Nitration and oxidation of a hydrophobic tyrosine probe by peroxynitrite in membranes: comparison with nitration and oxidation of tyrosine by peroxynitrite in aqueous solution

It has been reported that peroxynitrite will initiate both oxidation and nitration of tyrosine, forming dityrosine and nitrotyrosine, respectively. We compared peroxynitrite-dependent oxidation and nitration of a hydrophobic tyrosine analogue in membranes and tyrosine in aqueous solution. Reactions were carried out in the presence of either bolus addition or slow infusion of peroxynitrite, and also using the simultaneous generation of superoxide and nitric oxide. Results indicate that the level of nitration of the hydrophobic tyrosyl probe located in a lipid bilayer was significantly greater than its level of oxidation to the corresponding dimer. During slow infusion of peroxynitrite, the level of nitration of the membrane-incorporated tyrosyl probe was greater than that of tyrosine in aqueous solution. Evidence for hydroxyl radical formation from decomposition of peroxynitrite in a dimethylformamide/water mixture was obtained by electron spin resonance spin trapping. Mechanisms for nitration of the tyrosyl probe in the membrane are discussed. We conclude that nitration but not oxidation of a tyrosyl probe by peroxynitrite is a predominant reaction in the membrane. Thus, the local environment of target tyrosine residues is an important factor governing its propensity to undergo nitration in the presence of peroxynitrite. This work provides a new perspective on selective nitration of membrane-incorporated tyrosine analogues.

Influence of photoperiod, laboratory caging and aging on plasma lipid response to an atherogenic diet among F1B hamsters

The effects and interactions of photoperiod, animal caging, aging and diet on plasma lipid levels in male F1B hamsters were examined in the current study. Sixteen young and sixteen old animals were housed one or four per cage. Eight young animals from each housing group were placed in an animal room with either 12/12 h (PT-12) or 10/14 h (PT-10) light/dark cycle while the sixteen old animals were maintained under a PT-12 light cycle. Plasma cholesterol and triglyceride concentrations were determined in all animals after a 2-week period of acclimation on chow diet and following 4-week intervention on atherogenic diet. Baseline total cholesterol (TC) levels were 131+/-25 mg/dl and 142+/-39 mg/dl for young and old animals, respectively, while baseline triglyceride (Tg) levels were 202+/-48 mg/dl and 160+/-37 mg/dl respectively for the same animals. Following 4-weeks on an atherogenic diet, single-caged PT 12 animals had elevated but significantly lower TC levels than group-caged animals (161+/-30 mg/dl and 240 +/-58 mg/dl, respectively) while single and group housed PT10 animals had TC levels of 296+/-75 mg/dl and 351+/-124 mg/dl, respectively. Similarly, plasma Tg levels rose to 330+/-100 mg/dl and 486+/-200 mg/dl in single and group housed PT12 animals (respectively) and to 668+/-270 mg/dl and 545+/-199 mg/dl in single and group housed PT10 animals (respectively). No significant changes related to atherogenic diet were observed in plasma TC or Tg levels in the older animals. Although caging conditions influence the cholesterol and triglyceride response to the atherogenic diet (p<.05), light cycle photoperiod seems to exert a greater effect (p<.005). In conclusion, photoperiod length dramatically affects diet-induced plasma lipid concentrations in young male F1B hamsters, and thus needs be considered in experimental designs of animal-housed lipid research.

Volatile essential oil constituents of Alpinia smithiae (Zingiberaceae)

The composition of leaf and rhizome essential oils of Alpinia smithiae that grow wild in the Western Ghats of Kerala (South India) was analysed by gas chromatography. The major components were beta-caryophyllene, sabinene, myrcene and 1,8-cineole in both samples, but variation in the yield of oil as well as the major components between the two plant parts was observed.

Inhibition of oxidized low-density lipoprotein-induced apoptosis in endothelial cells by nitric oxide. Peroxyl radical scavenging as an antiapoptotic mechanism

Proatherogenic oxidized low-density lipoprotein (oxLDL) induces endothelial apoptosis. We investigated the anti-apoptotic effects of intracellular and extracellular nitric oxide (*NO) donors, iron chelators, cell-permeable superoxide dismutase (SOD), glutathione peroxidase mimetics, and nitrone spin traps. Peroxynitrite (ONOO-)-modified oxLDL induced endothelial apoptosis was measured by DNA fragmentation, TUNEL assay, and caspase-3 activation. Results indicated the following: (i) the lipid fraction of oxLDL was primarily responsible for endothelial apoptosis. (ii) Endothelial apoptosis was potently inhibited by *NO donors and lipophilic phenolic antioxidants. OxLDL severely depleted Bcl-2 levels in endothelial cells and *NO donors restored Bcl-2 protein in oxLDL-treated cells. (iii) The pretreatment of a lipid fraction derived from oxLDL with sodium borohydride or potassium iodide completely abrogated apoptosis in endothelial cells, suggesting that lipid hydroperoxides induce apoptosis. (iv) Metalloporphyrins dramatically inhibited oxLDL-induced apoptosis in endothelial cells. Neither S-nitrosation of caspase-3 nor induction of Hsp70 appeared to play a significant role in the antiapoptotic mechanism of *NO in oxLDL-induced endothelial apoptosis. We propose that cellular lipid peroxyl radicals or lipid hydroperoxides induce an apoptotic signaling cascade in endothelial cells exposed to oxLDL, and that *NO inhibits apoptosis by scavenging cellular lipid peroxyl radicals.

Urinary iodine and thyroid status of New Zealand residents

OBJECTIVES

The aim of this project was to assess the clinical significance of our low iodine excretions in terms of thyroid hormone status and thyroid volume in an adult population in a low soil iodine area of the South Island of New Zealand.

DESIGN AND SETTING

Two-hundred and thirty-three residents of Otago, New Zealand collected two 24 h urine samples for assessment of iodine status. Thyroid status was determined from serum total T(4), TSH and thyroglobulin, and thyroid volumes. Relationships between urinary iodide excretion and measures of thyroid status were determined and subjects were allocated to one of three groups according to low, medium and high iodide excretion, for comparison of thyroid hormones and thyroid volumes.

RESULTS

Significant correlations were found for relationships between measures of urinary iodide excretion and thyroid volume and thyroglobulin. Multiple regression analysis of data for subjects divided into three groups according to 24 h urinary iodide excretion (<60, 60-90; >90 microg iodide/day) or iodide/creatinine ratio (<40; 40-60; >60 microg/g Cr) showed significant differences in thyroid volume (P=0.029; P=0.035, respectively) and thyroglobulin (P=0.019; P=0.005, respectively) among the groups.

CONCLUSIONS

The results of this study confirm the low iodide excretions of Otago residents, and indicate that the fall in iodine status is being reflected in clinical measures of thyroid status, including enlarged thyroid glands and elevated thyroglobulin. Our observations suggest the possible re-emergence of mild iodine deficiency and goitres in New Zealand. This situation is likely to worsen should iodine intakes continue to fall and continued monitoring of the situation is imperative.

Imaging of small-scale features on 433 Eros from NEAR: evidence for a complex regolith

On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material infilling some topographic lows. The subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter-sized blocks.

Pediatric heart transplantation: improving results in high-risk patients

OBJECTIVES

Our institutional experience with 73 pediatric patients undergoing cardiac transplantation between January 1, 1990, and December 31, 1999, was reviewed to determine the impact of unconventional donor and recipient management protocols implemented to extend the availability of this therapy.

METHODS AND RESULTS

The introduction of donor blood cardioplegic solution with added insulin was associated with a significant improvement in patient and graft survival (hazard ratio [Cox] = 0.25, P =.08), despite significantly longer ischemic times with this protocol compared with the use of crystalloid-based donor procurement techniques (P <.01). Eleven patients underwent intentional transplantation of ABO-incompatible donor hearts with the aid of a protocol of plasma exchange on bypass. In this subgroup, there were 2 early deaths caused by nonspecific graft failure (n = 1) and respiratory complications with mild vascular rejection (n = 1), and there was 1 late death caused by lymphoma. ABO-incompatible transplantation was not a risk factor for death by multivariate analysis. The postoperative course in these patients suggests minimal reactivity directed against incompatible grafts on the basis of low anti-donor blood group antibody production, in association with a favorable rejection profile. Ten of 13 patients requiring preoperative support with an extracorporeal membrane oxygenator survived transplantation; there were 3 additional late deaths in this subgroup (hazard ratio = 2.88, P =.05).

CONCLUSIONS

The results with pediatric cardiac transplantation continue to improve as a result of changes in both surgical and medical protocols permitting successful treatment of patients conventionally considered at high risk or unsuitable for transplantation.

Mutational analysis of the NIa protease from pepper vein banding potyvirus

The nuclear inclusion protein a (NIa) protease plays an important role in the life cycle of potyviruses by processing the viral polyprotein into functional proteins. For functional characterization, the NIa protease from Pepper vein banding potyvir s (PVBV) was overexpressed in Escherichia coli and purified. Using a recombinant polyprotein substrate containing the nuclear inclusion protein b (NIb)-coat protein (CP) cleavage site, a trans-cleavage assay was developed for the NIa protease. The polyprotein substrate also possessed the cleavage site between NIa and NIb, in addition to the NIb-CP site. However, no trans-cleavage by the NIa protease between NIa and NIb was detected indicating that the cleavage between NIa and NIb under natural conditions would be by a cis-cleavage reaction. Site-specific mutations of the conserved residues D81, D90, C110, T146, C151 and H167 were performed to investigate their roles in the catalytic process of the protease. Such an analysis has revealed that D81 and C151 constitute two of the catalytic triad residues in the NIa protease, D90 and C110 are not essential for catalysis, and T146 and H167 are probably involved in binding to Gln at the P1 position of the substrate.

Cytochrome-c detection: a diagnostic marker for myocardial infarction

Following a myocardial infarction (MI) cells die or are damaged and their contents leak into the blood circulation, resulting in elevated serum levels of various enzymes, proteins, and organic molecules. Over the past few decades, it has become standard practice to employ the detection of these elevated substances as markers for the confirmation of MIs and to monitor MI patients' response to treatment. Although it has previously been shown that cytochrome-c, a small respiratory protein, is among those elevated, the lack of a suitable detection system has prevented its routine use in the diagnosis of MIs. We present a preliminary study in which chemiluminescence was employed to detect elevated levels of cytochrome-c in the serum of MI patients. The technique, which is specific for c-type proteins, is approx 30 times more sensitive than the traditional Coomassie blue stain and can detect as little as 0.03 microg of protein. It also has potential for diagnostic use in other diseases that are characterized by mitochondrial damage.

Don Jackson's "A critique of the literature on the genetics of schizophrenia": a reappraisal after 40 years

In 1960, Don Jackson published "A Critique of the Literature on the Genetics of Schizophrenia." Jackson's critique nearly relegated the classical twin method to obscurity as being hopelessly confounded by environmental factors. Jackson noted several trends in the schizophrenia twin data that were difficult to explain on genetic grounds. In fact, none of Jackson's 12 major points, examined in this article, have been satisfactorily answered by proponents of the twin method. The evidence in support of Jackson's most controversial claim-that the psychology of twinship itself might lead to a greater rate of schizophrenia among twins when compared with the single-born population--is inconclusive. However, although several leading twin researchers have dismissed Jackson's entire thesis on the basis of the inconclusiveness of this one claim, this idea was not central to Jackson's basic argument. The research undertaken for this article appears to confirm the validity of the most important points of Jackson's analysis and that therefore the classical twin method is of doubtful value as an indicator of genetic influences on schizophrenia and other diagnoses or psychological trait differences. Jackson's article demonstrated the implausibility of what came to be known as the MZ/DZ "equal environment assumption" of the twin method, implying that the twin method records nothing more than environmental differences between monozygotic and dizygotic twins.

Fractional fourier domain encrypted holographic memory by use of an anamorphic optical system

We propose and demonstrate a fractional Fourier domain encrypted holographic memory using an anamorphic optical system. The encryption is done by use of two statistically independent random-phase codes in the fractional Fourier domain. If the two random-phase codes are statistically independent white sequences, the encrypted data are stationary white noise. We exploit the capability of an optical system to process information in two dimensions by using two different sets of parameters along the two orthogonal axes to encode the data. The fractional Fourier transform parameters along with the random-phase codes constitute the key to the encrypted data. The knowledge of the key is essential to the successful decryption of data. The decoding of the encoded data is done by use of phase conjugation. We present a few experimental results.

Copernicus revisited: amyloid beta in Alzheimer's disease

The beta-amyloid hypothesis of Alzheimer's Disease (AD) has dominated the thinking and research in this area for over a decade and a half. While there has been a great deal of effort in attempting to prove its centrality in this devastating disease, and while an enormous amount has been learned about its properties (e.g., putative toxicity, processing and signaling), Abeta has not proven to be both necessary and sufficient for the development, neurotoxicity, and cognitive deficits associated with this disease. Instead, the few treatments that are available have emerged from aging research and are primarily directed toward modification of acetylcholine levels. Clearly, it is time to rethink this position and to propose instead that future approaches should focus upon altering the age-related sensitivity of the neuronal environment to insults involving such factors as inflammation and oxidative stress. In other words "solve the problems of aging and by extension those of AD will also be reduced." This review is being submitted as a rather Lutherian attempt to "nail an alternative thesis" to the gate of the Church of the Holy Amyloid to open its doors to the idea that aging is the most pervasive element in this disease and Abeta is merely one of the planets.

Unusual "floating balls" appearance of an ovarian cystic teratoma: sonographic and CT findings

Ovarian cystic teratomas are cystic fatty tumors that can be easily diagnosed by sonography and CT. We present a case of ovarian cystic teratoma with an unusual sonographic appearance of mobile, hyperechoic, intracystic fat balls; this finding correlated well with the appearance on CT.

Bicarbonate exacerbates oxidative injury induced by antitumor antibiotic doxorubicin in cardiomyocytes

Doxorubicin, a broad-spectrum antitumor antibiotic, causes dose-dependent cardiomyopathy and heart failure. Although the exact molecular mechanisms of cardiotoxicity are not well established, oxidative mechanisms involving doxorubicin-induced superoxide anion production have been proposed. In this study, we show that bicarbonate, a physiologically relevant tissue component, greatly amplified doxorubicin-induced cardiomyocyte injury. Bicarbonate also enhanced inactivation of aconitase, a crucial tricarboxylic acid cycle enzyme, in cardiomyocytes exposed to doxorubicin. The cell-permeable superoxide dismutase mimetic, Mn(III)tetrakis (4-benzoic acid) porphyrin, reversed doxorubicin-induced cardiomyocyte injury. Bicarbonate enhanced the inactivation of purified mitochondrial aconitase in the xanthine/xanthine oxidase system, generating superoxide. The results suggest that bicarbonate amplifies the prooxidant effect of superoxide. Bicarbonate also caused an increased loading of cardiomyocytes with doxorubicin. We conclude that the bicarbonate-mediated increase in doxorubicin toxicity is due to increased intracellular loading of doxorubicin in cardiomyocytes and subsequent exacerbation of superoxide-mediated cardiomyocyte injury.

Doxorubicin-induced apoptosis in endothelial cells and cardiomyocytes is ameliorated by nitrone spin traps and ebselen. Role of reactive oxygen and nitrogen species

Doxorubicin (DOX) is a broad spectrum anthracycline antibiotic used to treat a variety of cancers. Redox activation of DOX to form reactive oxygen species has been implicated in DOX-induced cardiotoxicity. In this work we investigated DOX-induced apoptosis in cultured bovine aortic endothelial cells and cardiomyocytes isolated from adult rat heart. Exposure of bovine aortic endothelial cells or myocytes to submicromolar levels of DOX induced significant apoptosis as measured by DNA fragmentation and terminal deoxynucleotidyltransferase-mediated nick-end labeling assays. Pretreatment of cells with 100 microm nitrone spin traps, N-tert-butyl-alpha-phenylnitrone (PBN) or alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) dramatically inhibited DOX-induced apoptosis. Ebselen (20-50 microm), a glutathione peroxidase mimetic, also significantly inhibited apoptosis. DOX (0.5-1 microm) inactivated mitochondrial complex I by a superoxide-dependent mechanism. PBN (100 microm), POBN (100 microm), and ebselen (50 microm) restored complex I activity. These compounds also inhibited DOX-induced caspase-3 activation and cytochrome c release. PBN and ebselen also restored glutathione levels in DOX-treated cells. We conclude that nitrone spin traps and ebselen inhibit the DOX-induced apoptotic signaling mechanism and that this antiapoptotic mechanism may be linked in part to the inhibition in formation or scavenging of hydrogen peroxide. Therapeutic strategies to mitigate DOX cardiotoxicity should be reexamined in light of these emerging antiapoptotic mechanisms of antioxidants.

Building the Hospital Without Walls--a CSIRO home telecare initiative

Aging populations and rising health costs have created the need to care for more patients in their own homes. Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) is developing a project, Hospital Without Walls, which aims to provide continuous monitoring of patients in certain diagnostic categories. The key technology is a miniature, wearable, low-power radio that can transmit vital sign and activity information to a home computer, from which data may be sent by telephone line and the Internet to appropriate medical professionals. The initial clinical scenario for this work is monitoring of elderly patients who have presented to hospitals following repeated falls. Accelerometers built into the radio sets will monitor activity and detect and characterise falls. Simultaneous measurement of heart rate will provide information about abnormalities of cardiovascular physiology at the time of a fall. The system has been tested in laboratory conditions and is being adapted for initial clinical trials.

NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.

Functional ionotropic glutamate receptors emerge during terminal cell division and early neuronal differentiation of rat neuroepithelial cells

Ionotropic glutamate receptors mediate fast forms of excitatory synaptic transmission in mature neurons and may play critical roles in neuronal development. However, the developmental stage at which neuronal cells begin to express functional receptors and their roles in lineage progression remain unclear. In the present study, neural precursor cells were isolated from the cortical neuroepithelium of embryonic day 13 rats, and rapidly expanded in serum-free medium in response to basic fibroblast growth factor. RT-PCR revealed the presence of mRNAs encoding AMPA(A), AMPA(C), KA(1), KA(2), NMDA(1), and NMDA(2D) subunits after 3 days in culture. The functional expression of AMPA/kainate and NMDA receptors was investigated using Ca(2+) imaging and whole-cell patch-clamp recording techniques in cells pulse-labeled with bromodeoxyuridine (BrdU) for 1-4 hr. The recorded cells were then double-immunostained for BrdU incorporation and neuron-specific beta-tubulin (TuJ1). The results show that AMPA/kainate and NMDA induced increases in cytosolic Ca(2+) and inward currents only in differentiating neurons. In contrast, proliferating (BrdU(+)TuJ1(-)) cells failed to respond to any ionotropic glutamate receptor agonists. Interestingly, Ca(2+) imaging revealed that a subpopulation of BrdU(+)TuJ1(+) cells also responded to AMPA, indicating the emergence of functional ionotropic AMPA/kainate receptors during terminal cell division and the earliest commitment to neuronal cell lineage. These in vitro results were supported by flow cytometric sorting of AMPA-responsive cells pulse-labeled with BrdU for 1 hr in vivo, which revealed that functional AMPA receptors appear in BrdU(+)TuJ1(+) cells under physiological conditions and may play a role in terminal cell division.

Compartment syndrome following isolated ankle fracture

We report two cases of compartment syndrome following isolated ankle fractures. Both required decompression of all the compartments following early clinical diagnosis and measurements of the intra-compartmental pressures.

Optical encryption by double-random phase encoding in the fractional Fourier domain

We propose an optical architecture that encodes a primary image to stationary white noise by using two statistically independent random phase codes. The encoding is done in the fractional Fourier domain. The optical distribution in any two planes of a quadratic phase system (QPS) are related by fractional Fourier transform of the appropriately scaled distribution in the two input planes. Thus a QPS offers a continuum of planes in which encoding can be done. The six parameters that characterize the QPS in addition to the random phase codes form the key to the encrypted image. The proposed method has an enhanced security value compared with earlier methods. Experimental results in support of the proposed idea are presented.

Antioxidant-rich diets improve cerebellar physiology and motor learning in aged rats

The free radical theory of aging predicts that reactive oxygen species are involved in the decline in function associated with aging. The present paper reports that diets supplemented with either spinach, strawberries or blueberries, nutritional sources of antioxidants, reverse age-induced declines in beta-adrenergic receptor function in cerebellar Purkinje neurons measured using electrophysiological techniques. In addition the spinach diet improved learning on a runway motor task, previously shown to be modulated by cerebellar norepinephrine. Motor learning is important for adaptation to changes in the environment and is thus critical for rehabilitation following stroke, spinal cord injury, and the onset of some neurodegenerative diseases. These data are the first to indicate that age-related deficits in motor learning and memory can be reversed with nutritional interventions.