Projected costs of ischemic stroke in the United States

BACKGROUND

There are barriers to acute stroke care in minority groups as well as a higher incidence of ischemic stroke when compared with non-Hispanic whites.

OBJECTIVE

To estimate the future economic burden of stroke in non-Hispanic whites, Hispanics, and African Americans in the United States from 2005 to 2050.

METHODS

We used U.S. Census estimates of the race-ethnic group populations age 45 years and older. We obtained stroke epidemiology and service utilization data from the Northern Manhattan Stroke Study and the Brain Attack Surveillance in Corpus Christi project and other published data. We estimated costs directly from Medicare reimbursement or from studies that used Medicare reimbursement. Direct and indirect costs considered included ambulance services, initial hospitalization, rehabilitation, nursing home costs, outpatient clinic visits, drugs, informal caregiving, and potential lost earnings.

RESULTS

The total cost of stroke from 2005 to 2050, in 2005 dollars, is projected to be 1.52 trillion dollars for non-Hispanic whites, 313 billion dollars for Hispanics, and 379 billion dollars for African Americans. The per capita cost of stroke estimates are highest in African Americans (25,782 dollars), followed by Hispanics (17,201 dollars), and non-Hispanic whites (15,597 dollars). Loss of earnings is expected to be the highest cost contributor in each race-ethnic group.

CONCLUSIONS

The economic burden of stroke in African Americans and Hispanics will be enormous over the next several decades. Further efforts to improve stroke prevention and treatment in these high stroke risk groups are necessary.

Overprescribing of lipid lowering agents

BACKGROUND

Undertreatment of hyperlipidemia has received considerable attention. However, little is known about trends in overprescribing of lipid lowering agents. We examined these trends and their associations with physician, practice, and organisational factors.

METHODS

2034 physicians were surveyed twice: baseline (1996-7) and follow up (1998-9). On each occasion they were asked: "For what percentage of 50 year old men without other cardiac risk factors would you recommend an oral agent for total cholesterol of 240, LDL 150, and HDL 50 after 6 months on a low cholesterol diet?" During the survey period the National Cholesterol Education Program guidelines did not recommend prescribing for these patients. Binomial and multinomial logistic regressions assessed baseline overprescribing and longitudinal changes in overprescribing, accounting for complex sampling.

RESULTS

39% of physicians recommended prescribing at baseline (round 1), increasing at follow up (round 2) to 51% (p < 0.001). Physicians who were more likely to overprescribe at baseline were less likely to be board certified (odds ratio (OR) 0.49, 95% confidence interval (CI) 0.38 to 0.63; p < 0.001), were in solo or two-physician practices (OR 1.88, 95% CI 1.46 to 2.41; p < 0.001), had more revenue from Medicare (OR 1.10, 95% CI 1.03 to 1.17; p = 0.004) or Medicaid (OR 1.09, 95% CI 1.01 to 1.18; p = 0.03), or were family physicians (OR 1.87, 95% CI 1.35 to 2.58; p < 0.001). Physicians with large increases in overprescibing were more likely than those with small increases in overprescribing to be international medical graduates (OR 2.09, 95% CI 1.20 to 3.64; p = 0.011) and to spend more hours in patient care (OR 1.14, 95% CI 1.03 to 1.26; p = 0.016).

CONCLUSIONS

Overprescribing of lipid lowering agents is commonplace and increased. At baseline and longitudinally, overprescribing was primarily associated with physician and practice characteristics and not with organisational factors.

Trace copper levels in the drinking water, but not zinc or aluminum influence CNS Alzheimer-like pathology

Mounting evidence suggests copper may influence the progression of Alzheimer's disease by reducing clearance of the amyloid beta protein (Abeta) from the brain. Previous experiments show that addition of only 0.12 PPM copper (one-tenth the Environmental Protection Agency Human consumption limits) to distilled water was sufficient to precipitate the accumulation of Abeta in the brains of cholesterol-fed rabbits (1). Here we report that addition of copper to the drinking water of spontaneously hypercholesterolemic Watanabe rabbits, cholesterol-fed beagles and rabbits, PS1/APP transgenic mice produced significantly enhanced brain levels of Abeta. In contrast to the effects of copper, we found that aluminum- or zinc-ion-supplemented distilled water did not have a significant effect on brain Ab accumulation in cholesterol-fed rabbits. We also report that administration of distilled water produced a reduction in the expected accumulation of Ab in three separate animal models. Collectively, these data suggest that water quality may have a significant influence on disease progression and Ab neuropathology in AD.

Ultrastructural analysis of a murine model of congenital hydrocephalus produced by overexpression of transforming growth factor-beta1 in the central nervous system

The purpose of this study was to elucidate using transmission electron microscopy (TEM) the ultrastructural changes that occur within the cortical gray matter of a novel reproducible model of congenital hydrocephalus in mice created to overexpress the cytokine transforming growth factor-beta1 (TGF-beta1) in the central nervous system. Brain tissue was obtained from mice from a colony engineered to overexpress TGF-beta1 at two days postpartum and compared to a wild-type aged-matched control. This tissue was fixed using a solution containing 1.25% paraformaldehyde and 1.25% glutaraldehyde in phosphate buffer at least 3-4 h and then cut into 40-50 microm sections. Randomly selected thin sections were stained with uranyl acetate and lead citrate, and then analyzed using a JEOL-100CX or 1200EX transmission electron microscope at accelerating voltage 80 kV. Dramatic neuronal and glial pathology was observed throughout the cortical neuropil in TGF-beta1 mice. The most striking change in the hydrocephalic mice was severe edema with extracellular fluid, possibly due to cerebrospinal fluid (CSF) penetration into the cortex. In addition, severe disruption of the cytoplasmic matrix was seen throughout the cortex, with damage to cellular organelles and particularly severe damage to mitochondria. Our results suggest that congenital hydrocephalus may be associated with significant damage to cortical tissue.

Differences in intracerebral hemorrhage between Mexican Americans and non-Hispanic whites

BACKGROUND

Mexican Americans (MAs) have higher incidence rates of intracerebral hemorrhage (ICH) than non-Hispanic whites (NHWs). The authors present clinical and imaging characteristics of ICH in MAs and NHWs in a population-based study.

METHODS

This work is part of the Brain Attack Surveillance in Corpus Christi (BASIC) project. Cases of nontraumatic ICH were identified from 2000 to 2003. Multivariable logistic regression was used to assess the independent associations between ethnicity and ICH location (lobar vs nonlobar) and volume (> or = 30 vs < 30 mL), adjusting for demographics and baseline clinical characteristics. Logistic regression was also used to determine the association between ethnicity and in-hospital mortality, adjusting for confounders.

RESULTS

A total of 149 MAs and 111 NHWs with ICH were identified. MAs were younger (70 vs 77, p < 0.001), more often male (55% vs 42%, p = 0.04), had a lower prevalence of atrial fibrillation (2.0% vs 13%, p < 0.001), and a higher prevalence of diabetes (39% vs 19%, p < 0.001). MA ethnicity was independently associated with nonlobar hemorrhage (OR 2.08, 95% CI: 1.15, 3.70). MAs had over two times the odds of having small (< 30 mL) hemorrhages compared with NHWs (OR = 2.41, 95% CI: 1.31, 4.46). NHWs had higher in-hospital mortality, though this association was no longer significant after adjustment for ICH volume, location, age, and sex.

CONCLUSIONS

There are significant differences in the characteristics of ICH in MAs and NHWs, with MA patients more likely to have smaller, nonlobar hemorrhages. These differences may be used to examine the underlying pathophysiology of ICH.

Differential induction of PPAR-gamma by luminal glutamine and iNOS by luminal arginine in the rodent postischemic small bowel

Using a rodent model of gut ischemia-reperfusion (I/R), we have previously shown that the induction of inducible nitric oxide synthase (iNOS) is harmful, whereas the induction of heme oxygenase 1 (HO-1) and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is protective. In the present study, we hypothesized that the luminal nutrients arginine and glutamine differentially modulate these molecular events in the postischemic gut. Jejunal sacs were created in rats at laparotomy, filled with either 60 mM glutamine, arginine, or magnesium sulfate (osmotic control) followed by 60 min of superior mesenteric artery occlusion and 6 h of reperfusion, and compared with shams. The jejunum was harvested for histology or myeloperoxidase (MPO) activity (inflammation). Heat shock proteins and iNOS were quantitated by Western blot analysis and PPAR-gamma by DNA binding activity. In some experiments, rats were pretreated with the PPAR-gamma inhibitor G9662 or with the iNOS inhibitor N-[3(aminomethyl)benzyl]acetamidine (1400W). iNOS was significantly increased by arginine but not by glutamine following gut I/R and was associated with increased MPO activity and mucosal injury. On the other hand, PPAR-gamma was significantly increased by glutamine but decreased by arginine, whereas heat shock proteins were similarly increased in all experimental groups. The PPAR-gamma inhibitor G9662 abrogated the protective effects of glutamine, whereas the iNOS inhibitor 1400W attenuated the injurious effects of arginine. We concluded that luminal arginine and glutamine differentially modulate the molecular events that regulate injurious I/R-mediated gut inflammation and injury. The induction of PPAR-gamma by luminal glutamine is a novel protective mechanism, whereas luminal arginine appears harmful to the postischemic gut due to enhanced expression of iNOS.

Presentation of intracerebral haemorrhage in a community

BACKGROUND

Studies on intracerebral haemorrhage (ICH) from tertiary care centres may not be an accurate representation of the true spectrum of disease presentation.

OBJECTIVE

To describe the clinical and imaging presentation of ICH in a community devoid of the referral bias of an academic medical centre; and to investigate factors associated with lower Glasgow coma scale (GCS) score at presentation, as GCS is crucial to early clinical decision making.

METHODS

The study formed part of the BASIC project (Brain Attack Surveillance in Corpus Christi), a population based stroke surveillance study in a bi-ethnic Texas community. Cases of first non-traumatic ICH were identified from years 2000 to 2003, using active and passive surveillance. Clinical data were collected from medical records by trained abstractors, and all computed tomography (CT) scans were reviewed by a study physician. Multivariable linear regression was used to identify clinical and CT predictors of a lower GCS score.

RESULTS

260 cases of non-traumatic ICH were identified. Median ICH volume was 11 ml (interquartile range 3 to 36) with hydrocephalus noted in 45%. Median initial GCS score was 12.5 (7 to 15). Hydrocephalus score (p = 0.0014), ambient cistern effacement (p = 0.0002), ICH volume (p = 0.014), and female sex (p = 0.024) were independently associated with lower GCS score at presentation, adjusting for other variables.

CONCLUSIONS

ICH has a wide range of severity at presentation. Hydrocephalus is a potentially reversible cause of a lower GCS score. Since early withdrawal of care decisions are often based on initial GCS, recognition of the important influence of hydrocephalus on GCS is warranted before withdrawal of care decisions are made.

Effect of fat content on infection by Listeria monocytogenes in a mouse model

An estimated 2,500 cases of listeriosis occur annually in the United States. Listeriosis is particularly severe among pregnant women and immunocompromised individuals. Little is known regarding the effect of the food matrix on the ability of L. monocytogenes to survive in the gastrointestinal tract and cause systemic infection. Mice were inoculated with various doses of L. monocytogenes in skim milk, Half & Half, or whipping cream to determine whether differences in milk fat content influence the ability of L. monocytogenes to survive passage through the gut and infect the liver or spleen. The number of fecal samples positive for L. monocytogenes increased with increasing doses of L. monocytogenes for all three vehicles. The number of L. monocytogenes cells isolated from liver or spleen of mice dosed with L. monocytogenes was not significantly different among treatment vehicles. Dose-response models revealed that as the dosage of L. monocytogenes was increased in different milk vehicles, the number of L. monocytogenes cells in liver or spleen also increased. Although fat content of food had no dose-dependent effect on L. monocytogenes infection in the murine gastrointestinal tract, we cannot discount the possibility that it may be a factor in L. monocytogenes infections of humans because of differences in the physiology of gastrointestinal tracts of mice and humans.

A scoring system for ascertainment of incident stroke; the Risk Index Score (RISc)

OBJECTIVES

The main objective of this study was to develop and validate a computer-based statistical algorithm that could be translated into a simple scoring system in order to ascertain incident stroke cases using hospital admission medical records data.

METHODS

The Risk Index Score (RISc) algorithm was developed using data collected prospectively by the Brain Attack Surveillance in Corpus Christi (BASIC) project, 2000. The validity of RISc was evaluated by estimating the concordance of scoring system stroke ascertainment to stroke ascertainment by physician and/or abstractor review of hospital admission records.

RESULTS

RISc was developed on 1718 randomly selected patients (training set) and then statistically validated on an independent sample of 858 patients (validation set). A multivariable logistic model was used to develop RISc and subsequently evaluated by goodness-of-fit and receiver operating characteristic (ROC) analyses. The higher the value of RISc, the higher the patient's risk of potential stroke. The study showed RISc was well calibrated and discriminated those who had potential stroke from those that did not on initial screening.

CONCLUSION

In this study we developed and validated a rapid, easy, efficient, and accurate method to ascertain incident stroke cases from routine hospital admission records for epidemiologic investigations. Validation of this scoring system was achieved statistically; however, clinical validation in a community hospital setting is warranted.

Brain and brawn: Parallels in oxidative strength

Neuronal oxidative stress occurs early in the progression of Alzheimer disease (AD), significantly before the development of the pathologic hallmarks, neurofibrillary tangles, and senile plaques. Study of Down syndrome, cases with autosomal dominant mutation, and sporadic AD all suggest amyloid-beta deposition and hyperphosphorylated tau function as compensatory responses and downstream adaptations to ensure that neuronal cells do not succumb to oxidative damage. Amyloid-beta and tau hyperphosphorylation also define vulnerable muscle cells in sporadic inclusion-body myositis (s-IBM). The role of the structural changes of s-IBM, as in AD, remains to be determined but may mark a critical response yielding a novel balance in oxidant homeostasis.

Evaluation of the clinical efficacy of prokinetic drugs in the management of post-operative ileus: Can retrospective data help us?

The objectives of the study were to determine whether retrospective data can be used to answer questions about the efficacy of prokinetic agents when used to treat horses with post-operative ileus (POI). We describe prevalence and mortality of POI with reference to treatment with four prokinetic agents. By combining data from two Hospitals a study population of 55 horses with POI following pedunculated lipoma obstruction (PLO) was established. Univariable and multivariable associations were determined between short term survival and potential explanatory variables. With death as outcome in multivariable models, breed and hospital were significantly associated with outcome but the use of prokinetic agents was not (P=0.15). However, sample size estimates indicate the low power of this study to detect differences in outcome. It was not possible definitively to evaluate the efficacy of prokinetics as treatment for POI following PLO using retrospective data. The data were suggestive of limited efficacy of prokinetics as treatment for POI. It is postulated that the identified association between hospital and survival reflects differences in clinician decision making. The study highlights the need for further prospective studies using randomised clinical trials to evaluate accurately the efficacy of prokinetic agents. This report illustrates difficulties with performing retrospective analysis of clinical data to determine the efficacy of treatment regimes.

Emergency department evaluation of ischemic stroke and TIA: the BASIC Project

OBJECTIVE

To identify demographic and clinical variables of emergency department (ED) practices in a community-based acute stroke study.

METHODS

By both active and passive surveillance, the authors identified cerebrovascular disease cases in Nueces County, TX, as part of the Brain Attack Surveillance in Corpus Christi (BASIC) Project, a population-based stroke surveillance study, between January 1, 2000, and December 31, 2002. With use of multivariable logistic regression, variables independently associated with three separate outcomes were sought: hospital admission, brain imaging in the ED, and neurologist consultation in the ED. Prespecified variables included age, sex, ethnicity, insurance status, NIH Stroke Scale score, type of stroke (ischemic stroke or TIA), vascular risk factors, and symptom presentation variables. Percentage use of recombinant tissue plasminogen activator (rt-PA) was calculated.

RESULTS

A total of 941 Mexican Americans (MAs) and 855 non-Hispanic whites (NHWs) were seen for ischemic stroke (66%) or TIA (34%). Only 8% of patients received an in-person neurology consultation in the ED, and 12% did not receive any head imaging. TIA was negatively associated with neurology consultations compared with completed stroke (odds ratio [OR] 0.35 [95% CI 0.21 to 0.57]). TIA (OR 0.14 [0.10 to 0.19]) and sensory symptoms (OR 0.59 [0.44 to 0.81]) were also negatively associated with hospital admission. MAs (OR 0.58 [0.35 to 0.98]) were less likely to have neurology consultations in the ED than NHWs. Only 1.7% of patients were treated with rt-PA.

CONCLUSIONS

Neurologists are seldom involved with acute cerebrovascular care in the emergency department (ED), especially in patients with TIA. Greater neurologist involvement may improve acute stroke diagnosis and treatment efforts in the ED.

Dissociation and ionization of H+2 by ultrashort intense laser pulses probed by coincidence 3D momentum imaging

Laser-induced dissociation and ionization of H(+)(2) were simultaneously measured using coincidence 3D momentum imaging, allowing direct separation of the two processes, even where the fragment kinetic energy is the same for both processes. The results for 45 and 135 fs 790 nm pulses with an intensity of approximately 2.5 x 10(14) W/cm(2) differ from each other much more than one would expect from previous measurements with longer pulses. Ionization was negligible for the longer pulse and was strongly aligned along the laser polarization for the shorter pulse, but showed no structure in its kinetic energy distribution. In addition, the ionization to dissociation ratio was found to be much smaller than theoretically predicted for H(+)(2).

Soft tissue sarcomas: are current referral guidelines sufficient?

INTRODUCTION

To investigate the adequacy of current early referral guidelines for patients with extremity soft tissue sarcomas.

PATIENTS & METHODS

365 patients with confirmed soft tissue sarcomas were evaluated. Data were collected prospectively and included the length of history and the presence of features in current guidelines suggestive of malignancy (pain, rapidity of growth, depth and tumour size). Statistical analysis included the t-test, ANOVA and the Chi test.

RESULTS

Deep tumours were the commonest (306 patients with deep tumours). Pain was the least consistent feature (176 patients with pain). 345 patients with one or more of the guideline features had an average history of 19.86 months, 238 of these were seen after more than 3 months.

CONCLUSION

Although the majority of soft tissue sarcomas in our patients had one or more of the clinical guideline features, there was still an unacceptable delay in referring these patients to a specialist unit. The referral guidelines should be modified with special emphasis on depth, which is the most sensitive, followed by size and a history of rapid growth. This combined with increased awareness of these guidelines and a well-advertised, open-access clinic linked to a specialist unit should allow for a more rapid evaluation of soft tissue tumours.

No Increase in Rejection or Graft Loss in Kidney Transplant Recipients With Thrombophilia Treated With Anticoagulation and Triple Immunosuppression

INTRODUCTION

Recent studies from Europe have demonstrated that patients with end-stage renal disease who receive a kidney transplant are at an increased risk for rejection and graft loss when compared with patients who have no known thrombophilia. The role of anticoagulation has not been investigated in these patients.

MATERIALS AND METHODS

We prospectively tested patients who were evaluated for a kidney transplant for 8 thrombophilias, protein S and C deficiencies, factor V Leiden mutation, antithrombin III deficiency, anticardiolipin antibody, lupus anticoagulant, prothrombin gene mutation, and heparin-induced platelet antibody (HIPA). Patients with any identified thrombophilia received heparin or argatroban (for HIPA (+) patients) followed by coumadin for 1 year after transplantation. Triple therapy included cyclosporine, prednisone, and CellCept (Roche Pharmaceuticals, Nutley, NJ, USA). Sensitized, black, or repeat transplantation patients received induction with an interleukin (IL)-2 inhibitor. Data were collected in a retrospective manner. Rejection was biopsy-proven.

RESULTS

Of the 112 transplant recipients who were tested for thrombophilia, 37 had 1 or more thrombophilia and 75 had no thrombophilia identified. Twenty-six patients received heparin and 11 received argatroban. There were no differences in recipient age, cold storage time, graft loss, HLA match, rejection episodes, 1-year graft survival, or serum creatinine level at 1 year. Significant differences were noted in posttransplantation bleeding, 35% versus 5%, and delayed graft function, 32% versus 15%, in patients with thrombophilia versus no thrombophilia, respectively.

CONCLUSION

This is the first study to demonstrate that there is no increase in rejection or graft loss in kidney transplant recipients with thrombophilia when treated with anticoagulation and triple immunosuppression.

Effects of x-ray irradiation on material properties

With a new commercial sterilisation technique about to enter the market, this article details a study that compared the effects of existing electron-beam irradiation with X-ray irradiation on different types of plastics commonly used in the manufacture of medical devices. The results are evaluated here.

Evaluation of the dosimetric performance of BANG3® polymer gel

New radiotherapy techniques call for three-dimensional dosimetric methods with high spatial resolution. Radiation sensitive gels read out using MRI T(2) mapping provide an extremely promising option, and commercially available BANG polymer gels provide a convenient route into gel dosimetry. Gel dosimetry is dependent on the ability to calibrate gel response against radiation dose. This in turn is dependent on the reproducibility of response both between gels irradiated to the same dose and for a single gel sample over time. This study aims to evaluate the performance of a commercially available BANG gel. Our experimental arrangement gave excellent precision of radiation delivery (<0.2%) and reproducibility of T(2) measurement (<0.5%). Seven groups of 10 test tubes containing BANG3 gel were irradiated in 0.5 Gy steps between 0 and 3 Gy. A further four groups of four samples were irradiated in 2 Gy steps between 4 and 10 Gy. The gel samples were identical and derived from the same manufacturing batch. MR imaging was carried out four days after irradiation and then at weekly intervals for four weeks. Short-term variation in gel response can readily be corrected using reference samples. Longer term systematic drift of the gel calibration curve was observed relative to reference samples prepared in-house for quality assurance purposes. This implies that read-out of the calibration gels and dosimetry phantom must be performed at the same time after irradiation, or errors of up to 25% may be incurred. Precision of gel response did not change significantly over time. The observation of significantly different T(2) values both prior to irradiation and following irradiation to the same dose (variation up to 15%) illustrates the current difficulties associated with BANG3 gel calibration and constrains the practical utility of these commercially available gels for clinical radiation dosimetry.

Evidence for the role of gonadotropin hormones in the development of Alzheimer disease

Differences in the prevalence and age of onset of Alzheimer disease (AD) in men and women, and observations that hormone replacement therapy (HRT) may prevent the development of AD, caused many to hypothesize that estrogen deficiency contributes to AD. However, recent trials using estrogen failed to show any benefit in preventing or alleviating the disease. To address this and other inconsistencies in the estrogen hypothesis, we suspect that another hormone of the hypothalamic-pituitary-gonadal axis, luteinizing hormone (LH), as a major factor in AD pathogenesis. Individuals with AD have elevated levels of LH when compared with controls, and both LH and its receptor are present in increased quantities in brain regions susceptible to degeneration in AD. LH is also known to be mitogenic, and could therefore initiate the cell cycle abnormalities known to be present in AD-affected neurons. In cell culture, LH increases amyloidogenic processing of amyloid-beta protein precursor, and in animal models of AD, pharmacologic suppression of LH and FSH reduces plaque formation. Given the evidence supporting a pathogenic role for LH in AD, a trial of leuprolide acetate, which suppresses LH release, has been initiated in patients.

Ischemic stroke subtypes among Mexican Americans and non-Hispanic whites: the BASIC Project

Ischemic stroke subtype distribution was compared between Mexican Americans (MAs) and non-Hispanic whites (NHWs) in a community-based stroke surveillance study in Nueces County, TX. There was no difference in the distribution of stroke subtype by ethnicity (p = 0.19). There was a similar proportion of small-vessel and large-artery strokes between the two ethnic groups (p = 0.32). Differences in stroke rates among MAs and NHWs are not explained by the distribution of ischemic stroke subtypes.

Proliferative responses observed following vancomycin treatment in renal proximal tubule epithelial cells

Vancomycin (VAN) is a glycopeptide antibiotic used to treat gram-positive infections. Nephrotoxicity is a common side effect observed with vancomycin therapy. However, the mechanism of vancomycin-induced nephrotoxicity has not been fully characterized. In this study we examined the effect of vancomycin on cellular proliferation in renal proximal tubule cells. A dose- and time-dependent increase in cell number and total cellular protein was observed following vancomycin exposure. Vancomycin exposure also caused an increase in BrdU incorporation followed by the accumulation of renal proximal tubule cells in G(2)/M phase of the cell cycle. These effects were inhibited by pretreatment with the mitogen-activated protein kinase inhibitor, PD098059, suggesting an association between the cell proliferative effect of VAN and the induction of the mitogen-activated protein kinase signaling pathway. Mitochondrial function in renal proximal tubule cells was assessed using oxygen consumption and ATP concentrations. We observed an increase in oxygen consumption and ATP concentrations following short-term exposure to vancomycin. Together, our data suggest that vancomycin treatment produces alterations in mitochondrial function that coincide with a cell proliferative response in renal proximal tubule epithelial cells.

beta-Site APP cleaving enzyme up-regulation induced by 4-hydroxynonenal is mediated by stress-activated protein kinases pathways

4-Hydroxynonenal (HNE), an aldehydic product of lipid peroxidation, up-regulates expression of the beta-site APP cleaving enzyme (BACE-1), an aspartyl protease responsible for the beta-secretase cleavage of amyloid precursor protein (AbetaPP), and results in increased levels of amyloid beta (Abeta) peptide. The mechanisms underlying this remain unclear but are of fundamental importance because prevention of BACE-1 up-regulation is viewed as an important therapeutic strategy. In this study, we exposed NT(2) neurons to a range of HNE concentrations (0.5-5 microm) that elicited an up-regulation of BACE-1 expression, a significant increase in intracellular and secreted levels of Abeta peptides as well as apoptosis involving poly-ADP ribose polymerase cleavage and activation of caspase 3. To delineate the molecular events involved in HNE-mediated BACE-1 activation, we investigated the involvement of stress-activated protein kinases (SAPK), signal transducers and activators of transcription (STAT) and serine-threonine kinase B/phosphatidylinositol phosphate 3 kinase (Akt/PtdIns3K). Using specific pharmacological inhibitors, our results show that activation of c-Jun N-terminal kinases and p38(MAPK.), but not STAT or Akt/PtdIns3K, pathways mediate the HNE-dependent up-regulation of BACE-1 expression. Therefore, HNE, an oxidative stress mediator detected in vivo in the brains of Alzheimer's disease patients, may play a pathogenetic role in Alzheimer's disease by selectively activating SAPK pathways and BACE-1 that regulate the proteolytic processing of AbetaPP.

Neurofilament proteins in neurodegenerative diseases

The function of neurofilaments, the major component in large myelinated neurons, is not well understood even though they were discovered as structures over 100 years ago. Recent studies have suggested that neuro-filaments are closely related to many neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson disease Alzheimer disease, and diabetes. Using in vitro assays, cultures and transgenic mice, these studies provided new insights into neurofilament function. The function of each subunit, the relationship of neurofilaments with other cytoskeletal elements and their clinical significance are topics of increasing attention.

Retinoic acid isomers protect hippocampal neurons from amyloid-beta induced neurodegeneration

Attenuating amyloid-beta mediated neurodegeneration is of major therapeutic consideration in the potential treatment of Alzheimer disease. Previously, we found that a high dietary consumption of retinoic acid was associated with a reduced incidence of Alzheimer disease. Therefore, in this study, we investigated whether amyloid-beta mediated cell death in primary hippocampal neurons could be prevented by retinoic acid isomers. Our results suggest that retinoic acid isomers, including all-trans retinoic acid, 9-cis retinoic acid, and 13-cis retinoic acid, may play an important role in protecting neurons from amyloid-beta -induced cell death. Retinoic acid may therefore afford a novel therapeutic mechanism for the treatment and prevention of Alzheimer disease.