Angiography revealed a dissection with total occlusion of the left internal carotid artery (ICA) with propagation of thrombus in the distribution of the middle cerebral artery (MCA). Therapy was directed at the MCA and not the ICA. Intra-arterial thrombolysis was performed on the M1 and M2 branches of the left middle cerebral artery, resulting in almost complete resolution of symptoms during the angiography procedure. Heparin was continued postprocedure, and the patient was discharged home on warfarin and aspirin with minimal residual symptoms.

Cytokine profile of a long-term pediatric HIV survivor with hyper-IgE syndrome and a normal CD4 T-cell count

BACKGROUND

An elevated IgE level and increased production of T(H2) cytokines are factors associated with poor prognosis in HIV infection. We report a pediatric long-term survivor of vertically acquired HIV infection with a normal CD4 count and a low viral burden despite the lack of antiretroviral therapy and a phenotype resembling hyper-IgE syndrome.

OBJECTIVE

We sought to characterize the patient's T(H1) versus T(H2) cytokine profile and anti-HIV-specific immune responses.

METHODS

Supernatants collected from cultures of peripheral blood T cells stimulated with phorbol myristate acetate plus ionomycin were assayed for T(H1) and T(H2) cytokines by means of ELISA. Specific IgE antibodies were determined by immunoblot. HIV-specific cytotoxic T-lymphocyte responses were measured from cell lysis by fresh T cells of autologous B-lymphoblastoid cells expressing recombinant HIV proteins.

RESULTS

Patient CD4(+) T cells secreted significantly more T(H2) cytokines, IL-4 (P <.003) and IL-5 (P <.03), than HIV-infected and seronegative control cells. No difference was noted in T(H1) cytokine production. IgE specific for HIV gp160, p24, p17, and p66 proteins and Aspergillus fumigatus was detected in patient sera. Despite predominance of T(H2) cytokines, HIV-specific cytotoxic T-lymphocyte activity was vigorous.

CONCLUSIONS

The patient demonstrated predominantly T(H2) cytokine production in vitro. Unlike other patients with HIV who have hyper-IgE and increased T(H2) cytokine production, our patient has maintained HIV-specific immune responses, a low viral load, and a normal CD4 count without antiretroviral therapy. These findings support a diagnosis of primary hyper-IgE syndrome. Presence of anti-HIV-specific IgE may represent a protective mechanism against HIV replication in our patient.

Vitamin D receptor gene polymorphisms and the risk of fractures in older women. For the Study of Osteoporotic Fractures Research Group

The association between vitamin D receptor gene polypmorphisms and bone mineral density is controversial. The relationship between vitamin D receptor genotype and risk of fracture is uncertain. To determine whether vitamin D receptor polymorphisms were associated with the risk of hip, vertebral, and other (nonhip, nonvertebral) fractures in elderly women, we conducted a case-cohort study within a prospective study of 9704 community-dwelling women aged 65 years and older. Vitamin D receptor allele and genotype frequencies in women who experienced first incident hip (n = 181), vertebral (n = 127), and other (n = 223) fractures were compared with those of control women selected randomly from the cohort. Average length of follow-up was 6.5, 3.7, and 5.4 years for women in hip, vertebral, and other fracture analyses, respectively. Vitamin D receptor polymorphisms were determined by polymerase chain reaction amplification of genomic DNA using TaqI and ApaI restriction site endonuclease digestion. All nonvertebral fractures were confirmed by X-ray reports; hip fractures were validated by review of X-ray films. Vertebral fractures were defined by morphometry using lateral spine radiography at baseline and an average of 3.7 years later. Allele or genotype frequencies did not differ between fracture cases and their respective controls. Vitamin D receptor genotype (defined by TaqI, ApaI, or the combination of TaqI and ApaI) was not significantly associated with the risk of hip, vertebral, or other fractures. For example, compared with the referent group of women with TT genotype, those with Tt and tt genotypes had similar age- and weight-adjusted risks of fracture at the hip (hazard ratios 0.9, 95% confidence interval [CI] 0.6-1.3, and 0.8, 95% CI 0.5-1.2, respectively), spine (odds ratios 1.1, 95% CI 0.7-1.8, and 0.7, 95% CI 0.4-1.3, respectively), or other skeletal site (hazard ratios 1.0, 95% CI 0. 7-1.4, and 1.0, 95% CI 0.7-1.5, respectively). These findings were not altered in additional analyses including those adjusted for and stratified by age, ethnic ancestry, calcaneal bone density, dietary calcium intake, use of calcium supplements, use of vitamin D supplements, and oral estrogen use. We conclude that Vitamin D receptor polymorphisms defined by TaqI and ApaI are not associated with the risk of fracture in older women. Our results suggest that determination of these vitamin D receptor polymorphisms is not a clinically useful test for the prediction of fracture risk in elderly women.

Extracellular metal-binding activity of the sulphate-reducing bacterium Desulfococcus multivorans

Polarography was used to measure the copper-binding ability of culture filtrates from a range of sulphate-reducing bacteria (SRB), including pure cultures and environmental isolates. Of those tested, Desulfococcus multivorans was shown to have the greatest copper-binding capacity and this organism was used for further experiments. Extracellular copper- and zinc-binding activities of Dc. multivorans culture filtrates from batch cultures increased over time and reached a maximum after 10 d growth. The culture filtrate was shown to bind copper reversibly and zinc irreversibly. Twelve-day-old Dc. multivorans culture filtrates were shown to have a copper-binding capacity of 3.64 +/- 0.33 micromol ml(-1) with a stability constant, log10K, of 5.68 +/- 0.64 (n=4). The metal-binding compound was partially purified from culture growth media by dichloromethane extraction followed by HPLC using an acetonitrile gradient.