A basic solution for a complex problem: does treatment of metabolic acidosis slow CKD progression?

PURPOSE OF THIS REVIEW

Metabolic acidosis is frequently encountered in patients with chronic kidney disease (CKD), with increasing prevalence as kidney function worsens. Treating electrolyte disturbances is the sine qua non of Nephrologists, and alkali therapy to normalize serum bicarbonate levels and slow progression of kidney disease has been embedded in clinical practice guidelines for decades on the basis of animal models and controversial clinical trials. This review will critically appraise the literature base for this recommendation and determine whether the available evidence supports this common practice, which is a timely endeavor considering the impending demotion of metabolic acidosis treatment from recommendation to practice point in forthcoming KDIGO guidelines.

RECENT FINDINGS

Earlier, open-label, studies supporting the utility of sodium bicarbonate therapy to slow progression of chronic kidney disease have been challenged by more recent, blinded, studies failing to show benefit on CKD progression. This was further demonstrated in the absence of concomitant sodium administration with the hydrochloric acid binder veverimer, which failed to demonstrate benefit on renal death, end stage kidney disease or 40% reduction in estimated glomerular filtration rate in a large multicenter trial.

SUMMARY

The current body of literature does not support the routine treatment of metabolic acidosis in patients with CKD and the authors agree with the forthcoming KDIGO guidelines to de-emphasize this common practice.

Serum Chloride and Heart Failure

Despite significant advances in management, heart failure continues to impose a significant epidemiologic burden with high prevalence and mortality rates. For decades, sodium has been the serum electrolyte most commonly associated with outcomes; however, challenging the conventional paradigm of sodium's influence, recent studies have identified a more prominent role in serum chloride in the pathophysiology of heart failure. More specifically, hypochloremia is associated with neurohumoral activation, diuretic resistance, and a worse prognosis in patients with heart failure. This review examines basic science, translational research, and clinical studies to better characterize the role of chloride in patients with heart failure and additionally discusses potential new therapies targeting chloride homeostasis that may impact the future of heart failure care.

Etiology and Management of Edema: A Review

The development of peripheral edema can often pose a significant diagnostic and therapeutic challenge for practitioners due to its association with a wide variety of underlying disorders ranging in severity. Updates to the original Starling's principle have provided new mechanistic insights into edema formation. Additionally, contemporary data highlighting the role of hypochloremia in the development of diuretic resistance provide a possible new therapeutic target. This article reviews the pathophysiology of edema formation and discusses implications for treatment.

Long-term cost-effectiveness of Dexcom G6 real-time continuous glucose monitoring system in people with type 1 diabetes in Australia

INTRODUCTION

Real-time continuous glucose monitoring (rt-CGM) allows patients with diabetes to adjust insulin dosing, potentially improving glucose control. This study aimed to compare the long-term cost-effectiveness of the Dexcom G6 rt-CGM device versus self-monitoring of blood glucose (SMBG) and flash glucose monitoring (FGM) in Australia in people with type 1 diabetes (T1D).

METHODS

Long-term costs and clinical outcomes were estimated using the CORE Diabetes Model. Clinical input data for the analysis of rt-CGM versus SMBG and FGM were sourced from the DIAMOND study and a network meta-analysis, respectively. Rt-CGM and FGM were associated with quality of life (QoL) benefits due to reduced fear of hypoglycaemia (FoH) and fingerstick testing. Analyses were performed over a lifetime time horizon from an Australian healthcare payer perspective, including direct costs from published data. Future costs and clinical outcomes were discounted at 5% per annum.

RESULTS

Rt-CGM was associated with an increased quality-adjusted life expectancy of 1.199 quality-adjusted life years (QALYs), increased mean total lifetime costs of AUD 21,596 and an incremental cost-effectiveness ratio (ICER) of AUD 18,020 per QALY gained compared with SMBG. Compared with FGM, rt-CGM was associated with an increased quality-adjusted life expectancy of 0.569 QALYs, increased mean total lifetime costs of AUD 11,064 and an ICER of AUD 19,455 per QALY gained. Key drivers of outcomes included HbA_1c benefits and QoL benefits associated with reduced FoH and fingerstick testing.

CONCLUSIONS

Due to improved clinical outcomes and QoL gains rt-CGM is highly cost-effective compared with SMBG and FGM in people with T1D in Australia.

Developing priorities for quality improvement in acute medicine using a modified Delphi method A consensus process hosted by the Society for Acute Medicine Quality Improvement Committee (SAM-QI)

INTRODUCTION

The SAM Quality Improvement Committee (SAM-QI), set up in 2016, has worked over the last year to determine the priority Acute Medicine QI topics. They have also discussed and put forward proposals to improve QI training for Acute Medicine professionals.

METHODS

A modified Delphi process was completed over four rounds to determine priority QI topics. Online meetings were also used to develop proposals for QI training.

RESULTS

Same Day Emergency Care (SDEC) was chosen as the priority topic for QI work within Acute Medicine.

CONCLUSION

The SAM-QI group settled on SDEC being the priority topic for Acute Medicine QI development. Throughout the Delphi process SAM-QI has also developed proposals for QI training that will help Acute Medicine professionals deliver coordinated meaningful improvements in care.

1686 Are We Addressing the Syndesmosis in All Ankle Fractures – 2nd Cycle Audit at an MTC

Aim

Assess compliance with BOAST guidelines – “Surgery should aim to achieve reduction and stabilisation of the ankle mortise. The syndesmosis should then be assessed and stabilised if unstable.”

Method

103 Ankle ORIF procedures done for closed malleolar fractures in skeletally mature induviduals over a 12-month period used for first audit. Review of Op notes and intra-operative images was done looking for evidence of assessment of syndesmotic stability. Results were presented to the department and specific guidance on assessment of syndesmosis distributed. 84 Ankle ORIF procedures performed in next 12-month period used to re-audit.

Results

In the first audit, 34% cases had inadequate documentation regarding the stability of syndesmosis. This is similar to finding of 32% in a previous audit in 2018. Re-audit after presentation and review of guidelines, showed improved compliance with only 14.3% cases having no documentation of syndesmosis status.

Conclusions

Distribution of evidence supporting assessment of syndesmosis and making all grades of surgeons aware of the relevant guideline led to an improved compliance of more than 85%. There always remains the vulnerability to miss syndesmotic injuries and potentially adversely affect patient outcomes, if not explicitly assessed on table after bony fixation. All surgeons and rotating trainees need to be aware of this requirement.

275 Validation of The Radiographic Union Score for Humeral Fractures (RUSHU) For Prediction of Humeral Shaft Nonunion

Aim

To validate the use of RUSHu score in prediction of humerus non union.

Method

All patients having radiographs of humerus performed between Jan 2016 to December 2018 were assessed based on inclusion and exclusion criteria. The RUSHu scoring system as published was used to score each 6-week radiograph, separately by 2 blinded observers. 6 months was used as end point to assess outcome. Cohort of 188 observations were used to assess utility of scoring system to predict non union.

Results

94 suitable fractures were identified. Union rate of 72.3% was observed. Mean score in union group was 9.6, 6.4 for non-unions. There was substantial inter-observer reliability with an ICC of 0.73. Rate of union progressively increases with increasing RUSHu scores. ROC curve analysis identifies 8 as most suitable for use as threshold. Area under the curve is high (0.9)

Conclusions

A low RUSH score at 6 weeks is a reliable predictor of non union down the line. If a score 7 or lower is observed, it should trigger a discussion with the patient and review of correctable factors contributing to development of non union. Consideration of surgical fixation should be made at this stage if instability is felt to be a major contributing cause. A patient with score of 8 or higher is more likely to go on to union. Routine use of RUSHu score can aid in clinical decision making and introduce an element of objectivity in clinical assessment. It has potential to prompt earlier intervention and reduce morbidity duration.

Strengthened capacity of India´s bedaquiline Conditional Access Programme for introducing new drugs and regimens

BACKGROUND: Addressing TB in India is critical to meeting global targets. With the scale-up of diagnostic networks and the availability of new TB drugs, India had the opportunity to improve the detection and treatment outcomes in drug-resistant TB (DR-TB).OBJECTIVE: To document how the introduction of new drugs and regimens is helping India improve the care of DR-TB patients.DESIGN: In 2016, India´s National TB Programme (NTP) introduced bedaquiline (BDQ) under a Conditional Access Programme (BDQ-CAP) at six sites after providing extensive training and strengthening laboratory testing, pre-treatment evaluation, active drug safety monitoring and management (aDSM) and follow-up systems.RESULTS: An interim analysis reflected earlier and better culture conversion rates: 83% of the 620 patients converted within a median time of 60 days. However, 248 serious adverse events were reported, including 73 deaths (12%) and 100 cardiotoxicity events (16.3%). Encouraged by the evidence of safety and efficacy of BDQ, the NTP took steps to systematically expand its access to cover the entire population by 2018.CONCLUSION: The cautious yet focused approach used to introduce BDQ under BDQ-CAP paved the way for the rapid introduction of delamanid, as well as the shorter treatment regimen and the all-oral regimen for DR-TB.

Hyperammonemia syndrome due to Ureaplasma infection after liver-kidney transplant

Hyperammonemia syndrome, with high levels of ammonia and neurologic dysfunction, is a syndrome with historically high mortality that may occur after solid organ transplantation. Recently, this has been associated with infection due to Ureaplasma, mostly following lung transplantation. We describe the first case of hyperammonemia syndrome due to Ureaplasma infection after liver-kidney transplantation. Our patient rapidly recovered after specific antibiotic treatment. It is important to consider these infections in the differential diagnosis for encephalopathy post-transplant, as these organisms often do not grow using routine culture methods and polymerase chain reaction testing is typically required for their detection. This is particularly critical after liver transplantation, where a number of other etiologies may be considered as a cause of hyperammonemia syndrome.

White Matter Disease and Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE

The increased severity of white matter disease is associated with worse outcomes and an increased rate of intracerebral hemorrhage in patients with ischemic stroke undergoing thrombolytic treatment. However, whether white matter disease is associated with outcomes in patients undergoing endovascular treatment remains unclear.

MATERIALS AND METHODS

In this prespecified exploratory analysis of our prospective multi-institutional study that enrolled consecutive adult patients with anterior circulation ischemic stroke undergoing endovascular treatment from November 2017 to September 2018, we compared the following outcomes between patients with none-to-minimal (van Swieten score, 0-2) and moderate-to-severe (van Swieten score, 3-4) white matter disease using logistic regression: 90-day mRS 3-6, death, intracerebral hemorrhage, successful recanalization, and early neurologic recovery.

RESULTS

Of the 485 patients enrolled in the Blood Pressure after Endovascular Stroke Therapy (BEST) study, 389 had white matter disease graded (50% women; median age, 68 years; range, 58-79 years). A van Swieten score of 3-4 (n = 74/389, 19%) was associated with a higher rate of 90-day mRS of 3-6 (45% versus 18%; adjusted OR, 2.73; 95% CI, 1.34-5.93; P = .008). Although the death rate was higher in patients with van Swieten scores of 3-4 (26% versus 15%), the adjusted likelihood was not significantly different (adjusted OR, 1.14; 95% CI, 0.56-2.26; P = .710). Ordered regression revealed a shift toward worse mRS scores with increasing van Swieten scores (adjusted common OR, 3.04; 95% CI, 1.93-4.84; P < .001). No associations between white matter disease severity and intracerebral hemorrhage, successful recanalization, and early neurologic recovery were observed.

CONCLUSIONS

Moderate-to-severe white matter disease is associated with worse outcomes in patients undergoing endovascular treatment without a significant increase in hemorrhagic complications. Studies comparing patients with and without endovascular treatment are necessary to determine whether the benefit of endovascular treatment is attenuated with greater white matter disease.

ACE Inhibitor/Angiotensin Receptor Blocker Use Patterns in Advanced CKD and Risk of Kidney Failure and Death

Rationale & Objective

The use of renin-angiotensin system (RAS) inhibitors is standard of care in people with early to moderate chronic kidney disease (CKD). Less is known regarding the efficacy of RAS inhibitors in very advanced CKD. In this study, we describe patterns of use of RAS inhibitors and associations of these patterns of use with risk for CKD progression and mortality in patients with advanced CKD.

Study Design

Propensity-matched cohort study.

Settings & Participants

We identified 678 participants who were enrolled in the multicenter Chronic Renal Insufficiency Cohort (CRIC) Study with estimated glomerular filtration rates (eGFRs) < 30 mL/min/1.73 m² at the baseline visit.

Exposure

Use of RAS inhibitors within the first year after the baseline visit, characterized by 4 patterns of use: never users, always users, dynamic users, and new users.

Outcome(s)

Progression to end-stage renal disease (ESRD) and all-cause mortality.

Analytical Approach

We generated propensity scores and matched participants in the always users group with a 1:1 ratio with a participant from the other 3 groups, matching by age, sex, race, diabetes, hypertension, systolic blood pressure, eGFR, urinary protein-creatinine ratio, and serum potassium level. Cox models were used to test the association of patterns of RAS inhibitor use with risk for kidney failure and death.

Results

Of the 678 participants with eGFRs < 30 mL/min/1.73 m², 57% were identified as always users of RAS inhibitors during the 1 year, 23% as never users, 13% as dynamic users, and 7% as new users. We found no differences in risk for ESRD across patterns of RAS inhibitor use (never users [HR, 1.09; 95% CI, 0.71-1.67], dynamic users [HR, 1.46; 95% CI, 0.83-2.55], new users [HR, 0.78; 95% CI, 0.33-1.84] vs the always users reference group). Similarly, there was no association of patterns of RAS inhibitor use with death (never users [HR, 1.02; CI, 0.74-1.40], dynamic users [HR, 1.23; 95% CI, 0.80-1.90], new users [HR, 1.10; 95% CI, 0.63-1.92] vs always users).

Limitations

Observational study.

Conclusions

Use of RAS inhibitors in patients with eGFRs < 30 mL/min/1.73 m² is heterogeneous.^.We found no difference in risk for progression to ESRD or mortality across patterns of RAS inhibitor use. Further research is required to identify optimal prescribing strategies of RAS inhibitors during advanced stages of CKD.

Hepatocellular carcinoma among US and non-US-born patients with chronic hepatitis B: Risk factors and age at diagnosis

BACKGROUND

Risk factors for hepatocellular carcinoma (HCC) have not been well characterized among African immigrants with chronic hepatitis B virus (HBV) infection. We conducted a case-control study to identify demographic and clinical factors associated with HCC among a diverse cohort of patients with chronic HBV infection seen in a large academic health setting.

METHODS

We identified a total of 278 patients with HCC and chronic HBV seen at two medical centers in a 14-year span from January 2002 to December 2015. These cases were age- and sex-matched in a 1:3 ratio with 823 non-cancer control subjects with chronic HBV. Conditional logistic regression was used to estimate the odds of HCC by race, with black race stratified by African-born status, after adjusting for diabetes, HIV or HCV coinfection, alcohol misuse and cirrhosis.

RESULTS

Of the 278 HCC cases, 67% were 60 years of age or older, 78% were male, 87% had cirrhosis and 72% were Asian. HIV infection was present in 6% of cases. Only 7% (19 of 278) of HCC cases were black, of whom 14 were African immigrants. The median age at HCC diagnosis was 44 years in Africans. Notably, nearly all (93%) of the African-born patients with HCC were diagnosed at an age younger than 60 years compared with 52% of Asian cases (P<0.001). The main factors independently associated with greater odds of HCC overall were Asian race (adjusted odds ratio [aOR] 3.3, 95% confidence interval [CI] 1.9-5.5) and cirrhosis (aOR 19.7, 95% CI 12.2-31.8).

CONCLUSION

African immigrants accounted for a small proportion of HBV-associated HCC cases overall compared with Asians but appeared to have greater likelihood of early-onset HCC. Optimal strategies for HCC prevention in these key subroups with chronic HBV warrant further study.

DIBI, a polymeric hydroxypyridinone iron chelator, reduces ocular inflammation in local and systemic endotoxin-induced uveitis

BACKGROUND/OBJECTIVE

Non-infectious uveitis is an inflammatory disease of the eye commonly treated by corticosteroids, though important side effects may result. A main mediator of inflammation are oxygen free radicals generated in iron-dependent pathways. As such, we investigated the efficacy of a novel iron chelator, DIBI, as an anti-inflammatory agent in local and systemic models of endotoxin induced uveitis (EIU).

METHODS

Firstly, the effects of DIBI in systemic EIU in Lewis rats were established. 2 hours post intravenous LPS or LPS/DIBI injections, leukocyte activation and functional capillary density (FCD) were examined using intravital microscopy (IVM) of the iridial microcirculation. Secondly, the toxicity of DIBI was evaluated in BALB/C mice for both acute and chronic dosages through gross ocular examination, intraocular pressure measurements and hematoxylin-eosin staining of ocular tissue. Lastly, three groups of BALB/C mice, control, LPS or DIBI + LPS, were studied to evaluate the effectiveness of DIBI in treating local EIU. Five hours post-local intravitreal (i.v) injection, leukocyte activation and capillary density were examined via IVM.

RESULTS

Treatment of systemic EIU with DIBI resulted in a reduction of leukocyte activation and FCD improvement within the iridial microcirculation. Toxicity studies suggested that acute and chronic DIBI administration had no adverse effects in the eye. In the local EIU model, DIBI was shown to reduce leukocyte activation and restored the FCD/DCD ratio, providing evidence for its anti-inflammatory properties.

CONCLUSIONS

Our study has provided evidence that DIBI has anti-inflammatory effects in experimental uveitis. Additionally, no local ocular toxicity was observed.

Serine protease allergen favours Th2 responses via PAR-2 and STAT3 activation in murine model

BACKGROUND

Protease activity of Per a 10 favours Th2 responses by differential regulation of IL-12p70 and IL-23 cytokine subunits. This study aimed to elucidate the underlying mechanism of differential regulation of IL-12p70 and IL-23.

METHODS

PAR-2 activation was blocked in murine model by administering SAM11 before each sensitization. CD11c⁺ p-STAT3⁺ cells were measured in lungs by flow cytometry. BMDCs were pretreated with SAM11 or isotype control or stattic and stimulated with Per a 10. p-STAT3 levels were measured using Western blot. Transcript levels of IL-12p35, IL-12/23p40 and IL-23p19 were measured using RT-PCR. Cytokine levels were analysed using ELISA.

RESULTS

Protease activity of Per a 10 increased p-STAT3 levels in mouse lungs, which was reduced upon PAR-2 blockage. Percentage of p-STAT3⁺ CD11c⁺ cells was higher in Per a 10-administered mice and was reduced upon PAR-2 blockage. IL-12p35 and IL-12p70 levels were higher, and IL-23p19 and IL-23 levels were lower in both SAM11-treated mice and BMDCs indicating a role of PAR-2-mediated signalling. IL-4, TSLP, IL-17A, EPO activity, total cell count and specific IgE and IgG1 levels were lower in SAM11-administered mice. Inhibiting STAT3 activation via stattic also leads to lower levels of IL-23p19 and IL-23 and higher levels of IL-12p35.

CONCLUSIONS

Per a 10 leads to PAR-2 activation on BMDCs resulting in downstream activation of STAT3 to regulate the balance between IL-12/IL-23 subunits causing a cytokine milieu rich in IL-23 to favour Th2 polarization.

Distinct epitope structures of defensin-like proteins linked to proline-rich regions give rise to differences in their allergenic activity

Background

Art v 1, Amb a 4, and Par h 1 are allergenic defensin‐polyproline–linked proteins present in mugwort, ragweed, and feverfew pollen, respectively. We aimed to investigate the physicochemical and immunological features underlying the different allergenic capacities of those allergens.

Methods

Recombinant defensin‐polyproline–linked proteins were expressed in E. coli and physicochemically characterized in detail regarding identity, secondary structure, and aggregation status. Allergenic activity was assessed by mediator releases assay, serum IgE reactivity, and IgE inhibition ELISA using sera of patients from Austria, Canada, and Korea. Endolysosomal protein degradation and T‐cell cross‐reactivity were studied in vitro.

Results

Despite variations in the proline‐rich region, similar secondary structure elements were observed in the defensin‐like domains. Seventy‐four percent and 52% of the Austrian and Canadian patients reacted to all three allergens, while Korean patients were almost exclusively sensitized to Art v 1. This was reflected by IgE inhibition assays demonstrating high cross‐reactivity for Austrian, medium for Canadian, and low for Korean sera. In a subgroup of patients, IgE reactivity toward structurally altered Amb a 4 and Par h 1 was not changed suggesting involvement of linear epitopes. Immunologically relevant endolysosomal stability of the defensin‐like domain was limited to Art v 1 and no T‐cell cross‐reactivity with Art v 1_25‐36 was observed.

Conclusions

Despite structural similarity, different IgE‐binding profiles and proteolytic processing impacted the allergenic capacity of defensin‐polyproline–linked molecules. Based on the fact that Amb a 4 demonstrated distinct IgE‐binding epitopes, we suggest inclusion in molecule‐based allergy diagnosis.

Recent advancements and new perspectives in animal models for Neurocysticercosis immunopathogenesis

Neurocysticercosis (NCC), one of the most common parasitic diseases of the central nervous system, is caused by Taenia solium. This parasite involves two hosts, intermediate hosts (pig and human) and a definitive host (human) and has various stages in its complex life cycle (eggs, oncosphere, cysticerci and adult tapeworm). Hence, developing an animal model for T. solium that mimics its natural course of infection is quite challenging. We have reviewed here the animal models frequently used to study immunopathogenesis of cysticercosis and also discussed their usefulness for NCC studies. We found that researchers have used mice, rats, guinea pigs, dogs, cats and pigs as models for this disease with varying degrees of success. Mice and rats models have been utilized extensively for immunopathogenesis studies due to their relative ease of handling and abundance of commercially available reagents to study these small animal models. These models have provided some very exciting results for in-depth understanding of the disease. Of late, the experimentally/naturally infected swine model is turning out to be the best animal model as the disease progression closely resembles human infection in pigs. However, handling large experimental animals has its own challenges and limitations.

Phosphate replacement in the critically ill: potential implications for military patients

BACKGROUND

Severe hypophosphataemia in the intensive care unit (ICU) setting has been widely associated with adverse clinical outcomes across multiple organ systems, as well as increased mortality. However, the clinical significance of mild or moderate hypophosphataemia remains uncertain. This can lead to heterogeneous phosphate replacement protocols across different institutions. The aim of this study was to assess the significance of mild and moderate hypophosphataemia on clinical outcomes across several organ systems.

METHOD

All patients over a 3-week period in our ICU were retrospectively analysed with admission serum phosphate compared with subsequent clinical outcomes after admission. Low serum phosphate (0.3-1.0 mmol/L), according to local protocol, was compared with normal serum phosphate (>1.0 mmol/L).

RESULTS

Of the 72 patients admitted to intensive therapy unit during this period, 14/72 (19%) had phosphate levels deemed low (<1.0 mmol/L) and received phosphate supplementation. No significant difference was found between groups in terms of cardiac arrhythmias (p=0.55), capillary blood glucose (p=0.08) and serum lactate (p=0.32). Low phosphate (0.3-1.0 mmol/L) was not associated with increased likelihood of requiring ventilation. Platelet count was significantly lower in the low phosphate group (p=0.008).

CONCLUSION

In our study, mild and moderate hypophosphataemia was not associated with adverse clinical outcome across most organ systems analysed. Given the current evidence and results of this study, we would suggest that there is a trend towards over-replacement of phosphate, representing a potential clinical safety issue as well as clear financial implications.

Evaluation of iris functional capillary density in experimental local and systemic inflammation

The ocular microcirculation represents an important target to treat inflammatory diseases of eye, where impairment of microvascular blood flow plays key role as, for example, in anterior uveitis. To evaluate novel interventions targeting the microcirculation, appropriate and reliable tools to study this particular microvascular bed are needed. Intravital microscopy (IVM) belongs to several methods allowing evaluation of microcirculation experimentally, even in small animals. The aim of our study was to examine the iridial microcirculation (IMIC) in uveitis induced by local or systemic endotoxin administration in rats and mice by IVM and to propose new parameters to quantify the changes within the IMIC. Systemic inflammation was induced in rats by intravenous endotoxin administration, control group received normal saline intravenously. Local inflammation was induced in mice by intravitreal endotoxin administration, the control group received normal saline intravitreally. IVM of IMIC was performed in animals receiving systemic endotoxin prior injection and 1 and 2 h afterwards, respectively, in animals receiving intravitreal endotoxin/saline prior local injection and 5 h afterwards. Obtained video recordings were analyzed off-line. Functional capillary density (FCD) and dysfunctional capillary density (DCD) were evaluated for description of IMIC, and calculation of FCD/DCD ratio was performed. In systemic inflammation, FCD was significantly decreased compared to control animals. In local inflammation, the number of functional capillaries in the IMIC was significantly reduced following the endotoxin challenge. Analysis of the DCD revealed a significant increase in capillaries with reduced perfusion after intravitreal endotoxin administration and right shift of the FCD/DCD ratio was observed after endotoxin local injection. Detecting and quantifying changes in IMIC during systemic or local inflammation in experimental animals by IVM was feasible. Therefore, IVM of the IMIC represents a valuable tool to evaluate and quantify inflammatory changes in experimental eye disease.

How Do Hydrogen Bonds Contribute to Protein-DNA Recognition?

Abstract The average strength of hydrogen bonding interactions at the interface of 40 protein-DNA complexes comprising ∼ 1500 potential hydrogen bonds and their free energies of formation have been estimated employing some recent advances in theoretical treatments of electrostatic interactions. The hydrogen bond spatial frequency distribution shows a maximum at a proton-acceptor distance of 2.1Å. The corresponding average interaction energy and the binding free energy are computed to be -1 kcal and +4 kcal/mol.H-bond respectively. Thus hydrogen bonds do not appear to provide the driving force for the formation of specific complexes from initially separated protein and DNA but serve to optimize the interactions in the specific complex once it is formed, via distance and angle requirements.

Per a 10 protease activity modulates CD40 expression on dendritic cell surface by nuclear factor-kappaB pathway

Serine protease activity of Per a 10 from Periplaneta americana modulates dendritic cell (DC) functions by a mechanism(s) that remains unclear. In the present study, Per a 10 protease activity on CD40 expression and downstream signalling was evaluated in DCs. Monocyte-derived DCs from cockroach-allergic patients were treated with proteolytically active/heat-inactivated Per a 10. Stimulation with active Per a 10 demonstrated low CD40 expression on DCs surface (P < 0·05), while enhanced soluble CD40 level in the culture supernatant (P < 0·05) compared to the heat-inactivated Per a 10, suggesting cleavage of CD40. Per a 10 activity reduced the interleukin (IL)-12 and interferon (IFN)-γ secretion by DCs (P < 0·05) compared to heat-inactivated Per a 10, indicating that low CD40 expression is associated with low levels of IL-12 secretion. Active Per a 10 stimulation caused low nuclear factor-kappa B (NF-κB) activation in DCs compared to heat-inactivated Per a 10. Inhibition of the NF-κB pathway suppressed the CD40 expression and IL-12 secretion by DCs, further indicating that NF-κB is required for CD40 up-regulation. CD40 expression activated the tumour necrosis factor (TNF) receptor-associated factor 6 (TRAF6), thereby suggesting its involvement in NF-κB activation. Protease activity of Per a 10 induced p38 mitogen-activated protein kinase (MAPK) activation that showed no significant effect on CD40 expression by DCs. However, inhibiting p38 MAPK or NF-κB suppressed the secretion of IL-12, IFN-γ, IL-6 and TNF-α by DCs. Such DCs further reduced the secretion of IL-4, IL-6, IL-12 and TNF-α by CD4(+) T cells. In conclusion, protease activity of Per a 10 reduces CD40 expression on DCs. CD40 down-regulation leads to low NF-κB levels, thereby modulating DC-mediated immune responses.

Immunotherapy with B cell epitopes ameliorates inflammatory responses in Balb/c mice

Osmotin, a protein from the pathogenesis-related family (PR-5), has been identified as an allergen based on in-silico and in-vitro studies. In the present study, three B cell epitopes of osmotin with single and double amino acid modifications were studied for immunotherapy in a murine model. The single-modification peptides (P-1-1, P-2-1 and P-3-1) and double-modification peptides (P-1-2, P-2-2 and P-3-2) showed significantly lower immunoglobulin (Ig)E binding with patients' sera compared to osmotin (P < 0·01). These peptides showed reduced IgE binding compared to the unmodified peptides (B cell epitopes) P-1, P-2 and P-3. Among the modified peptides, P-2-1, P-3-1, P-2-2 and P-3-2 showed significant reduction in IgE binding and were used for immunotherapy in mice. The sera of mice group treated with peptides showed a significant increase in IgG2a level and a significant decrease in IgE and IgG1 levels (P < 0·05). The mice that received peptide immunotherapy showed a shift from a T helper type 2 (Th2) to Th1 type where interferon (IFN)-γ and interleukin (IL)-10 levels were elevated, with a significant increase in groups treated with peptides P-3-1 and P-3-2 (P < 0·05). There was a reduction in the IL-4 and IL-5 levels in bronchoalveolar lavage fluid (BALF) in the peptide-treated mice groups. Total cell count and eosinophil count in BALF of the peptide-treated groups was also reduced compared to the phosphate-buffered saline (PBS)-treated group. Lung histology showed a significant reduction in cellular infiltrate in mice treated with P-2-2 and P-3-2 compared to PBS. In conclusion, peptides P-2-2 and P-3-2 lowered inflammatory responses and induced a Th1 response in mice.