Biphasic Temporal Pattern Research Articles

Uterine artery Doppler indices throughout gestation in women with and without previous Cesarean deliveries: a prospective longitudinal case–control study

To determine whether a history of previous Cesarean delivery (CD) impacts uterine artery (UtA) Doppler indices throughout pregnancy. Women with and without CD (NCD) were prospectively enrolled for sequential assessments of the UtA mean/median pulsatility index (UtA-PI), resistance index (UtA-RI), and systolic/diastolic ratio (UtA-S/D) at 11–13 + 6, 14–19 + 6, 30–34 + 6, and 35–37 + 6 weeks’ gestation. Data from 269/269, 246/257, 237/254, and 219/242 CD/NCD participants from each gestational period were available for analysis. Multiples of the median (MoMs) of UtA Doppler indices showed biphasic temporal (Δ) pattern; with an initial dropping until the second trimester, then a subsequent elevation until late in pregnancy (p < 0.05). The measurements and Δs of the UtA indices between CD and NCD were not different (p > 0.05). Mixed-effects modelling ruled out effects from nulliparity (n = 0 and 167 for CD and NCD, respectively) (p > 0.05). History of CD neither influenced the measurements nor the temporal changes of the UtA Doppler indices throughout pregnancy. The biphasic Δs of UtA Doppler indices added to the longitudinal data pool, and may aid in future development of a more personalized prediction using sequential/contingent methodologies, which may reduce the false results from the current cross-sectional screening.

Sex-specific effects of neuropathic pain on long-term pain behavior and mortality in mice.

Human epidemiological studies suggest that chronic pain can increase mortality risk. We investigated whether this was true in mice so that underlying mechanisms might be identified. At 10 weeks of age, C57BL/6 mice of both sexes received sham or spared nerve injury (SNI) surgery producing neuropathic pain. Mice were weighed monthly, tested behaviorally for mechanical and cold sensitivity and guarding behavior every 3 months postsurgery, and otherwise left undisturbed in their cages until death by natural causes. Evidence of pain over the lifespan displayed a strikingly sex-specific pattern. Male mice displayed largely stable mechanical and cold hypersensitivity and guarding at 6 to 30 months post-SNI. By contrast, female mice displayed a biphasic temporal pattern of mechanical hypersensitivity and guarding behavior, with a complete resolution of SNI-induced pain behavior at 6 to 9 months post-SNI followed by the return of pain thereafter. Mouse lifespan was not significantly altered by SNI in either sex nor was frailty as assessed by cage inspection in the last 6 months of life. However, in male mice with SNI, we observe a significant correlation between average lifetime mechanical hypersensitivity and lifespan, such that death occurred sooner in male mice exhibiting more evidence of chronic pain. This relationship was not observed in female SNI mice nor in sham-operated mice of either sex. This experiment is the first to investigate pain behavior over an entire adult lifetime and suggests that biology of relevance to human chronic pain is being ignored by the very short timespans of most extant preclinical pain research.

MANET 3.0: Hierarchy and modularity in evolving metabolic networks.

Enzyme recruitment is a fundamental evolutionary driver of modern metabolism. We see evidence of recruitment at work in the metabolic Molecular Ancestry Networks (MANET) database, an online resource that integrates data from KEGG, SCOP and structural phylogenomic reconstruction. The database, which was introduced in 2006, traces the deep history of the structural domains of enzymes in metabolic pathways. Here we release version 3.0 of MANET, which updates data from KEGG and SCOP, links enzyme and PDB information with PDBsum, and traces evolutionary information of domains defined at fold family level of SCOP classification in metabolic subnetwork diagrams. Compared to SCOP folds used in the previous versions, fold families are cohesive units of functional similarity that are highly conserved at sequence level and offer a 10-fold increase of data entries. We surveyed enzymatic, functional and catalytic site distributions among superkingdoms showing that ancient enzymatic innovations followed a biphasic temporal pattern of diversification typical of module innovation. We grouped enzymatic activities of MANET into a hierarchical system of subnetworks and mesonetworks matching KEGG classification. The evolutionary growth of these modules of metabolic activity was studied using bipartite networks and their one-mode projections at enzyme, subnetwork and mesonetwork levels of organization. Evolving metabolic networks revealed patterns of enzyme sharing that transcended mesonetwork boundaries and supported the patchwork model of metabolic evolution. We also explored the scale-freeness, randomness and small-world properties of evolving networks as possible organizing principles of network growth and diversification. The network structure shows an increase in hierarchical modularity and scale-free behavior as metabolic networks unfold in evolutionary time. Remarkably, this evolutionary constraint on structure was stronger at lower levels of metabolic organization. Evolving metabolic structure reveals a ‘principle of granularity’, an evolutionary increase of the cohesiveness of lower-level parts of a hierarchical system. MANET is available at http://manet.illinois.edu.

Body Patches in Inferior Temporal Cortex Encode Categories with Different Temporal Dynamics.

An unresolved question in cognitive neuroscience is how representations of object categories at different levels (basic and superordinate) develop during the course of the neural response within an area. To address this, we decoded categories of different levels from the spiking responses of populations of neurons recorded in two fMRI-defined body patches in the macaque STS. Recordings of the two patches were made in the same animals with the same stimuli. Support vector machine classifiers were trained at brief response epochs and tested at the same or different epochs, thus assessing whether category representations change during the course of the response. In agreement with hierarchical processing within the body patch network, the posterior body patch mid STS body (MSB) showed an earlier onset of categorization compared with the anterior body patch anterior STS body (ASB), irrespective of the categorization level. Decoding of the superordinate body versus nonbody categories was less dynamic in MSB than in ASB, with ASB showing a biphasic temporal pattern. Decoding of the ordinate-level category human versus monkey bodies showed similar temporal patterns in both patches. The decoding onset of superordinate categorizations involving bodies was as early as for basic-level categorization, suggesting that previously reported differences between the onset of basic and superordinate categorizations may depend on the area. The qualitative difference between areas in their dynamics of category representation may hinder the interpretation of decoding dynamics based on EEG or MEG, methods that may mix signals of different areas.

Prognostic Impact of Persistent Thrombocytopenia During Extracorporeal Membrane Oxygenation: A Retrospective Analysis of Prospectively Collected Data From a Cohort of Patients With Left Ventricular Dysfunction After Cardiac Surgery.

The prognostic impact of thrombocytopenia in patients supported by extracorporeal membrane oxygenation after cardiac surgery is uncertain. We investigated whether thrombocytopenia is independently predictive of poor outcome and describe the incidence and time course of thrombocytopenia in extracorporeal membrane oxygenation patients. Retrospective analysis of prospectively collected data. Cardiosurgical ICU at a tertiary referral center. Three hundred adult patients supported with venoarterial extracorporeal membrane oxygenation for more than 24 hours because of refractory cardiogenic shock after heart surgery between January 2001 and December 2014. None. Two-way analysis of variance was used to compare the time course of platelet count changes between survivors and nonsurvivors. Using multiple Cox regression with time-dependent covariates, we investigated the impact of platelet count on 90-day mortality. In nonsurvivors, the daily incidence of moderate (< 100 - 50 × 10/L), severe (49 - 20 × 10/L), and very severe (< 20 × 10/L) thrombocytopenia was 50%, 54%, and 7%, respectively. Platelet count had a biphasic temporal pattern with an initial decrease until day 4-5 after the initiation of extracorporeal membrane oxygenation. Although a significant recovery of the platelet count was observed in survivors, a recovery did not occur in nonsurvivors (p = 0.0001). After adjusting for suspected confounders, moderate, severe, and very severe thrombocytopenia were independently associated with 90-day mortality. The highest risk was associated with severe (hazard ratio, 5.9 [2.7-12.6]; p < 0.0001) and very severe thrombocytopenia (hazard ratio, 25.9 [10.7-62.9], p < 0.0001). Thrombocytopenia is an independent risk factor for poor outcome in extracorporeal membrane oxygenation patients after cardiac surgery, with persistent severe thrombocytopenia likely reflecting a high degree of physiologic imbalance.

The Mechanism of Mitral Regurgitation Influences the Temporal Dynamics of the Vena Contracta Area as Measured with Color Flow Doppler.

In patients with mitral regurgitation (MR), the effective regurgitant orifice area can be estimated by measuring the vena contracta area (VCA). We hypothesize that the VCA has characteristic temporal dynamics related to the underlying mechanism of functional mitral regurgitation (FMR) versus degenerative mitral valve disease (DMVD). VCA measurements obtained by planimetry of the proximal jet from 3D transesophageal echocardiographic (TEE) color flow Doppler data sets were acquired in 42 cardiac surgical patients, including 22 with FMR and 20 with DMVD. Serial VCAs were measured throughout systole for each patient to evaluate variation in the effective regurgitant orifice area. Tercile averages were compared within and between the FMR and DMVD groups using repeated measures analysis of variance. Pairwise tests were Bonferroni-corrected for the number of comparisons. Normalized average VCA values in patients with FMR revealed a biphasic pattern compared with a monophasic pattern in patients with DMVD. Among FMR patients, normalized average VCA values in early (1.10 ± 0.32 cm2) and late systole (1.11 ± 0.33 cm2) were similar but were both significantly greater compared with mid-systole (0.79 ± 0.22 cm; P = 0.0144 and P = 0.0106, respectively). Among DMVD patients, normalized average VCA values in mid-systole (1.37 ± 0.15 cm2) were significantly greater than those in early (0.53 ± 0.14 cm2) and late systole (1.09 ± 0.18 cm2; P < 0.0001 for both). An analysis of normalized average VCAs also revealed significant differences between the FMR and the DMVD groups during early (1.10 ± 0.32 cm vs 0.53 ± 0.14 cm2) and mid-systole (0.79 ± 0.22 cm2 vs 1.37 ± 0.15 cm2; P < 0.0001 for both). VCA dynamics are governed by the mechanism of MR and are observed in FMR patients primarily as a biphasic temporal pattern compared with a monophasic temporal pattern in patients with DMVD.

Extracellular lectins from saprophytic strains of bacteria of the genus Bacillus (review)

The present review summarizes both the authors' own and other researchers' reports concerning the synthesis and properties of sialic acid-specific extracellular lectins from saprophytic bacteria of the genus Bacillus. Bacilli of this genus isolated from different ecological niches differ with regard to the ability to synthesize lectins. The biphasic temporal pattern of lectin synthesis in culture and the effect of cultivation conditions on lectin production have been demonstrated. The advantages of the technological procedure used for the isolation and purification of these biopolymers have been characterized. Specificity towards sialic acid, which is characteristic only of a small number of lectins from bacilli and underlies a wide range of biological effects of these proteins, receives particular attention. Adaptation mechanisms involving lectins--carbohydrate-recognizing proteins--are suggested to have developed in saprophytic bacilli to ensure the survival of these organisms in a constantly changing environment.

Hsp12.6 Expression Is Inducible by Host Immunity in Adult Worms of the Parasitic Nematode Nippostrongylus brasiliensis

Heat shock proteins (Hsp) are a family of stress-inducible molecular chaperones that play multiple roles in a wide variety of animals. However, the roles of Hsps in parasitic nematodes remain largely unknown. To elucidate the roles of Hsps in the survival and longevity of nematodes, particularly at the 2 most critical stages in their lifecycle, the infective-L3 stage and adult stage, which is subjected to host-derived immunological pressure, we examined the temporal gene transcription patterns of Hsp12.6, Hsp20, Hsp70, and Hsp90 throughout the developmental course of the nematode Nippostrongylus brasiliensis by reverse transcriptase real-time PCR. Nb-Hsp70 and Nb-Hsp90 expression were observed throughout the nematode's lifecycle, while the expression of Nb-Hsp20 was restricted to adults. Interestingly, Nb-Hsp12.6 showed a biphasic temporal expression pattern; i.e., it was expressed in infective-L3 larvae and in adults during worm expulsion from immunocompetent rats. However, the activation of Nb-Hsp12.6 in adult worms was aborted when they infected permissive athymic-rnu/rnu rats and was only marginal when they infected mast-cell-deficient Ws/Ws rats, which exhibited a low response of rat mast cell protease (RMCP) II and resistin-like molecule (Relm)- β expression compared to those observed in immunocompetent rats. Moreover, the activation of Nb-Hsp12.6 was reversed when adult worms were transplanted into the naive rat intestine. These features of Nb-Hsp12.6, the expression of which is not only stage-specific in infective-L3, but is also inducible by mucosal immunity in adults, have implications for the survival strategies of parasitic nematodes in deleterious environmental conditions both outside and inside the host.

Behavioural and Electrophysiological Characterisation of Experimentally Induced Osteoarthritis and Neuropathy in C57Bl/6 Mice

BackgroundOsteoarthritis is a widespread condition affecting the elderly where ~70–90% of over 75 year olds are affected, representing one of the largest cost burdens to healthcare in the western world. The monosodium iodoacetate (MIA) osteoarthritis model has been well described in the rat especially in terms of the pathological progression of the disease and more recently pain behaviour. In this study, we characterise, for the first time, MIA induced osteoarthritis in mice and compare it with nerve-injured mice (partial sciatic nerve injury), using both behavioural and in vivo electrophysiological measurements. These approaches uniquely allow the threshold and suprathreshold measures to many modalities to be quantified and so form a basis for improving and expanding transgenic studies.ResultsSignificant mechanical hypersensitivity was observed in the ipsilateral hindpaw in MIA injected mice at all observed time points following infrapetellar MIA injection (p < 0.05). The mechanical hypersensitivity exhibited a partial biphasic temporal pattern, but thermal hypersensitivity was absent. Electrically-evoked dorsal horn neuronal responses in MIA injected mice were significantly elevated (p < 0.05) with respect to A- and C-fibre firing, input, pinch and noxious von Frey (26 and 60 g). No significant changes in A- or C-fibre thresholds were observed. Nerve-injured mice displayed significant behavioural thermal and mechanical hypersensitivity (p < 0.05) and evoked dorsal horn responses were significantly increased with respect to C-fibre firing, pinch and wind-up (p < 0.05).ConclusionThe MIA model of osteoarthritic pain in mice displays behavioural characteristics similar to those observed in rats. Changes in both behavioural measures and neuronal activity from the paw, suggest that central changes are involved in this pain state, although a role for peripheral drives is also likely. Moreover, the behavioural and neuronal measures in these two pain models showed overlapping alterations in terms of certain neuronal measures and mechanical sensitivity despite their very different pathologies and a loss of input in neuropathy, suggesting some commonalities in the central processing of different peripheral pain states. This murine model of osteoarthritis will allow the exploitation of knock out animals to better understand underlying mechanisms and identify novel molecular targets.

Ultra violet-induced localized inflammatory hyperalgesia in awake rats and the role of sensory and sympathetic innervation of the skin

Exposure to mid range ultrat violet radiations (UVBs) has been shown to produce systemic inflammation and hyperalgesia in mice [Saadé, N.E., Nasr, I.W., Massaad, C.A., Safieh-Garabedian, B., Jabbur, S.J., Kanaan, S.A., 2000. Modulation of ultraviolet-induced hyperalgesia and cytokine upregulation by interleukins 10 and 13. Br. J. Pharmacol. 131, 1317–1324]. Our aim was to characterize a new rat model of localized exposure to UVB and to determine the role of skin innervation in the observed hyperalgesia and cytokine upregulation. In several groups of rats one hindpaw was exposed to UVB (250–350 mJ/cm 2) and this was followed by the application, to the plantar area of the paw, of either Von Frey hairs or a few acetone drops to measure tactile and cold allodynia, respectively. Thermal hyperalgesia was assessed by the paw withdrawal latency and duration. Cytokine levels were determined, by ELISA, in processed samples of skin tissue isolated from the exposed and non-exposed paws. UVB induced a biphasic thermal hyperalgesia and cold and tactile allodynia with an early phase that peaked at 3–6 h and disappeared at 24 h and a late phase with a peak at 48 h and recovery at 72-h post-exposure. Tumor necrosis factor, interleukins 1β, 6, 8, 10 and NGF levels were significantly increased following the same biphasic temporal pattern. Chemical ablation of capsaicin sensitive afferents and guanethidine injection produced significant alteration of the hyperalgesia and allodynia. The increase in cytokine levels by UVB was also altered by both treatments. The present study describes a new animal model for localized UVB-induced inflammatory hyperalgesia and provides evidence about the involvement of neurogenic mechanisms in the observed hyperalgesia and upregulation of proinflammatory mediators.

Insomnia and Circadian Variation of Attacks in Episodic Migraine

To assess the influence of insomnia on the 24-hour temporal pattern of migraine. Migraine attacks have been reported to occur in a harmonic (monophasic) or a biphasic 24-hour cyclic manner, and in some studies to have preponderance in the morning hours. The influence of insomnia on the circadian pattern has not been evaluated. Based on a previous study of the circadian variation in migraine, an explorative data analysis was made to compare the circadian pattern of insomnia-related migraine attacks to the circadian pattern of migraine attacks not related to insomnia. If the patients reported difficulties in falling asleep and/or maintaining sleep the night prior to the reported attack or the night the attack occurred, the attack was defined as insomnia-related. Relapses were not counted as distinctive attacks. Sixty-eight female migraineurs (mean +/- SD age: 35.5 +/- 7.0) prospectively recorded 1869 migraine attacks. Five hundred-and-thirty-three attacks (29%) were insomnia-related. Insomnia-related attacks had a biphasic temporal pattern with one peak in the morning hours and one peak after noon. They had a preponderance in the morning hours compared to attacks not related to insomnia (t= 3.27, df = 62, P= .002). In 79% of attacks insomnia was experienced prior to the headache. Episodic morning migraine is associated with insomnia. The cause and consequences of insomnia in migraine is not clarified, but sleep obviously protects against attacks rather than provokes them.

Suppression of Microglial Inflammatory Activity by Myelin Phagocytosis: Role of p47-PHOX-Mediated Generation of Reactive Oxygen Species

Multiple sclerosis (MS) is pathologically characterized by inflammatory demyelination and neuronal injury. Although phagocytosis of myelin debris by microglia and macrophages in acute MS lesions is well documented, its pathophysiological significance is unclear. Using real-time quantitative PCR, flow cytometry, ELISA, and reactive oxygen species (ROS) measurement assays, we demonstrated that phagocytosis of myelin modulates activation of microglial cells prestimulated by interferon-gamma (IFN-gamma) or a combination of IFN-gamma and lipopolysaccharide with a biphasic temporal pattern, i.e., enhanced production of proinflammatory mediators during the first phase (< or = 6 h), followed by suppression during the second (6-24 h) phase. In this second phase, myelin phagocytosis leads to an enhanced release of prostaglandin E2 and ROS in microglia, whereas the production of anti-inflammatory cytokines (particularly interleukin-10) remains unchanged. Suppression of inflammatory microglial activation by myelin phagocytosis was reversed by treatment with superoxide dismutase and catalase, by inhibition of the NADPH-oxidase complex, or by specific knockdown of the NADPH-oxidase-required adaptor p47-phagocyte oxidase (PHOX). Furthermore, we observed that myelin phagocytosis destabilized tumor necrosis factor-alpha and interferon-induced protein-10 mRNA through an adenine-uridine-rich elements-involved mechanism, which was reversed by blocking the function of NADPH-oxidase complex. We conclude that phagocytosis of myelin suppresses microglial inflammatory activities via enhancement of p47-PHOX-mediated ROS generation. These results suggest that intervention in ROS generation could represent a novel therapeutic strategy to reduce neuroinflammation in MS.

Enhanced cone dysfunction in rats homozygous for the P23H rhodopsin mutation

The heterozygous P23H transgenic rat is a model of autosomal dominant retinitis pigmentosa, in which a mutation in the rhodopsin gene leads to a rapid loss of rods and a more protracted loss of cones. It has been suggested that rods play an essential role in preserving cones. We tested this hypothesis by examining whether higher levels of dysfunctional rhodopsin in rats homozygous for the P23H mutation would result in exacerbated cone dysfunction when compared with heterozygous P23H rats. Electroretinogram (ERG) responses were recorded from P21 to P250 in Sprague–Dawley (SD) and homozygous P23H rats. Both scotopic and photopic intensity response ERGs were severely depressed already at P21 when compared with age-matched SD rats. Furthermore, flicker amplitudes and critical fusion frequencies were also lower in P23H compared with SD rats at P21. Scotopic and photopic intensity responses as well as flicker amplitude and critical fusion frequencies declined rapidly up to P60, reaching a steady state that was maintained up to P200. We conclude that in rats homozygous for P23H rhodopsin mutations, the severe loss of rod function already seen by P21 is accompanied by substantial cone functional loss at that age. While rod-related responses are more severely affected than cone-related responses at all ages, their actual rate of decline with age is surprisingly similar. Both undergo a biphasic temporal pattern of decline: very rapid (P21–P60) followed by very slow (P60–P200) deterioration in response parameters, implying a tight link between rod and cone functional deterioration.

Biphasic temporal pattern in exercise capacity after myocardial infarction in the rat: relationship to left ventricular remodeling.

After myocardial infarction (MI), there is progressive left ventricular (LV) remodeling and impaired exercise capacity. We tested the hypothesis that LV remodeling results in structural and functional changes that determine exercise impairment post-MI. Rats underwent coronary artery ligation (n = 12) or sham (n = 11) surgery followed by serial exercise tests and echocardiography for 16 wk post-MI. LV pressure-volume relationships were determined using a blood-perfused Langendorff preparation. Exercise capacity was 60% of shams immediately post-MI (P < 0.05) followed by a recovery to near normal during weeks 5-8. Thereafter, there was a progressive decline in exercise capacity to +/-40% of shams (P < 0.01). At both 8 and 16 wk post-MI, fractional shortening (FS) was reduced and end-diastolic diameter (EDD) was increased (P < 0.01). However, neither FS nor EDD correlated with exercise at 8 or 16 wk (r(2) < 0.12, P > 0.30). LV septal wall thickness was increased at both 8 (P = 0.17 vs. shams) and 16 wk (P = 0.035 vs. shams) post-MI and correlated with exercise at both times (r(2) >/= 0.50 and P </= 0.02 at 8 and 16 wk). Neither end-diastolic volume nor maximum LV developed pressure at 16 wk correlated with exercise capacity. Exercise capacity follows a biphasic time course post-MI. An immediate decrease is followed by an early recovery phase that is associated with compensatory LV hypertrophy. Subsequently, there is a progressive decrease in exercise capacity that is independent of further changes in LV volume or contractile function.

Temporal Responses of the Brachial Artery Following Forearm Occlusion

0436 Measurement of flow-mediated dilation of the brachial artery in response to a sudden change in blood flow has emerged as a useful tool for atherosclerosis research. In the setting of cardiovascular disease risk factors flow-mediated dilation declines, perhaps suggesting a loss of normal endothelial function. Interestingly, little attention has been given to the temporal responses of the vessel's behavior following the occlusion period. PURPOSE: To examine the temporal response of the brachial artery following forearm occlusion. METHODS: Twelve healthy males (28 ± 5.47y) underwent highresolution ultrasonography of the brachial artery before and after 5 minutes of forearm occlusion. RESULTS: As show in the figure the average brachial artery diameter at rest was 3.52 ± 0.46mm. A significant decrease in brachial artery diameter was observed approx. 10 ± 4 sec after release of the occlusion (3.45 ± 0.47mm vs. baseline, p = 0.03), which was followed by a rapid increase in the diameter reaching a peak at approx. 49 ± 16sec (3.81 ± 0.48mm vs. baseline, p = 0.001). CONCLUSION: These results indicate a biphasic temporal pattern following 5 minutes of forearm occlusion. The mechanism for the initial decrease in diameter is uncertain, but may be a response to a change in fluid mechanics following cuff release or a myogenic influence. The subsequent increase in brachial diameter may in part be a reflection of endothelial mediated mechanisms. The temporal pattern may provide additional information regarding the structural and physiological status of the artery.Figure

Induced Autocrine Signaling through the Epidermal Growth Factor Receptor Contributes to the Response of Mammary Epithelial Cells to Tumor Necrosis Factor α

In contrast to the well known cytotoxic effects of tumor necrosis factor (TNF) alpha in many mammary cancer cells, we have found that TNF stimulates the proliferation and motility of human mammary epithelial cells (HMECs). Since the response of HMECs to TNF is similar to effects mediated by epidermal growth factor receptor (EGFR) activation, we explored the potential role of cross-talk through the EGFR signaling pathways in mediating cellular responses to TNF. Using a microarray enzyme-linked immunoassay, we found that exposure to TNF stimulated the dose-dependent shedding of the EGFR ligand transforming growth factor alpha (TGFalpha). Both proliferation and motility of HMECs induced by TNF was prevented either by inhibiting membrane protein shedding with a metalloprotease inhibitor, by blocking epidermal growth factor receptor (EGFR) kinase activity, or by limiting ligand-receptor interactions with an antagonistic anti-EGFR antibody. EGFR activity was also necessary for TNF-induced release of matrix metalloprotease-9, thought to be an essential regulator of mammary cell migration. The cellular response to TNF was associated with a biphasic temporal pattern of extracellular signal-regulated kinase (ERK) phosphorylation, which was EGFR-dependent and modulated by inhibition of metalloprotease-mediated shedding. Significantly, the late phase of ERK phosphorylation, detectable within 4 h after exposure, was blocked by the metalloprotease inhibitor batimastat, indicating that autocrine signaling through ligand shedding was responsible for this secondary wave of ERK activity. Our results indicate a novel and important role for metalloprotease activation and EGFR transmodulation in mediating the cellular response to TNF.

The hepatoprotective effect of putrescine against cadmium-induced acute liver injury.

The hepatoprotective effect of putrescine against cadmium liver injury was investigated. Male Wistar rats were injected with a dose of cadmium (6.5 mg CdCl(2)/kg bodyweight, intraperitoneally). Normal saline (group I) or putrescine (300 micro mol/kg bodyweight; group II) were injected 2, 5 and 8 h later. A number of animals of both groups were killed 0, 12, 16, 24, 48 or 60 h after cadmium intoxication. Liver tissue was histologically assessed for necrosis, apoptosis, peliosis, mitoses, and inflammatory infiltration. Apoptosis was also quantified by the TUNEL assay for hepatocytes and nonparenchymal liver cells. The discrimination between hepatic cell subpopulations was achieved histochemically. The mitotic index in hematoxylin-eosin-stained sections and by the immunochemical detection of Ki67 nuclear antigen, (3)H-thymidine incorporation into hepatic DNA, and hepatic thymidine kinase activity were all used as indices of liver regeneration. Both hepatocyte apoptosis and liver necrosis evolved in a biphasic temporal pattern. Nonparenchymal cell apoptosis and peliosis hepatis evolved in a monophasic pattern and were correlated closely. Putrescine administration totally reversed liver necrosis and hepatocyte apoptosis. The time profile of nonparenchymal apoptosis was altered and peliosis hepatis was also totally attenuated. In conclusion, putrescine protected hepatocytes and modulated the mechanism of cadmium-induced acute hepatotoxicity.

Preconditioning with ethanol prevents postischemic leukocyte-endothelial cell adhesive interactions.

Long-term ethanol consumption at low to moderate levels exerts cardioprotective effects in the setting of ischemia and reperfusion (I/R). The aims of this study were to determine whether 1) a single orally administered dose of ethanol [ethanol preconditioning (EtOH-PC)] would induce a biphasic temporal pattern of protection (early and late phases) against the inflammatory responses to I/R and 2) adenosine and nitric oxide (NO) act as initiators of the late phase of protection. Ethanol was administered as a bolus to C57BL/6 mice at a dose that achieved a peak plasma concentration of ~45 mg/dl 30 min after gavage and returned to control levels within 60 min of alcohol ingestion. The superior mesenteric artery was occluded for 45 min followed by 60 min of reperfusion beginning 10 min or 1, 2, 3, 4, or 24 h after ethanol ingestion, and the numbers of fluorescently labeled rolling and firmly adherent (stationary) leukocytes in single postcapillary venules of the small intestine were quantified using intravital microscopic approaches. I/R induced marked increases in leukocyte rolling and adhesion, effects that were attenuated by EtOH-PC 2-3 h before I/R (early phase), absent when assessed after 10 min, 1 h, and 4 h of ethanol ingestion, with an even more powerful late phase of protection reemerging when I/R was induced 24 h later. The anti-inflammatory effects of late EtOH-PC were abolished by treatment with adenosine deaminase, an adenosine A(2) (but not A(1)) receptor antagonist, or a NO synthase (NOS) inhibitor during the period of EtOH-PC. Preconditioning with an adenosine A(2) (but not an A(1)) receptor agonist in lieu of ethanol 24 h before I/R mimicked the protective actions of late phase EtOH-PC. Like EtOH-PC, the effect of preconditioning with an adenosine A(2) receptor agonist was abrogated by coincident NOS inhibition. These findings suggest that EtOH-PC induces a biphasic temporal pattern of protection against the proinflammatory effects of I/R. In addition, our observations are consistent with the hypothesis that the late phase of EtOH-PC is triggered by NO formed secondary to adenosine A(2) receptor-dependent activation of NOS during the period of ethanol exposure.

Autoradiographic evidence that prolonged withdrawal from intermittent cocaine reduces mu-opioid receptor expression in limbic regions of the rat brain.

Numerous reports support evidence that dopaminergic mesolimbic pathways interact with opioid systems to influence the reinforcing properties of cocaine. Withdrawal from chronic administration of cocaine in rats causes an upregulation of mesocorticolimbic mu-opioid receptors during early stages, but information about prolonged cocaine abstinence is lacking. We addressed this issue by treating rats with cocaine or saline (control) intermittently (1 mg/kg, i.v., every 12 min for 2 h daily) for 10 days followed by a 10- or 20-day withdrawal period. The animals were then decapitated and the brains removed for quantitative in vitro autoradiographic analysis of 14 brain regions with (125)I-DAMGO. A separate group of animals received two consecutive cycles of the 10-day cocaine/10-day withdrawal regimen. Only the group that participated in the two consecutive cycles showed a significant effect of treatment: downregulation of mu-opiate receptors in limbic cortical layer 3 (17% lower than saline-treated controls, P = 0.03), the core of the nucleus accumbens (16% decrease, P = 0.05), and the nucleus of the diagonal band (18% decrease, P = 0.05). The mu-receptor may manifest, as do other neural markers (e.g., dopamine transporter, dopamine efflux), a biphasic temporal pattern with upregulation during early phases of cocaine withdrawal but a downregulation at later times.

Upregulation of Tumor Necrosis Factor α Transport across the Blood–Brain Barrier after Acute Compressive Spinal Cord Injury

Tumor necrosis factor alpha (TNF) is a cytokine that is involved in the inflammatory process after CNS injury and is implicated in neuroregeneration. A saturable transport system for TNF located at the blood-brain barrier (BBB) is responsible for the limited entry of TNF from blood to the CNS in normal mice. After partial disruption of the BBB by compression of the lumbar spinal cord, permeability to TNF was increased not only in the lumbar spinal cord but also in brain and distal spinal cord segments, where the BBB remained intact. The increase in the entry of TNF to the CNS followed a biphasic temporal pattern, with a first peak immediately after injury and a second peak starting on day 3; these changes lasted longer than the mere disruption of the BBB. The increased entry of TNF was abolished by addition of excess unlabeled TNF, showing that the transport system for TNF remained saturable after spinal cord injury (SCI) and providing evidence that the enhanced entry of TNF could not be explained by diffusion or leakage. This study adds strong support for our concept that the saturable transport system for TNF across the BBB can be upregulated in the diseased state, and it suggests that the BBB is actively involved in the modulation of the processes of degeneration and regeneration after SCI.