Cardiolipin biosynthesis and remodeling enzymes are altered during development of heart failure

Cardiolipin (CL) is responsible for modulation of activities of various enzymes involved in oxidative phosphorylation. Although energy production decreases in heart failure (HF), regulation of cardiolipin during HF development is unknown. Enzymes involved in cardiac cardiolipin synthesis and remodeling were studied in spontaneously hypertensive HF (SHHF) rats, explanted hearts from human HF patients, and nonfailing Sprague Dawley (SD) rats. The biosynthetic enzymes cytidinediphosphatediacylglycerol synthetase (CDS), phosphatidylglycerolphosphate synthase (PGPS) and cardiolipin synthase (CLS) were investigated. Mitochondrial CDS activity and CDS-1 mRNA increased in HF whereas CDS-2 mRNA in SHHF and humans, not in SD rats, decreased. PGPS activity, but not mRNA, increased in SHHF. CLS activity and mRNA decreased in SHHF, but mRNA was not significantly altered in humans. Cardiolipin remodeling enzymes, monolysocardiolipin acyltransferase (MLCL AT) and tafazzin, showed variable changes during HF. MLCL AT activity increased in SHHF. Tafazzin mRNA decreased in SHHF and human HF, but not in SD rats. The gene expression of acyl-CoA: lysocardiolipin acyltransferase-1, an endoplasmic reticulum MLCL AT, remained unaltered in SHHF rats. The results provide mechanisms whereby both cardiolipin biosynthesis and remodeling are altered during HF. Increases in CDS-1, PGPS, and MLCL AT suggest compensatory mechanisms during the development of HF. Human and SD data imply that similar trends may occur in human HF, but not during nonpathological aging, consistent with previous cardiolipin studies.     

Utilization of exogenous thymidine by Chlamydia psittaci growing in the thymidine kinase-containing and thymidine kinase-deficient L cells.

The incorporation of [3H]thymidine into the deoxyribonucleic acid (DNA) of Chlamydia psittaci (strain 6BC) growing in thymidine kinase (adenosine 5'-triphosphate-thymidine 5'-phosphotransferase, EC 1.7.1.21)-containing L cells, L(TK+), and thymidine kinase-deficient L cells, LM(TK-), was examined by autoradiography. Label was detected over C. psittaci inclusions in L(TK+) but not LM(TK-) cells. No evidence for a chlamydia-specific thymidine kinase activity in either L(TK+) or LM(TK-) cells was obtained. Entry of [3H]thymidine into the DNA of C. psittaci growing in L(TK+) cells was quantitated by measuring label in purified C. psittaci. It was 265 times less efficient than entry into infected host cell DNA. It is concluded that low levels of exogenous thymidine are incorporated into the DNA of C. psittaci and that this incorporation is dependent on a fully competent host thymidine kinase activity. Evidence also is presented that L cells possess at least two thymidine kinase activities, both of which are capable of supplying thymidylate precursors for nuclear DNA synthesis.     

Regulation of NADP-malate dehydrogenase in C4 plants: relationship among enzyme activity, NADPH to NADP ratios, and thioredoxin redox states in intact maize mesophyll chloroplasts

NADP-malate dehydrogenase activity, the ratio of NADPH to NADP, and thioredoxin redox state in Zea mays chloroplasts were determined after various treatments. Following transfer from dark to light, NADP-malate dehydrogenase was activated more than 20-fold within 10 min while the proportion of pyridine nucleotide as NADPH increased from about 25 to 90%, and the proportion of thioredoxin in the reduced form increased from 20 to more than 90%, in less than 1 min. After transfer back to the dark, NADPH levels dropped very rapidly to the initial values recorded before illumination, while enzyme activity and reduced thioredoxin levels decreased more slowly. Addition of oxaloacetate or 3-phosphoglycerate to illuminated chloroplasts results in a decrease of about 70% in the activity of NADP-malate dehydrogenase, a 30% decrease in the level of NADPH, and a 25% decrease in the reduced thioredoxin content. Adding dihydroxyacetone phosphate and pyruvate had no effect. These results are considered in relation to the hypothesis that NADP-malate dehydrogenase activity in chloroplasts may be determined by factors regulating the ratio of NADPH to NADP as well as those influencing the redox state of thioredoxin.     

Karyometric image analysis for intraepithelial and invasive cervical lesions

OBJECTIVE: To derive an objective, numeric measure for the progression of intraepithelial and invasive squamous cell cervical lesions. STUDY DESIGN: Thin-layer cervical cytology preparations from colposcopically confirmed normal cervix, low grade squamous intraepithelial lesions, high grade squamous intraepithelial lesions and carcinoma were identified from a cross-sectional study. Fifty-nine cases representing 4 diagnostic categories were selected, and 2,375 nuclei from epithelial cells representative of the diagnostic category were randomly selected for imaging and measurement from these cases. Additionally, 1,378 visually normal appearing intermediate cells from low and high grade squamous intraepithelial lesions, as well as from carcinoma cases, were identified for analysis. The nuclei were quantitatively characterized, and discriminant analyses were performed to derive a progression curve from normal cytology to carcinoma. RESULTS: The lesion signatures show a clear increase in nuclear abnormality with increasing progression. A progression curve was derived based on mean discriminant function scores for each diagnostic category and on the mean nuclear abnormality values for the nuclei in each category, as expressed by their deviation in feature values from normal reference nuclei. CONCLUSION: A numeric assessment of lesion progression for cervical precancerous and cancerous lesions based on karyometric measurements is possible and may provide an objective, precise characterization of each lesion as well as a basis for improved performance in automated cytology-based cervical cancer screening.     

Investigating Exposure to Violence and Mental Health in a Diverse Urban Community Sample: Data from the South East London Community Health (SELCoH) Survey

Background

General population surveys have seldom examined violence as a multidimensional concept and in relation to an array of mental disorders.

Methods

Data from the South East London Community Health Study was used to examine the prevalence, overlap and distribution of proximal witnessed, victimised and perpetrated violence and their association with current mental disorders. We further investigated the cumulative effect of lifetime exposure to violence on current mental disorders. Unadjusted and adjusted (for confounders and violence) models were examined.

Results

In the last twelve months, 7.4% reported witnessing violence, 6.3% victimisation and 3.2% perpetration of violence. There was a significant overlap across violence types, with some shared correlates across the groups such as being younger and male. Witnessing violence in the past year was associated with current common mental disorders (CMD) and post-traumatic stress disorder (PTSD) symptoms. Proximal perpetration was associated with current CMD, PTSD symptoms and past 12 months drug use; whereas proximal victimisation was associated with lifetime and past 12 months drug use. Lifetime exposure to two or more types of violence was associated with increased risk for all mental health outcomes, suggesting a cumulative effect.

Conclusion

Exposure to violence needs to be examined in a multi-faceted manner: i) as discrete distal and proximal events, which may have distinct patterns of association with mental health and ii) as a concept with different but overlapping dimensions, thus also accounting for possible cumulative effects.     

Exogenous arachidonic acid mediates permeability of human brain microvessel endothelial cells through prostaglandin E2 activation of EP3 and EP4 receptors

The blood–brain barrier, formed by microvessel endothelial cells, is the restrictive barrier between the brain parenchyma and the circulating blood. Arachidonic acid (ARA; 5,8,11,14‐cis‐eicosatetraenoic acid) is a conditionally essential polyunsaturated fatty acid [20:4(n ? 6)] and is a major constituent of brain lipids. The current study examined the transport processes for ARA in confluent monolayers of human brain microvascular endothelial cells (HBMEC). Addition of radioactive ARA to the apical compartment of HBMEC cultured on Transwell^® inserts resulted in rapid incorporation of radioactivity into the basolateral medium. Knock down of fatty acid transport proteins did not alter ARA passage into the basolateral medium as a result of the rapid generation of prostaglandin E₂ (PGE₂), an eicosanoid known to facilitate opening of the blood–brain barrier. Permeability following ARA or PGE₂ exposure was confirmed by an increased movement of fluorescein‐labeled dextran from apical to basolateral medium. ARA‐mediated permeability was attenuated by specific cyclooxygenase‐2 inhibitors. EP₃ and EP₄ receptor antagonists attenuated the ARA‐mediated permeability of HBMEC. The results indicate that ARA increases permeability of HBMEC monolayers likely via increased production of PGE₂ which acts upon EP₃ and EP₄ receptors to mediate permeability. These observations may explain the rapid influx of ARA into the brain previously observed upon plasma infusion with ARA.