Association of mitral annulus calcification, aortic valve sclerosis and aortic root calcification with abnormal myocardial perfusion single photon emission tomography in subjects age < or =65 years old

OBJECTIVES

We examined the hypothesis that mitral annulus calcification (MAC), aortic valve sclerosis (AVS) and aortic root calcification (ARC) are associated with coronary artery disease (CAD) in subjects age < or =65 years.

BACKGROUND

Mitral annulus calcification, AVS and ARC frequently coexist and are associated with coronary risk factors and CAD in the elderly.

METHODS

We studied 338 subjects age < or =65 years who underwent evaluation of chest pain with myocardial perfusion single photon emission computed tomography (SPECT) and a two-dimensional transthoracic echocardiogram for other indications. The association of MAC, AVS and ARC with abnormal SPECT was evaluated by using chi-square analyses and logistic regression analyses.

RESULTS

Compared with no or one calcium deposit and no or one coronary risk factor other than diabetes, multiple (> or =2) calcium (or sclerosis) deposits with diabetes or multiple (> or =2) coronary risk factors were significantly associated with abnormal SPECT in women age < or =55 years old (odds ratio [OR], 20.00), in women age >55 years old (OR, 10.00) and in men age < or =55 years old (OR, 5.55). Multivariate analyses identified multiple calcium deposits as a significant predictor for an abnormal SPECT in women (p < 0.001), younger subjects age < or =55 years (p < 0.05) and the total group of subjects (p < 0.01).

CONCLUSIONS

When coronary risk factors are also taken into consideration, the presence of multiple calcium deposits in the mitral annulus, aortic valve or aortic root appears to be a marker of CAD in men < or =55 years old and women.

Delta13C and deltaD values of Opuntia atacamensis depending on different environmental conditions in the Atacama desert of Northern Chile

We analysed 13carbon and deuterium discrimination in Opuntia atacamensis PHIL. at three different sites in the Atacama desert in Northern Chile: At the western Andean slopes, influenced by summer rainfall, in the very arid Chilean central valley, and at coastal fog mountains. At the most arid site, the central valley, discrimination of 13C and D was less (delta-values less negative) and also discrimination more against deuterium. This is an aridity, not an altitude effect. The differences in 13C content may be due to some carbon fixation via the C3 photosynthetic pathway at the more humid sites. Deuterium enrichment at the arid sites might be due to greater discrimination of HDO against H2O during transpirational water loss.

Molecular determinants of inactivation in voltage-gated Ca2+ channels

Evolution has created a large family of different classes of voltage-gated Ca2+ channels and a variety of additional splice variants with different inactivation properties. Inactivation controls the amount of Ca2+ entry during an action potential and is, therefore, believed to play an important role in tissue-specific Ca2+ signalling. Furthermore, mutations in a neuronal Ca2+ channel (Ca(v)2.1) that are associated with the aetiology of neurological disorders such as familial hemiplegic migraine and ataxia cause significant changes in the process of channel inactivation. Ca2+ channels of a given subtype may inactivate by three different conformational changes: a fast and a slow voltage-dependent inactivation process and in some channel types by an additional Ca2+-dependent inactivation mechanism. Inactivation kinetics of Ca2+ channels are determined by the intrinsic properties of their pore-forming alpha1-subunits and by interactions with other channel subunits. This review focuses on structural determinants of Ca2+ channel inactivation in different parts of Ca2+ channel alpha1-subunits, including pore-forming transmembrane segments and loops, intracellular domain linkers and the carboxyl terminus. Inactivation is also affected by the interaction of the alpha1-subunits with auxiliary beta-subunits and intracellular regulator proteins. The evidence shows that pore-forming S6 segments and conformational changes in extra- (pore loop) and intracellular linkers connected to pore-forming segments may play a principal role in the modulation of Ca2+ channel inactivation. Structural concepts of Ca2+ channel inactivation are discussed.

Molecular determinants of inactivation in voltage-gated Ca2+ channels

Evolution has created a large family of different classes of voltage-gated Ca2+ channels and a variety of additional splice variants with different inactivation properties. Inactivation controls the amount of Ca2+ entry during an action potential and is, therefore, believed to play an important role in tissue-specific Ca2+ signalling. Furthermore, mutations in a neuronal Ca2+ channel (Ca(v)2.1) that are associated with the aetiology of neurological disorders such as familial hemiplegic migraine and ataxia cause significant changes in the process of channel inactivation. Ca2+ channels of a given subtype may inactivate by three different conformational changes: a fast and a slow voltage-dependent inactivation process and in some channel types by an additional Ca2+-dependent inactivation mechanism. Inactivation kinetics of Ca2+ channels are determined by the intrinsic properties of their pore-forming alpha1-subunits and by interactions with other channel subunits. This review focuses on structural determinants of Ca2+ channel inactivation in different parts of Ca2+ channel alpha1-subunits, including pore-forming transmembrane segments and loops, intracellular domain linkers and the carboxyl terminus. Inactivation is also affected by the interaction of the alpha1-subunits with auxiliary beta-subunits and intracellular regulator proteins. The evidence shows that pore-forming S6 segments and conformational changes in extra- (pore loop) and intracellular linkers connected to pore-forming segments may play a principal role in the modulation of Ca2+ channel inactivation. Structural concepts of Ca2+ channel inactivation are discussed.

The effect of audit and feedback on immunization delivery: a systematic review

OBJECTIVE

To assess the effective of audit and feedback (A&F) on immunization delivery by health care professionals.

DESIGN

Systematic review of published literature.

MAIN OUTCOME MEASURES

Changes in immunization rates.

METHODS

We searched Medline between 1966 and 1997. We obtained additional studies from back-searching reference lists and the files of study collaborators. We included studies that were written in English, that included audit and feedback in at least one arm of the study, that studied universally recommended childhood or adult vaccines, and that provided immunization coverage data. Two reviewers read studies independently and abstracted using a validated checklist. Study quality was assessed using criteria standardized by the Cochrane Collaboration. Differences between reviewers were resolved by consensus.

RESULTS

The search process resulted in 60 citations; 44 were fully reviewed and 15 met eligibility criteria. Five were randomized trials. Twelve of the fifteen studies found that A&F, alone or in combination with other interventions, were associated with improvements in immunization rates. The magnitude of the effect varied from -17% to +49% change. Study design heterogeneity precluded statistical pooling of study results.

CONCLUSIONS

The evidence available from published studies suggests that A&F alone may be an effective strategy for improving immunization rates. The number of well-conducted studies is small, and the effect is variable. Additional well-designed studies are needed to identify the independent effects of A&F, optimal format and frequency of A&F, and to examine its long-term effect on provider immunization practices and costs.

A randomized study of tracking with outreach and provider prompting to improve immunization coverage and primary care

OBJECTIVE

To compare and measure the effects and cost-effectiveness of two interventions designed to raise immunization rates.

SETTINGS

Nine primary care sites serving impoverished and middle-class children.

SUBJECTS

Complete birth cohorts (ages 0 to 12 months; n = 3015) from these sites.

INTERVENTIONS

Two 18-month duration interventions: 1) tracking with outreach [tracking/outreach] to bring underimmunized children to their primary care provider office, and 2) a primary care provider office policy change to identify and reduce missed immunization opportunities (prompting).

DESIGN

Randomized, controlled trial, randomizing within sites using a two-by-two factorial design. Subjects were allocated to one of four study groups: control, prompting only, tracking/outreach only, and combined prompting with tracking/outreach. Outcomes were obtained by blinded chart abstraction.

MEASURES

Immunization status for age; number of days of delay in immunization; primary care utilization; and rates of screening for occult disease.

RESULTS

Out of 3015 subjects, 274 subjects (9%) transferred out of the participating sites or had incomplete charts and were excluded. The 2741 (91%) remaining subjects were assessed. At baseline, study groups did not differ in age, gender, insurance type, or immunization status. Of the remaining subjects, 63% received Medicaid. Final series-complete immunization coverage levels were: control, 74%; prompting-only, 76%; tracking/outreach-only 95%; and combined tracking/outreach with prompting, 95%. Analysis of variance showed that: 1) tracking/outreach increased immunization rates 20 percentage points; 2) tracking/outreach decreased mean immunization delay 63 days; 3) tracking/outreach increased mean health supervision visits 0.44 visits per child; 4) tracking/outreach increased mean anemia screening 0.17 screenings per child and mean lead screenings 0.12 screenings per child; 5) impact of tracking/outreach was greatest for uninsured and impoverished patients; and 6) the prompting intervention had no impact on the studied outcomes, and its failure was caused by inconsistent use of prompts and failure to vaccinate ill children when prompted. Using tracking/outreach, the cost per additional child fully immunized was $474. Each $1000 spent on the tracking/outreach intervention resulted in: 2.1 additional fully vaccinated children and 668 fewer child-days of delayed immunization; 4.6 additional health supervision visits and 5.9 additional other visits to the primary care provider; and 1.8 additional anemia screenings and 1.3 additional lead screenings.

CONCLUSIONS

Outreach directed toward children not up-to-date on immunizations improves not only immunization status, but also health supervision visit attendance and screening rates. The cost per additional child immunized was high, but should be interpreted in view of the spillover benefits that accompanied improved immunization. Effective means to improve coverage by reducing missed immunization opportunities still need to be identified.

Beta subunit heterogeneity in neuronal L-type Ca2+ channels

Heterologous expression studies have shown that the activity of voltage-gated Ca2+ channels is regulated by their beta subunits in a beta subunit isoform-specific manner. In this study we therefore investigated if one or several beta subunit isoforms associate with L-type Ca2+ channels in different regions of mammalian brain. All four beta subunit isoforms (beta1b, beta2, beta3, and beta4) are expressed in cerebral cortex as shown in immunoblots. Immunoprecipitation of (+)-[3H]isradipine-labeled L-type channels revealed that the majority of beta subunit-associated L-type channels was associated with beta3 (42 +/- 8%) and beta4 (42 +/- 7%) subunits, whereas beta1b and beta2 were present in a smaller fraction of channel complexes. beta3 and beta4 were also the major L-type channel beta subunits in hippocampus. In cerebellum beta1b, beta2, and beta3 but not beta4 subunits were expressed at lower levels than in cortex. Accordingly, beta4 was the most prominent beta subunit in cerebellar L-type channels. This beta subunit composition was very similar to the one determined for 125I-omega-conotoxin-GVIA-labeled N-type and 125I-omega-conotoxin-MVIIC-labeled P/Q-type channel complexes in cerebral cortex and cerebellum. Our data show that all four beta subunit isoforms associate with L-type Ca2+ channels in mammalian brain. This beta subunit heterogeneity may play an important role for the fine tuning of L-type channel function and modulation in neurons.

DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites in urine of coke oven workers

OBJECTIVES

To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, 32P postlabelling assay, measurement of sister chromatid exchange) in workers exposed to polycyclic aromatic hydrocarbons (PAHs).

METHODS

29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (alkaline filter elution assay), sister chromatid exchange, and DNA adducts (32P postlabelling assay) in lymphocytes. Phenanthrene and pyrene metabolites were measured in 24 hour urine samples. 19 different PAHs (including benzo(a)pyrene, pyrene, and phenanthrene) were measured at the workplace by personal air monitoring. The GSTT1 activity in erythrocytes and lymphocyte subpopulations in blood was also measured.

RESULTS

Concentrations of phenanthrene, pyrene, and benzo(a)pyrene in air correlated well with the concentration of total PAHs in air; they could be used for comparisons of different workplaces if the emission compositions were known. The measurement of phenanthrene metabolites in urine proved to be a better biological monitoring variable than the measurement of 1-hydroxypyrene. Significantly more DNA strand breaks in lymphocytes of coke oven workers were found (alkaline filter elution assay); the DNA adduct rate was not significantly increased in workers, but correlated with exposure to PAHs in a semiquantitative manner. The number of sister chromatid exchanges was lower in coke oven workers but this was not significant; thus counting sister chromatid exchanges was not a good variable for biomonitoring of coke oven workers. Also, indications for immunotoxic influences (changes in lymphocyte subpopulations) were found.

CONCLUSIONS

The measurement of phenanthrene metabolites in urine seems to be a better biological monitoring variable for exposure to PAHs than measurement of hydroxypyrene. The alkaline filter elution assay proved to be the most sensitive biomarker for genotoxic damage, whereas the postlabelling assay was the only one with some specificity for DNA alterations caused by known compounds.

Gangliosides GM1, GM2 and GM3 inhibit the platelet-derived growth factor-induced signalling transduction pathway in vascular smooth muscle cells by different mechanisms

Gangliosides appear to regulate proliferation of different cell types. In the present study, we investigated the effects of gangliosides GM1, GM2 and GM3 on platelet-derived growth factor (PDGF)-induced vascular smooth muscle cell (VSMC) growth. In addition, we examined the effects of gangliosides on the PDGF-BB-dependent signalling transduction pathway in rat aortic VSMC. GM2 and GM1 inhibit the PDGF-BB-dependent receptor tyrosine autophosphorylation, stimulation of the PLC-gamma 1, increase of inositol-1,4,5-trisphosphate (InsP3), elevation in cytosolic free Ca2+ ([Ca2+]i), expression of the immediate early growth response gene c-fos and cell proliferation with the following rank order of potency GM2 > GM1. Although GM3 did not influence the PDGF-BB-dependent receptor autophosphorylation and PLC-gamma 1 activation, it effectively inhibited the PDGF-BB-dependent InsP3 formation, [Ca2+]i and cell growth. Binding studies with 125I-PDGF-BB on VSMC in the presence and absence of 10 to 50 microM of each ganglioside revealed that GM1 and GM2 effectively inhibited the specific binding of PDGF-BB with an IC50 value of 20 microM for GM2 and 30 microM for GM1. GM3 had no significant effect on the specific 125I-PDGF-BB binding. These observations suggest that GM1 and GM2 may interact with PDGF-BB or its receptor resulting in a prevention of its binding. GM3 was able to suppress the PDGF-BB-dependent increase of InsP3 and [Ca2+]i downstream of the PDGF-BB-dependent receptor autophosphorylation and PLC-gamma 1 activity.

Identification of benz(othi)azepine-binding regions within L-type calcium channel alpha1 subunits

To identify the binding domain for diltiazem-like Ca2+ antagonists on L-type Ca2+ channel alpha1 subunits we synthesized the benzazepine [3H]benziazem as a novel photoaffinity probe. [3H]Benziazem reversibly labeled the benzothiazepine (BTZ)-binding domain of partially purified skeletal muscle Ca2+ channels with high affinity (Kd = 12 nM) and photoincorporated into its binding domain with high yield (>66%). Antibody mapping of proteolytic labeled fragments revealed specific labeling of regions associated with transmembrane segments S6 in repeats III and IV. More than 50% of the labeling was found in the tryptic fragment alanine 1023-lysine 1077 containing IIIS6 together with extracellular and intracellular amino acid residues. The remaining labeling was identified in a second site comprising segment S6 in repeat IV and adjacent residues. Unlike for dihydropyridines, no labeling was observed in the connecting IIIS5-IIIS6 linker. The [3H]benziazem photolabeled regions must be in close contact to the drug molecule when bound to the channel. We propose that the determinants for high affinity BTZ binding are located within or in close proximity to segments IIIS6 and/or IVS6. Therefore the binding domain for BTZs, like for the other main classes of Ca2+ antagonists, must be located in close proximity to pore-forming regions of the channel.

32P-postlabeling analysis of DNA adducts in different populations

Blood samples were obtained from different populations exposed occupationally or by lifestyle habits to polycyclic aromatic hydrocarbons (PAH). DNA adducts were determined by 32P-postlabeling assay either in white blood cells (WBC) or lymphocytes. The level of DNA adducts ranged from 1.5 per 10(9) nucleotides in one of the control groups up to 7.1 per 10(9) nucleotides in one group of PAH-exposed workers. Comparison of the adduct thin layer chromatography (TLC) profiles revealed individual variation in both pattern and level of DNA adducts. Significant differences of adduct levels were detected between one group of PAH-exposed coke-oven workers and the corresponding control group. Only a weak influence of the smoking habits on the amount of adducts was detectable in occupationally exposed or unexposed individuals.

Sister chromatid exchange frequencies in lymphocytes of oral cancer patients seem to be influenced by drinking habits

Sister chromatid exchange (SCE) values were determined in the lymphocytes of 24 oral cancer patients before therapy and in the lymphocytes of 24 control persons standardized with respect to sex, age and smoking habits. Oral cancer patients showed significantly elevated SCE values (mean 7.82 versus 6.42). In both groups the highest SCE values were found in the subgroups with the highest alcohol consumption. A significant correlation between SCE and gamma-glutamyltranspeptidase (GGT) values by Spearman correlation analysis was detected in the combined group (cancer patients and control persons) (n = 32, r = 0.40, P = 0.023). The SCE values in the oral cancer patients were weakly correlated (Pearson) to DNA adduct levels (n = 22, r = 0.39, P = 0.068) and DNA single-strand breakage frequencies (n = 12, r = 0.56, P = 0.054) in lymphocytes. The correlation (Pearson) between SCE values and DNA strand breakage values in lymphocytes was significant (n = 10, r = 0.67, P = 0.036) in smoking cancer patients. The increase of SCE values with respect to alcohol drinking habits underlines epidemiologic findings that alcohol is an important co-carcinogen in many cancers, especially in oral cancers. Because of the influences on SCE and adduct levels in lymphocytes, alcohol drinking habits should be controlled as broadly as possible in biomarker studies.

DNA strand breakage and DNA adducts in lymphocytes of oral cancer patients

In lymphocytes of 12 oral cancer patients (and two control groups) the frequencies of DNA single-strand breaks and DNA-protein cross-linking were determined by alkaline filter elution. We found elevated DNA elution rates, which must be interpreted as an increased strand breakage frequency. There were significant correlations between the DNA strand breakage frequency and smoking habits. Using the 32P-postlabelling assay we determined the DNA adduct level in lymphocytes of 23 oral cancer patients (and two control groups). No significant influence of smoking habit on the DNA adduct level could be detected. There was a significant correlation between the DNA adduct level and the gamma-glutamyltranspeptidase (GGT) value, suggesting systemic influences of alcohol drinking habits on the adduct level.

[Polychlorinated biphenyls (PCBs) and reproduction disturbances]

A review of the impact of chlorinated biphenyls (PCBs) on reproduction is presented. PCBs are able to pass the placenta; accumulation in offspring is mainly achieved by breast feeding. Disturbances of fertility and embryotoxicity were detected in animals; teratogenicity without maternal toxicity was only observed in mice. In animal experiments disturbances of fetal and postnatal development were detected as well as in human studies. Neurotoxicity was observed even at low-level exposures in monkeys, which are most comparable to humans because of the development of the same clinical symptoms. Technical PCBs which are dominating in occupational and environmental exposure until now must be judged as toxic for reproduction: dermal exposure (especially in accidents) should be considered as an important route of exposure beside inhalation. Work to list possible PCB exposure risks and to develop ways to reduce these risks are necessary now.

Activity testing of alveolar macrophages and changes in surfactant phospholipids after irradiation in bronchoalveolar lavage: experimental and clinical data

This study presents results of bronchoalveolar lavage (BAL) after irradiation to the lungs in mice as well as clinical data. The number of BAL cells, mainly macrophages, lymphocytes, and granulocytes, changed in a time-dependent manner. The phagocytic activity of the macrophages measured as the phagocytosis of microbeads and measured as the esterase activity also showed a strong time-dependent increase during the acute phase up to 21 days after irradiation. The contents of surfactant phospholipids (SF) and sphingomyelin (SPH; as a parameter for cell death) were quantified by HPLC. Both were significantly changed between day 2 and 21 after irradiation. Three BALs of a patient with idiopathic interstitial pneumonitis, who had received an allogenic bone marrow graft after total body irradiation with 10 Gy, showed similar effects in the cellular and surfactant parameters. These data indicate that there are positive interactions between the number of different BAL cells, macrophage activity, and SF and SPH content in the preclinical model of the mouse as well as in the clinical situation after lung irradiation.

Radiation-induced changes in lung tissue and development of fibrosis determined by quantitative morphometric methods

This study presents results of morphometric investigations of mouse lungs after single irradiation. An automatic image analyser was used to monitor pathological changes in morphological structure, especially the size and distribution of collagen fibres, the thickness of the septa and the diameters of alveoli in the lung. Radiation-induced changes in the area of alveoli and septa as well as collagen content were seen 11 weeks after irradiation. A dose-dependent increase in tissue and decrease in alveolar surface as well as a quantifiable increase in radiation oedema were seen. The septa were thickened and the total collagen content increased in a dose-dependent manner. The morphometric methods used here are suitable for determining changes in lung structure, particularly those in collagen content in the early phase of a pathological response after thorax or total body irradiation for conditioning in bone marrow transplantation.