Fluorescence of putative chromophores in Skh-1 and citrate-soluble calf skin collagens.

Background/purpose: Fluorescence of Skh-1 hairless mouse and calf skin acid-soluble type I collagens are envelopes of several bands putatively due to tyrosine (excitation/emission peak at 275/300 nm), dihydroxyphenylalanine (dopa; 280/325 nm), tyrosine aggregate (285/360 nm), dityrosine 325/400 nm), and advanced glycation end (AGE) product (370/450 nm), respectively. As these fluorophores can be markers of pathological conditions, we wish to present further evidence for or against these assignments.

Methods: We analysed intact type I mouse collagens and AGE by conventional fluorescence spectroscopy, synchronous spectroscopy, high-performance liquid chromatography (HPLC), and borate quenching.

Toward understanding the influence of soil metals and sulfate content on plant thiols.

Plants respond to increased concentrations of metals by a number of mechanisms, including chelation with phytochelatins (PCs). Soil specimens and plants (Veronica anagalis-aquatica, Typha domingensis, Cynodon dactylon, Chenopodium album, Rumex dentatus, Amaranthus gracilis, Chenopodium murale, Inula viscosa) leaves were collected from two sites in northern Jordan and subsequently metals (cadmium, copper, and lead), sulfate, and PC (from leaves) levels were determined. One of these sites was contaminated with metals and the other served as a control site.

Effect of palm oil on blood pressure, endothelial function and oxidative stress.

The pathogenesis of hypertension has been associated with endothelial dysfunction and oxidative stress. We have previously shown that palm oil (PO), with an unsaturated-to-saturated fatty acid ratio close to one and rich in antioxidants vitamins, reduces oxidative stress-induced hypertension in normal rats. Here, we investigated the cardiovascular effects of natural vitamin-rich PO using the Dahl Salt-sensitive hypertension model.

Polyamines protect against radiation-induced oxidative stress.

Astronauts and cosmonauts are exposed to a wide variety of different hazards while in space that include radiation, which presents one of the most critical barriers to long-term missions. A major deleterious effect directly associated with ionizing radiation is the production of reactive oxygen species (ROS) such as peroxides and hydroxyl radicals. The free radicals generated by ultraviolet (UV) or ionizing radiation can attack cellular lipids, proteins and DNA.

Amlodipine attenuates oxidative stress-induced hypertension.

Background: Dihydropyridine Ca2+-blockers, frequently used as antihypertensive and antianginal agents, have been found to exert potent antioxidant and cytoprotective activities against free radical-mediated vascular injury.

Methods: In the current study we examined the effect of amlodipine (AMLOD) on oxidative stress-induced hypertension in Sprague-Dawley rats administered buthionine-sulfoximine (BSO), a glutathione (GSH) synthase inhibitor, in the drinking water. The control animals received drug-free water.

Relation of endothelial nitric oxide synthase gene to plasma nitric oxide level, endothelial function, and blood pressure in African Americans.

Background: The role of eNOS gene polymorphisms on plasma nitrite or nitrate (NOx) level, endothelial function, and blood pressure (BP) remains unclear.

Methods: We estimated the relationship of eNOS polymorphisms (the T(-786)C in the 5'-flanking promoter region, T(-786)C; 27-bp repeat in intron 4, eNOS4; and Glu298Asp in exon 7, G894T) with plasma NOx level, brachial endothelial function assessed by ultrasound measure of brachial artery flow-mediated dilation (FMD), and BP in 60 healthy African Americans, 30 men and 30 women aged 18 to 73 years.

Results: Among them, 73.

The role of oxidative stress in salt-induced hypertension.

Background: Impairment of endothelial function during hypertension is associated with increased production of superoxide radicals and reduced antioxidants. We investigated the involvement of oxidative stress in Dahl salt-sensitive (SS) and salt-resistant (SR) rats.

Methods: For a 2-week period, male rats were fed either high salt (HS; 8% sodium chloride) or low salt (LS; 0.

Effect of losartan on oxidative stress-induced hypertension in Sprague-Dawley rats.

Background: Hypertension induced by oxidative stress has been demonstrated in normal rats. In the current study, we investigated the effect of the oral AT(1) receptor blocker losartan (10 mmol/kg/day) on oxidative stress, induced by glutathione (GSH) depletion (using buthionine-sulfoximine, BSO, 30 mmol/L/day in the drinking water), in Sprague-Dawley rats.

Methods: Mean arterial pressure (MAP) was measured by tail-cuff plethysmography and the plasma levels of total 8-isoprostane, nitric oxide, prostacyclin, thromboxane A(2), angiotensin II, aldosterone, and aortic cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were determined by enzyme immunoassay.

Effect of UV on the susceptibility of acid-soluble Skh-1 hairless mouse collagen to collagenase.

Background/purpose: Photoaging of the skin is a result of chronic exposure to environmental ultraviolet radiation (UV). The milieu provided by the extracellular matrix, which significantly influences the behaviour of resident fibroblasts, depends critically on the supermolecular collagen structure. We ask whether direct photochemical treatment of type I collagen with solar wavelengths capable of reaching the dermis can modify the substrate's susceptibility to collagenase in a model in vitro system.

Changes in muscle proteins and spermidine content in response to unloading and clenbuterol treatment.

Anabolic agents such clenbuterol (Cb) are useful tools for probing the mechanisms by which muscles respond to disuse. Cb was examined under different loading conditions with respect to its effects on muscle mass, protein (myofibrillar and cytosolic), and spermidine content in mature male rats. Compared with control treatment, Cb significantly increased loaded and unloaded soleus, plantaris, and extensor digitorum longus (EDL) mass.

Influences of prostanoids and nitric oxide on post-suspension hypotension in female Sprague-Dawley rats.

Impairment in cardiovascular functions sometimes manifested in astronauts during standing postflight, may be related to the diminished autonomic function and/or excessive production of endothelium-dependent relaxing factors. In the present study, using the 30 degrees head-down tilt (HDT) model, we compared the cardiovascular and biochemical effects of 7 days of suspension and a subsequent 6-h post-suspension period between suspended and non-suspended conscious female Sprague-Dawley rats. Mean arterial pressure (MAP) and heart rate were measured prior to suspension (basal), daily thereafter, and every 2h post-suspension.

Acute inhibition of glutathione biosynthesis alters endothelial function and blood pressure in rats.

The cardiovascular and biochemical responses during acute oxidative stress induced by D,L-buthionine-(S,R)-sulfoximine (BSO) were investigated in Sprague-Dawley rats. Mean arterial pressure, heart rate and vascular reactivity were measured after subcutaneous injection of BSO (4 mmol/kg). Control rats received saline.

Effect of palm oil on oxidative stress-induced hypertension in Sprague-Dawley rats.

Background: Oxidative stress, associated with increased plasma isoprostane (ISO) and reductions in plasma glutathione (GSH), has been shown to cause severe hypertension in normal rats. Palm oil (PO), with an unsaturated-to-saturated fatty acid ratio close to one and rich in antioxidant vitamins, has been investigated for its beneficial effects on arterial thrombosis and atherosclerosis. In this study, the effect of PO on oxidative stress induced by inhibition of GSH synthesis (using buthionine sulfoximine [BSO]) was examined.

Muscle-specific effects of hindlimb suspension and clenbuterol in mature male rats.

Anabolic agents are useful tools for probing the mechanisms by which muscle fibers perceive and respond to disuse. beta(2)-Adrenergic agonists exert protective, and/or reparative, effects on atrophying muscle tissue. The effects of one such agent, clenbuterol (Cb), were examined on muscle mass, total protein content, and myofibrillar protein content in selected hindlimb muscles [adductor longus (ADL), extensor digitorum longus (EDL), plantaris (PLAN), soleus (SOL)] of mature male rats, under different loading conditions.

Effect of hindlimb suspension and clenbuterol treatment on polyamine levels in skeletal muscle.

Polyamines are unbiquitous, naturally occurring small aliphatic, polycationic, endogenous compounds. They are involved in many cellular processes and may serve as secondary or tertiary messengers to hormonal regulation. The relationship of polyamines and skeletal muscle mass of adductor longus, extensor digitorum longus, and gastrocnemius under unloading (hindlimb suspension) conditions was investigated.

High performance liquid chromatographic assay for the quantitation of total glutathione in plasma.

A simple and widely used homocysteine HPLC procedure was applied for the HPLC identification and quantitation of glutathione in plasma. The method, which utilizes SBDF as a derivatizing agent utilizes only 50 microl of sample volume. Linear quantitative response curve was generated for glutathione over a concentration range of 0.

Distribution and muscle-sparing effects of clenbuterol in hindlimb-suspended rats.

Based on their anabolic properties in skeletal muscles, beta-adrenergic agonists are of interest as potential countermeasures to microgravity-induced skeletal muscle atrophy. The levels of clenbuterol (Cb), a beta(2)-adrenergic agonist, in both plasma and skeletal muscle were higher in hindlimb-suspended rats than in their nonsuspended Cb-treated controls. Cb treatment was shown to help maintain the body weight in suspended rats, while reducing the amount of mesenteric fat.

Temporal indication of marijuana use can be estimated from plasma and urine concentrations of delta9-tetrahydrocannabinol, 11-hydroxy-delta9-tetrahydrocannabinol, and 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid.

Current technology establishes marijuana use based upon detection of the pharmacologically inactive cannabinoid metabolite (11-nor-delta9-carboxy-tetrahydrocannabinol-9-carboxylic acid, THC-COOH) in urine. No accurate prediction of time of use is possible because THC-COOH has a half-life of 6 days. To determine if a temporal relationship between marijuana use and metabolite excretion patterns could be established, eight healthy user-volunteers (18-35 years old) smoked marijuana cigarettes containing 0% (placebo), 1.

Beta-agonist-induced alterations in organ weights and protein content: comparison of racemic clenbuterol and its enantiomers.

Clenbuterol is a relatively selective beta2-adrenergic partial agonist that has bronchodilator activity. This drug has been investigated as a potential countermeasure to microgravity- or disuse-induced skeletal muscle atrophy because of presumed anabolic effects. The purpose of this study was to: 1) analyze the anabolic effect of clenbuterol's (-)-R and (+)-S enantiomers (0.

Comparative analytical quantitation of clenbuterol in biological matrices using GC-MS and EIA.

A simple and sensitive procedure utilizing GC-MS for the identification and quantitation of clenbuterol in biofluids and tissues is described. This improved method utilizes trimethylboroxine for the derivatization of clenbuterol, requires only 1 mL/g of biological sample, and most importantly does not require an extra cleaning step for urine specimens prior to extraction. Linear quantitative response curves have been generated for derivatized clenbuterol over a concentration range of 5-200 ng/mL.

Cannabinoids in humans. II. The influence of three methods of hydrolysis on the concentration of THC and two metabolites in urine.

Glucuronide conjugates of cannabinoids were previously identified in humans. For gas chromatographic-mass spectrometric (GC-MS) analysis of the unconjugated compounds in human urine, it is necessary to cleave the glucuronide moiety. Base hydrolysis and two forms of enzymatic hydrolysis were compared in this study to examine any quantitative differences between the hydrolysis methods.

Cannabinoids in humans. I. Analysis of delta 9-tetrahydrocannabinol and six metabolites in plasma and urine using GC-MS.

This report describes a method for the quantitative analysis of delta 9-tetrahydrocannabinol and six of its metabolites, 8 alpha-hydroxy-delta 9-tetrahydrocannabinol, 8 beta-hydroxy-delta 9-tetrahydrocannabinol, 11-hydroxy-delta 9-tetrahydrocannabinol, 8 alpha,11-dihydroxy-delta 9-tetrahydrocannabinol, 8 beta,11-dihydroxy-delta 9-tetrahydrocannabinol, and 11-nor-9-carboxy-delta 9-tetrahydrocannabinol. In addition, the method was designed to detect cannabidiol and cannabinol, two naturally occurring cannabinoids. Plasma and urine samples were hydrolyzed with bacterial (Escherichia coli) beta-glucuronidase and extracted with hexane-ethyl acetate (7:1).

Solid-phase extraction and GC/MS quantitation of cocaine, ecgonine methyl ester, benzoylecgonine, and cocaethylene from meconium, whole blood, and plasma.

A selective solid-phase extraction technique has been applied to the analysis of cocaine and selected cocaine metabolites in meconium, whole blood, and plasma. This technique uses a mixed-mode Bond Elut Certify column that utilizes the characteristics of hydrophobic and polar interactions and ion exchange chromatography. Following extraction, cocaine, ecgonine methyl ester, benzoylecgonine, and cocaethylene were identified and quantitated using GC/MS.