More than 500,000 deaths are attributed to rotavirus gastroenteritis annually worldwide, with the highest mortality in India. Two successive, naturally occurring rotavirus infections have been shown to confer complete protection against moderate or severe gastroenteritis during subsequent infections in a birth cohort in Mexico. We studied the protective effect of rotavirus infection on subsequent infection and disease in a birth cohort in India (where the efficacy of oral vaccines in general has been lower than expected).
We recruited children at birth in urban slums in Vellore; they were followed for 3 years after birth, with home visits twice weekly. Stool samples were collected every 2 weeks, as well as on alternate days during diarrheal episodes, and were tested by means of enzyme-linked immunosorbent assay and polymerase-chain-reaction assay. Serum samples were obtained every 6 months and evaluated for seroconversion, defined as an increase in the IgG antibody level by a factor of 4 or in the IgA antibody level by a factor of 3.
Of 452 recruited children, 373 completed 3 years of follow-up. Rotavirus infection generally occurred early in life, with 56% of children infected by 6 months of age. Levels of reinfection were high, with only approximately 30% of all infections identified being primary. Protection against moderate or severe disease increased with the order of infection but was only 79% after three infections. With G1P, the most common viral strain, there was no evidence of homotypic protection.
Early infection and frequent reinfection in a locale with high viral diversity resulted in lower protection than has been reported elsewhere, providing a possible explanation why rotavirus vaccines have had lower-than-expected efficacy in Asia and Africa. (Funded by the Wellcome Trust.)
The TGF-b superfamily cytokine MIC-1/GDF15 circulates in all humans and when overproduced in cancer leads to anorexia/cachexia, by direct action on brain feeding centres. In these studies we have examined the role of physiologically relevant levels of MIC-1/GDF15 in the regulation of appetite, body weight and basal metabolic rate. MIC-1/GDF15 gene knockout mice (MIC-1−/−) weighed more and had increased adiposity, which was associated with increased spontaneous food intake. Female MIC-1−/− mice exhibited some additional alterations in reduced basal energy expenditure and physical activity, possibly owing to the associated decrease in total lean mass. Further, infusion of human recombinant MIC-1/GDF15 sufficient to raise serum levels in MIC-1−/− mice to within the normal human range reduced body weight and food intake. Taken together, our findings suggest that MIC-1/GDF15 is involved in the physiological regulation of appetite and energy storage.
High serum levels of macrophage inhibitory cytokine 1 (MIC-1) are strongly associated with metastatic prostate cancer, suggesting MIC-1 is a biomarker for prostate cancer prognosis.
We conducted a prospective cohort study of 1,442 Swedish men with a pathologically verified diagnosis of prostate cancer between 2001 and 2003. Blood was drawn either pretreatment (n = 431) or posttreatment (n = 1,011) and cases were followed for a mean time of 4.9 years (range, 0.1–6.8 years).
MIC-1 serum levels independently predicted poor cancer-specific survival with an almost 3-fold higher cancer death rate in patients with serum levels in the highest quartile compared with men with serum levels in the lowest quartile (adjusted hazard ratio, 2.98; 95% confidence interval, 1.82–4.68). Pretreatment MIC-1 levels revealed an even stronger association with disease outcome with an 8-fold higher death rate in the highest compared with the lowest category (adjusted hazard ratio, 7.98; 95% confidence interval, 1.73–36.86). Among patients considered to have localized disease, MIC-1 significantly increased the discriminative capacity between indolent and lethal prostate cancer compared with the established prognostic markers clinical stage, pathologic grade, and prostate-specific antigen level (P = 0.016). A sequence variant in the MIC-1 gene was associated with decreased MIC-1 serum levels (P = 0.002) and decreased prostate cancer mortality (P = 0.003), suggesting a causative role of MIC-1 in prostate cancer prognosis.
Serum MIC-1 concentration is a novel biomarker capable of predicting prostate cancer prognosis.
Severe spinal cord injuries above mid-thoracic levels can lead to a potentially life-threatening hypertensive condition termed autonomic dysreflexia that is often triggered by painful distension of pelvic viscera (bladder or bowel) and consequent sensory fiber activation, including nociceptive C-fibers. Interruption of tonically active medullo-spinal pathways after injury causes disinhibition of thoracolumbar sympathetic preganglionic neurons, and intraspinal sprouting of nerve growth factor (NGF)-responsive primary afferent fibers is thought to contribute to their hyperactivity. We investigated spinal levels that are critical for eliciting autonomic dysreflexia using a model of noxious colorectal distension (CRD) after complete spinal transection at the 4th thoracic segment in rats. Post-traumatic sprouting of calcitonin gene-related peptide (CGRP)-immunoreactive primary afferent fibers was selectively altered at specific spinal levels caudal to the injury with bilateral microinjections of adenovirus encoding the growth-promoting NGF or growth-inhibitory semaphorin 3A (Sema3a) compared to control green fluorescent protein (GFP). Two weeks later, cardio-physiological responses to CRD were assessed among treatment groups prior to histological analysis of afferent fiber density at the injection sites. Dysreflexic hypertension was significantly higher with NGF over-expression in lumboscral segments compared to GFP, whereas similar over-expression of Sema3a significantly reduced noxious CRD-evoked hypertension. Quantitative analysis of CGRP immunostaining in the spinal dorsal horns showed a significant correlation between the extent of fiber sprouting into the spinal segments injected and the severity of autonomic dysreflexia. These results demonstrate that site-directed genetic manipulation of axon guidance molecules after complete spinal cord injury can alter endogenous circuitry in order to modulate plasticity-induced autonomic pathophysiology.
nerve growth factor; semaphorin 3A; sprouting; sympathetic; neurotrophin
Low-threshold voltage-gated M-type potassium channels (M channels) are tetraheteromers, commonly of two Kv7.2 and two Kv7.3 subunits. Though gated by voltage, the channels have an absolute requirement for binding of the membrane phospholipid phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) to open. We have investigated the quantitative relation between the concentration of a water-soluble PI(4,5)P2 analog, dioctanoyl-PI(4,5)P2 (DiC8-PI(4,5)P2), and channel open probability (Popen) by fast application of increasing concentrations of DiC8-PI(4,5)P2 to the inside face of membrane patches excised from Chinese hamster ovary cells expressing M channels as heteromeric Kv7.2/7.3 subunits. The rationale for the experiments is that this will mimic the effect of changes in membrane PI(4,5)P2 concentration. Single-channel conductances from channel current–voltage relations in cell-attached mode were 9.2 ± 0.1 pS with a 2.5-mM pipette [K+]. Plots of Popen against DiC8-PI(4,5)P2 concentration were best fitted using a two-component concentration–Popen relationship with high and low affinity, half-maximal effective concentration (EC50) values of 1.3 ± 0.14 and 75.5 ± 2.5 µM, respectively, and Hill slopes of 1.4 ± 0.06. In contrast, homomeric channels from cells expressing only Kv7.2 or Kv7.3 constructs yielded single-component curves with EC50 values of 76.2 ± 19.9 or 3.6 ± 1.0 µM, respectively. When wild-type (WT) Kv7.2 was coexpressed with a mutated Kv7.3 subunit with >100-fold reduced sensitivity to PI(4,5)P2, the high-affinity component of the activation curve was lost. Fitting the data for WT and mutant channels to an activation mechanism with independent PI(4,5)P2 binding to two Kv7.2 and two Kv7.3 subunits suggests that the two components of the M-channel activation curve correspond to the interaction of PI(4,5)P2 with the Kv7.3 and Kv7.2 subunits, respectively, that channels can open when only the two Kv7.3 subunits have bound DiC8-PI(4,5)P2, and that maximum channel opening requires binding to all four subunits.
Some of the excitatory effects of norepinephrine on central neurons are mediated by alpha-1 (α1) adrenoceptors. These receptors are coupled to the Gq family of G proteins, and hence stimulate hydrolysis of the membrane phospholipid phosphatidylinositol-4,5-bisphosphate. Other receptors of this type can excite neurons by inhibiting the subthreshold voltage-gated potassium M-current. We tested this possibility using rat sympathetic neurons transformed to express α1a receptors. The α1 agonist phenylephrine strongly inhibited the M-current recorded under voltageclamp by 72 ± 11 % (n = 4) and in an unclamped neuron dramatically increased the number of action potentials produced by a 2 s depolarizing current step from 2 to 40, without effect on control neurons devoid of α1 receptors. We suggest that this might be a potential cause of the increased excitability produced by norepinephrine in some central neurons.
α1 Adrenoceptors; Norepinephrine; Phenylephrine; M-current; Potassium current; Sympathetic neurons
Multiple sclerosis (MS) is a devastating neurological disease that predominantly affects young adults resulting in severe personal and economic impact. The majority of therapies for this disease were developed in, or are beneficial in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. While known to target adaptive anti-CNS immune responses, they also target, the innate immune arm. This mini-review focuses on the role of dendritic cells (DCs), the professional antigen presenting cells of the innate immune system. The evidence for a role for DCs in the appropriate regulation of anti-CNS autoimmune responses and their role in MS disease susceptibility and possible therapeutic utility are discussed. Additionally, the current controversy regarding the evidence for the presence of functional DCs in the normal CNS is reviewed. Furthermore, the role of CNS DCs and potential routes of their intercourse between the CNS and cervical lymph nodes are considered. Finally, the future role that this nexus between the CNS and the cervical lymph nodes might play in site directed molecular and cellular therapy for MS is outlined.
multiple sclerosis; dendritic cell; experimental autoimmune encephalomyelitis; cervical lymph node; molecular therapy; cellular therapy; site directed local therapy
Expressed metabotropic group 1 glutamate mGluR5 receptors and nucleotide P2Y1 receptors (P2Y1Rs) show promiscuous ion channel coupling in sympathetic neurons: their stimulation inhibits M-type (Kv7, K(M)) potassium currents and N-type (CaV2.2) calcium currents (Kammermeier and Ikeda, 1999; Brown et al., 2000). These effects are mediated by Gq and Gi/o G-proteins respectively. Via their C-terminal tetrapeptide, these receptors also bind to the PDZ-domain of the scaffold protein NHERF2, which enhances their coupling to Gq-mediated Ca2+-signaling (Fam et al., 2005; Paquet et al., 2006b). We investigated whether NHERF2 could modulate coupling to neuronal ion channels. We find that co-expression of NHERF2 in sympathetic neurons (by intranuclear cDNA injections) does not affect the extent of M-current inhibition produced by either receptor but strongly reduced CaV2.2 inhibition by both P2Y1R and mGluR5 activation. NHERF2 expression had no significant effect on CaV2.2 inhibition by norepinephrine (via α2-adrenoceptors, which do not bind NHERF2), nor on CaV2.2 inhibition produced by an expressed P2Y1R lacking the NHERF2-binding DTSL motif. Thus, NHERF2 selectively restricts downstream coupling of mGluR5 and P2Y1Rs in neurons to Gq-mediated responses such as K(M) inhibition. Differential distribution of NHERF2 in neurons may therefore determine coupling of mGluR5 receptors and P2Y1 receptors to calcium channels.
P2Y; metabotropic glutamate receptor; scaffolding proteins; calcium channels; M-current; Neuron; Sympathetic; Transduction; Patch Clamp; Immunoreactivity
Ion channels are pores that allow the exchange of molecules across cell membranes. In nerve cells (neurons) of the hippocampus (a brain region involved in learning and memory), the potassium KV7 channel is present predominantly in the cell body (the soma) and in its axon, a projection from the cell body that produces brief electrical signals known as action potentials. We have previously shown that axonal KV7 channels control action potential initiation and so regulate cell excitability. However, cells also receive inputs from other cells connected to them, resulting in longer lasting electrical signals known as synaptic potentials. In this study, we show that only somatic KV7 channels influence synaptic potential shapes and summation, whereas axonal channels increase the ability of synaptic potentials to generate action potentials. Hence, axonal and somatic KV7 channels differentially contribute to information processing within hippocampal neurons, which may be important for processes such as cognition
The KV7/M-current is an important determinant of neuronal excitability and plays a critical role in modulating action potential firing. In this study, using a combination of electrophysiology and computational modelling, we show that these channels selectively influence peri-somatic but not dendritic post-synaptic excitatory synaptic potential (EPSP) integration in CA1 pyramidal cells. KV7/M-channels are highly concentrated in axons. However, the competing peptide, ankyrin G binding peptide (ABP) that disrupts axonal KV7/M-channel function, had little effect on somatic EPSP integration, suggesting that this effect was due to local somatic channels only. This interpretation was confirmed using computer simulations. Further, in accordance with the biophysical properties of the KV7/M-current, the effect of somatic KV7/M-channels on synaptic potential summation was dependent upon the neuronal membrane potential. Somatic KV7/M-channels thus affect EPSP–spike coupling by altering EPSP integration. Interestingly, disruption of axonal channels enhanced EPSP–spike coupling by lowering the action potential threshold. Hence, somatic and axonal KV7/M-channels influence EPSP–spike coupling via different mechanisms. This may be important for their relative contributions to physiological processes such as synaptic plasticity as well as patho-physiological conditions such as epilepsy.
Anorexia/cachexia is a common and currently mostly untreatable complication of advanced cancer. It is also a feature of a number of chronic diseases and can also occur as part of the normal ageing process. Over recent years, two different, but sometimes overlapping, processes have been identified to mediate anorexia/cachexia: those that act primarily on muscle reducing its mass and function, and processes that decrease nutrition leading to loss of both fat and muscle. In the case of at least some cancers, the latter process is sometimes driven by marked overexpression of macrophage inhibitory cytokine-1/growth differentiation factor 15 (MIC-1/GDF15). MIC-1/GDF15 is a transforming growth factor beta (TGF-β) family cytokine that is found in the serum of all normal individuals at an average concentration of about 0.6 ng/ml. Its increased expression in both cancers and other diseases can result in 10–100-fold or more elevation of its serum levels. In experimental animals, serum MIC-1/GDF15 levels at the lower end of this range induce anorexia by direct actions of the circulating cytokine on feeding centres in the brain. Mice with tumours overexpressing MIC-1/GDF15 display decreased food intake, loss of lean and fat mass and cachexia. That this process also mediates anorexia/cachexia in humans is suggested by the fact that there is a direct correlation between the degree of serum MIC-1/GDF15 elevation and the amount of cancer-related weight loss, the first such relationship demonstrated. Further, in experimental animals, weight loss can be reversed by neutralisation of tumour-produced MIC-1/GDF15 with a specific monoclonal antibody, suggesting the possibility of effective therapy of patients with the devastating complication of anorexia/cachexia.
MIC-1/GDF15; Macrophage inhibitory cytokine 1; Anorexia; Cachexia; TGF-β; Appetite regulation
CCAAT enhancer binding protein-delta (C/EBPδ) is a transcription factor that regulates inflammatory processes mediating bystander neuronal injury and CNS autoimmune inflammatory disease. The mechanism of C/EBPδ’s involvement in these processes remains to be determined. Here we examined the cellular source(s) and mechanisms by which C/EBPδ may be involved in an animal model of multiple sclerosis. Mice deficient in C/EBPδ expression exhibited less severe clinical disease than wild type littermates in response to induction of experimental autoimmune encephalomyelitis (EAE) by vaccination with a myelin oligodendrocyte glycoprotein (MOG) fragment. This reduction in EAE severity was associated with a significant alteration in the complement of major CNS T-helper (Th) cell subtypes throughout disease, manifest as reduced ratios of Th17 cells to regulatory T-cells (Tregs). Studies in bone marrow chimeric mice indicated that C/EBPδ expression by peripherally derived immune cells mediates C/EBPδ involvement in EAE. Follow up in vitro and in vivo examination of dendritic cell (DC) mediated Th-cell development suggests C/EBPδ suppresses DC expression of interleukin-10 (IL-10) and favours Th17 over Treg development. In vitro and in vivo blockade of IL-10 signalling reduced the effect of reduced DC C/EBPδ expression on Th17:Treg ratios. These findings identify C/EBPδ as an important DC transcription factor in CNS autoimmune inflammatory disease by virtue of its capacity to alter the Th17:Treg balance in an IL-10 dependent fashion.
Production of official statistics frequently requires expert judgement to evaluate and reconcile data of unknown and varying quality from multiple and potentially conflicting sources. Moreover, exceptional events may be difficult to incorporate in modelled estimates. Computational logic provides a methodology and tools for incorporating analyst's judgement, integrating multiple data sources and modelling methods, ensuring transparency and replicability, and making documentation computationally accessible. Representations using computational logic can be implemented in a variety of computer-based languages for automated production. Computational logic complements standard mathematical and statistical techniques and extends the flexibility of mathematical and statistical modelling. A basic overview of computational logic is presented and its application to official statistics is illustrated with the WHO & UNICEF estimates of national immunization coverage.
Previous studies demonstrated that stroke survivors have a limited capacity to increase their walking speeds beyond their self-selected maximum walking speed (SMWS). The purpose of this study was to determine the capacity of stroke survivors to reach faster speeds than their SMWS while walking on a treadmill belt or while being pushed by a robotic system (i.e. “push mode”).
Eighteen chronic stroke survivors with hemiplegia were involved in the study. We calculated their self-selected comfortable walking speed (SCWS) and SMWS overground using a 5-meter walk test (5-MWT). Then, they were exposed to walking at increased speeds, on a treadmill and while in “push mode” in an overground robotic device, the KineAssist, until they were tested at a speed that they could not sustain without losing balance. We recorded the time and number of steps during each trial and calculated gait speed, average cadence and average step length.
Maximum walking speed in the “push mode” was 13% higher than the maximum walking speed on the treadmill and both were higher (“push mode”: 61%; treadmill: 40%) than the maximum walking speed overground. Subjects achieved these faster speeds by initially increasing both step length and cadence and, once individuals stopped increasing their step length, by only increasing cadence.
With post-stroke hemiplegia, individuals are able to walk at faster speeds than their SMWS overground, when provided with a safe environment that provides external forces that requires them to attempt dynamic stability maintenance at higher gait speeds. Therefore, this study suggests the possibility that, given the appropriate conditions, people post-stroke can be trained at higher speeds than previously attempted.
Stroke; Overground walking; KineAssist; Treadmill; Maximum walking speed
The objective of this study was to test cladribine (2-CDA) alone and in combination with rituximab in patients with mantle cell lymphoma (MCL).
Patients with MCL were treated on 2 sequential trials. In Trial 95-80-53, patients received 2-CDA as initial therapy or at relapse. In Trial N0189, patients received combination 2-CDA and rituximab as initial therapy. In both trials, 2-CDA was administered at a dose of 5 mg/m2 intravenously on Days 1 through 5 every 4 weeks for 2 to 6 cycles, depending on response. In Trial N0189, rituximab 375 mg/m2 was administered on Day 1 of each cycle.
Results were reported for 80 patients. Twenty-six previously untreated patients and 25 patients who had recurrent disease with a median age of 68 years received single-agent 2-CDA. The overall response rate (ORR) was 81% with 42% complete responses (CRs) in the previously untreated group. The median progression-free survival (PFS) was 13.6 months (95% confidence interval [95% CI], 7.2–22.1 months), and 81% of patients remained alive at 2 years. The ORR was 46% with a 21% CR rate in the recurrent disease group. The median PFS was 5.4 months (95% CI, 4.6–13.1 months), and 36% of patients remained alive at 2 years. Twenty-nine eligible patients with a median age of 70 years received 2-CDA plus rituximab. The ORR was 66% (19 of 29 patient), and the CR rate was 52% (15 of 29 patients). The median duration of response for patients who achieved a CR had not been reached at the time of the current report, and only 3 of the patients who achieved a CR developed recurrent disease at a median follow-up of 21.5 months.
2-CDA had substantial single-agent activity in both recurrent and untreated MCL, and the results indicated that it may be administered safely to elderly patients. The addition of rituximab to 2-CDA may increase the duration of response.
mantle cell lymphoma; cladribine; response duration; rituximab
Infant and young child feeding is critical for child health and survival. Proportion of infants 0–5 months who are fed exclusively with breast milk is a common indicator used for monitoring and evaluating infant and young child feeding in a given country and region. Despite progress made since 1990, a previous review in 2006 of global and regional trends found improvement to be modest. The current study provides an update in global and regional trends in exclusive breastfeeding from 1995 to 2010, taking advantage of the wealth of data from recent household surveys.
Using the global database of infant and young child feeding maintained by the United Nations Children’s Fund, the authors examined estimates from 440 household surveys in 140 countries over the period between 1995 and 2010 and calculated global and regional averages of the rate of exclusive breastfeeding among infants 0–5 months for the two time points to assess the trends.
Trend data suggest the prevalence of exclusive breastfeeding among infants younger than six months in developing countries increased from 33% in 1995 to 39% in 2010. The prevalence increased in almost all regions in the developing world, with the biggest improvement seen in West and Central Africa.
In spite of the well-recognized importance of exclusive breastfeeding, the practice is not widespread in the developing world and increase on the global level is still very modest with much room for improvement. Child nutrition programmes worldwide continue to require investments and commitments to improve infant feeding practices in order to have maximum impact on children’s lives.
Exclusive breastfeeding; Rate; Trends; Developing countries; Household survey
Peyer's patches constitute both an inductive immune site and an enteropathogen invasion route. Peyer's patch mucosae from porcine jejunum were mounted in Ussing chambers, and either Salmonella choleraesuis vaccine strain SC-54 or non-pathogenic rodent and porcine E. coli strains contacted the Peyer's patch mucosa for 90 min. Internalized bacteria were quantified by a gentamicin resistance assay. Monodansylcadaverine (300 µM, luminal addition), an inhibitor of clathrin-mediated endocytosis, significantly inhibited internalization of both E. coli strains relative to tissues untreated with the inhibitor; internalization of SC-54 was unaffected. The actin-disrupting agent cytochalasin D (10 µM, luminal addition), inhibited internalization of pig-adapted E. coli but not that of rodent-adapted E. coli or SC-54. Internalization of SC-54 and non-pathogenic E. coli in Peyer's patches appears to occur through different cellular routes.
Salmonella choleraesuis; Escherichia coli; mucosal immunity; enteropathogen; endocytosis; clathrin
Bacillus anthracis, the bacterium that causes anthrax, is an agent of bioterrorism. The most effective antimicrobial therapy for B. anthracis infections is unknown. An in vitro pharmacodynamic model of B. anthracis was used to compare the efficacies of simulated clinically prescribed regimens of moxifloxacin, linezolid, and meropenem with the “gold standards,” doxycycline and ciprofloxacin. Treatment outcomes for isogenic spore-forming and non-spore-forming strains of B. anthracis were compared. Against spore-forming B. anthracis, ciprofloxacin, moxifloxacin, linezolid, and meropenem reduced the B. anthracis population by 4 log10 CFU/ml over 10 days. Doxycycline reduced the population of this B. anthracis strain by 5 log10 CFU/ml (analysis of variance [ANOVA] P = 0.01 versus other drugs). Against an isogenic non-spore-forming strain, meropenem killed the vegetative B. anthracis the fastest, followed by moxifloxacin and ciprofloxacin and then doxycycline. Linezolid offered the lowest bacterial kill rate. Heat shock studies using the spore-producing B. anthracis strain showed that with moxifloxacin, ciprofloxacin, and meropenem therapies the total population was mostly spores, while the population was primarily vegetative bacteria with linezolid and doxycycline therapies. Spores have a profound impact on the rate and extent of killing of B. anthracis. Against spore-forming B. anthracis, the five antibiotics killed the total (spore and vegetative) bacterial population at similar rates (within 1 log10 CFU/ml of each other). However, bactericidal antibiotics killed vegetative B. anthracis faster than bacteriostatic drugs. Since only vegetative-phase B. anthracis produces the toxins that may kill the infected host, the rate and mechanism of killing of an antibiotic may determine its overall in vivo efficacy. Further studies are needed to examine this important observation.
Macrophage inhibitory cytokine-1 (MIC-1/GDF15), a divergent member of the TGF-β superfamily, is over-expressed by many common cancers including those of the prostate (PCa) and its expression is linked to cancer outcome. We have evaluated the effect of MIC-1/GDF15 overexpression on PCa development and spread in the TRAMP transgenic model of spontaneous prostate cancer. TRAMP mice were crossed with MIC-1/GDF15 overexpressing mice (MIC-1fms) to produce syngeneic TRAMPfmsmic-1 mice. Survival rate, prostate tumor size, histopathological grades and extent of distant organ metastases were compared. Metastasis of TC1-T5, an androgen independent TRAMP cell line that lacks MIC-1/GDF15 expression, was compared by injecting intravenously into MIC-1fms and syngeneic C57BL/6 mice. Whilst TRAMPfmsmic-1 survived on average 7.4 weeks longer, had significantly smaller genitourinary (GU) tumors and lower PCa histopathological grades than TRAMP mice, more of these mice developed distant organ metastases. Additionally, a higher number of TC1-T5 lung tumor colonies were observed in MIC-1fms mice than syngeneic WT C57BL/6 mice. Our studies strongly suggest that MIC-1/GDF15 has complex actions on tumor behavior: it limits local tumor growth but may with advancing disease, promote metastases. As MIC-1/GDF15 is induced by all cancer treatments and metastasis is the major cause of cancer treatment failure and cancer deaths, these results, if applicable to humans, may have a direct impact on patient care.
To determine whether there are identifiable factors associated with increased risk of aortic arch reintervention in patients who have undergone balloon aortoplasty (BD) for aortic arch obstruction (COA) after the Norwood procedure (NP).
BD has been shown to be an effective acute therapy for COA after the NP. However, recurrent obstruction requiring repeat intervention is not uncommon.
All patients who underwent BD as the initial intervention for COA following the NP at our institution from to 01/93-05/09 were retrospectively analyzed (n=116).
The median age at initial BD was 4.5 months. The median follow-up period was 3.4 years. The procedure was considered acutely successful in 92% of patients, with a median gradient reduction overall from 26 to 3 mmHg (p<0.0001) and COA diameter increase of 52% (p<0.0001). By Kaplan-Meier analysis, freedom from reintervention was 69% at 1 year, and 58% at 5 years; freedom from reoperation was 82% at 1 year, and 79% at 5 years. By Cox regression analysis, proximal arch obstruction, age <3 months at BD, ≥moderate ventricular dysfunction, ≥moderate atrioventricular valve regurgitation on pre-catheterization echocardiogram, and higher post-BD coarctation gradient were associated with shorter freedom from reoperation.
Despite a high acute success rate, a significant proportion of patients treated with BD for post-NP COA underwent reintervention during follow-up. The risk of arch reintervention is highest in patients with proximal arch obstruction, those who are younger than 3 months of age at the time of BD, and those with a less successful acute result.
Coarctation; Balloon angioplasty; Norwood procedure; Reintervention; Hypoplastic left heart syndrome
Some of the excitatory effects of norepinephrine on central neurons are mediated by alpha-1 (α1) adrenoceptors. These receptors are coupled to the Gq family of G proteins, and hence stimulate hydrolysis of the membrane phospholipid phosphatidylinositol-4,5-bisphosphate. Other receptors of this type can excite neurons by inhibiting the subthreshold voltage-gated potassium M-current. We tested this possibility using rat sympathetic neurons transformed to express α1a receptors. The α1 agonist phenylephrine strongly inhibited the M-current recorded under voltage-clamp by 72 ± 11 % (n = 4) and in an unclamped neuron dramatically increased the number of action potentials produced by a 2 s depolarizing current step from 2 to 40, without effect on control neurons devoid of α1 receptors. We suggest that this might be a potential cause of the increased excitability produced by norepinephrine in some central neurons.
α1 Adrenoceptors; Norepinephrine; Phenylephrine; M-current; Potassium current; Sympathetic neurons
Bacillus anthracis causes anthrax. Ciprofloxacin is a gold standard for the treatment of anthrax. Previously, using the non-toxin-producing ΔSterne strain of B. anthracis, we demonstrated that linezolid was equivalent to ciprofloxacin for reducing the total (vegetative and spore) bacterial population. With ciprofloxacin therapy, the total population consisted of spores. With linezolid therapy, the population consisted primarily of vegetative bacteria. Linezolid is a protein synthesis inhibitor, while ciprofloxacin is not. Since toxins are produced only by vegetative B. anthracis, the effect of linezolid and ciprofloxacin on toxin production is of interest. The effect of simulated clinical regimens of ciprofloxacin and linezolid on the vegetative and spore populations and on toxin production was examined in an in vitro pharmacodynamic model over 15 days by using the toxin-producing Sterne strain of B. anthracis. Ciprofloxacin and linezolid reduced the total Sterne population at similar rates. With ciprofloxacin therapy, the total Sterne population consisted of spores. With linezolid therapy, >90% of the population was vegetative B. anthracis. With ciprofloxacin therapy, toxin was first detectable at 3 h and remained detectable for at least 5 h. Toxin was never detected with linezolid therapy. Ciprofloxacin and linezolid reduced the total Sterne population at similar rates. However, the B. anthracis population was primarily spores with ciprofloxacin therapy and was primarily vegetative bacteria with linezolid therapy. Toxin production was detected for at least 5 h with ciprofloxacin therapy but was never detected with linezolid treatment. Linezolid may have an advantage over ciprofloxacin for the treatment of B. anthracis infections.
The panoply of resistance mechanisms in Pseudomonas aeruginosa makes resistance suppression difficult. Defining optimal regimens is critical. Cefepime is a cephalosporin whose 3′ side chain provides some stability against AmpC β-lactamases. We examined the activity of cefepime against P. aeruginosa wild-type strain PAO1 and its isogenic AmpC stably derepressed mutant in our hollow-fiber infection model. Dose-ranging studies demonstrated complete failure with resistance emergence (both isolates). Inoculum range studies demonstrated ultimate failure for all inocula. Lower inocula failed last (10 days to 2 weeks). Addition of a β-lactamase inhibitor suppressed resistance even with the stably derepressed isolate. Tobramycin combination studies demonstrated resistance suppression in both the wild-type and the stably derepressed isolates. Quantitating the RNA message by quantitative PCR demonstrated that tobramycin decreased the message relative to that in cefepime-alone experiments. Western blotting with AmpC-specific antibody for P. aeruginosa demonstrated decreased expression. We concluded that suppression of β-lactamase expression by tobramycin (a protein synthesis inhibitor) was at least part of the mechanism behind resistance suppression. Monte Carlo simulation demonstrated that a regimen of 2 g of cefepime every 8 h plus 7 mg/kg of body weight of tobramycin daily would provide robust resistance suppression for Pseudomonas isolates with cefepime MIC values up to 8 mg/liter and tobramycin MIC values up to 1 mg/liter. For P. aeruginosa resistance suppression, combination therapy is critical.
New broad-spectrum β-lactamases such as KPC enzymes and CTX-M-15 enzymes threaten to markedly reduce the utility of our armamentarium of β-lactam agents, even our most potent drugs, such as carbapenems. NXL104 is a broad-spectrum non-β-lactam β-lactamase inhibitor. In this evaluation, we examined organisms carrying defined β-lactamases and identified doses and schedules of NXL104 in combination with the new cephalosporin ceftaroline, which would maintain good bacterial cell kill and suppress resistance emergence for a clinically relevant period of 10 days in our hollow-fiber infection model. We examined three strains of Klebsiella pneumoniae and one isolate of Enterobacter cloacae. K. pneumoniae 27-908M carried KPC-2, SHV-27, and TEM-1 β-lactamases. Its isogenic mutant, K. pneumoniae 4207J, was “cured” of the plasmid expressing the KPC-2 enzyme. K. pneumoniae 24-1318A carried a CTX-M-15 enzyme, and E. cloacae 2-77C expressed a stably derepressed AmpC chromosomal β-lactamase. Dose-ranging experiments for NXL104 administered as a continuous infusion with ceftaroline at 600 mg every 8 h allowed identification of a 24-h area under the concentration-time curve (AUC) for NXL104 that mediated bactericidal activity and resistance suppression. Dose fractionation experiments identified that “time > threshold” was the pharmacodynamic index linked to cell kill and resistance suppression. Given these results, we conclude that NXL104 combined with ceftaroline on an 8-hourly administration schedule would be optimal for circumstances in which highly resistant pathogens are likely to be encountered. This combination dosing regimen should allow for optimal bacterial cell kill (highest likelihood of successful clinical outcome) and the suppression of resistance emergence.
The bidirectional Glenn procedure (BDG) is a routine intermediary step in single-ventricle palliation. In this study, we examined risk factors for death or transplant and failure to reach Fontan completion after BDG in patients, who had previously undergone stage one palliation (S1P).
All patients at our institution, who underwent BDG following S1P between 2002 and 2009 (n = 194), were included in the analysis.
Transplant-free survival through 18 months post BDG was 91%. Univariable competing risk analyses showed atrioventricular valve regurgitation (AVVR) >mild, age ≤3 months at BDG, ventricular dysfunction >mild, and prolonged hospital stay after S1P to be associated with increased risk of death or orthotopic heart transplant. Multivariable competing risk analysis through 5 years of follow-up showed >mild AVVR (hazard ratio (HR) 7.5, 95% confidence interval (CI) 3.0–18.8), prolonged hospitalization after S1P (HR 4.5, 95% CI 1.8–11.5), and age ≤3 months at BDG (HR 6.8, 95% CI 2.3–20.0) to be independent risk factors for death or transplant. Concomitantly, >mild AVVR and age ≤3 months were independently associated with an overall decreased rate of Fontan completion.
Pre-BDG AVVR, age ≤3 months at time of BDG, and prolonged hospitalization after S1P are independently associated with decreased successful progression of staged palliation in midterm follow-up after BDG.
Congenital heart disease; CHD; Hypoplastic left heart syndrome; Outcomes; Pediatric