Bacterially derived synthetic mimetics of mammalian oligomannose prime antibody responses that neutralize HIV infectivity

Oligomannose-type glycans are among the major targets on the gp120 component of the HIV envelope protein (Env) for broadly neutralizing antibodies (bnAbs). However, attempts to elicit oligomannose-specific nAbs by immunizing with natural or synthetic oligomannose have so far not been successful, possibly due to B cell tolerance checkpoints. Here we design and synthesize oligomannose mimetics, based on the unique chemical structure of a recently identified bacterial lipooligosaccharide, to appear foreign to the immune system. One of these mimetics is bound avidly by members of a family of oligomannose-specific bnAbs and their putative common germline precursor when presented as a glycoconjugate. The crystal structure of one of the mimetics bound to a member of this bnAb family confirms the antigenic resemblance. Lastly, immunization of human-antibody transgenic animals with a lead mimetic evokes nAbs with specificities approaching those of existing bnAbs. These results provide evidence for utilizing antigenic mimicry to elicit oligomannose-specific bnAbs to HIV-1.

Impact of brodalumab treatment on psoriasis symptoms and health-related quality of life: use of a novel patient-reported outcome measure, the Psoriasis Symptom Inventory

Background

Psoriasis symptoms have a significant negative impact on health-related quality of life, impairing physical functioning and well-being.

Objective

To evaluate the impact of brodalumab, a human anti-interleukin-17R monoclonal antibody, on psoriasis symptom severity as measured by a novel patient-reported outcome measure, the Psoriasis Symptom Inventory, and dermatology-specific health-related quality of life as measured by the Dermatology Life Quality Index (DLQI).

Methods

This was a secondary analysis of a phase II, randomized, double-blind, placebo-controlled clinical study of patients with moderate-to-severe psoriasis (n = 198) treated with brodalumab or placebo. This analysis assessed Psoriasis Symptom Inventory scores and DLQI scores over time. Analyses were conducted on all patients who were randomized and received one or more injections of the study drug according to intention to treat using last observation carried forward to impute missing data.

Results

At week 12, subjects in the brodalumab groups had significant improvements in mean Psoriasis Symptom Inventory total scores [8·5 (70 mg), 15·8 (140 mg), 16·2 (210 mg) and 12·7 (280 mg)] compared with placebo (4·8). Mean improvements in DLQI were clinically meaningful (≥ 5·7) in the brodalumab groups (6·2, 9·1, 9·6 and 7·1, respectively) and significantly greater than placebo (3·1). Improvements in Psoriasis Symptom Inventory were observed as early as week 2 and in DLQI by week 4. All eight Psoriasis Symptom Inventory item scores improved significantly among the brodalumab groups by week 12.

Conclusions

Results were from a single randomized clinical trial and may not generalize to broader patient populations. However, treatment with brodalumab provided significant improvement in psoriasis symptoms in patients with moderate-to-severe psoriasis.

Griscelli syndrome

We report a case of Griscelli Syndrome (GS). Our patient initially presented with a diagnosis of haemophagocytic lymphistiocytosis (HLH). Subsequent microscopic analysis of the patient's hair follicle revealed abnormal distribution of melanosomes in the shaft, which is a hallmark for GS. Analysis of RAB27A gene in this patient revealed a homozygous mutation in exon 6, c.550C>T, p.R184X . This nonsense mutation causes premature truncation of the protein resulting in a dysfunctional RAB27A. Recognition of GS allows appropriate institution of therapy namely chemotherapy for HLH and curative haemotopoeitic stem cell transplantation.

The presence of glutamine at position 315 but not epitope masking predominantly hinders HIV subtype C neutralization by the anti-V3 antibody B4e8

Antibody B4e8 exhibits modest cross-neutralizing activity, with preference for HIV subtype B. This preference might be explained by B4e8׳s extensive interaction with Arg315, which occurs at the center of most subtype B V3 sequences but is replaced by Gln in subtype C. The extent to which B4e8׳s ability to neutralize subtype C strains is hindered by Gln315 and/or other factors, e.g. epitope masking, is unclear. We confirmed here that an Arg315-to-Gln substitution in a subtype B virus abrogates B4e8 neutralizing activity. Conversely, B4e8-resistant subtype C viruses were rendered sensitive upon Gln 315-to-Arg substitution. V2 region swapping between B4e8-sensitive and- resistant subtype C strains revealed a role for V2 in limiting B4e8 access, but this was less significant than the absence of Arg315. Our findings, while illustrating the importance of Arg315 for B4e8, suggest that some subtype C strains may be vulnerable to B4e8 derivatives capable of binding stronger to Gln315-containing sequences.

Cre transgene results in global attenuation of the cAMP/PKA pathway

Use of the cre transgene in in vivo mouse models to delete a specific 'floxed' allele is a well-accepted method for studying the effects of spatially or temporarily regulated genes. During the course of our investigation into the effect of cyclic adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) expression on cell death, we found that cre expression either in cultured cell lines or in transgenic mice results in global changes in PKA target phosphorylation. This consequently alters gene expression profile and changes in cytokine secretion such as IL-6. These effects are dependent on its recombinase activity and can be attributed to the upregulation of specific inhibitors of PKA (PKI). These results may explain the cytotoxicity often associated with cre expression in many transgenic animals and may also explain many of the phenotypes observed in the context of Cre-mediated gene deletion. Our results may therefore influence the interpretation of data generated using the conventional cre transgenic system.

Cost-effectiveness of denosumab in the treatment of postmenopausal osteoporosis in Canada

OBJECTIVE

Denosumab is a novel biologic agent approved in Canada for treatment of post-menopausal osteoporosis (PMO) in women at high risk for fracture or who have failed or are intolerant to other osteoporosis therapies. This study estimated cost-effectiveness of denosumab vs usual care from the perspective of the Ontario public payer.

METHODS

A previously published PMO Markov cohort model was adapted for Canada to estimate cost-effectiveness of denosumab. The primary analysis included women with demographic characteristics similar to those from the pivotal phase III denosumab PMO trial (FREEDOM; age 72 years, femoral neck BMD T-score -2.16 SD, vertebral fracture prevalence 23.6%). Three additional scenario sub-groups were examined including women: (1) at high fracture risk, defined in FREEDOM as having at least two of three risk factors (age 70+; T-score ≤ -3.0 SD at lumbar spine, total hip, or femoral neck; prevalent vertebral fracture); (2) age 75+; and (3) intolerant or contraindicated to oral bisphosphonates (BPs). Analyses were conducted over a lifetime horizon comparing denosumab to usual care ('no therapy', alendronate, risedronate, or raloxifene [sub-group 3 only]). The analysis considered treatment-specific persistence and post-discontinuation residual efficacy, as well as treatment-specific adverse events. Both deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

The multi-therapy comparisons resulted in incremental cost-effectiveness ratios for denosumab vs alendronate of $60,266 (2010 CDN$) (primary analysis) and $27,287 per quality-adjusted life year gained for scenario sub-group 1. Denosumab dominated all therapies in the remaining scenarios.

LIMITATIONS

Key limitations include a lack of long-term, real-world, Canadian data on persistence with denosumab as well as an absence of head-to-head clinical data, leaving one to rely on meta-analyses based on trials comparing treatment to placebo.

CONCLUSIONS

Denosumab may be cost-effective compared to oral PMO treatments for women at high risk of fractures and those who are intolerant and/or contraindicated to oral BPs.

A comparison of flux chambers and ambient air sampling to measure gamma-hexachlorocyclohexane volatilisation from canola (Brassica napus) fields

The insecticide gamma-hexachlorocyclohexane (gamma-HCH) is primarily used in Canada in treatments of canola (Brassica napus) seed. It has been shown that gamma-HCH so applied will volatilise with 12-30% entering the atmosphere within 6 wk after the seed is planted. Both flux chambers and high-volume air samplers were used to measure gamma-HCH volatilisation from a canola field and the results from each method compared. Daily samples were collected from three flux chambers located on the field. gamma-HCH was found in the air of the chambers on the first day after planting. Volatilisation rates were low for the first 7d (40.0 mg ha(-1) wk(-1)) but increased during the second week (143.8 mg ha(-1) wk(-1)). This was consistent with previous studies. Weekly composite air samples, from three heights above the canola field, were used to calculate volatilisation rates from the field. These were 190 mg ha(-1) wk(-1) (week 1) and 420 mg ha(-1) wk(-1) (week 2). Soil temperatures in the open field were warmer than those under the flux chambers and this may have contributed to the higher ambient air measurements.

Development of a second generation monoclonal single chain variable fragment antibody against Venezuelan equine encephalitis virus: expression and functional analysis

We have generated a single chain variable fragment (ScFv) antibody from a well-characterized monoclonal antibody (MAb) against Venezuelan equine encephalitis virus (VEE), by cloning variable regions of the heavy (V(H)) and the light (V(L)) chain antibody genes, connected by a DNA linker, in phagemid expression vector pCANTAB 5 E. MAb 1A4A1 was successfully cloned as a ScFv in Escherichia coli strain TG-1 and expressed as a approximately 30 kDa ScFv protein which was functional in recognizing VEE by ELISA. Results were reproduced in Escherichia coli strain HB2151 where the same clone, designated A116, was expressed primarily as soluble periplasmic protein. The 30 kDa A116 antibody displayed weak binding specificity to VEE antigen. Sequence analysis revealed a frame shift in the N-terminal region of the V(L) domain, upstream to the complementarity-determining region 1 (CDR1), as the probable cause of reduced activity. The protein sequence of A116 was highly homologous to published murine ScFv protein sequences except in the region of the identified frame shift.

Ongoing and stimulus-evoked activity of sympathetically correlated neurons in the intermediate zone and dorsal horn of acutely spinalized rats

We have shown previously that in the acutely spinalized anesthetized rat the activities of many dorsal horn interneurons (DHN) at the T(10) level are correlated positively with both ongoing and stimulus-evoked renal sympathetic nerve activity (RSNA) and therefore may belong to networks generating RSNA after acute, cervical, spinal transection. In the present study, we recorded from both DHN and interneurons in the intermediate zone (IZN) of the T(10) spinal segment in acutely C(1)-transected, chloralose-anesthetized, artificially respired rats. The activities of a similar percentage of IZN and DHN were correlated positively with ongoing RSNA, but the peaks of spike-triggered averages of RSNA based on the activity of IZN were larger, relative to dummy averages, than spike-triggered averages of RSNA based on the activity of DHN. Sympathetically correlated DHN and IZN differed in their responses to noxious somatic stimuli. Most correlated DHN had relatively simple somatic fields; they were excited by noxious stimulation of the T(10) and nearby dermatomes and inhibited by stimulation of more distal dermatomes. As we have shown previously, the excitatory and inhibitory fields of these neurons were very similar to fields that, respectively, excited and inhibited RSNA. On the other hand, the somatic fields of 50% of sympathetically correlated IZN were significantly more complex, indicating a difference between either the inputs or the processing properties of IZN and DHN. Sympathetically correlated IZN and DHN also differed in their responses to colorectal distension (CRD), a noxious visceral stimulus. CRD increased RSNA in 11/15 rats and increased the activity of most sympathetically correlated T(10) IZN. On the other hand, CRD decreased the activity of a majority of sympathetically correlated T(10) DHN. These observations suggest that the same stimulus may differentially affect separate, putative, sympathoexcitatory pathways, exciting one and inhibiting the other. Thus the magnitude and even the polarity of responses to a given stimulus may be determined by the modality and location of the stimulus, the degree to which multiple pathways are affected by the stimulus, and the ongoing activity of presympathetic neurons, at multiple rostrocaudal levels, before stimulation. A multipathway system may explain the variability in autonomic responses to visceral and somatic stimuli exhibited in spinally injured patients.

Expression of transforming growth factor beta 1, 2, and 3 proteins in keloids

Keloids represent a pathological response to cutaneous injury, creating disfiguring scars with no known satisfactory treatment. They are characterized by an excessive accumulation of extracellular matrix, especially collagen. Transforming growth factor beta (TGF-beta) has been implicated in the pathogenesis of keloids. The three TGF-beta isoforms identified in mammals (TGF-beta1, -beta2, and -beta3), are thought to have different biological activities in wound healing. TGF-beta1 and TGF-beta2 are believed to promote fibrosis and scar formation, whereas TGF-beta3 has been shown to be either scar inducing or reducing, depending on the study. The aim of this study was to characterize expression of TGF-beta isoforms in keloids at the protein level using Western blot analysis. The authors found that TGF-beta1 and -beta2 proteins were at higher levels in keloid fibroblast cultures compared with normal human dermal fibroblast cultures. In contrast, the expression of TGF-beta3 protein was comparable in both the normal (N = 3) and keloid (N = 3) cell lines. These findings, demonstrating increased TGF-beta1 and -beta2 protein expression in keloids relative to normal human dermal fibroblasts further support the roles of TGF-beta1 and -beta2 as fibrosis-inducing cytokines.

Hypoxia upregulates VEGF production in keloid fibroblasts

The etiology of keloid formation is diverse. They are characterized grossly as thick scar tissue that extends beyond the boundaries of the original wound. Histologically, keloids are composed of excessive collagen with an abnormally large number of partially or totally occluded microvessels. This occlusion of keloid microvessels has been hypothesized to contribute to a hypoxic microenvironment within these pathological scars. Vascular endothelial growth factor (VEGF), a potent endothelial cell mitogen, and proangiogenic cytokine have been implicated in normal and pathological wound healing. The purpose of this study was to evaluate the amount of VEGF protein production by fibroblast cell lines derived from keloids and normal human dermal skin in hypoxic compared with normoxic culture conditions. By enzyme-linked immunosorbent protein assay, VEGF was increased in both keloid and normal human dermal fibroblasts in hypoxia over normoxic controls. There was not, however, a significant difference between upregulation of VEGF protein when comparing the keloid and normal fibroblast groups. As the result of the data, alternative hypotheses for hypoxia-induced keloid formation were explored: (1) downstream modulation or signal transduction of VEGF, (2) VEGF production from cells other than fibroblasts, (3) the importance of matrix accumulation stimulated by hypoxia, or (4) increased migration of cells (other than fibroblasts) specific to keloid biology. These hypotheses may help explain the possible role of hypoxia in the pathogenesis of keloid formation. Future studies involving in situ hybridization or immunohistochemical analysis may offer greater insight into the mechanisms underlying keloid formation. Ultimately, our therapeutic goal is the utilization of biomolecular approaches for the suppression of keloid formation.

Analysis of TGF-beta production by fusing and nonfusing mouse cranial sutures in vitro

The role of transforming growth factor beta (TGF-beta) in the regulation of cranial suture fusion has been studied by various qualitative techniques such as in situ hybridization and immunohistochemistry. Although the relative expression of TGF-beta isoforms has been assessed in these studies, increased expression of TGF-beta has not been demonstrated in a quantitative fashion. Therefore, the purpose of this study was to quantify TGF-beta production by fusing (posterofrontal [PF]) and nonfusing (sagittal) mouse sutures using two different quantitative TGF-beta assays. The PF and sagittal sutures of 25-day-old mice were harvested and cultured separately in vitro. Culture media conditioned for 48 hours were collected after 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days of culture, and total TGF-beta production was assessed using a TGF-beta bioassay. For a quantitative TGF-beta1 immunoassay, media conditioned for 48 hours were collected after 3, 5, 7, 9, 14, 22, and 28 days of culture. The TGF-beta bioassay revealed large amounts of total TGF-beta activity in both PF and sagittal sutures during the first week of culture, with decreasing amounts thereafter. Absolute TGF-beta activity in conditioned media collected from PF sutures at several early time points was higher than those obtained from sagittal sutures; however, these differences were not statistically significant. The results of the TGF-beta1 immunoassay (enzyme-linked immunosorbent assay) were similar to the bioassay in that the highest TGF-beta1 levels were noted during the first week of culture period and decreased thereafter. Analysis of variance of these samples, however, revealed significantly more TGF-beta1 protein in samples collected from the PF suture compared with the sagittal suture on days 3 and 5 of culture (p < 0.05). TGF-beta1 levels in the conditioned media obtained from PF sutures remained elevated compared with the sagittal suture on days 7 and 9; however, these differences were not statistically significant. Increased production of TGF-beta in the conditioned media of fusing PF sutures is the first such quantitative demonstration of growth factor upregulation during suture fusion and supports the hypothesis that TGF-beta expression may be important in cranial suture fusion.

Painful stimuli evoke potentials recorded from the parasylvian cortex in humans

Cutaneous stimulation of the face and hand with a CO2 laser in three awake patients evoked potentials (LEPs) recorded from the dominant left parasylvian cortex. These were recorded by means of a subdural grid of electrodes implanted for evaluation of epilepsy. Stimulation of the contralateral face resulted in waveforms consisting of a negative potential (N2, 162 +/- 5 ms; mean +/- SE) followed by a positive potential (P2, 340 +/- 18 ms). Both waves occurred at longer latency after hand than after facial stimulation. N2 and P2 potentials recorded from the grid correspond well in morphology to those recorded from the scalp in four additional patients tested with the same stimulation paradigm. The N2 waves recorded from the subdural grid occurred at significantly shorter latencies than did those recorded from the scalp (184 +/- 6 ms), but the P2 waves at the grid occurred at significantly longer latencies than did those recorded at the scalp (281 +/- 13 ms). The amplitudes of the potentials recorded from the grid were maximal over the parietal operculum both for contralateral stimulation of the face or hand and for ipsilateral stimulation of the face. Potentials also were recorded in this area after stimulation of the ipsilateral hand. The cortical distributions of these potentials suggest that their generators are located in the parietal operculum or in the insula, or in both, consistent with previous PET, magnetoencephalographic, and scalp LEP source analyses. These previous analyses provide indirect evidence of nociceptive input to parasylvian cortex because the interpretation of each analysis incorporates multiple assumptions. The present results are the first direct evidence of nociceptive input to the human parasylvian cortex.

Tamoxifen downregulates TGF-beta production in keloid fibroblasts

Keloids occur only in humans and are characterized by fibroblast overproduction of collagen types I and III. Keloid fibroblasts have been shown to make elevated levels of transforming growth factor beta (TGF-beta), a growth factor known to promote extracellular matrix production and fibrosis. Thus, the pathophysiology underlying keloid formation may be driven by the biological activity of TGF-beta. Tamoxifen, a synthetic, nonsteroidal antiestrogen has been shown to inhibit keloid fibroblast proliferation and decrease collagen production. The purpose of this study was to determine if a mechanism by which tamoxifen decreases keloid collagen production is through a downregulation of TGF-beta. Through a luciferase TGF-beta bioassay we found that 4 microM of tamoxifen generated a 49% reduction in total TGF-beta activity and 8 microM generated an 85% reduction compared with controls. Thus we propose that one of the mechanisms by which tamoxifen decreases keloid fibroblast collagen synthesis is by decreasing TGF-beta production.

Painful stimuli evoke potentials recorded over the human anterior cingulate gyrus

Clinical studies of cingulotomy patients and imaging studies predict that the human cingulate gyrus might display pain-related activity. We now report potentials evoked by painful cutaneous stimulation with a CO2 laser (LEP) and recorded from subdural electrodes over the medial wall of the hemisphere. In response to facial laser stimulation on both sides, a negative (latency 211-242 ms) and then a positive wave (325-352 ms) were recorded from the cortex of right medial wall and from the falcine dura overlying the left medial wall. Medial wall LEPs were similar to scalp LEPs and were largest over the anterior cingulate and superior frontal gyri just anterior to motor cortex contralateral to the side of stimulation. These results demonstrate that there is significant direct nociceptive input to the human anterior cingulate gyrus (Brodmann's area 24).

Sympathetically correlated activity of dorsal horn neurons in spinally transected rats

In mammals with an intact neuraxis, most sympathetic nerve activity is generated by brain stem systems. Therefore these systems have attracted much more attention than spinal systems that generate excitatory inputs to sympathetic preganglionic neurons. The purpose of this study was to determine whether, within hours of C1 spinal cord transection, spinal dorsal horn neurons (DHNs) play a role in generating sympathetic nerve activity. Experiments were conducted in chloralose-anesthetized rats. We recorded renal sympathetic nerve activity (RSNA) in the left renal nerve, and we recorded the activity of neurons located in the left dorsal horn at T2, T8, T10, T13, and L2. We also recorded the activity of neurons in the right dorsal horn at T10. The somatic fields and cutaneous modalities of most neurons were determined. Spike-triggered averaging was used to determine relationships between the ongoing activity of DHNs and ongoing RSNA. In the left dorsal horn, bursts of ongoing activity of 16% of DHNs at T8 and 43% of DHNs at T10 were positively correlated with bursts of ongoing RSNA at latencies of 59 +/- 8 (SE) ms. At no other level on the left side, nor in the T10 segment on the right side, was the activity of DHNs correlated with RSNA. DHNs with activity correlated with RSNA were located only in dorsal horn laminae III-V. Deeper laminae were not investigated in these experiments. The activity of all sympathetically correlated DHNs exhibited bursts of action potentials with interspike intervals of < 10 ms. All but one of the sympathetically correlated DHNs exhibited wide-dynamic-range modalities. The modalities of sympathetically uncorrelated neurons were more heterogeneous. Brief (5-10 s) noxious cutaneous stimulation of mid- and lower thoracic dermatomes on the left side excited all sympathetically correlated DHNs and simultaneously increased RSNA. The excitatory cutaneous fields of sympathetically correlated neurons were circumscribed by the excitatory fields for RSNA. The excitatory cutaneous fields of some sympathetically uncorrelated DHNs extended beyond the excitatory fields for RSNA. Noxious cutaneous stimulation of the extremities on the left side that decreased RSNA simultaneously decreased the activity of all sympathetically correlated DHNs. These data provide electrophysiological evidence that, in spinally transected rats, a population of DHNs may generate or convey excitatory input to renal sympathetic preganglionic neurons.

N-Trifluoroacetyl-ethanolamine: a proposed urinary metabolite of halothane: validation and measurement in children

It has been postulated that trifluoroacetyl chloride, a halothane metabolite, can bind covalently with the phosphatidylethanolamine component of the hepatic cell membrane and cause cell necrosis. Breakdown of the necrotic hepatocyte would release N-trifluoroacetyl-ethanolamine (TFAE) into the serum with subsequent urinary excretion. An original High Performance Liquid Chromatography (HPLC) method for the measurement of TFAE is described. In six children 1% halothane was administered for one hour and the halothane uptake measured. Urinary excretion of TFAE was measured for up to eight days and found to be 0.09 +/- 0.07% or less of the absorbed halothane. In children TFAE is not a major urinary metabolite of halothane.

Biliary excretion of the halothane metabolite trifluoroacetic acid in infants

In humans the biliary excretion of trifluoroacetic acid, the major halothane metabolite, has not been studied. We investigated the biliary excretion of trifluoroacetic acid in two infants aged five months and two months following halothane anaesthesia for the operation of choledocholithotomy. Bile, urine and faeces were collected continuously for five days after operation and trifluoroacetic acid excretion measured. Estimates of halothane uptake, daily bile flow and the proportion of daily bile flow collected via the T-tube drainage catheter were subject to percentage errors possibly as large as 50%. Of the total trifluoroacetic acid produced from halothane metabolism, it was estimated that 17% in the five-month-old infant and 20% in the two-month infant was excreted in bile. In the five-month-old infant where approximately 80% of the bile produced entered the duodenum in the normal way, no faecal trifluoroacetic acid was detected suggesting an enterohepatic circulation for this metabolite.