Site-Specific Protein Labeling with Fluorophores as a Tool To Monitor Protein Turnover

Proteins that terminally fail to acquire their native structure are detected and degraded by cellular quality control systems. Insights into cellular protein quality control are key to a better understanding of how cells establish and maintain the integrity of their proteome and of how failures in these processes cause human disease. Here we have used genetic code expansion and fast bio‐orthogonal reactions to monitor protein turnover in mammalian cells through a fluorescence‐based assay. We have used immune signaling molecules (interleukins) as model substrates and shown that our approach preserves normal cellular quality control, assembly processes, and protein functionality and works for different proteins and fluorophores. We have further extended our approach to a pulse‐chase type of assay that can provide kinetic insights into cellular protein behavior. Taken together, this study establishes a minimally invasive method to investigate protein turnover in cells as a key determinant of cellular homeostasis.

An in vivo evaluation of the ontogeny of stereoselective fluoxetine metabolism and disposition in lambs from birth to one year of age

1. The objective was to determine the ontogeny of stereoselective fluoxetine (FX) disposition in postnatal sheep from newborn to adulthood. 2. Catheters were implanted in a carotid artery and jugular vein. FX was administered intravenously, followed by serial arterial blood and cumulative urine collection. The concentrations of R,S-FX and R,S-norfluoxetine (R,S-NFX) in samples were measured using a validated enantioselective LC/MS/MS analytical method. 3. The metabolism of FX at 4.2 ± 0.4 days was limited compared to adults, but had developed compared to the fetus. Total body clearance (Cl_TB) did not significantly increase up to 33.6 ± 0.9 days, but significantly increased at 98.5 ± 2.0 days, with no further changes up to 397.3 ± 8.5 days. Up to 13.4 ± 0.8 days, the disposition of FX included Phase I metabolism to NFX and trifluoromethylphenol (TFMP), and renal elimination. At 32.9 ± 0.9 days, metabolism included Phase II conjugates of FX and NFX. Renal elimination of these compounds was low. 4. The elimination of FX increased in a non-linear manner during the first year in sheep. The metabolism and disposition of FX and NFX in plasma and urine were stereoselective and this appeared due to both stereoselective protein binding and metabolism.

Expanding the Genetic Code to Study Protein-Protein Interactions

Protein-protein interactions are central to many biological processes. A considerable challenge consists however in understanding and deciphering when and how proteins interact, and this can be particularly difficult when interactions are weak and transient. The site-specific incorporation of unnatural amino acids (UAAs) that crosslink with nearby molecules in response to light provides a powerful tool for mapping transient protein-protein interactions and for defining the structure and topology of protein complexes both in vitro and in vivo. Complementary strategies consist in site-specific incorporation of UAAs bearing electrophilic moieties that react with natural nucleophilic amino acids in a proximity-dependent manner, thereby chemically stabilizing low-affinity interactions and providing additional constraints on distances and geometries in protein complexes. Herein, we review how UAAs bearing fine-tuned chemical moieties that react with proteins in their vicinity can be utilized to map, study, and characterize weak and transient protein-protein interactions in living systems.

The role of macroscopic sputum quality assessments to optimise sputum testing for tuberculosis

SETTING

Community-wide active case finding for tuberculosis (TB) using Xpert® MTB/RIF as the primary screening tool, Ca Mau Province, Viet Nam.

OBJECTIVES

To determine whether macroscopic sputum quality characteristics (sputum colour and volume) can be used to predict Xpert MTB-negative sputum and hence exclude sputum samples from testing.

DESIGN

Field staff conducted household visits to approximately 51,200 adults in 58 villages randomly selected from throughout the province. Sputum samples from all screened participants who were able to produce ⩾1 ml sputum underwent macroscopic sputum assessment and were tested with Xpert.

RESULTS

Of the 21,624 sputum samples tested, 159 (0.74%) were Xpert MTB-positive; 93% of the samples were 1-2 ml and nearly all were mucoid (93%) or mucopurulent (5.7%). One salivary sample was Xpert MTB-positive (2.0% of all salivary samples). The lowest positive predictive value for any sputum volume or colour characteristic was 0.66%. This was not substantially different from the overall prevalence of positive sputum Xpert MTB (0.74%).

CONCLUSION

Sputum colour and volume cannot be used to predict the presence or absence of M. tuberculosis in sputum detected using Xpert. These sputum quality parameters cannot therefore be used to exclude sputum samples from testing for TB.

Cutaneous skeletal hypophosphatemia syndrome: clinical spectrum, natural history, and treatment

Cutaneous skeletal hypophosphatemia syndrome (CSHS), caused by somatic RAS mutations, features excess fibroblast growth factor-23 (FGF23) and skeletal dysplasia. Records from 56 individuals were reviewed and demonstrated fractures, scoliosis, and non-congenital hypophosphatemia that in some cases were resolved. Phosphate and calcitriol, but not skin lesion removal, were effective at controlling hypophosphatemia. No skeletal malignancies were found.

PURPOSE

CSHS is a disorder defined by the association of epidermal and/or melanocytic nevi, a mosaic skeletal dysplasia, and an FGF23-mediated hypophosphatemia. To date, somatic RAS mutations have been identified in all patients whose affected tissue has undergone DNA sequencing. However, the clinical spectrum and treatment are poorly defined in CSHS. The purpose of this study is to determine the spectrum of the phenotype, natural history of the disease, and response to treatment of hypophosphatemia.

METHODS

Five CSHS subjects underwent prospective data collection at clinical research centers. A review of the literature identified 45 reports that included a total of 51 additional patients, in whom the findings were compatible with CSHS. Data on nevi subtypes, bone histology, mineral and skeletal disorders, abnormalities in other tissues, and response to treatment of hypophosphatemia were analyzed.

RESULTS

Fractures, limb deformities, and scoliosis affected most CSHS subjects. Hypophosphatemia was not present at birth. Histology revealed severe osteomalacia but no other abnormalities. Skeletal dysplasia was reported in all anatomical compartments, though less frequently in the spine; there was no clear correlation between the location of nevi and the skeletal lesions. Phosphate and calcitriol supplementation was the most effective therapy for rickets. Convincing data that nevi removal improved blood phosphate levels was lacking. An age-dependent improvement in mineral abnormalities was observed. A spectrum of extra-osseous/extra-cutaneous manifestations that included both benign and malignant neoplasms was present in many subjects, though osteosarcoma remains unreported.

CONCLUSION

An understanding of the spectrum, natural history, and efficacy of treatment of hypophosphatemia in CSHS may improve the care of these patients.

Medical image denoising via optimal implementation of non-local means on hybrid parallel architecture

The Non-local means denoising filter has been established as gold standard for image denoising problem in general and particularly in medical imaging due to its efficiency. However, its computation time limited its applications in real world application, especially in medical imaging. In this paper, a distributed version on parallel hybrid architecture is proposed to solve the computation time problem and a new method to compute the filters' coefficients is also proposed, where we focused on the implementation and the enhancement of filters' parameters via taking the neighborhood of the current voxel more accurately into account. In terms of implementation, our key contribution consists in reducing the number of shared memory accesses. The different tests of the proposed method were performed on the brain-web database for different levels of noise. Performances and the sensitivity were quantified in terms of speedup, peak signal to noise ratio, execution time, the number of floating point operations. The obtained results demonstrate the efficiency of the proposed method. Moreover, the implementation is compared to that of other techniques, recently published in the literature.

Critical Casimir forces for colloidal assembly

Critical Casimir forces attract increasing interest due to their opportunities for reversible particle assembly in soft matter and nano science. These forces provide a thermodynamic analogue of the celebrated quantum mechanical Casimir force that arises from the confinement of vacuum fluctuations of the electromagnetic field. In its thermodynamic analogue, solvent fluctuations, confined between suspended particles, give rise to an attractive or repulsive force between the particles. Due to its unique temperature dependence, this effect allows in situ control of reversible assembly. Both the force magnitude and range vary with the solvent correlation length in a universal manner, adjusting with temperature from fractions of the thermal energy, k B T, and nanometre range to several ten kT and micrometer length scale. Combined with recent breakthroughs in the synthesis of complex particles, critical Casimir forces promise the design and assembly of complex colloidal structures, for fundamental studies of equilibrium and out-of-equilibrium phase behaviour. This review highlights recent developments in this evolving field, with special emphasis on the dynamic interaction control to assemble colloidal structures, in and out of equilibrium.

General practitioner management plans delaying time to next potentially preventable hospitalisation for patients with heart failure

BACKGROUND

Several studies have shown that the Australian Medicare-funded chronic disease management programme can lead to improvements in care processes. No study has examined the impact on long-term health outcomes.

AIMS

This retrospective cohort study assessed the association between provision of a general practitioner management plan and time to next potentially preventable hospitalisation for older patients with heart failure.

METHODS

We used the Australian Government Department of Veterans' Affairs (DVA) claims database and compared patients exposed to a general practitioner management plan with those who did not receive the service. Kaplan-Meier analysis and Cox proportional hazards models were used to compare time until next potentially preventable hospitalisation for heart failure between the exposed and unexposed groups.

RESULTS

There were 1993 patients exposed to a general practitioner management plan and 3986 unexposed patients. Adjusted results showed a 23% reduction in the rate of potentially preventable hospitalisation for heart failure at any time (adjusted hazard ratio, 0.77; 95% confidence interval, 0.64 to 0.92; P = 0.0051) among those with a general practitioner management plan compared with the unexposed patients. Within one year, 8.6% of the exposed group compared with 10.7% of the unexposed group had a potentially preventable hospitalisation for heart failure.

CONCLUSIONS

A general practitioner management plan is associated with delayed time to next potentially preventable hospitalisation for heart failure.

Multistate outbreak of Escherichia coli O145 infections associated with romaine lettuce consumption, 2010

Non-O157 Shiga toxin-producing Escherichia coli (STEC) can cause severe illness, including hemolytic uremic syndrome (HUS). STEC O145 is the sixth most commonly reported non-O157 STEC in the United States, although outbreaks have been infrequent. In April and May 2010, we investigated a multistate outbreak of STEC O145 infection. Confirmed cases were STEC O145 infections with isolate pulsed-field gel electrophoresis patterns indistinguishable from those of the outbreak strain. Probable cases were STEC O145 infections or HUS in persons who were epidemiologically linked. Case-control studies were conducted in Michigan and Ohio; food exposures were analyzed at the restaurant, menu, and ingredient level. Environmental inspections were conducted in implicated food establishments, and food samples were collected and tested. To characterize clinical findings associated with infections, we conducted a chart review for case patients who sought medical care. We identified 27 confirmed and 4 probable cases from five states. Of these, 14 (45%) were hospitalized, 3 (10%) developed HUS, and none died. Among two case-control studies conducted, illness was significantly associated with consumption of shredded romaine lettuce in Michigan (odds ratio [OR] = undefined; 95% confidence interval [CI] = 1.6 to undefined) and Ohio (OR = 10.9; 95% CI = 3.1 to 40.5). Samples from an unopened bag of shredded romaine lettuce yielded the predominant outbreak strain. Of 15 case patients included in the chart review, 14 (93%) had diarrhea and abdominal cramps and 11 (73%) developed bloody diarrhea. This report documents the first foodborne outbreak of STEC O145 infections in the United States. Current surveillance efforts focus primarily on E. coli O157 infections; however, non-O157 STEC can cause similar disease and outbreaks, and efforts should be made to identify both O157 and non-O157 STEC infections. Providers should test all patients with bloody diarrhea for both non-O157 and O157 STEC.

Synthesis and characterization of conductive core-shell polyacrylonitrile-polypyrrole nanofibers

Nonwoven polyacrylonitrile-polypyrrole (PAN-PPy) core-shell nanofiber mats were prepared through the growth of PPy layers on electrospun PAN nanofibers via a two-step vapor-phase polymerization, i.e., the wet-coating of ferric tosylate (FeTos) oxidants on PAN nanofibers followed by exposure to pyrrole monomers in the gas phase. Under the conditions ([FeTos] = 10 wt%, reaction time = 15 min, temperature = 15 degrees C), the PPy polymerization procedure led to both a uniform coating over the PAN surface with an average thickness of 18 nm and cross-linkages among the nanofibers without a noticeable change in the highly porous nanofibrous structures. The oxidant concentration and polymerization time were found to be key parameters for achieving a good nanostructured core-shell fiber mat. FT-IR, XPS, XRD and conductivity measurements confirmed the synthesis of Tos-doped PPy with some degree of crystallinity and a high conductivity.

Evaluation of shellfish consumption in Nha Trang City, Southern coastal Vietnam

INTRODUCTION

Shellfish consumption may be a significant pathway to food contaminants such as heavy metals, pesticides and phycotoxins. Currently, little information exists about consumption of shellfish in Vietnam. Such data could be of interest in terms of nutritional value or risk assessment.

METHODS

Consumption of shellfish was assessed using a food frequency questionnaire and validated by a 7-day recall method. Approximately 1% of the city population of Nha Trang was selected yielding a final sample of 440 participants. The participants were above 18 years of age, in apparently good health and were shellfish consumers.

RESULTS

In South coastal Vietnam, the types of shellfish most consumed are green mussel, squid, crab and shrimp. The mean consumption rates of the bivalves, crustaceans, gastropods, cephalopods, echinoderms and all shellfish combined were 39.3, 20.9, 16.4, 11.2, 0.3 and 88.1 g/person/day, respectively. The consumption rate was slightly higher in the age group of 30-54 years, than in the younger (18-29 years) and older (55 years and above) age groups. Shellfish is essentially purchased in the markets and temporary markets, and mostly consumed during the dry season.

CONCLUSION

Shellfish consumption in the Southern coastal region of Vietnam is high compared to consumption levels in other countries; it is also high compared to consumption levels of Vietnamese emigrants. Such data may be useful for further investigation on nutrition perspectives and in term of risk assessment of shellfish contaminants.

Hydronephrosis and urine retention in estrogen-implanted athymic nude mice

Subcutaneous estrogen pellet implantation is commonly practiced to induce tumor promotion in nude (Nu-FOXn1(nu)) mice for xenograft tumor modeling. Twelve of 23, 18-week-old nude mice developed dysuria after estrogen pellet implantation. Physical examination revealed variably distended abdomens with palpable distended bladders. All mice were euthanatized and postmortem examinations were made. Blood samples of the mice were collected, and serum estrogen concentration was measured. Postmortem examination revealed variable dilation of the urinary bladder and unilateral or bilateral dilations of ureters and kidneys. Microscopically, 12 of 23 mice and 13 of 23 mice showed dilated urinary bladder and hydronephrosis, respectively.

Dealing with a positive result: routine HIV testing of pregnant women in Vietnam

HIV testing is an essential component of PMTCT. It can be offered to pregnant women through different testing models, ranging from voluntary counseling and testing (VCT) to routine and mandatory testing. This study was conducted in Hanoi, Vietnam, where HIV-prevalence is low among the general population, but high among young, urban, sexually active, male intravenous drug users. Women who want to deliver in a state hospital are routinely tested for HIV in the absence of well-defined opt-out procedures. In-depth interviews with a convenience sample of 38 seropositive pregnant women and mothers and 53 health workers explored the acceptability of routine testing. Patients and healthcare workers appeared to accept routine 'blood' tests (including HIV tests) because they feel uncomfortable discussing issues specific to HIV/AIDS. To avoid having to inform women directly about their HIV status, health workers at routine testing sites rely on the official notification system, shifting the responsibility from the hospitals to district and commune health staff. The notification system in Hanoi informs these local officials about the HIV status of people living in their catchment area without patients' consent. Our study shows that this non-confidential process can have serious social, economic and health consequences for the HIV-positive women and their children.

Social determinants of discharge destination for patients after stroke with low admission FIM instrument scores

OBJECTIVE

To investigate the effects of immigrant status (via country of birth), marital status, and area-based socioeconomic status (SES) on discharge destination after stroke for those with low admission scores on the FIM instrument.

DESIGN

Cross-sectional study.

SETTING

Inpatient rehabilitation ward at an urban community hospital in Australia.

PARTICIPANTS

A total of 326 inpatients admitted for rehabilitation poststroke.

INTERVENTION

Multidisciplinary rehabilitation.

MAIN OUTCOME MEASURE

Discharge home versus nursing home.

RESULTS

A total admission FIM score of 75 or lower was associated with a higher probability of nursing home discharge. Married patients with a total FIM admission score of 75 or lower were significantly more likely to be discharged home, after adjusting for immigrant status, type and side of stroke, sex, and age (odds ratio, 6.07; 95% confidence interval, 1.65-22.40; P<.01). This effect was also observed for low motor and cognition components of FIM admission score. The effect of immigrant status did not remain significant after adjusting for marital status. Area-based SES and stroke characteristics did not substantially attenuate the relationship between immigrant status, marital status, and discharge location.

CONCLUSIONS

Marital status is a significant determinant of discharge destination. Immigrant status and area-based SES were not significant predictors of discharge disposition.

Changing distribution of group A rotavirus G-types and genetic analysis of G9 circulating in Japan

A total of 1,797 fecal specimens from infants and children with acute gastroenteritis in Japan from July 2000 to June 2003 were tested for group A rotavirus by ELISA, RT-PCR, RNA-PAGE and latex agglutination methods. Of these, 439 were found to be positive for group A rotavirus and this presented 24.4%. In 2000-2001, G1 was the most prevalent (45.5%) followed by G2 (32.5%), G3 (12.3%), G9 (5.9%) and G4 (2.6%). However, G2 was found predominant with 40% in the following year (2001-2002). Interestingly, G9 had a rapid increase of infection up to 17.8%. In 2002-2003, G3 dominated over other G-types with 34%. Another interesting feature of the study was the demonstration of great genetic diversity among G9 strains in Japan. Worth of note was the first prevalence pattern of rotavirus G-types with an increase of G2, G3 as well as G9 and a decrease of G1 during the 20 year-survey of rotavirus infection in Japan.

Existence of multiple outbreaks of viral gastroenteritis among infants in a day care center in Japan

A total of 921 fecal specimens collected from 44 infants in a day care center (DCC) in Tokyo, Japan during June 1999 to July 2000 were tested for the presence of rotavirus, norovirus, sapovirus, astrovirus and adenovirus by reverse-transcription-multiplex polymerase chain reaction (RT-multiplex PCR) and sequence analysis. Of 88 fecal specimens from infants with acute gastroenteritis, 51.1% (45) were found to be positive for diarrheal viruses. Astrovirus was the most prevalent (15.9%, 14 of 88), followed by norovirus GII (14.8%, 13 of 88), adenovirus (12.5%, 11 of 88), and sapovirus (2.3%, 2 of 88). Viral mixed infection accounted for 5.7% (5 of 88). Interestingly, 230 of 833 (27.6%) fecal specimens collected from asymptomatic infants were also infected with diarrheal viruses. Of these, astrovirus, norovirus GII, adenovirus and sapovirus were identified in 53, 46, 96 and 22 fecal specimens (23%, 20%, 41.7%, and 9.6%, respectively). Moreover, 13 of 833 (1.6%) normal specimens showed mixed viral infections. Surprisingly, no rotavirus (known as the most common causative agent of acute gastroenteritis in DCCs) was detected in those subjects. Another interesting feature was the demonstration of five separate outbreaks of acute gastroenteritis identified in a single DCC. Outbreak A was associated with both astrovirus serotype 1 and norovirus GII/3 (known as Toronto virus cluster); Outbreak B with adenovirus 12; Outbreak C with norovirus GII/4 (Lordsdale virus cluster); Outbreak D with sapovirus GIV and Outbreak E with astrovirus serotype 1. To our knowledge, this is the first proof of multiple outbreaks of viral gastroenteritis in Japanese infants in a single DCC. Our results confirm the presence as well as the importance of these viruses and warn of the threat they pose.

Etiologic agents of acute gastroenteritis among Japanese infants and children: virus diversity and genetic analysis of sapovirus

A total of 371 fecal specimens from infants and children with acute gastroenteritis in Maizuru, Tokyo and Osaka, Japan from July 2002 to June 2003 were tested for the presence of diarrheal viruses by reverse transcription-polymerase chain reaction (RT-PCR), reverse passive hemagglutination (PRHA), RNA-polyacrylamide gel electrophoresis (PAGE), latex agglutination and sequence analysis methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (42.2%) followed by norovirus (28.9%), group C rotavirus (8.4%), sapovirus (6.7%), adenovirus (5.3%) and astrovirus (0.9%), respectively. There was the high rate (7.6%) of viral mixed infections. Sapovirus was classified into 6 genotypes (GI/1, GI/4, GI/5, GI/6 and GII/1 and one novel tentatively called GII/5). It is noteworthy that genogroup II sapovirus can be classified into 5 genotypes. Our findings confirmed the presence of many diarrheal viruses co-circulating among Japanese infants and children and showed the great genetic diversity among sapoviruses.

A novel RT-multiplex PCR for enteroviruses, hepatitis A and E viruses and influenza A virus among infants and children with diarrhea in Vietnam

A novel reverse transcription-multiplex polymerase chain reaction (RT-multiplex PCR) assay that can detect enteroviruses, hepatitis A and E viruses and influenza A virus from various hosts (avian species, human, swine and horse) was developed. The identification of that group of viruses was performed with the mixture of four pairs of published specific primers (F1 and R1, P3 and P4, 2s and 2as, MMU42 and MMU43) for amplifying viral genomes and specifically generated four different amplicon sizes of 440, 267, 146 and 219 bp for enteroviruses, hepatitis A and E viruses and influenza A virus, respectively. A total of 276 fecal specimens (previously screened for rotavirus, adenovirus, norovirus, sapovirus and astrovirus-negative) from infants and children admitted into hospital with acute gastroenteritis in Ho Chi Minh city, Vietnam during October 2002 and September 2003 were collected and further tested for the presence of those viruses by RT-multiplex PCR. Enteroviruses were identified in 27 specimens and this represented 9.8%. No hepatitis A and E viruses and influenza A virus was found among these subjects. The sensitivity and specificity of RT-multiplex PCR were also assessed and demonstrated the strong validation against RT-monoplex PCR. Taken together, the findings clearly indicated that this novel RT-multiplex PCR is a simple and potential assay for rapid, sensitive, specific and cost-effective laboratory diagnosis to investigate molecular epidemiology of acute gastroenteritis caused by enteroviruses, hepatitis A and E viruses and influenza A virus. This report is the first, to our knowledge, detecting these kinds of viruses in diarrheal feces from infants and children in Vietnam.

Genetic diversity of sapovirus in fecal specimens from infants and children with acute gastroenteritis in Pakistan

A total of 517 fecal specimens collected from infants and children with acute gastroenteritis in Karachi city, Pakistan during 1990-1994 were examined for the presence of sapovirus by RT-PCR and sequence analysis methods. Sapovirus was identified in 17 of 517 (3.2%) specimens. Sapovirus was further clustered into three distinct genogroups (I, II and IV) and these presented 70.6%, 23.5% and 5.9%, respectively. Our results clearly indicated that sapovirus could be classified into 7 GI and 4 GII genotypes. It was noteworthy to point out that sapovirus detected among Pakistani infants and children with acute gastroenteritis demonstrated the great genetic diversity and presented novel sapovirus genotypes.