Atmospheric dynamics drive most interannual U.S. droughts over the last millennium.

The American West exemplifies drought-sensitive regions with growing populations. Paleoclimate investigations have documented severe droughts in this region before European settling, with major implications for water management and planning. Here, we leverage paleoclimate data assimilation to reconstruct past climate states, enabling a large-scale multivariate investigation of U.S. drought dynamics over the last millennium. These results confirm that La Niña conditions significantly influence southwest U.S. drought over the past millennium but only account for, by one metric, ~13% of interannual drought variability in that region. Atlantic sea surface temperatures may also contribute a small influence, but unexplained variability suggests a substantial role for internal atmospheric variability. This conclusion is buttressed by analysis of simulations from the Community Earth System Model Last Millennium Ensemble. While greenhouse gases will increase future drought risk, as shown in other work, interannual U.S. drought variations will also be widely influenced by processes internal to the atmosphere.

Apoptotic activities of thymoquinone, an active ingredient of black seed (Nigella sativa), in cervical cancer cell lines.

Thymoquinone (TQ) is the main constituent of black seed (Nigella sativa, spp) essential oil which shows promising in vitro and in vivo anti-neoplastic activities in different tumor cell lines. However, to date there are only a few reports regarding the apoptotic effects of TQ on cervical cancer cells. Here, we report that TQ stimulated distinct apoptotic pathways in two human cervical cell lines, Siha and C33A. TQ markedly induced apoptosis as demonstrated by cell cycle analysis in both cell lines. Moreover, quantitative PCR revealed that TQ induced apoptosis in Siha cells through p53-dependent pathway as shown by elevated level of p53-mediated apoptosis target genes, whereas apoptosis in C33A cells was mainly associated with the activation of caspase-3. These results support previous findings on TQ as a potential therapeutic agent for human cervical cancer.

Computer-assisted pre- and postoperative evaluation of surgically assisted rapid maxillary expansion.

OBJECTIVE: Computer-assisted methods were used to evaluate different variants of surgically assisted rapid maxillary expansion (SARME) in terms of bone repositioning, new bone formation in the osteotomy gap, and bone quality before and after surgery. MATERIALS AND METHODS: Twenty-nine patients (18 male, 11 female) with a mean age of 29 years (16 to 44 years) were included in the study. Surgically assisted rapid maxillary expansion with Le Fort I osteotomy was performed in all patients studied. High-resolution computed tomography (CT) was carried out directly before and 6 to 8 weeks after surgery. After registration of the preoperative CT data on the postoperative data, 3D models were constructed and superimposed. New bone formation in the osteotomy gap was visualized by means of a visualization procedure developed specifically for this purpose. Bone quality was analyzed by dividing the models into different anatomical segments. A qualitative comparison of the data was accomplished using a direct volume rendering procedure with a special transfer function. A quantitative comparison was carried out based on the pre- and postoperative histograms of each region. RESULTS: Maxillary widening was confirmed in all patients by computer-assisted analysis. Four patients exhibited significant maxillary asymmetry after surgery. New bone formation within the osteotomy gap was irregular along the osteotomy lines but often symmetrical on both sides. The more symmetrical the osteotomy, the more symmetrical the new bone formation proved to be. In all but two cases, the postoperative qualitative and quantitative analyses showed a significant decrease in Hounsfield units, particularly in the vestibular bone. CONCLUSION: The differences in new bone formation in the osteotomy gap suggest that the type of surgical technique and distractor used influence the outcome. Our results indicate that SAME results in a decrease in bone quality, particularly in the vestibular bone. Computer-assisted analysis clearly results in an information gain.

Effects of shock waves on microcirculation, perfusion, and pain management in critical limb ischemia.

Shock waves (SW) are used to control pain in different clinical conditions (eg, painful knee, elbow, and shoulder, etc). The effects of SWs may be due to cellular ;;stunning'' (particularly nervous components). It may also be the consequence of unknown metabolic actions on tissues, which may include changes in cellular permeability, the liberation of proteins and mediators locally acting on pain and nerve endings. The aim of this study was to evaluate the reduction in pain and the improvement in microcirculation induced by SW treatment in a 2-week study in patients with chronic limb ischemia (CLI). Of the 32 patients with CLI, 30 (20 with rest pain only, 10 with necrosis) completed the study. The treatment was well tolerated. Foot radiographs performed before and after treatment indicate no bone damage after treatment. Foot (tibial arteries) blood pressure was unchanged after 2 weeks. The increase in laser Doppler flux was significant (p <0.05) after treatment. The ORACLE score at 2 weeks was decreased (p <0.05). The same trend was observed with the analogue scale line for pain (p <0.05). Partial pressure of oxygen (PO2) increased (p <0.05) and partial pressure of carbon dioxide (PCO2) decreased (p <0.05). In all patients an increase in pain-free walking distance was observed (the distance increased on average 2.4 times). Flux improvement was still present after 1 month. The outcome at 3 months in these patients indicates that the improvement (concerning the survival of the limbs) was persistent. In conclusion SWs treatment in CLI produced changes both on the microcirculation and pain. These results are very interesting, confirming previous observations, and opening new treatment options in CLI. The skin flow improvement did not relate to an increase in pressure.

Acute regulation of glucose transport in a human megakaryocytic cell line: difference between growth factors and H(2)O(2).

The present study was undertaken to: (i) compare the effect of some hematopoietic growth factors, like interleukine-3, thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, stem cell factor, and reactive oxygen species such as H(2)O(2) on glucose uptake in a human leukemic megakaryocytic cell line, M07; (ii) investigate the changes in kinetic parameters of the transport activity induced by these stimuli; and (iii) evaluate the effect of genistein, a tyrosine kinase inhibitor, on the glucose uptake activation by the cited agents. The results are as follows: (i) exposure of M07 cells to thrombopoietin, granulocyte-megakaryocyte colony-stimulating factor, and stem cell factor resulted in a rapid stimulation of glucose transport; interleukine-3-treated cells exhibited no increase in the rate of glucose uptake, although M07 proliferation is interleukine-3 dependent; a rapid glucose transport enhancement was also observed when M07 cells were exposed to low doses of H(2)O(2); (ii) the transport kinetic parameters point out that an important difference exists between the effect of cytokines and that of H(2)O(2): cytokines increased predominantly the affinity for glucose, while H(2)O(2) raised both the V(max) and K(m) values; (iii) the isoflavone genistein, at a very low concentration, inhibited the stem cell factor- or H(2)O(2)-induced stimulation of hexose transport, reversing the variations of K(m) and V(max), but it did not affect the transport activity of granulocyte-megakaryocyte colony-stimulating factor-treated cells; and (iv) catalase completely abolished the stimulatory action of H(2)O(2) on glucose transport and slightly prevented the effect of stem cell factor, while caffeic acid phenethyl ester was only able to affect the activation due to stem cell factor.

The effect of oxygen radicals on rat thymocyte glucose transport is independent of the site of their generation.

We studied the relationship between the site of production of oxygen radicals and their effect on a rat thymocyte functional activity, the glucose transport, measured using a radioactive analogue of glucose, 2-deoxy-glucose. We compared the effects of a hydrophilic thermolabile azo compound, mimicking a radical attack outside the cell, with the lipid-soluble cumene hydroperoxide, which initiates lipid peroxidation in cell membranes. Our results show that a low grade oxidative stress stimulated glucose uptake rapidly, independently of the site of radical generation. In the presence of the azocompound, glucose uptake increased smoothly, attaining its maximum extent within 1 h. In thymocytes treated with cumene hydroperoxide the rate of glucose transport increased suddenly and remained constant over 1 h. The effects of the radical donors on TBARS production and protein sulfhydryl groups content were also evaluated. In thymocytes treated with the azo derivative no lipid peroxidation was observed, but a slow decrease of protein thiol groups occurred; after the addition of cumene hydroperoxide sulfhydryl groups did not change and TBARS increased significantly. The water-soluble antioxidant Trolox was able to remove the glucose uptake increase induced by the hydrophilic initiator and to delay the loss of membrane integrity.

Electromechanical characterization of chronic myocardial infarction in the canine coronary occlusion model.

BACKGROUND: Defining the presence, extent, and nature of the dysfunctional myocardial tissue remains a cornerstone in diagnostic cardiology. A nonfluoroscopic, catheter-based mapping technique that can spatially associate endocardial mechanical and electrical data was used to quantify electromechanical changes in the canine chronic infarction model. METHODS AND RESULTS: We mapped the left ventricular (LV) electromechanical regional properties in 11 dogs with chronic infarction (4 weeks after LAD ligation) and 6 controls. By sampling the location of a special catheter throughout the cardiac cycle at multiple endocardial sites and simultaneously recording local electrograms from the catheter tip, the dynamic 3-dimensional electromechanical map of the LV was reconstructed. Average endocardial local shortening (LS, measured at end systole and normalized to end diastole) and intracardiac bipolar electrogram amplitude were quantified at 13 LV regions. Endocardial LS was significantly lower at the infarcted area (1.2+/-0.9% [mean+/-SEM], P<0.01) compared with the noninfarcted regions (7.2+/-1.1% to 13. 5+/-1.5%) and with the same area in controls (15.5+/-1.2%, P<0.01). Average bipolar amplitude was also significantly lower at the infarcted zone (2.3+/-0.2 mV, P<0.01) compared with the same region in controls (10.3+/-1.3 mV) and with the noninfarcted regions (4. 0+/-0.7 to 10.2+/-1.5 mV, P<0.01) in the infarcted group. In addition, the electrical maps could accurately delineate both the location and extent of the infarct, as demonstrated by the high correlation with pathology (Pearson's correlation coefficient=0.90) and by the precise identification of the infarct border. CONCLUSIONS: Chronic myocardial infarcted tissue can be characterized and quantified by abnormal regional mechanical and electrical functions. The unique ability to assess the regional ventricular electromechanical properties in various myocardial disease states may become a powerful tool in both clinical and research cardiology.

HPLC and light scattering detection allow the determination of phospholipids in biological samples and the assay of phospholipase A2.

Some applications to biological samples of a method for the separation and the quantitative analysis of phospholipids by high performance liquid chromatography (HPLC) and light scattering mass detection are described. Results obtained in the determination of phospholipid classes from rat tissues such as liver, heart and kidney have been compared with data from the literature. The method has been applied to the evaluation of phospholipids in human low-density lipoproteins (LDL), about which little is known. The procedure is also suitable for a rapid and reliable assay of the water-soluble phospholipase A2 activity; the relationship between the aggregation state of substrate phospholipids (mixed micelles, multilamellar and unilamellar vesicles) and the enzyme activity has been studied.

Iron (III) stimulation of lipid hydroperoxide-dependent lipid peroxidation.

In an experimental system where both Fe2+ autoxidation and generation of reactive oxygen species is negligible, the effect of FeCl2 and FeCl3 on the peroxidation of phosphatidylcholine (PC) liposomes containing different amounts of lipid hydroperoxides (LOOH) was studied; Fe2+ oxidation, oxygen consumption and oxidation index of the liposomes were measured. No peroxidation was observed at variable FeCl2/FeCl3 ratio when PC liposomes deprived of LOOH by triphenylphosphine treatment were utilized. By contrast, LOOH containing liposomes were peroxidized by FeCl2. The FeCl2 concentration at which Fe2+ oxidation was maximal, defined as critical Fe2+ concentration [Fe2+]*, depended on the LOOH concentration and not on the amount of PC liposomes in the assay. The LOOH-dependent lipid peroxidation was stimulated by FeCl3 addition; the oxidized form of the metal increased the average length of radical chains, shifted to higher values the [Fe2+]* and shortened the latent period. The iron chelator KSCN exerted effects opposite to those exerted by FeCl3 addition. The experimental data obtained indicate the kinetics of LOOH-dependent lipid peroxidation depends on the Fe2+/Fe3+ ratio at each moment during the time course of lipid peroxidation. The results confirm that exogenously added FeCl3 does not affect the LOOH-independent but the LOOH-dependent lipid peroxidation; and suggest that the Fe3+ endogenously generated exerts a major role in the control of the LOOH-dependent lipid peroxidation.

The mechanism of iron (III) stimulation of lipid peroxidation.

A study conducted on Fe2+ autoxidation showed that its rate was extremely slow at acidic pH values and increased by increasing the pH; it was stimulated by Fe3+ addition but the stimulation did not present a maximum at a Fe2+/Fe3+ ratio approaching 1:1. The species generated during Fe(3+)-catalyzed Fe2+ autoxidation was able to oxidize deoxyribose; the increased Fe2+ oxidation observed at higher pHs was paralleled by increased deoxyribose degradation. The species generated during Fe(3+)-catalyzed Fe2+ autoxidation could not initiate lipid peroxidation in phosphatidylcholine liposomes from which lipid hydroperoxides (LOOH) had been removed by treatment with triphenylphosphine. Neither Fe2+ oxidation nor changes in the oxidation index of the liposomes due to lipid peroxidation were observed at pHs where the Fe3+ effect on Fe2+ autoxidation and on deoxyribose degradation was evident. In our experimental system, a Fe2+/Fe3+ ratio ranging from 1:3 to 2:1 was unable to initiate lipid peroxidation in LOOH-free phosphatidylcholine liposomes. By contrast Fe3+ stimulated the peroxidation of liposomes where increasing amounts of cumene hydroperoxide were incorporated. These results argue against the participation of Fe3+ in the initiation of LOOH-independent lipid peroxidation and suggest its possible involvement in LOOH-dependent lipid peroxidation.

Plasma protein's glycation is decreased in Sprague Dawley rats under caloric restriction.

Different dietary regimens were applied to three cohorts of rats. The first was fed ad libitum every day (AL), the second was fed ad libitum every other day (EOD) and the third was fed a diet equivalent to 60% of the caloric intake (60% CI) of the AL cohort. Levels of stable early glycation products in plasma proteins were then measured according to two different methods. Glycation of plasma proteins progressively increased in AL animals belonging to the 2-12 month age interval, while it showed a less pronounced age-dependent increase in EOD and 60% CI animals. The lowest degree of glycation was detected 2-3 months after the beginning of caloric restriction. After 12 months of age a lower level of glycation was detected in 60% CI rats than in EOD animals. Body weight was lower in restricted animals than in AL animals and was lowest in 60% CI rats. During the life span, glycemia was lower in fasting 60% CI than in EOD or AL rats.

Measurement of glycated proteins in human plasma or murine hepatic cytosolic fractions by a competitive enzyme linked immune assay (ELISA).

After planned immunization, a rabbit polyclonal antibody has been produced that recognized the Schiff base moiety of glycated proteins. Using an ELISA technique, antiserum specifically recognized reduced and glycated epitopes on a variety of proteins, and did not react with nonreduced and glycated proteins. The antiserum showed very low cross-reactivity with reduced but not glycated proteins. The assay was also used to determine the degree of ex vivo glycation of serum proteins from diabetic patients or hepatic cytosolic proteins from mice. Thus, this assay may be used to determine the amount of in vitro or ex vivo glycation of blood or tissue proteins.

Dietary restriction diminishes early glycation adducts on murine hepatic cytosolic proteins.

The effect of three dietary regimes on the amount of Schiff base adducts, as well as acid-stable (Amadori) glycation adducts in murine hepatic cytosolic fractions was studied. The dietary regimes consisted of an unrestricted diet or two different diets in which the caloric restriction was 25 and 50% of the caloric intake of unrestricted animals. The concentration of the Schiff bases in ad libitum and slightly restricted mice (25%) was higher than that observed in severely restricted mice (50%). The concentration of the Schiff bases in the severely restricted mice did not reach values observed in ad libitum or slightly restricted mice even in 45-month old animals. The concentration of the Amadori products was essentially the same for all three dietary groups. Our results show that a severe caloric restriction decreases the formation of early glycation adducts which might influence the rate of aging of laboratory animals under caloric restriction.

Kinetics of the glycation of bovine serum albumin by mannose and fucose in vitro.

Glycation of bovine serum albumin was measured for mannose and fucose at 37 degrees C. Mannose as well as fucose demonstrated an initial rapid increase in rate of formation of total adducts followed by a slower secondary reaction. The equilibrium constant for Schiff base formation was almost two times larger for mannose than fucose, although the Schiff base formed by fucose rearranged 1.5 times faster than that for mannose. Both sugars showed parallel lines for the formation of total and acid stable products after three hours. Discussion integrates new mechanistic data with previously suggested mechanisms.

Effect of AD6 (8-monochloro-3-beta-diethylamino-ethyl-4-methyl-7-ethoxycarbonylme tho xy coumarin) on cyclic nucleotide phosphodiesterases in human platelets.

The effect of AD6 (8-monochloro-3-beta-diethylamino-ethyl-4-methyl-7-ethoxycarbonylmeth oxy coumarin), an inhibitor of platelet aggregation, on cyclic nucleotide metabolism was investigated. AD6 inhibited selectively human platelet cyclic GMP phosphodiesterase, which was separated from cyclic AMP phosphodiesterase by DEAE-cellulose chromatography. Addition of AD6 to washed platelets increased cyclic GMP levels significantly in two minutes. These results could be useful in elucidating the action of AD6 on intact platelets.

Inhibitory action of polyamines on protein kinase C association to membranes.

Physiological activation of protein kinase C requires the interaction of this enzyme with cellular membranes [Nishizuka (1986) Science 233, 305-312]. In the present work a reconstituted system of protein kinase C and human inside-out erythrocyte vesicles was utilized to study the effect in vitro of naturally occurring polyamines on the activation process of protein kinase C. The active membrane-associated complex was conveniently determined by its ability to bind radioactive phorbol ester with an exact 1:1 stoichiometry. The association reaction of the enzyme to membrane was rapid, being complete within 1 min at 25 degrees C. The addition of polyamines, particularly spermine, greatly decreased in a dose-dependent manner the amount of protein kinase C bound to membranes (i.e. in the activated form). The effect observed was quite specific, since it was dependent on the chemical structure of the polyamine and it was manifest at micromolar concentrations of the polycation; the order of potency was spermine greater than spermidine greater than putrescine. A characterization of this effect is presented and possible physiological implications are discussed.

Intracellular location of polyamines associated to red blood cells.

The polyamines associated to human erythrocytes from healthy donors are mainly localized intracellularly. In fact chromatography of the erythrocytes on a resin which has a high affinity and capacity for polyamines does not affect the amount of polyamines associated to the erythrocytes. The low ability of spermine to adsorb to the external surface of erythrocytes at physiological ionic strength is suggested also by studies conducted with sealed ghosts. Also erythrocytes from patients with hematological and dermatological diseases which contain increased levels of polyamines show an intracellular location of these amines.

Interaction of smooth muscle relaxant drugs with calmodulin and cyclic nucleotide phosphodiesterase.

Some smooth muscle relaxant drugs with an unknown mechanism of action have been tested for their interaction with calmodulin and with calmodulin-induced cyclic nucleotide phosphodiesterase (PDE) activity. The affinity of these drugs for calmodulin does not parallel their inhibitory effect on the calmodulin activation of PDE. The lack of parallelism could be due to a binding of the drugs to different sites on calmodulin; furthermore a binding of papaverine, octylonium bromide and felodipine to PDE molecule might also be considered to explain their inhibitory effect on PDE basal activity. The myolytic effect of octylonium bromide and pinaverium bromide may be due to their interaction with calmodulin-dependent systems.