Stability of carotenoids and tocopherols in ready-to-eat baby-leaf lettuce and salad rocket during low-temperature storage

Minimally processed ready-to-eat baby-leaf vegetables (BLVs) are the most convenient source to include the health beneficial bioactive in the daily diet. In the present study, the visual quality and storage stability of carotenoids, tocopherols were investigated in lettuce (green and red romaine) and salad rocket BLVs. The commercially packed samples of BLVs were stored at 0 °C and 4 °C in dark conditions and analyzed after 0, 2, 4, 8 and 12 days of storage. All the studied samples were found in better visual quality up to eight days of storage at both the temperatures. In most cases, the quality was correlated with the chlorophyll contents. The highest significant (p < 0.05) positive changes in total carotenoids and tocopherols were observed in samples stored at 4 °C. Also, carotenoids and tocopherols are maximum stable in green and red romaine lettuce, respectively.

Hyper-Rayleigh scattering from gold nanoparticles: effect of size and shape

We report hyper-Rayleigh scattering (HRS) properties of gold nanoparticles (GNPs) of five different shapes, quasi-spherical (∼10 and ∼20 nm diameter), rod (aspect ratio ∼2), and branched shapes, tetrapod, flower and star with 800 nm, 150 fs laser excitation. Using ∼10 nm spherical GNPs as reference, the first hyperpolarizability (β) values were calculated for all other shapes. Star and flower shaped GNPs have the highest hyperpolarizability (∼130 and ∼52 times higher, respectively), while rod and tetrapod shaped GNPs only have modest enhancement (∼7 times), which is similar to ∼20 nm size quasi-spherical particles. These enhancements are attributed to reduced symmetry as well as the presence of sharp tips on GNP surface. When the β values are normalized with respect to the number of atoms per particle, the flower and star shaped GNPs still have the highest hyperpolarizability values. The polar plots of vertically polarized HRS signal as a function of the angle of polarization of the incoming incident light shows two lobes, indicating that excitation is predominantly dipolar in nature although the size of some GNPs are big enough to show a quadrupolar response. It is believed that the presence of sharp tips at the surface of these large sized GNPs is responsible for the observed dipolar response. This study shows that GNPs having sharp tips might be a better candidate when their nonlinear properties are used for sensing applications.

Dietary iron supplements and Moringa oleifera leaves influence the liver hepcidin messenger RNA expression and biochemical indices of iron status in rats

In this study, the effects of iron depletion and repletion on biochemical and molecular indices of iron status were investigated in growing male Wistar rats. We hypothesized that iron from Moringa leaves could overcome the effects of iron deficiency and modulate the expression of iron-responsive genes better than conventional iron supplements. Iron deficiency was induced by feeding rats an iron-deficient diet for 10 weeks, whereas control rats were maintained on an iron-sufficient diet (35.0-mg Fe/kg diet). After the depletion period, animals were repleted with different source of iron, in combination with ascorbic acid. Iron deficiency caused a significant (P < .05) decrease in serum iron and ferritin levels by 57% and 40%, respectively, as compared with nondepleted control animals. Significant changes in the expression (0.5- to100-fold) of liver hepcidin (HAMP), transferrin, transferrin receptor-2, hemochromatosis type 2, ferroportin 1, ceruloplasmin, and ferritin-H were recorded in iron-depleted and iron-repleted rats, as compared with nondepleted rats (P < .05). Dietary iron from Moringa leaf was found to be superior compared with ferric citrate in overcoming the effects of iron deficiency in rats. These results suggest that changes in the relative expression of liver hepcidin messenger RNA can be used as a sensitive molecular marker for iron deficiency.

Effect of dehydration methods on retention of carotenoids, tocopherols, ascorbic acid and antioxidant activity in Moringa oleifera leaves and preparation of a RTE product

Fresh leaves of M. oleifera plants were analysed for nutritionally important phytoconstituents and feasible commercially used dehydration method were evaluated to preserve these in dehydrated leaves. Trans-lutein, trans-β-carotene and trans-zeaxanthin were found as the major carotenoids in fresh leaves, accounting for 36.9, 18.2 and 5.5 mg/100 g FW, respectively. Similarly, high amounts of ascorbic acid, α-tocopherol and total phenolic content (271.0, 36.9 and 512.0 mg/100 g FW), respectively were recorded in leaves. α-tocopherol was the most stable vitamin under all drying conditions (86.4 % retention during oven drying), compare to other studied phytoconstituents. Cabinet tray drying was found as efficient as lyophilisation to retain maximum content of total carotenoids (60.1 %), trans-β-carotene (90.1 %), 13-cis-lutein (93.2 %), and DPPH activity, however, lutein (51.3 %) and ascorbic acid (97.8 %) was best preserved by lyophilisation. During dehydration, significant trans to cis isomerization of β-carotene and lutein was also recorded. A ready to eat (RTE) chutney powder (adjunct) was developed from dehydrated leaves. The product was evaluated using Quantitative Descriptive Analysis and was accepted with a high overall quality score. The present investigation explores the nutritional potential of M. oleifera leaves and suitable methods of drying that could be useful for processed food formulation.

Identification of major components of larviposition pheromone from larvae of tsetse fliesGlossina morsitans morsitans Westwood andGlossina morsitans centralis Machado

The presence of pheromones produced by larvae ofGlossina morsitans morsitans andG. m. centralis, respectively, which attract gravid females and result in aggregation of pupae, is confirmed. Behavioral experiments indicated that females preferred to larviposit over moist sand conditioned by previously allowing larvae to pupariate in it. Similar results were obtained with filter papers contaminated with the prepupariation excretions of larvae and with volatiles collected from larvae prior to pupariation.n-Pentadecane andn-dodecane were identified as the dominant electrophysiologically active components of the larviposition pheromones ofG. m. morsitans andG. m. centralis, respectively, by GC-EAD and GC-MS analysis of the trapped larval volatiles. Both identified compounds were shown to significantly attract gravid females to larviposition sites in laboratory behavioral assays.

Effect of curcumin on the diffusion kinetics of a hemicyanine dye, LDS-698, across a lipid bilayer probed by second harmonic spectroscopy

The diffusion kinetics of a hemicyanine dye, LDS-698, across model membrane bilayers was studied in real time by the surface specific second harmonic technique. Using liposomes made from different headgroups, it has been established that the diffusion is initiated by electrostatic adsorption of the positively charged dye to the outer surface of negatively charged liposomes and its time constant is affected by the rigidity of the bilayer. In the presence of the liphophilic drug curcumin (curcumin/lipid mole ratio ~ 0.2), the diffusion of LDS-698 was observed to be faster by ~56 times (from 780 to 14 s) at 25 °C. Under similar curcumin concentration, when cholesterol containing liposomes are used at 2 °C, the observed diffusion time constant increases from 14 to 65 s, showing that the effect of curcumin is superior to the effect of increasing bilayer rigidity on the diffusion process. Control experiments with other lipophilic molecules such as DPH and Nile Red showed that the effect of liposomal curcumin is superior. Consistent with previous reports of curcumin affecting the bilayer organization, this study additionally demonstrates increased permeability of liposomal curcumin, in particular against organic cations. It is speculated that origin of this enhanced membrane permeability by lipophilic molecules may depend upon the interaction of the molecule with the polar headgroup region of the lipid which, in turn, is expected to depend on the chemical structure of the molecule.

Diffusion of chlorin-p6 across phosphatidyl choline liposome bilayer probed by second harmonic generation

We have investigated the diffusion of the photosensitizer Chlorin-p(6) (Cp(6)) across a egg lecithin lipid bilayer at different pH by the Second Harmonic Generation (SHG) method. Cp(6) has three ionizable carboxylic acid groups, and consequently, neutral and several ionic forms of Cp(6) are expected to be present in the pH range 3-8. The absorption spectra of Cp(6) get considerably modified in the presence of liposomes as the pH is decreased indicating that the drug liposome binding is pH dependent. The first pK(a) of interconversion (D-C) has been identified at pH ~7.0 by fluorescence measurement in an earlier work. In this work, the second pK(a) of interconversion (C-B) has been identified at pH ~4.8 by the hyper-Rayleigh scattering method. At acidic pH (3, 4, and 5), where species A, B, and C are dominant, the addition of liposomes to a Cp(6) solution generates an instantaneous rise (less than 1 s) in the second harmonic (SH) signal followed by decays whose time constants ranged from ten to hundreds of seconds. The instantaneous rise is attributed to the adsorption of Cp(6) to the outer lipid bilayer, and the decay is attributed to the diffusion of the neutral and charged (A and B) species of the drug. The observed fast and slow time constants for diffusion in the pH range 3-5 are attributed to the neutral (A) and ionic form (B) of Cp(6), respectively. At pH 6, the intensity of the generated SH signals on the addition of liposome reduced, and at physiological pH, it was too weak to be detected. These results are consistent with previous studies that show that the interaction between Cp(6) and egg-PC liposomes is pH dependent. At lower pH due to the presence of the hydrophobic species (A and B) of Cp(6), its interaction with liposomes is strong, and at higher pH, the abundance of the negatively charged hydrophilic species (C and D) decreases the interaction with the like charged liposomes. We have also studied the effect of increasing the bilayer rigidity by decreasing the temperature of the medium or by incorporating 50 mol % cholesterol in the lipid bilayer and observed that lowering of temperature has more profound effect on the diffusion rates. The characteristics of the SH signal changed significantly when liposomes incorporating 50 mol % cholesterol were used at a low (3 °C) temperature. Under these conditions, the SH signal consisted of an instantaneous (<1s) followed by a slower rise (10-90s), and then, it decayed on a much longer time scale. This slow rise of the SH signal at pH 3 and 4 may be attributed to the temperature dependent adsorption of the anionic species (B) of Cp(6) with the liposomes. Further investigations are required in order to understand clearly the pH dependent diffusion of this drug across lipid bilayers.

Efficiency of RAPD, SSR and cytochrome P450 gene based markers in accessing genetic variability amongst finger millet (Eleusine coracana) accessions

Finger millet (Eleusine coracana L.) is an important crop used for food, forage, and industrial products. Three DNA marker techniques, random amplified polymorphic DNA (RAPD), simple sequence repeat (SSR) and cytochrome P(450) gene based markers were used for the detection of genetic polymorphism in 83 accessions of finger millet collected from various geographical regions of India and Africa. A total of 18 RAPD, 10 SSR and 10 pairs of cytochrome P(450) gene based markers were generated 56.17, 70.19 and 54.29% polymorphism, respectively. Mean polymorphism information content (PIC) for each of these marker systems (0.280 for RAPD, 0.89 for SSR and 0.327 for cytochrome P(450) gene based markers) suggested that SSR marker were highly effective in determining polymorphism. The phenograms based on the three markers data indicate that genotypes from different geographical regions are clearly distinguishable as separate clusters. Mantel test employed for detection of goodness of fit established cophenetic correlation values above 0.90 for all the three marker systems. The dendrograms and PCA plots derived from the binary data matrices of the three marker systems are highly concordant. High bootstrap values were obtained at major nodes of phenograms through WINBOOT software. Based on the results of present study, SSR and cytochrome P(450) gene based markers appear to be particularly useful for the estimation of genetic diversity. This study reveals the potential of RAPD, SSR and gene based markers for characterizing germplasm of Eleusine coracana and narrow down the vast germplasm into distinct core groups.

Chemopreventive effect of nonsteroidal anti-inflammatory drugs on 9,10-dimethylbenz[a]anthracene-induced lung carcinogenesis in mice

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, celecoxib, and etoricoxib were studied as chemopreventive agents in lung cancer in mice induced by 9,10-dimethylbenz[a]anthracene (DMBA). The animals were subjected to a single intratracheal instillation of DMBA by surgical intervention, while they were treated with oral NSAIDs daily at their following anti-inflammatory dose: aspirin 25 mg/kg, celicoxib 6 mg/kg, and etoricoxib 0.6 mg/kg body weight, respectively. The animals were sacrificed after 18 weeks of treatment. Results showed a significant incidence of pulmonary tumors, dysplastic changes in histopathology, and signs of inflammatory occurrence in the DMBA-treated animals, which were grossly reversed by the NSAIDs. A greater number of macrophages, neutrophils, and lymphocytes were seen in the bronchoalveolar lavage (BAL) smear while the inflammatory cell counts decreased in DMBA + NSAIDs groups. A significant increase in the drug-metabolizing enzymes viz. cytochrome p450, cytochrome b5, and glutathione-S-transferase was noted in the DMBA group, which was reverted back in the NSAID-treated mice. Similarly, the subcelluler enzymes were elevated in DMBA, but significantly fell in the NSAID groups. DMBA also caused a higher level of lipid peroxidation as well as the different antioxidant enzyme activity, which were corrected by the NSAIDs. A marked elevation was noticed in the total lipid composition and its individual constituents in the DMBA group, which was reverted back appreciably by the NSAIDs. The results suggest that the DMBA-induced lung tumor development in balb/c mice could be a reliable model to test the chemopreventive potential of the NSAIDs.

Pulmonary carcinogenesis in mice with a single intratracheal instillation of 9, 10-dimethyl benz[a]anthracene

A single intratracheal instillation of 9,10-dimethyl benz(a)anthracene (DMBA) at 3 different doses of 5, 10, and 20 mg/kg body weight to Balb/c mice for 12 weeks had caused a significant incidence of pulmonary tumors along with inflammatory changes. The number of macrophages in the broncho-alveolar lavage (BAL) fluid increased significantly, while the neutrophil and lymphocyte count as well as the protein content in the BAL fluid remained unchanged. A marked elevation in the lipid peroxidation product as well as the antioxidative enzymes were noted in the DMBA-treated group. The BAL fluid, which contains the surfactant membrane, was tested for rotational diffusion of the small hydrocarbon fluorophore, diphenyl hexatriene, and resulted in an enhanced fluorescence polarization and anisotropy value as well as the order parameter. DMBA treatment also altered the toxicity parameters, such as the lipid peroxidation, catalase, total protein, reduced glutathione, and alanine and amino transferase activities in the liver and kidney tissues. The results suggest that DMBA-induced lung tumor development in Balb/c mice could be an important model for the study of pathophysiology of BAL-fluid-associated surfactant and offers to test a variety of promising chemopreventive/chemotherapeutic agents.

Livestock farmers' perception and epidemiology of bovine trypanosomosis in Kwale District, Kenya

We did cross-sectional surveys in Kwale District, Kenya to determine the epidemiology of bovine trypanosomosis and livestock owners' perceptions of the disease. The surveys involved relative importance of trypanosomosis, examination of the current disease constraints, current control practices and drug-use patterns. Informal meetings were held with farmers and cattle census undertaken. Tsetse-fly densities and trypanosomosis prevalences in cattle were determined. A total of 132 farmers were interviewed. Trypanosomosis, anaplasmosis, East Coast fever, foot-and-mouth diseases were reported to be the major constraints to livestock production. Trypanosomosis was the most important compared to other diseases. Chemotherapy was the most widely used method of controlling the disease. Farmer-based tsetse-control technologies were poorly adopted. Respondents were quite knowledgeable on the symptoms, causes and treatment of trypanosomosis. Glossina austeni, G. brevipalpis and G. pallidipes were found in the area; the latter was the most common (0.2-738 flies/trap). Trypanosoma congolense and T. vivax were found in cattle with the former more prevalent. Infection prevalences in cattle varied between 0 and 25% (median: 22%).

Thermoelectric power of p-doped single-wall carbon nanotubes and the role of phonon drag

We measured thermoelectric power S of bulk single-wall carbon nanotube materials p doped with acids. In contrast to oxygen-exposed or degassed samples, S is very small at the lowest temperatures, increases superlinearly above a characteristic and sample-dependent T, and then levels off. We attribute this unusual behavior to 1D phonon drag, in which the depression of the Fermi energy cuts off electron-phonon scattering at temperatures below a characteristic T0. This idea is supported by a model calculation in which the low temperature behavior of phonon drag is specifically related to the one-dimensional character of the electronic spectrum.

Formation, isolation, spectroscopic properties, and calculated properties of some isomers of C(60)H(36)

Isomers of C(60)H(36) and He@C(60)H(36) have been synthesized by the Birch or dihydroanthracene reduction of C(60) and isolated by preparative high-pressure liquid chromatography. (3)He, (13)C, and (1)H NMR spectroscopic properties were then determined. A comparison of experimental chemical shifts against those computed using density functional theory (B3LYP) with polarized triple- and double-zeta basis sets for He and C,H, respectively, allowed provisional assignment of structure for several isomers to be made. Theoretical calculations have also been carried out to identify low-energy structures. The transfer hydrogenation method using dihydroanthracene gives a major C(60)H(36) isomer and a minor C(60)H(36) isomer with C(3) symmetry as determined by the (13)C NMR spectrum of C(60)H(36) and the (3)He NMR spectrum of the corresponding sample of (3)He@C(60)H(36). In view of the HPLC retention times and the (3)He chemical shifts observed for the Birch and dihydroanthracene reduction products, the two isomers generated by the latter procedure can be only minor isomers of the Birch reduction. A significant energy barrier apparently exists in the dihydroanthracene reduction of C(60) for the conversion of the C(3) and C(1) symmetry isomers of C(60)H(36) to the T symmetry isomer previously predicted by many calculations to be among the most stable C(60)H(36) isomers. Many of the (1)H NMR signals exhibited by C(60)H(36) (and C(60)H(18), previously reported) are unusually deshielded compared to "ordinary" organic compounds, presumably because the unusual structures of C(60)H(36) and C(60)H(18) result in chemical shift tensors with one or more unusual principal values. Calculations clearly show a relationship between exceptionally deshielded protons beta to a benzene ring in C(60)H(18) and C(60)H(36) and relatively long C-C bonds associated with these protons. The additional information obtained from 1D and 2D (1)H NMR spectra obtained at ultrahigh field strengths (up to 900 MHz) will serve as a critical test of chemical shifts to be obtained from future calculations on different C(60)H(36) isomers.

Reactions of cycloproparenes with metal carbenes

[figure: see text] Benzocyclopropene and cyclopropa[b]naphthalene react with dichloro-bis(tricyclohexylphosphine)methylideneruthenium, incorporating the metallacarbene to form unstable 3-ruthenacyclopentenes, which decompose to give o-xylylenes that can be trapped as Diels-Alder adducts by dimethyl acetylenedicarboxylate. In contrast, bis(eta 5-cyclopentadienyl)methylidenetitanium forms moderately stable 2- and 3-titanacyclopentene complexes.

Behaviour of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) on waterbuck Kobus defassa Ruppel and feeding membranes smeared with waterbuck sebum indicates the presence of allomones

The behavioural responses of caged individual teneral Glossina morsitans morsitans on waterbuck and ox and on feeding membranes with and without smears of different doses of waterbuck sebum were compared. No significant difference was found in the initial landing behaviour on the two animals, nor on treated and control parts of the membrane. However, the subsequent behaviours of the flies were significantly different. Whereas none of the flies that landed on the ox showed any escape behaviour, more than a third of those that initially landed on waterbuck departed before probing. Similar results were obtained on feeding membranes treated in part with 1.0 or 1.4 mg cm(-2) of waterbuck sebum. Moreover, flies that landed on waterbuck or its sebum changed probing sites more often and probed significantly longer. The proportions that initiated feeding during the 10 min observation period were also significantly less. Our results suggest the presence of both volatile and non-volatile allomones on waterbuck which would account for low numbers of flies found attracted to and feeding on waterbuck in the wild.

Effects of fly abundance on catch index of traps for Glossina fuscipes fuscipes (Diptera: Glossinidae)

The effect of fly abundance on the catch index of traps and that of rain as a source of variation in fly abundance were investigated for Glossina fuscipes fuscipes Newstead around Lake Victoria, western Kenya, using odor-baited and color-improved traps. There was a significant inverse relationship between the catch index of experimental traps and abundance of flies; the catch index being the ratio of catch in the experimental trap per catch in a reference trap. At low tsetse abundance (< 10 flies per trap per day) there was a 3-fold increase of the catch of females in the experimental trap compared with the control. Rainfall alone explained 22-87% of the total variation of fly abundance. It is suggested that fly abundance should be considered in evaluating baits for G. f. fuscipes or when using traps for monitoring. The relative depression of the catch index at high abundance may be related to avoidance of conspecifics. Flies entered standard traps in an inverse proportion to the number observed at the trap. Females approached traps in greater numbers when fewer decoys (dead flies) were placed on traps.

Use of the factorial design and quadratic response surface models to evaluate the fosinopril and hydrochlorothiazide combination therapy in hypertension

The combination of angiotensin converting enzyme (ACE) inhibitor and thiazide diuretic has advantages over monotherapy for the treatment of hypertension. Previous study designs have often been inadequate to demonstrate the details of interactions between these antihypertensive agents. This study used a modified 4 x 4 factorial randomized, double-blind, placebo-controlled, parallel group design to study the efficacy of 17 different doses of fosinopril (Fos), a phosphinic acid derived ACE inhibitor, and hydrochlorothiazide (HCTZ) in 550 patients with mild to moderate hypertension. Data from these variables were fit to quadratic response surface models (QRSM) using polynomial functions in the doses of the two components. Using QRSM, seated systolic (SeSBP) and diastolic blood pressure (SeDBP) responses at 8 weeks were predicted for actual doses and interpolated for intermediate doses not studied. Fos and HCTZ alone and in combination produced a dose-related reduction in SeSBP and SeDBP. Using 10 mg Fos + 12.5 mg HCTZ reduced the adjusted mean SeDBP 6.3 mm Hg and 20 mg Fos + 12.5 mg HCTZ lowered the same measure 9.1 mm Hg. Coadministration of Fos and HCTZ produced an additive antihypertensive effect. This study of combination agents for hypertension using a factorial design with QRSM accurately predicts dose responses and is a valuable clinical trial methodology.

Efficacy and safety of fosinopril/hydrochlorothiazide combinations on ambulatory blood pressure profiles in hypertension. Fosinopril/Hydrochlorothiazide Investigators

Twenty-four-hour ambulatory blood pressure monitoring (ABPM) was used to assess the antihypertensive efficacy and safety of the angiotensin converting enzyme (ACE) inhibitor fosinopril (Fos) in combination with hydrochlorothiazide (HCTZ) in doses of 10/12.5 mg and 20/12.5 mg taken once daily versus placebo in patients with mild-to-moderate hypertension. In two methodologically identical studies, the antihypertensive effects were evaluated by 24-h ABPM and by seated office diastolic (DBP) and systolic (SBP) blood pressures. After a 4- or 5-week placebo washout, 79 patients received randomized, double-blind treatment for 8 weeks with either the Fos/HCTZ 10/12.5-mg dose combination (n = 41) or placebo (n = 38), and in the second study, 62 patients were treated with either the Fos/HCTZ 20/12.5-mg dose combination (n = 30) or placebo (n = 32). Changes from baseline in mean 24-h systolic and diastolic ABPM were significantly different from placebo for both doses (SBP/DBP with 10/12.5 mg, -18.2/ -10.1 mm Hg, P <or= .001; SBP/DBP with 20/12.5 mg, -22.9/ -11.2 mm Hg, P <or= .001); whereas ambulatory SBP and DBP in the placebo group were virtually unchanged. Although the antihypertensive effect of the higher Fos/HCTZ dose combination (20/12.5 mg) appeared greater than the lower dose (10/12.5 mg), no attempt was made to make a comparison between the two doses over these two independent studies. This difference in blood pressure lowering was not reproduced by the office blood pressure readings. Both dose combinations of Fos/HCTZ produced significantly greater reductions in the office seated DBP than placebo at all time points tested with a maximum treatment effect (drug effect - placebo effect) of -7.3 mm Hg for the 10/12.5-mg dose and -8.2 mm Hg for the 20/12.5-mg dose after 8 weeks of therapy (P <or= .01). Based on the results obtained in these trials, both dose combinations of Fos/HCTZ taken once daily were safe and effective in the management of patients with mild-to-moderate hypertension. Twenty-four-hour ABPM detected what appears to be an enhanced blood pressure reduction with the higher Fos/HCTZ dose combination (20/12.5 mg) at peak and trough, which was not reproduced by trough office blood pressure measurements, suggesting greater sensitivity of 24-h ABPM for evaluating antihypertensive effects.

Empowering young girls for health and development

Yuvati Vikas Kendra (YVK) model of empowering young girls in the age bracket of 7-19 years could raise the level of awareness and generate self-esteem and self-confidence in over 50% of young girls over a period of six months of operation. The YVK model was utilised by 37-55% of enrolled girls in different age brackets; thus these centres functioned well below their installed capacity. Functional inter-sectoral linkages have to be developed for better impact and better coverage. Data based information from other models of empowerment such as schools, non-formal system of education and Integrated Child Development Services Scheme, is called for to choose different alternatives for our country, as no uniform system can succeed in this vast country. Diversified modes and approaches for empowerment of young girls are needed.

Effects of SQ 26,533 on reperfusion arrhythmias, ST-segment elevation and on infarct size in anesthetized dogs

The antiarrhythmic, antifibrillatory activities and the ability of SQ 26,533 to reduce infarct size were investigated in the canine models of reperfusion arrhythmias. In model 1, halothane-anesthetized dogs were subjected to acute occlusion of left circumflex coronary artery (LCX) for 30 min followed by reperfusion. SQ 26,533 infused at 50 micrograms/kg/min for 45 min significantly reduced (78%) the incidence of ventricular ectopic beats during the 30-min ligation of LCX. In addition, four of seven dogs (57%) survived after reperfusion, in contrast to 100% mortality observed in untreated animals. In model 2, left anterior descending artery under pentobarbital anesthesia was occluded for 20 min and released. SQ 26,533 (2.5 mg/kg i.v.) given 1 hr before occlusion significantly reduced (81%) ventricular ectopic beats during acute occlusion and four of five animals (80%) survived left anterior descending artery reperfusion, unlike saline controls (100% mortality). Similar efficacy was seen in a feline model of reperfusion arrhythmias. The model 3 animals under pentobarbital anesthesia were occluded for 60 min followed by reperfusion of the LCX in the presence of critical stenosis. SQ 26,533 (2.5 mg/kg every 90 min) given 50 min after LCX occlusion not only resulted in a significant reduction (91%) of postreperfusion ventricular ectopic beats for the entire 5-hr observation period but also significantly reduced (42%) the infarct size at 24 hr. Antiarrhythmic doses of SQ 26,533 caused minimal hemodynamic changes, except for a marked decrease in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of tiapamil and nifedepine during critical coronary stenosis and in the presence of adrenergic beta-receptor blockade in anesthetized dogs

The hemodynamic effects exerted by two chemically dissimilar calcium antagonists (tiapamil and nifedipine) were studied in anesthetized dogs during control conditions, following critical stenosis of the left circumflex coronary artery, and in the presence of beta-receptor blockade with nadolol (1 mg/kg). Dose-dependent hemodynamic changes were observed following the intravenous administration of three different doses of tiapamil (0.5, 1.0, and 2.0 mg/kg) and nifedipine (2.5, 5.0, and 10.0 micrograms/kg) during control conditions. In the presence of critical coronary stenosis, tiapamil and nifedipine produced similar magnitudes of decreases in blood pressure and changes in heart rate. Tiapamil produced paradoxic increases in left ventricular (LV) dP/dt and contractile force since these changes were accompanied by a slight decrease in heart rate. Nifedipine, unlike tiapamil, resulted in reflex increases in heart rate and myocardial contractility in response to reduction in the afterload. Also, nifedipine, unlike tiapamil, produced relatively minor changes in the coronary flow of the unoccluded left anterior descending coronary artery. In the presence of nadolol and critical stenosis, both agents produced markedly different hemodynamic responses. In the tiapamil series, three out of five dogs died due to severe cardiodepression consisting of bradycardia, hypotension, reduced myocardial contractility, and coronary blood flow. No mortality was observed in the nifedipine series since the cardiac function was adequately maintained in the presence of beta-blockade. Our results are in close agreement with the clinical observations, indicating a much higher incidence of dangerous drug interactions with combined use of verapamil-like compounds (e.g., tiapamil) with beta-blockers than with nifedipine, especially in patients with coronary artery disease and AV conduction disturbances.

Streptozotocin-induced diabetes in the spontaneously hypertensive rat

Spontaneously hypertensive rats (SHR) were more sensitive to the diabetogenic effects of streptozotocin than normotensive Wistar-Kyoto (WKY) rats. Thus, 10 days after intravenous administration of 25 mg/kg streptozotocin in SHR, mean pancreatic insulin content was decreased by 42% (p less than 0.05), and mean plasma glucose concentration was increased from 85 to 215 mg/dl (p less than 0.001), whereas between 37.5 and 50 mg/kg of streptozotocin was required to produce similar effects in normotensive WKY rats. Also, there was a progressive decrease in blood pressure in SHR injected with 25, 35.7, or 50 mg/kg of streptozotocin, whereas blood pressure was progressively increased after streptozotocin in normotensive WKY rats. The opposite effects of streptozotocin-induced diabetes on blood pressure in SHR and WKY rats could be observed at similar degrees of hyperglycemia and are presently unexplained.

Characterization of the coronary vasodilator and hemodynamic actions of monensin, a carboxylic ionophore

The effects of monensin on coronary blood flow (CBF) and other hemodynamic parameters were studied in anesthetized dogs. A dose-response relationship was established, and it was found that the lowest doses of monensin (5-25 micrograms/kg) produced a dose-dependent increase (3-5x) in CBF with a concomitant decrease in total peripheral resistance (TPR). Pretreatment with diphenhydramine, atropine, indomethacin, or propranolol resulted in no reduction in peak increase in CBF or in the duration of response to monensin. However, the response was partially blocked by aminophylline. Large doses (100 and 200 micrograms/kg) produced a dose-dependent increase in cardiac output, aortic pressure, and LV dP/dt max. The duration of these effects was dose-dependent, ranging from 60 to 120 min or longer. Heart rate remained unchanged with all doses of monensin. Pretreatment with propranolol, H87/07 (a cardioselective beta-blocker), and D-600 given alone or in combination significantly reduced, but did not completely abolish, the monensin-induced increase in LV dP/dt max and aortic pressure responses. The increase in CBF in the left anterior descending coronary artery was not significantly affected by these drug pretreatments. Thus, our studies indicate that monensin has two distinct pharmacological effects--in the lower dose range (less than 25 micrograms/kg) it produces a direct relaxation of the blood vessels resulting in an increase in CBF and a decrease in TPR; at high doses (greater than 25 micrograms/kg) it increases myocardial contractility and aortic blood pressure.

In vivo monitoring of the death rate of artificial murine pulmonary micrometastases

A system is described for direct monitoring of the death rate of artificial murine pulmonary microscopic metastases in vivo. Metastatic fibrosarcoma cells or benign connective tissue cells labeled with [125I]iododeoxyuridine were injected i.v. Comparison of the long-term radioactive decay rate of these two cell types in the lung permitted identification of the portion of the decay curve reflecting the initial period of micrometastasis development and growth. About 5% of the injected tumor cells were retained in the lung in micrometastasis, and their average death rate could be monitored by loss of radioactivity from the lung. Systemic methotrexate (75.0 mg/kg) was administered as a single dose 80 hr after injection of tumor cells at a time when micrometastases had not yet become vascularized. This treatment killed about 60% of the micrometases and suppressed the appearance of gross metastases at 14 days.

On the use of functional antagonism to estimate dissociation constants for beta adrenergic receptor agonists in isolated guinea-pig trachea

In guinea-pig trachea, the maximum degree of relaxation that can be elicited by beta adrenergic receptor agonists depends upon the degree of contraction of the smooth muscle induced by cholinergic agonists. In these studies, it is shown that increasing concentrations of carbamylcholine (carbachol) result in a shift to the right of the dose-response curves to (-)-isoproterenol and (-)-soterenol and a reduction of the maximum degree of relaxation produced by these agonists relative to that produced by papaverine. Soterenol is demonstrated to be a partial agonist relative to isoproterenol since its maximum response is reduced to a greater extent by carbachol and it displaces the carbachol dose-response curves to the right less than does isoproterenol. The data were used to calculate, by three different theoretical models of drug-receptor interactions, a dissociation constant (KA) for soterenol. All values obtained were within 2-fold differences. The range of KA values for soterenol was from 5.4 to 9.6 times 10(-8) M. These values are about 100 times larger than the ED50 value for soterenol obtained in the absence of carbachol. The KA value estimated for (-)-isoproterenol (about 3 times 10(-8) M) by one of the models is also around 100 times larger than its ED50 value. This demonstrates further that ED50 values are unreliable indicators of the affinities of agonists for receptors.