2-year survival estimation for decompensated cirrhosis patients of prognostic scoring systems

OBJECTIVE

Prognostic models proposed for cirrhotic patients' survival have not been satisfactorily investigated in the Vietnam population, especially in the medium-term period.

PATIENTS AND METHODS

In this prospective study, we enrolled a total of 904 patients admitted to Hepato-Gastroenterology Center, Bach Mai Hospital from December 2019 to November 2021 and calculated their CP, MELD, MELD-Na score, IMELD, Refit MELD, and Refit MELD-Na after 2-year follow-up to compare their survival prognosis.

RESULTS

The mean age of the patients was 53.8 ±10.8 years, and males constituted 91%. Compared with the surviving group, deceased patients had statistically significant lower albumin, higher INR, serum bilirubin, and creatinine levels with higher means of all prognostic scores. RefitMELD score had the highest AUC (0.768), followed by MELD (0.766), and the lowest belonged to RefitMELDNa (0.669).

CONCLUSIONS

In conclusion, deceased patients had significantly higher values of Child-Pugh score and all MELD-based scores than survival. RefitMELD is the most reliable scoring system to predict 2-year mortality in patients with decompensated liver cirrhosis.

Stent-Assisted Coiling in the Treatment of Unruptured Intracranial Aneurysms: A Randomized Clinical Trial

BACKGROUND AND PURPOSE

Stent-assisted coiling may improve angiographic results of endovascular treatment of unruptured intracranial aneurysms compared with coiling alone, but this has never been shown in a randomized trial.

MATERIALS AND METHODS

The Stenting in the Treatment of Aneurysm Trial was an investigator-led, parallel, randomized (1:1) trial conducted in 4 university hospitals. Patients with intracranial aneurysms at risk of recurrence, defined as large aneurysms (≥10 mm), postcoiling recurrent aneurysms, or small aneurysms with a wide neck (≥4 mm), were randomly allocated to stent-assisted coiling or coiling alone. The composite primary efficacy outcome was "treatment failure," defined as initial failure to treat the aneurysm; aneurysm rupture or retreatment during follow-up; death or dependency (mRS > 2); or an angiographic residual aneurysm adjudicated by an independent core laboratory at 12 months. The primary hypothesis (revised for slow accrual) was that stent-assisted coiling would decrease treatment failures from 33% to 15%, requiring 200 patients. Primary analyses were intent to treat.

RESULTS

Of 205 patients recruited between 2011 and 2021, ninety-four were allocated to stent-assisted coiling and 111 to coiling alone. The primary outcome, ascertainable in 203 patients, was reached in 28/93 patients allocated to stent-assisted coiling (30.1%; 95% CI, 21.2%-40.6%) compared with 30/110 (27.3%; 95% CI, 19.4%-36.7%) allocated to coiling alone (relative risk = 1.10; 95% CI, 0.7-1.7; P  = .66). Poor clinical outcomes (mRS >2) occurred in 8/94 patients allocated to stent-assisted coiling (8.5%; 95% CI, 4.0%-16.6%) compared with 6/111 (5.4%; 95% CI, 2.2%-11.9%) allocated to coiling alone (relative risk = 1.6; 95% CI, 0.6%-4.4%; P  = .38).

CONCLUSIONS

The STAT trial did not show stent-assisted coiling to be superior to coiling alone for wide-neck, large, or recurrent unruptured aneurysms.

Comorbidity patterns in older patients with diabetes in primary care: a cross-sectional study

Funding Acknowledgements

Type of funding sources: None.

Background

Diabetes is a well-known risk factor for cardiovascular diseases and continues to be a global public health challenge. In Australia, prevalence rates of diabetes increase with age with almost 1 in 5 older people reported being diagnosed with diabetes. Older persons with diabetes are also more likely to have multiple comorbidities adding to their complexity. A better understanding of comorbidity patterns and their associated factors in older people with diabetes is instrumental to identify groups of individuals that differ in healthcare needs, resources utilized, and health trajectories.

Purpose

To identify comorbidity patterns in community-dwelling older adults with type 2 diabetes attending general practice settings in Australia.

Methods

This is a cross-sectional study based on the Bettering the Evaluation And Care of Health (BEACH) data. The BEACH program was a continuous, national study of the state of general practice clinical activity in Australia from 1998 to 2016. As part of the program, General Practitioners (GPs) would collect additional patient information during patient visits through structured paper-based recording sheets. For the purposes of this sub-study, a random sample of 1800 participating GPs were invited to record all diagnosed chronic conditions for 30 consecutive patients over twelve five-weeks recording periods between November 2012 and March 2016. The dataset was analyzed with descriptive analysis and exploratory factor analyses were applied to examine comorbidity patterns.

Result

From the dataset, there were 14 042 patients aged ≥65 with recorded chronic conditions. Of these, 2688 reported to have other comorbidities in addition to the diagnosis of diabetes. Hypertension was present in 67.33% (95% CI: 64.62 – 70.04) of these participants, followed by hyperlipidemia, 44.85% (95% CI: 41.80 –47.90), ischemic heart disease, 22.81% (95% CI: 20.74 – 24.87), atrial fibrillation, 10.25% (95% CI: 8.86 – 11.63), congestive heart failure, 7.03% (95% CI: 5.99 – 8.09), stroke/cerebrovascular accident, 6.76% (95% CI:5.36 -8.16) and peripheral vascular disease 5.26% (4.36 – 6.15). Top non-cardiovascular co-morbidities included arthritis, 51.78% (95% CI: 48.80–54.77) and depression, 15.52% (95% CI 13.78 –17.27). We identified two comorbidity patterns among older people with diabetes. The first were primarily psychological and musculoskeletal (Depression, Anxiety, Insomnia, Chronic Back Pain, Arthritis, Gastroesophageal Reflux Disease, Osteoporosis) and the second were cardiovascular conditions (Congestive Heart Failure, Ischaemic Heart Disease, Atrial Fibrillation, Peripheral Vascular Disease) and Chronic Renal Failure.

Conclusion

The prevalence of cardiovascular and non-cardiovascular comorbidities in older patients with diabetes was high. These findings highlight the need for elaborating primary care strategies to reduce cardiovascular risk and improve long-term care for this population.

Intake of Flavonoids and Odds of Frailty Onset in Adults in the Framingham Offspring Cohort

Polyphenols (antioxidants derived from plant-foods) could play a role in inhibition of oxidative stress and frailty reduction, yet data on the polyphenol subclass of dietary flavonoids is limited. This study sought to determine the association between dietary flavonoids and frailty onset in middle-aged and older adults. This prospective cohort study included non-frail individuals from the Framingham Offspring Cohort (FOC) with total flavonoid intake (mg/day; defined as sum flavonols, flavan-3-ols, flavonones, flavones, and anthocyanins via Harvard Food Frequency Questionnaire), frailty (via Fried phenotype), and covariate information measured at baseline (1998-2001). Follow-up frailty was evaluated in 2011-2014. Logistic regression estimated odds ratio (OR) and 95% confidence intervals (95% CI) adjusting for relevant confounders. Participants (n=1,701; 55.5% female) had a mean age of 58.4 years (SD ± 8.3). Mean flavonoid intake was 309 mg/d (SD ± 266). After 12.4 years (SD ± 0.8), 224 (13.2%) individuals exhibited frailty. In age and sex adjusted models, every 50 mg/day of higher total flavonoid intake was associated with 3% reduced odds of frailty [OR (95%CI): 0.97 (0.94-1.00), p-value: 0.05). Further adjustment for smoking, energy and protein intake, and disease indicators did not appreciably change the association, and associations became non-significant (p-value=0.12). Thus, there was no association between flavonoid intake and odds of frailty onset in adults in the FOC. This could be due to participants' higher intake of flavonoids compared to average intake of ~200 mg/d in Americans.

P–428 Uterine infusion of autologous platelet rich plasma (PRP) before embryo transfer may improve the transfer outcomes in recurrent implantation failure and thin/scarred endometrium patients

Study question

Does the infusion of autologous platelet rich plasma (PRP) to the uterus improve the outcomes of embryo transfer of thin endometrial or recurrent implantation failure (RIF) patients?

Summary answer

Autologous PRP uterine infusion may improve the result of embryo transfer (ET) in RIF group and thin/scarred endometrial group.

What is known already

Autologous PRP has been proposed to improve the outcomes of various treatment procedures. In infertility, several trials have reported an improvement in endometrial thickness in patients having thin endometrium thus previously cancelled ET cycles. Uterine injection of PRP shortly before ET has been proposed to improve the results of ET in patients having RIF. Platelets in PRP would be activated via different pathways to release growth factors and cytokines. In this study, we applied our in-house-developed PRP extraction kits that use a mechanical activation/platelet breaking down method to infuse/inject into the uterine of the poor prognosis transfer patients.

Study design, size, duration

This study includes two phases: Phase 1 (04/2019–12/2019): we tested the safety and effectiveness of the PRP extraction kits in 30 volunteers regardless of the gender by derma-rolling process using PRP extracted by our kits. Phase 2 (02/2020–12/2020): 111 IVF patients who had thin/scarred endometrium previously having at least one cancelled ET cycle (group 1) or patients who had at least two implantation failure ETs (group 2) were enrolled in the study.

Participants/materials, setting, methods

20 mL blood was drawn from the vein. After centrifugation, PRP was filtrated through a filter to break down platelets releasing growth factors/cytokines. Firstly, 30 volunteers (average age of 34.4 ± 5.5) were derma-rolled on the facial skin twice (one week apart). Secondly, IVF group 1 was uterine-infused with 0.5 mL PRP on day 7/8 of the ET cycle, both groups were uterine-infused with 0.5 mL PRP two days (40–48 hours) before ET.

Main results and the role of chance

0.5 mL of PRP before filtering was measured and calculated to have 8–12 folds increase of platelet concentration. In phase 1, no side-effects or complications were recorded. The average skin pore size reduced by approximately 0.01 mm2 in all patients two weeks after treatment. In phase 2, the average age was 35.6 ± 6.1. Group 1 had 31 patients and group 2 had 99 ones. In group 1, five patient did not obtained improvement in endometrium then ET cycles were cancelled, one patient did not have blastocyst to transfer and 25 patients had endometrium of at least 7 mm thick before ET and ET (100 frozen ET) were carried on. One couple was not contactable. Out of 24 couples, 13 had biochemical pregnancy (54.2%) and 11 had clinical pregnancy (44.0%). Group 2 had 80 patients. One of them did not have embryo to transfer. 37/79 embryo transfers had biochemical pregnancy (46.8%) and 44.3% clinical pregnancy. No complication was recorded. In our cohort, several successful patients had more than 7 unsuccessful ETs previously. For reference, in 2020, our clinic had 4260 ETs in total, the clinical pregnancy rate was 60.1%, the average age was 31.82 years old.

Limitations, reasons for caution

Each case in phase 2 of this study had a complicated fertility medical history therefore it was impossible to select the control group. This study is descriptive only. The size of each group was relatively small requiring ongoing data recording.

Wider implications of the findings: This study support the idea that cytokines and growth factors in PRP may help to prepare endometrium for ET, safely and effectively.

Trial registration number

Not applicable

Noninvasive Angiographic Results of Clipped or Coiled Intracranial Aneurysms: An Inter- and Intraobserver Reliability Study

BACKGROUND AND PURPOSE

Noninvasive angiography is commonly used to assess the outcome of surgical or endovascular treatment of intracranial aneurysms in clinical series or randomized trials. We sought to assess whether a standardized 3-grade classification system could be reliably used to compare the CTA and MRA results of both treatments.

MATERIALS AND METHODS

An electronic portfolio composed of CTAs of 30 clipped and MRAs of 30 coiled aneurysms was independently evaluated by 24 raters of diverse experience and training backgrounds. Twenty raters performed a second evaluation 1 month later. Raters were asked which angiographic grade and management decision (retreatment; close or long-term follow-up) would be most appropriate for each case. Agreement was analyzed using the Krippendorff α (α_K) statistic, and the relationship between angiographic grade and clinical management choice, using the Fisher exact and Cramer V tests.

RESULTS

Interrater agreement was substantial (α_K = 0.63; 95% CI, 0.55-0.70); results were slightly better for MRA results of coiling (α_K = 0.69; 95% CI, 0.56-0.76) than for CTA results of clipping (α_K = 0.58; 95% CI, 0.44-0.69). Intrarater agreement was substantial to almost perfect. Interrater agreement regarding clinical management was moderate for both clipped (α_K = 0.49; 95% CI, 0.32-0.61) and coiled subgroups (α_K = 0.47; 95% CI, 0.34-0.54). The choice of clinical management was strongly associated with the size of the residuum (mean Cramer V = 0.77 [SD, 0.14]), but complete occlusions (grade 1) were followed more closely after coiling than after clipping (P = .01).

CONCLUSIONS

A standardized 3-grade scale was found to be a reliable and clinically meaningful tool to compare the results of clipping and coiling of aneurysms using CTA or MRA.

Reliability of the Diagnosis of Cerebral Vasospasm Using Catheter Cerebral Angiography: A Systematic Review and Inter- and Intraobserver Study

BACKGROUND AND PURPOSE

Conventional angiography is the benchmark examination to diagnose cerebral vasospasm, but there is limited evidence regarding its reliability. Our goals were the following: 1) to systematically review the literature on the reliability of the diagnosis of cerebral vasospasm using conventional angiography, and 2) to perform an agreement study among clinicians who perform endovascular treatment.

MATERIALS AND METHODS

Articles reporting a classification system on the degree of cerebral vasospasm on conventional angiography were systematically searched, and agreement studies were identified. We assembled a portfolio of 221 cases of patients with subarachnoid hemorrhage and asked 17 raters with different backgrounds (radiology, neurosurgery, or neurology) and experience (junior ≤10 and senior >10 years) to independently evaluate cerebral vasospasm in 7 vessel segments using a 3-point scale and to evaluate, for each case, whether findings would justify endovascular treatment. Nine raters took part in the intraobserver reliability study.

RESULTS

The systematic review showed a very heterogeneous literature, with 140 studies using 60 different nomenclatures and 21 different thresholds to define cerebral vasospasm, and 5 interobserver studies reporting a wide range of reliability (κ = 0.14-0.87). In our study, only senior raters reached substantial agreement (κ ≥ 0.6) on vasospasm of the supraclinoid ICA, M1, and basilar segments and only when assessments were dichotomized (presence or absence of ≥50% narrowing). Agreement on whether to proceed with endovascular management of vasospasm was only fair (κ ≤ 0.4).

CONCLUSIONS

Research on cerebral vasospasm would benefit from standardization of definitions and thresholds. Dichotomized decisions by experienced readers are required for the reliable angiographic diagnosis of cerebral vasospasm.

The Effect of Freezing Time on Muscle Fiber Mechanical Properties

The purpose of this study was to investigate the effect of freezing time on the functional behavior of mouse muscle fibers. Passive mechanical tests were performed on single soleus muscle fibers from fresh (0 month) and preserved (stored at -20°C for 3, 6, 9 and 12 months) 3 month old mice. The Young's modulus and the dynamic and the static stresses were measured. A viscoelastic Hill model of 3rd order was used to fit the experimental relaxation test data. The statistical analysis corresponding to the elastic modulus of single muscle fibers did not differ when comparing fresh and stored samples for 3 and 6 months at -20 °C. From 9 months, fibers were less resistant and the mechanical properties were damaged. The primary goal of this study was to complete the gold standard process of muscle fiber preservation for subsequent mechanical property studies. We have demonstrated that muscle fibers can be stored at -20°C for up to 6 months without altering their mechanical properties.

Real-time Subject-specific Head and Facial Mimic Animation System using a Contactless Kinect Sensor and System of Systems Approach

Facial palsies due to stroke, accidental and sportive injuries or sometimes without etiology, affect the professional and personal lives of involved patients. These disorders are not only a functional handicap but also a social integration impairment. The recovery of facial mimics with a normal and symmetrical facial expression allows involved patients to improve their living conditions and social identity. Current approaches lack of visual feedbacks. To monitor facial mimics and head movements in a quantitative and objective manners, a computer-aided animation system needs to be developed. Numerous systems have been proposed using single camera, stereo camera, 3-D scanner, and Kinect approaches. In particular, Kinect contactless sensor has been proven to be very suitable for 3-D facial simulation applications. However, little studies have employed the Kinect sensor for real-time head animation applications. Consequently, this study developed a real-time head and facial mimic animation system using the contactless Kinect sensor and the system of systems approach. To evaluate the accuracy of the subject-specific Kinect-based geometrical models, magnetic resonance imaging (MRI) data were used. As results, the mean distance deviation between generated Kinect-based and reconstructed MRI-based geometrical head models are approximately 1 mm for two tested subjects. The generation times are 9.7 s ± 0.3 and 0.046 s ± 0.005 by using the full facial landmarks and MPEG-4 facial landmarks respectively. Real-time head and facial mimic animations were illustrated. Particularly, the system could be executed at a very high framerate (60 fps). Further developments relate to the integration of texture information and internal structures such as a skull and muscle network to develop a full subject specific head and facial mimic animation system for facial mimic rehabilitation.

Does Increasing Packing Density Using Larger Caliber Coils Improve Angiographic Results of Embolization of Intracranial Aneurysms at 1 Year: A Randomized Trial

BACKGROUND AND PURPOSE

The impact of increased aneurysm packing density on angiographic outcomes has not been studied in a randomized trial. We sought to determine the potential for larger caliber coils to achieve higher packing densities and to improve the angiographic results of embolization of intracranial aneurysms at 1 year.

MATERIALS AND METHODS

Does Embolization with Larger Coils Lead to Better Treatment of Aneurysms (DELTA) was an investigator-initiated multicenter prospective, parallel, randomized, controlled clinical trial. Patients had 4- to 12-mm unruptured aneurysms. Treatment allocation to either 15- (experimental) or 10-caliber coils (control group) was randomized 1:1 using a Web-based platform. The primary efficacy outcome was a major recurrence or a residual aneurysm at follow-up angiography at 12 ± 2 months adjudicated by an independent core lab blinded to the treatment allocation. Secondary outcomes included indices of treatment success and standard safety outcomes. Recruitment of 564 patients was judged necessary to show a decrease in poor outcomes from 33% to 20% with 15-caliber coils.

RESULTS

Funding was interrupted and the trial was stopped after 210 patients were recruited between November 2013 and June 2017. On an intent-to-treat analysis, the primary outcome was reached in 37 patients allocated to 15-caliber coils and 36 patients allocated to 10-caliber coils (OR = 0.931; 95% CI, 0.528-1.644; P = .885). Safety and other clinical outcomes were similar. The 15-caliber coil group had a higher mean packing density (37.0% versus 26.9%, P = .0001). Packing density had no effect on the primary outcome when adjusted for initial angiographic results (OR = 1.001; 95% CI, 0.981-1.022; P = .879).

CONCLUSIONS

Coiling of aneurysms randomized to 15-caliber coils achieved higher packing densities compared with 10-caliber coils, but this had no impact on the angiographic outcomes at 1 year, which were primarily driven by aneurysm size and initial angiographic results.

Progress towards rabies control and elimination in Vietnam

Rabies is a fatal viral disease that causes an estimated 59,000 human deaths each year. The majority of these deaths occur in developing countries in Asia. Canine rabies is endemic to Vietnam, which is, however, moving towards the disease's elimination. Many countries, such as Vietnam, have invested tremendous resources in controlling rabies, highlighting the goal of regional and global elimination of this neglected disease. In Vietnam, rabies is recognised as one of five high-priority, zoonotic diseases by the Ministry of Health and the Ministry of Agriculture and Rural Development. Investment by the government and by international partners for rabies prevention and control has played a substantial role in reducing human rabies deaths from 404 cases in 1992 to 74 cases in 2017. The catalyst for this effort was the Prime Minister's creation of the National Rabies Program in 1996, which led to increased support and resources for rabies prevention and control. Interventions carried out since then include the expansion of post-exposure prophylaxis centres throughout the country, the introduction or revision of key legislation and guidelines, and improved multisectoral One Health collaboration. In addition, support from international partners, such as the World Organisation for Animal Health (OIE), the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), and the Centers for Disease Control and Prevention (CDC), has helped to increase awareness, manage dog populations more effectively, and improve Vietnam's surveillance and diagnostic capabilities. To pursue the goal of eliminating dog-mediated rabies in Vietnam, political commitment is crucial. Resources must be made available to enforce the regulations and guidelines that will enable Vietnam to achieve greater canine rabies vaccination coverage. In this paper, the authors provide an overview of the animal and human health systems in Vietnam, as well as past, current and future directions of rabies prevention and control.

Encapsulation of Neurotoxins, Blockers of Nicotinic Acetylcholine Receptors, in Nanomaterials Based on Sulfated Polysaccharides

Three-finger snake neurotoxins are selective antagonists of some nicotinic acetylcholine receptor subtypes and are widely used to study these receptors. The peptide neurotoxin azemiopsin, recently isolated from the venom of Azemipos feae, is a selective blocker of muscle-type nicotinic acetylcholine receptor. In order to reduce their toxicity and increase resistance under physiological conditions, we have encapsulated these toxins into nanomaterials. The study of nanomaterials after interaction with neurotoxins by the methods of transmission electron microscopy and dynamic light scattering revealed an increase in the size of nanoparticles, which indicates the inclusion of neurotoxins in nanomaterials.

Appearance of reassortant European avian-origin H1 influenza A viruses of swine in Vietnam

Three subtypes-H1N1, H1N2 and H3N2-of influenza A viruses of swine (IAVs-S) are currently endemic in swine worldwide, but there is considerable genotypic diversity among each subtype and limited geographical distribution. Through IAVs-S monitoring in Vietnam, two H1N2 influenza A viruses were isolated from healthy pigs in Ba Ria-Vung Tau Province, Southern Vietnam, on 2 December 2016. BLAST and phylogenetic analyses revealed that their HA and NA genes were derived from those of European avian-like H1N2 IAVs-S that contained avian-origin H1 and human-like N2 genes, and were particularly closely related to those of IAVs-S circulating in the Netherlands, Germany or Denmark. In addition, the internal genes of these Vietnamese isolates were derived from human A(H1N1)pdm09 viruses, suggesting that the Vietnamese H1N2 IAVs-S are reassortants between European H1N2 IAVs-S and human A(H1N1)pdm09v. The appearance of European avian-like H1N2 IAVs-S in Vietnam marks their first transmission outside Europe. Our results and statistical analyses of the number of live pigs imported into Vietnam suggest that the European avian-like H1N2 IAVs-S may have been introduced into Vietnam with their hosts through international trade. These findings highlight the importance of quarantining imported pigs to impede the introduction of new IAVs-S.

A cross-sectional study to quantify the prevalence of avian influenza viruses in poultry at intervention and non-intervention live bird markets in central Vietnam, 2014

In Vietnam, live bird markets are found in most populated centres, providing the means by which fresh poultry can be purchased by consumers for immediate consumption. Live bird markets are aggregation points for large numbers of poultry, and therefore, it is common for a range of avian influenza viruses to be mixed within live bird markets as a result of different poultry types and species being brought together from different geographical locations. We conducted a cross-sectional study in seven live bird markets in four districts of Thua Thien Hue Province in August and December, 2014. The aims of this study were to (i) document the prevalence of avian influenza in live bird markets (as measured by virus isolation); and (ii) quantify individual bird-, seller- and market-level characteristics that rendered poultry more likely to be positive for avian influenza virus at the time of sale. A questionnaire soliciting details of knowledge, attitude and avian influenza practices was administered to poultry sellers in study markets. At the same time, swabs and faecal samples were collected from individual poultry and submitted for isolation of avian influenza virus. The final data set comprised samples from 1,629 birds from 83 sellers in the seven live bird markets. A total of 113 birds were positive for virus isolation; a prevalence of 6.9 (95% CI 5.8-8.3) avian influenza virus-positive birds per 100 birds submitted for sale. After adjusting for clustering at the market and individual seller levels, none of the explanatory variables solicited in the questionnaire were significantly associated with avian influenza virus isolation positivity. The proportions of variance at the individual market, seller and individual bird levels were 6%, 48% and 46%, respectively. We conclude that the emphasis of avian influenza control efforts in Vietnam should be at the individual seller level as opposed to the market level.

What is the mechanism of Ketamine's rapid-onset antidepressant effect? A concise overview of the surprisingly large number of possibilities

WHAT IS KNOWN AND OBJECTIVE

Abundant clinical data now confirm that ketamine produces a remarkable rapid-onset antidepressant effect - hours or days - in contrast to the delayed onset (typically weeks) of current antidepressant drugs. This surprising and revolutionary finding may lead to the development of life-saving pharmacotherapy for depressive illness by reducing the high suicide risk associated with the delayed onset of effect of current drugs. As ketamine has serious self-limiting drawbacks that restrict its widespread use for this purpose, a safer alternative is needed. Our objective is to review the proposed mechanism(s) of ketamine's rapid-onset antidepressant action for new insights into the physiological basis of depressive illness that may lead to new and novel targets for antidepressant drug discovery.

METHODS

A search was conducted on published literature (e.g. PubMed) and Internet sources to identify information relevant to ketamine's rapid-acting antidepressant action and, specifically, to the possible mechanism(s) of this action. Key search words included 'ketamine', 'antidepressant', 'mechanism of action', 'depression' and 'rapid acting', either individually or in combination. Information was sought that would include less well-known, as well as well-known, basic pharmacologic properties of ketamine and that identified and evaluated the several hypotheses about ketamine's mechanism of antidepressant action.

RESULTS

Whether the mechanistic explanation for ketamine's rapid-onset antidepressant action is related to its well-known antagonism of the NMDA (N-Methyl-d-aspartate) subtype of glutamate receptor or to something else has not yet been fully elucidated. The evidence from pharmacologic, medicinal chemistry, animal model and drug-discovery sources reveals a wide variety of postulated mechanisms.

WHAT IS NEW AND CONCLUSION

The surprising discovery of ketamine's rapid-onset antidepressant effect is a game-changer for the understanding and treatment of depressive illness. There is some convergence on NMDA receptor antagonism as a likely, but to date unproven, common mechanism. The surprising number of other mechanisms, and the several novel biochemical aetiologies of depression proposed, suggests exciting new drug-discovery targets.

Inter- and Intrarater Agreement on the Outcome of Endovascular Treatment of Aneurysms Using MRA

BACKGROUND AND PURPOSE

Patients treated with coiling are often followed by MR angiography. Our objective was to assess the inter- and intraobserver agreement in diagnosing aneurysm remnants and recurrences by using multimodality imaging, including TOF MRA.

MATERIALS AND METHODS

A portfolio composed of 120 selected images from 56 patients was sent to 15 neuroradiologists from 10 institutions. For each case, raters were asked to classify angiographic results (3 classes) of 2 studies (32 MRA-MRA and 24 DSA-MRA pairs) and to provide a final judgment regarding the presence of a recurrence (no, minor, major). Six raters were asked to independently review the portfolio twice. A second study, restricted to 4 raters having full access to all images, was designed to validate the results of the electronic survey.

RESULTS

The proportion of cases judged to have a major recurrence varied between 16.1% and 71.4% (mean, 35.0% ± 12.7%). There was moderate agreement overall (κ = 0.474 ± 0.009), increasing to nearly substantial (κ = 0.581 ± 0.014) when the judgment was dichotomized (presence or absence of a major recurrence). Agreement on cases followed-up by MRA-MRA was similarly substantial (κ = 0.601 ± 0.018). The intrarater agreement varied between fair (κ = 0.257 ± 0.093) and substantial (κ= 0.699 ± 0.084), improving with a dichotomized judgment concerning MRA-MRA comparisons. Agreement was no better when raters had access to all images.

CONCLUSIONS

There is an important variability in the assessment of angiographic outcomes of endovascular treatments. Agreement on the presence of a major recurrence when comparing 2 MRA studies or the MRA with the last catheter angiographic study can be substantial.

A Review of Frailty in Developing Countries

BACKGROUND

As the population ages, the prevalence and clinical importance of frailty are increasing. There have been few published studies about frailty in developing world. This study aims to review the evidence from developing countries on the prevalence of frailty, definition of frailty and factors associated with frailty.

METHOD

A literature search was conducted via MEDLINE and EMBASE. Keywords included "frail", "frailty", "prevalence", "criteria", "definition", "risk factors", "outcomes", "developing country", "developing world", and names of low and middle income countries according to the classification of the World Bank.

RESULT

A total of 14 articles were reviewed from Brazil (n=6), China (n=3), Mexico (n=2), and one each from Russia, India, and Peru. There were 9 articles from community-based studies and 5 articles from hospital-based studies. Fried's phenotype for frailty was used to define frailty in the majority of studies. The prevalence of frailty in community-dwelling older people was 17%-31% in Brazil, 15% in Mexico, 5%-31% in China, and 21%-44% in Russia. The prevalence of frailty was 49% in institutionalized older patients in Brazil and 32% in hospitalized older patients in India. The prevalence of frailty in outpatient clinics was 55%-71% in Brazil and 28% in Peru. Frailty was associated with increased mortality and comorbidities, decreased physical and cognitive function, and poor perceptions of health.

CONCLUSION

The limited studies available suggest that frailty occurs frequently in older people in the developing world and it appears to be associated with adverse outcomes. This has implications for policy and health care provision for these ageing populations.

Modulation contrast optimization for wavelength conversion of a 20 Gbit/s data signal in hybrid InP/SOI photonic crystal nanocavity

Photonic crystal cavity-based switching is studied both theoretically and experimentally in order to identify the best configuration to maximize "wavelength conversion" efficiency. In particular, it is shown that an enhanced contrast can be reached when the probe is blueshifted with respect to the resonance. The use of an InP/SOI hybrid photonic crystal nanocavity is reported for the first time for all-optical error-free "wavelength conversion" at 20  Gbit/s with a nonreturn to zero on-off keying signal.

Abnormal patterns of theta frequency oscillations during the temporal evolution of freezing of gait in Parkinson's disease

OBJECTIVE

We sought to characterize the electrophysiological signature of Freezing of gait in Parkinson's disease.

METHODS

We examined 24 patients with idiopathic Parkinson's disease and significant freezing of gait as they performed a series of timed up-and-go tasks in their 'off' state while electroencephalographic data was collected from four scalp leads. Fast Fourier Transformation was utilized to explore the power spectral density between periods of normal walking and periods of freezing, as well as during the transition between the two states. In addition, Cross Spectrum and Cross Frequency analyses were used to explore the role of impaired temporal and spatial connectivity.

RESULTS

When compared to walking, episodes of freezing were associated with a significant increase in theta band power within the central and frontal leads. The transition from normal walking to freezing of gait was also associated with increased theta frequency coupling between the central and frontal leads, along with an increase in cross-frequency coupling in the central lead.

CONCLUSIONS

Episodes of freezing of gait in Parkinson's disease are associated with abnormal oscillatory activity in the brain.

SIGNIFICANCE

These results provide novel insights into the pattern of spatiotemporal dynamics underlying freezing of gait and may provide a potential means for therapeutic prediction and alleviation of freezing episodes in susceptible patients.

Normal dispersion femtosecond fiber optical parametric oscillator

We propose and demonstrate a synchronously pumped fiber optical parametric oscillator (FOPO) operating in the normal dispersion regime. The FOPO generates chirped pulses at the output, allowing significant pulse energy scaling potential without pulse breaking. The output average power of the FOPO at 1600 nm was ∼60  mW (corresponding to 1.45 nJ pulse energy and ∼55% slope power conversion efficiency). The output pulses directly from the FOPO were highly chirped (∼3  ps duration), and they could be compressed outside of the cavity to 180 fs by using a standard optical fiber compressor. Detailed numerical simulation was also performed to understand the pulse evolution dynamics around the laser cavity. We believe that the proposed design concept is useful for scaling up the pulse energy in the FOPO using different pumping wavelengths.

Fourth-order cascaded Raman shift in AsSe chalcogenide suspended-core fiber pumped at 2 μm

Cascaded Raman wavelength shifting up to the fourth order ranging from 2092 to 2450 nm is demonstrated using a nanosecond pump at 1995 nm in a low-loss As(38)Se(62) suspended-core microstructured fiber. These four Stokes shifts are obtained with a low peak power of 11 W, and only 3 W are required to obtain three shifts. The Raman gain coefficient for the fiber is estimated to (1.6±0.5)×10(-11) m/W at 1995 nm. The positions and the amplitudes of the Raman peaks are well reproduced by the numerical simulations of the nonlinear propagation.

Adapting liver motion models using a navigator channel technique

Deformable registration can improve the accuracy of tumor targeting; however for online applications, efficiency as well as accuracy is important. A navigator channel technique has been developed to combine a biomechanical model-based deformable registration algorithm with a population motion model and patient specific motion information to perform fast deformable registration for application in image-guided radiation therapy. A respiratory population-based liver motion model was generated from breath-hold CT data sets of ten patients using a finite element model as a framework. The population model provides a biomechanical reference template of the average liver motions, which were found to be (absolute mean +/-SD) 0.12 +/- 0.10, 0.84 +/- 0.13, and 1.24 +/- 0.18 cm in the left-right (LR), anterior-posterior (AP), and superior-inferior (SI) directions, respectively. The population motion model was then adapted to the specific liver motion of 13 patients based on their exhale and inhale CT images. The patient motion was calculated using a navigator channel (a narrow region of interest window) on liver boundaries in the images. The absolute average accuracy of the navigator channel to predict the 1D SI and AP motions of the liver was less than 0.11, which is less than the out-of-plane image voxel size, 0.25 cm. This 1D information was then used to adapt the 4D population motion model in the SI and AP directions to predict the patient specific liver motion. The absolute average residual error of the navigator channel technique to adapt the population motion to the patients' specific motion was verified using three verification methods: (1) vessel bifurcation, (2) tumor center of mass, and (3) MORFEUS deformable algorithm. All three verification methods showed statistically similar results where the technique's accuracy was approximately on the order of the voxel image sizes. This method has potential applications in online assessment of motion at the time of treatment to improve image-guided radiotherapy and monitoring of intrafraction motion.

A comparative evaluation of the sensitivity of two automated and two manual nucleic acid extraction methods for the detection of norovirus by RT-PCR

The aim of the study was to compare the sensitivity of a norovirus RT-PCR method using two manual RNA extraction methods (Qiagen and Roche) and two automated RNA extraction methods (Qiagen and Corbett). All four RNA extraction methods gave similar sensitivities although the automated methods, especially the Corbett, required significantly less labour than the manual methods. The automated methods also enabled RNA extraction of approximately two to three times the number of specimens in a given time period compared to manual methods.

Iatrogenic arterial perforation during acute stroke interventions

Arterial perforation is a feared complication of acute stroke intervention. A high index of suspicion is important to recognize this complication and tailor patient management to prevent further deterioration in clinical outcome. This report describes the endovascular management of microcatheter arterial perforation in a 66-year-old woman with an acute left middle cerebral artery stroke. The microcatheter was retained in the patient to seal the perforated site, resulting in good outcome at 3-month follow-up.

Vertebral artery stump syndrome

After occlusion of flow in an artery, further ischaemic episodes are not expected due to lack of a flow conduit to carry the embolus. In the carotid stump syndrome, ongoing ischaemic events may continue due to collateral flow via the external carotid artery. We report two patients presenting with posterior circulation strokes after documented vertebral artery occlusion, due to a vertebral stump syndrome. Their presentation, the pathophysiology of cervico-vertebral anastomoses and management are described.

Interventional neuroradiology: the role of experimental models in scientific progress

SUMMARY

The ultimate methodology necessary to adopt a treatment as generally beneficial is the randomized controlled trial, a method designed by and for clinicians to maximize the care of their patients in the presence of uncertainty. Some selection is however necessary to limit trials to more promising and less risky endeavors. Experimental models are the privileged answer to the problem of finding scientific evidence while refraining from harming patients in the course of this pursuit. They allow a step by step assessment, from simple but artificial settings to more complex and realistic animal models. But the use of animal models can only be justified if the community can be convinced that alternatives have been considered but are invalid, when the project is scientifically sound and methodologically irreproachable. As neurointerventional methods develop and gain wider clinical applications, progress should proceed in an orderly fashion, within limits set by prudence and human values, from the less risky, costly, time consuming methods, to the more definite, pragmatic, labor intensive but inescapable clinical trials. Each step is essential and the sequence cannot be violated without risks of errors that eventually translate into clinical morbidity.

White matter lesions, cognition, and recurrent hemorrhage in lobar intracerebral hemorrhage

BACKGROUND

Accumulating evidence suggests that white matter lesions are associated with vascular cognitive impairment. The authors investigated the relationships between white matter lesions, cognitive impairment, and risk of recurrent hemorrhage in a prospectively identified cohort of patients with lobar intracerebral hemorrhage (ICH).

METHODS

The authors collected clinical and genetic information on 182 consecutive patients age > or = 55 who had CT scan at admission for lobar ICH. White matter disease was graded on CT in all subjects and on MRI in a subset of 82 patients. All scans were interpreted blinded to clinical information. Survivors were followed for recurrent ICH by telephone interview.

RESULTS

White matter damage was common (present on CT in 77%) and severe (advanced CT grade in 32%). White matter damage was correlated with the total number of hemorrhages on gradient-echo MRI and with risk of recurrent ICH. Subjects with cognitive impairment prior to their index ICH were more likely to have severe white matter damage on CT (OR 3.6, 95% CI 1.6 to 8.1, p = 0.003) and more likely to have advanced periventricular hyperintensities on MRI. The relationships between white matter damage and cognitive impairment were similar in the subset of 88 subjects meeting criteria for probable or definite cerebral amyloid angiopathy and remained independent after adjustment for age, cortical atrophy, and APOE genotype.

CONCLUSIONS

White matter damage in lobar ICH is common and is associated with cognitive impairment. These data support the possibility that an underlying vasculopathy in lobar ICH patients, possibly cerebral amyloid angiopathy, can cause clinically important vascular dysfunction.

Virulent Toxoplasma gondii strain RH promotes T-cell-independent overproduction of proinflammatory cytokines IL12 and gamma-interferon

The aim of this study was the analysis of the cytokine response in BALB/c mice infected with the highly virulent RH or the weakly virulent Beverley strains of Toxoplasma gondii. Analysis of cytokine messages showed increased expression of IL12, IFN-gamma and TNF-alpha, but not IL4 mRNAs in spleen cells after infection with the T. gondii strains RH and Beverley. High levels of circulating IL12 and IFN-gamma were detected in the serum of mice infected with strain RH, although TNF-alpha levels remained low. In contrast, the same cytokines were detected at only low levels in the serum of mice infected with the Beverley strain. Administration of antibody against IL12 or IFN-gamma significantly delayed time to death of mice infected with strain RH compared to controls. T-Cell-deficient as well as normal mice were equally infected by strain RH, suggesting that T lymphocytes do not contribute to the response. Depletion of natural killer cells from the splenocyte population abolished the in vitro production of IFN-gamma. Together, our data suggest that the virulent strain RH induces in BALB/c mice a type 1 cytokine pattern with T-cell-independent overproduction of IL12 and IFN-gamma that may be involved in the pathogenesis of this micro-organism.

Safety and immunogenicity of a novel recombinant subunit respiratory syncytial virus vaccine (BBG2Na) in healthy young adults

A novel recombinant respiratory syncytial virus (RSV) subunit vaccine, designated BBG2Na, was administered to 108 healthy adults randomly assigned to receive 10, 100, or 300 microg of BBG2Na in aluminum phosphate or saline placebo. Each subject received 1, 2, or 3 intramuscular injections of the assigned dose at monthly intervals. Local and systemic reactions were mild, and no evidence of harmful properties of BBG2Na was reported. The highest ELISA and virus-neutralizing (VN) antibody responses were evident in the 100- and 300-microg groups; second or third injections provided no significant boosts against RSV-derived antigens. BBG2Na induced > or 2-fold and > or =4-fold increases in G2Na-specific ELISA units in up to 100% and 57% of subjects, respectively; corresponding RSV-A-specific responses were 89% and 67%. Furthermore, up to 71% of subjects had > or =2-fold VN titer increases. Antibody responses to 2 murine lung protective epitopes were also highly boosted after vaccination. Therefore, BBG2Na is safe, well tolerated, and highly immunogenic in RSV-seropositive adults.

Differential histopathology and chemokine gene expression in lung tissues following respiratory syncytial virus (RSV) challenge of formalin-inactivated RSV- or BBG2Na-immunized mice

A BALB/c mouse model of enhanced pulmonary pathology following vaccination with formalin-inactivated alum-adsorbed respiratory syncytial virus (FI-RSV) and live RSV challenge was used to determine the type and kinetics of histopathologic lesions induced and chemokine gene expression profiles in lung tissues. These data were compared and contrasted with data generated following primary and/or secondary RSV infection or RSV challenge following vaccination with a promising subunit vaccine, BBG2Na. Severe peribronchiolitis and perivascularitis coupled with alveolitis and interstitial inflammation were the hallmarks of lesions in the lungs of FI-RSV-primed mice, with peak histopathology evident on days 5 and 9. In contrast, primary RSV infection resulted in no discernible lesions, while challenge of RSV-primed mice resulted in rare but mild peribronchiolitis and perivascularitis, with no evidence of alveolitis or interstitial inflammation. Importantly, mice vaccinated with a broad dose range (20 to 0.02 microg) of a clinical formulation of BBG2Na in aluminium phosphate demonstrated histopathology similar to that observed in secondary RSV infection. At the molecular level, FI-RSV priming was characterized by a rapid and strong up-regulation of eotaxin and monocyte chemotactic protein 3 (MCP-3) relative gene expression (potent lymphocyte and eosinophil chemoattractants) that was sustained through late time points, early but intermittent up-regulation of GRO/melanoma growth stimulatory activity gene and inducible protein 10 gene expression, while macrophage inflammatory protein 2 (MIP-2) and especially MCP-1 were up-regulated only at late time points. By comparison, primary RSV infection or BBG2Na priming resulted in considerably lower eotaxin and MCP-3 gene expression increases postchallenge, while expression of lymphocyte or monocyte chemoattractant chemokine genes (MIP-1beta, MCP-1, and MIP-2) were of higher magnitude and kinetics at early, but not late, time points. Our combined histopathologic and chemokine gene expression data provide a basis for differentiating between aberrant FI-RSV-induced immune responses and normal responses associated with RSV infection in the mouse model. Consequently, our data suggest that BBG2Na may constitute a safe RSV subunit vaccine for use in seronegative infants.

Lipophilic quaternary ammonium salt acts as a mucosal adjuvant when co-administered by the nasal route with vaccine antigens

Nasal administration of vaccines is an attractive approach which offers several significant advantages over traditional intramuscular vaccine delivery. These advantages include easier administration and induction of immune responses in the mucosal secretions of the body. In this study we describe a new potent nasal adjuvant, dimethyldioctadecylammonium bromide (DDA), that induces both mucosal and systemic immune responses when co-administered with diphtheria toxoid (DT), tetanus toxoid (TT) and BBG2Na antigens. In particular, we show that the nasal delivery of recombinant fragment (BBG2Na) of the G protein of respiratory syncytial virus (RSV) mixed with DDA induces both local and systemic anti-RSV immune responses and protects against viral challenge. Furthermore, we provide evidence that the DDA+BBG2Na vaccine does not induce lung immunopathology upon subsequent RSV challenge.

Development of potent non-carbohydrate imidazole-based small molecule selectin inhibitors with antiinflammatory activity

A novel series of non-carbohydrate imidazole-based selectin inhibitors has been discovered via high-throughput screening using a P-selectin ELISA-based assay system. The initial lead 1 had an IC(50) of 17 microM in the P-selectin ELISA; this potency was significantly improved via an extensive SAR exploration. One of the current lead compounds (29) has an IC(50) of 300 nM in a P-selectin ELISA; it also has good activity in P- and E-selectin cell adhesion assays and shows efficacy in vivo. These compounds represent a novel series of sLe(X) mimetics with antiinflammatory activity. Their unique profile supports our interest in their further evaluation as drug candidates for the treatment of inflammation. Herein we describe the syntheses, optimization, and SAR of this series of novel potent selectin antagonists.

Synthesis and characterization of respiratory syncytial virus protein G related peptides containing two disulphide bridges

Respiratory Syncytial Virus (RSV) is the most important cause of bronchiolitis and viral pneumoniae in infants and young children. Approximately 100,000 children are hospitalized in the USA each year as a result of RSV infections. During the research and development of subunit human RSV vaccines, we have produced numerous synthetic peptides and recombinant proteins containing the four cysteines of the highly conserved central region of the G attachment protein. For several of these disulphide bridges containing peptides, all possible oxidizing isomers were synthesized using various oxidising conditions, resulting in different ratios of isomers. Each isolated isomer was fully characterized by RP-HPLC, FZCE and ES-MS after purification by preparative RP-HPLC. The different cysteine pairings were unambiguously established after enzymatic digestion, LC-MS analysis and peptide microsequencing. These synthetic and analytical methods were developed for the characterization of recombinant fusion protein BBG2Na which is currently investigated in clinical phase II and seems to be as a very promising vaccine candidate, and for peptides which were synthesized to be evaluated as conjugate vaccines or as immunochemical tools, after covalent coupling to carrier proteins. Furthermore, these studies allowed us to determine which of the different possible isomers was the most stable and probably the preferred form in native conditions. Finally, the different oxidising and analysis conditions, should be useful for disulphide pairing studies of other peptides and proteins having the same "xCxxCxxxxxCxxxCx" framework, such as G proteins of non-human RSV strains, developed for example as veterinary vaccine candidates.

Development of a quantitative assay for residual host cell proteins in a recombinant subunit vaccine against human respiratory syncytial virus

We have developed and validated a process-specific immunoligand assay based on the Threshold system for the quantification of residual host cell proteins (HCPs) in a recombinant subunit vaccine candidate against the human respiratory syncytial virus (hRSV). The industrial process of this vaccine produced in Escherichia coli, involved five chromatography steps for the production of clinical-grade batches. The clearance of non-product-related protein throughout the purification process was documented by the evaluation of the HCP content in the chromatographic fractions at each step of the downstream processing. The assay had a detection limit of 0.5 ng/ml of HCP equivalent to 10 parts per million (ppm). The quantification limit was 1.3 ng/ml of HCP, giving a sensitivity range of the assay of 10 to 30 ppm. To our knowledge, this is the first sensitive HCP assay reported for a vaccine.

Human Taf(II)130 is a coactivator for NFATp

NFATp is one member of a family of transcriptional activators that regulate the expression of cytokine genes. To study mechanisms of NFATp transcriptional activation, we established a reconstituted transcription system consisting of human components that is responsive to activation by full-length NFATp. The TATA-associated factor (TAF(II)) subunits of the TFIID complex were required for NFATp-mediated activation in this transcription system, since TATA-binding protein (TBP) alone was insufficient in supporting activated transcription. In vitro interaction assays revealed that human TAF(II)130 (hTAF(II)130) and its Drosophila melanogaster homolog dTAF(II)110 bound specifically and reproducibly to immobilized NFATp. Sequences contained in the C-terminal domain of NFATp (amino acids 688 to 921) were necessary and sufficient for hTAF(II)130 binding. A partial TFIID complex assembled from recombinant hTBP, hTAF(II)250, and hTAF(II)130 supported NFATp-activated transcription, demonstrating the ability of hTAF(II)130 to serve as a coactivator for NFATp in vitro. Overexpression of hTAF(II)130 in Cos-1 cells inhibited NFATp activation of a luciferase reporter. These studies demonstrate that hTAF(II)130 is a coactivator for NFATp and represent the first biochemical characterization of the mechanism of transcriptional activation by the NFAT family of activators.

Identification and characterisation of multiple linear B cell protectopes in the respiratory syncytial virus G protein

Respiratory syncytial virus (RSV) is an important respiratory pathogen in man, against which no vaccine is available. However, recent evidence suggests that antibodies to the RSV F and G proteins may play an important role in disease prevention. We previously demonstrated that BBG2Na, a subunit vaccine candidate including residues 130-230 of the Long strain G protein, protects rodents against RSV challenge. Using a panel of monoclonal antibodies (MAb) and synthetic peptides, five linear B cell epitopes were identified that mapped to residues 152-163, 165-172, 171-187 (two over-lapping epitopes) and 196-204. Antibody passive transfer and peptide immunisation studies revealed that all were protective. Pepscan analyses of anti-RSV-A and BBG2Na murine polyclonal sera suggested stronger immunogenicity of some protective epitopes (protectopes) in the context of BBG2Na compared with live virus. However, all the identified murine B cell protectopes were conserved in RSV seropositive humans. Should these protectopes correspond with protection in humans, BBG2Na may constitute a very interesting vaccine candidate against RSV.

Differential gene expression in Thermotoga neapolitana in response to growth substrate

We have previously shown that beta-galactosidase activity expressed in Thermotoga neapolitana cells grown on lactose is subject to repression by glucose when they are grown on both substrates whereas beta-galactosidase and beta-glucosidase activities observed in cells grown on cellobiose are not repressed by growth on both glucose and cellobiose. To examine the differential expression of bgalA, bgalB, bglA and bglB in T. neapolitana, total RNA was isolated from cells growing on either glucose, lactose or cellobiose as the sole source of carbon and transcripts encoding these genes were quantitated by Northern blot analyses. BglA expression was induced by cellobiose while bglB was expressed under all three conditions at a lower level. Expression of the beta-galactosidase genes, bgalA and bgalB, was detected only in lactose-grown cells. beta-Glucosidase enzyme activity was only found in cell extracts of cellobiose-grown cells while beta-galactosidase activity was found in both lactose- and cellobiose-grown cell extracts. Our results show that in cellobiose-grown cells, the high beta-glucosidase activity is likely due to expression of bglA and that neither bgalA nor bgalB is responsible for the beta-galactosidase activity.

Staphylococcal surface display and its applications

Novel surface proteins can be introduced onto the bacterial cell surface by recombinant means. Here, we describe the development of such display systems for two food-grade bacteria, Staphylococcus carnosus and Staphylococcus xylosus, and present how such engineered bacteria can be used in different applications. A study will be described in which such staphylococci were employed as vaccine delivery vehicles to elicit protective antibody responses to respiratory syncytial virus (RSV). The use of surface-engineered staphylococci as novel microbial biocatalysts, as a new type of whole-cell diagnostic devices or for adsorption of metal ions with potential environmental or biosensor applications, will also be discussed.

Deuterium-proton exchange on the native wild-type transthyretin tetramer identifies the stable core of the individual subunits and indicates mobility at the subunit interface

Transthyretin is a human protein capable of amyloid formation that is believed to cause several types of amyloid disease, depending on the sequence deposited. Previous studies have demonstrated that wild-type transthyretin (TTR), although quite stable, forms amyloid upon dissociation from its native tetrameric form into monomers with an altered conformation. Many naturally occurring single-site variants of TTR display decreased stability in vitro, manifested by the early onset familial amyloid diseases in vivo. Only subtle structural changes were observed in X-ray crystallographic structures of these disease associated variants. In this study, the stability of the wild-type TTR tetramer was investigated at the residue-resolution level by monitoring (2)H-H exchange via NMR spectroscopy. The measured protection factors for slowly-exchanging amide hydrogen atoms reveal a stable core consisting of strands A, B, E, F, and interestingly, the loop between strands A and B. In addition, the faster exchange of amide groups from residues at the subunit interfaces suggests unexpected mobility in these regions. This information is crucial for future comparisons between disease-associated and wild-type tetramers. Such studies can directly address the regions of TTR that become destabilized as a consequence of single amino acid substitutions, providing clues to aspects of TTR amyloidogenesis.

Regulation of the formation of tumor cell pseudopodia by the Na(+)/H(+) exchanger NHE1

The Na(+)/H(+) exchanger NHE1 is involved in intracellular pH homeostasis and cell volume regulation and accumulates with actin in the lamellipodia of fibroblasts. In order to determine the role of NHE1 following epithelial transformation and the acquisition of motile and invasive properties, we studied NHE1 expression in polarized MDCK cells, Moloney Sarcoma virus (MSV) transformed MDCK cells and an invasive MSV-MDCK cell variant (MSV-MDCK-INV). Expression of NHE1 was significantly increased in MSV-MDCK-INV cells relative to MSV-MDCK and MDCK cells. NHE1 was localized with b-actin to the tips of MSV-MDCK-INV cell pseudopodia by immunofluorescence. Sensitivity of NHE1-mediated (22)Na uptake to ethylisopropylamiloride, a specific inhibitor of NHE1, was increased in MSV-MDCK cells relative to MDCK cells. Changes in intracellular pH induced upon EIPA treatment were also of higher magnitude in MSV-MDCK and MSV-MDCK-INV cells compared to wild-type MDCK cells, especially in Hepes-buffered DMEM medium. Inhibition of NHE1 by 50 microM ethylisopropylamiloride induced the disassembly of actin stress fibers and redistribution of the actin cytoskeleton in all cell types. However, in MSV-MDCK-INV cells, the effect of ethylisopropylamiloride treatment was more pronounced and associated with the increased reversible detachment of the cells from the substrate. Videomicroscopy of MSV-MDCK-INV cells revealed that within 20 minutes of addition, ethylisopropylamiloride induced pseudopodial retraction and inhibited cell motility. The ability of ethylisopropylamiloride to prevent nocodazole-induced formation of actin stress fibers in MSV-MDCK cells was more pronounced in Hepes medium relative to NaHCO(3) medium, showing that NHE1 can regulate actin stress fiber assembly in transformed MSV-MDCK cells via its intracellular pH regulatory effect. These results implicate NHE1 in the regulation of the actin cytoskeleton dynamics necessary for the adhesion and pseudopodial protrusion of motile, invasive tumor cells.