Ultraviolet-radiation-induced damage to and aggregation of human lens crystallin proteins are thought to be a significant pathway to age-related cataract. The aromatic residues within the duplicated Greek key domains of γ-and β-crystallins are the main ultraviolet absorbers and are susceptible to direct and indirect ultraviolet damage. The previous site-directed mutagenesis studies have revealed a striking difference for two highly conserved homologous β-hairpin Tyr pairs, at the N-terminal domain (N-td) and C-terminal domain (C-td) respectively, in their contribution to the overall stability of HγD-Crys, but why they behave so differently still remains a mystery. In this paper, we systematically investigated the underlying molecular mechanism and detailed contributions of these two Tyr pairs with large scale molecular dynamics simulations. A series of different tyrosine-to-alanine pair(s) substitutions were performed in either the N-td, the C-td, or both. Our results suggest that the Y45A/Y50A pair substitution in the N-td mainly affects the stability of the N-td itself, while the Y133A/Y138A pair substitution in the C-td leads to a more cooperative unfolding of both N-td and C-td. The stability of motif 2 in the N-td is mainly determined by the interdomain interface, while motif 1 in the N-td or motifs 3 and 4 in the C-td are mainly stabilized by the intradomain hydrophobic core. The damage to any tyrosine pair(s) can directly introduce some apparent water leakage to the hydrophobic core at the interface, which in turn causes a serious loss in stability of the N-td. However, for the C-td substitutions, it may further impair the stable “sandwich-like” Y133-R167-Y138 cluster (through cation-π interactions) in the wild-type, thus causing the loop regions near the residue A138 to undergo large fluctuations, which in turn results in the intrusion of water into the hydrophobic core of the C-td and induces the C-td to lose its stability. These findings help resolve the “mystery” on why these two Tyr pairs display such a striking difference in their contributions to the overall protein stability despite their highly homologous nature.
γD-Crystallins; Cataract; Ultraviolet radiation; Tyrosine; Alanine; Protein unfolding; Molecular dynamics; Hydrophobic interactions; Ophthalmic disease
Massively parallel sequencing (MPS) technologies have the capacity to sequence targeted regions or whole genomes of multiple nucleic acid samples with high coverage by sequencing millions of DNA fragments simultaneously. Compared with Sanger sequencing, MPS also can reduce labor and cost on a per nucleotide basis and indeed on a per sample basis. In this study, whole genomes of human mitochondria (mtGenome) were sequenced on the Personal Genome Machine (PGMTM) (Life Technologies, San Francisco, CA), the out data were assessed, and the results were compared with data previously generated on the MiSeqTM (Illumina, San Diego, CA). The objectives of this paper were to determine the feasibility, accuracy, and reliability of sequence data obtained from the PGM.
24 samples were multiplexed (in groups of six) and sequenced on the at least 10 megabase throughput 314 chip. The depth of coverage pattern was similar among all 24 samples; however the coverage across the genome varied. For strand bias, the average ratio of coverage between the forward and reverse strands at each nucleotide position indicated that two-thirds of the positions of the genome had ratios that were greater than 0.5. A few sites had more extreme strand bias. Another observation was that 156 positions had a false deletion rate greater than 0.15 in one or more individuals. There were 31-98 (SNP) mtGenome variants observed per sample for the 24 samples analyzed. The total 1237 (SNP) variants were concordant between the results from the PGM and MiSeq. The quality scores for haplogroup assignment for all 24 samples ranged between 88.8%-100%.
In this study, mtDNA sequence data generated from the PGM were analyzed and the output evaluated. Depth of coverage variation and strand bias were identified but generally were infrequent and did not impact reliability of variant calls. Multiplexing of samples was demonstrated which can improve throughput and reduce cost per sample analyzed. Overall, the results of this study, based on orthogonal concordance testing and phylogenetic scrutiny, supported that whole mtGenome sequence data with high accuracy can be obtained using the PGM platform.
radiation (UVR) exposure is a major risk factor for
age-related cataract, a protein-aggregation disease of the human lens
often involving the major proteins of the lens, the crystallins. γD-Crystallin
(HγD-Crys) is abundant in the nucleus of the human lens, and
its folding and aggregation have been extensively studied. Previous
work showed that HγD-Crys photoaggregates in vitro upon exposure
to UVA/UVB light and that its conserved tryptophans are not required
for aggregation. Surprisingly, the tryptophan residues play a photoprotective
role because of a distinctive energy-transfer mechanism. HγD-Crys
also contains 14 tyrosine residues, 12 of which are organized as six
pairs. We investigated the role of the tyrosines of HγD-Crys
by replacing pairs with alanines and monitoring photoaggregation using
light scattering and SDS-PAGE. Mutating both tyrosines in the Y16/Y28
pair to alanine slowed the formation of light-scattering aggregates.
Further mutant studies implicated Y16 as important for photoaggregation.
Mass spectrometry revealed that C18, in contact with Y16, is heavily
oxidized during UVR exposure. Analysis of multiple mutant proteins
by mass spectrometry suggested that Y16 and C18 likely participate
in the same photochemical process. The data suggest an initial photoaggregation
pathway for HγD-Crys in which excited-state Y16 interacts with
C18, initiating radical polymerization.
Advances in electron cryo-tomography open up a new avenue to visualize the 3-D internal structure of a single bacterium before and after its infection by bacteriophages in its native environment, without using chemical fixatives, fluorescent dyes or negative stains. Such direct observation reveals the presence of assembly intermediates of the bacteriophage and thus allows us to map out the maturation pathway of the bacteriophage inside its host.
electron cryo-tomography; Zernike phase optics; marine cyanobacterium; phage assembly intermediates; transient biological processes; 3-D structures
The efficacy, acceptability and tolerability of the new oral phosphate binder Lenziaren® (SBR759) were evaluated in a randomized parallel-group design study in 36 healthy cats (n = 6 per group). Five groups were fed once daily with a commercial diet containing 0.2% phosphorus (“standard diet”) into which was mixed Lenziaren® at 0.25, 0.5, 1.0 or 2.0 g/day or no treatment (control group) daily for 30 days. A sixth group was fed a commercial diet containing lower amounts (0.12%) of phosphorus (“renal diet”) and no treatment.
When compared to the control group, Lenziaren® produced significant dose-related reductions in urine phosphate concentrations, urine phosphate excretion and fractional urinary phosphate excretion. Significant effects versus the control group were observed at the 0.5, 1.0 and 2.0 g/day dosages. Lenziaren® was well tolerated and was associated with higher food consumption and serum iron concentrations versus the control.
When compared to the control group, the renal diet was associated with significantly lower urine phosphate concentrations and loss of body weight. Lenziaren® had similar effects on urine phosphate concentrations compared to the renal diet, but was not associated with loss of body weight.
Lenziaren® was effective as an oral phosphate binder in cats fed with a standard diet containing 0.2% phosphorus. The acceptability and tolerability were good. Dosages of 0.5-1.0 g/cat per day are recommended for clinical testing in cats fed with a standard diet.
Cat; Lenziaren; Phosphate; Phosphate binder; SBR759
The marine cyanophage Syn5 can be propagated to a high titer in the laboratory on marine photosynthetic Synechococcus sp. strain WH8109. The purified particles carry a novel slender horn structure projecting from the vertex opposite the tail vertex. The genome of Syn5 includes a number of genes coding for novel proteins. Using immune-electron microscopy with gold-labeled antibodies, we show that two of these novel proteins, products of genes 53 and 54, are part of the horn structure. A third novel protein, the product of gene 58, is assembled onto the icosahedral capsid lattice. Characterization of radioactively labeled precursor procapsids by sucrose gradient centrifugation shows that there appear to be three classes of particles—procapsids, scaffold-deficient procapsids, and expanded capsids. These lack fully assembled horn appendages. The horn presumably assembles onto the virion just before or after DNA packaging. Antibodies raised to the recombinant novel Syn5 proteins did not interfere with phage infectivity, suggesting that the functions of these proteins are not directly involved in phage attachment or infection of the host WH8109. The horn structure may represent some adaption to the marine environment, whose function will require additional investigation.
To determine the effects of cognitive training on cognitive abilities and everyday function over 10 years.
Design, Setting, and Participants
Ten-year follow-up of a randomized, controlled single-blind trial with 3 intervention groups and a no-contact control group. A volunteer sample of 2832 persons (mean baseline age, 73.6 years; 26% African American) living independently in 6 US cities.
Ten-session training for memory, reasoning, or speed-of-processing.; 4-session booster training at 11 and at 35 months after training.
Objectively measured cognitive abilities and self-reported and performance-based measures of everyday function.
Participants in each intervention group reported less difficulty with instrumental activities of daily living (IADL) (memory: effect size, 0.48 [99% CI, 0.12-0.84]; reasoning: effect size, 0.38 [99% CI, 0.02-0.74]; speed-of-processing: effect size, 0.36 [99% CI, 0.01-0.72]). At mean age of 82 years, about 60% of trained participants compared to 50% of controls (p<.05) were at or above their baseline level of self-reported IADL function at 10 years. The reasoning and speed-of-processing interventions maintained their effects on their targeted cognitive abilities at 10 years (reasoning: effect size, 0.23 [99% CI, 0.09-0.38]; speed-of-processing: effect size, 0.66 [99% CI, 0.43-0.88]). Memory training effects were no longer maintained for memory performance. Booster training produced additional and durable improvement for the reasoning intervention for reasoning performance (effect size, 0.21 [99% CI, 0.01-0.41]) and the speed-of-processing intervention for speed-of-processing performance (effect size, 0.62 [99% CI, 0.31-0.93]).
Each ACTIVE cognitive intervention resulted in less decline in self-reported IADL compared with the control group. Reasoning and speed, but not memory, training resulted in improved targeted cognitive abilities for 10 years.
cognitive training; elderly; cognitive abilities; everyday function; training maintenance
Sphingosine-1-phosphate (S1P) is a cardioprotective agent. Signal transducer and activator of transcription 3 (STAT-3) is a key mediator of many cardioprotective agents. We aimed to explore whether STAT-3 is a key mediator in S1P-induced preconditioning.
Langendorff-perfused hearts from Wistar rats and wild-type or cardiomyocyte-specific STAT-3 knockout mice were pre-treated with S1P (10 nmol/l), with or without the STAT-3 pathway inhibitor AG490, before an ischaemia–reperfusion insult. Triphenyltetrazolium chloride and Evans blue staining were used for the determination of infarct size. Western blot analysis was carried out on the S1P pre-treated hearts for detection of cytosolic, nuclear and mitochondrial phosphorylated and total STAT-3 proteins.
Pre-treatment with S1P decreased the infarct size in isolated rat (5 ± 3% vs control 26 ± 8%, p < 0.01) and wild-type mouse hearts (13 ± 1% vs control 33 ± 3%, p < 0.05). This protective effect was abolished in the rat hearts pre-treated with AG490 (30 ± 10%, p = ns vs control) and in the hearts from STAT-3 knockout mice (35 ± 4% vs control 30 ± 3%, p = ns). Levels of phosphorylated STAT-3 were significantly increased in both the nuclear (p < 0.05 vs control) and mitochondrial (p < 0.05 vs control) fractions in the S1P pre-treated hearts, but remained unchanged in the cytosolic fraction (p = ns vs control).
These novel results demonstrate that pharmacological preconditioning with S1P in the isolated heart is mediated by activation of mitochondrial and nuclear STAT-3, therefore suggesting that S1P may be a novel therapeutic target to modulate mitochondrial and nuclear function in cardiovascular disease in order to protect the heart against ischaemia–reperfusion.
STAT-3; cardioprotection; preconditioning; sphingosine-1-phosphate; myocardial infarction
Cyanobacteria are photosynthetic organisms responsible for ~25% of organic carbon fixation on earth. These bacteria began to convert solar energy and carbon dioxide into bioenergy and oxygen billions of years ago. Cyanophages, which infect these bacteria, play an important role in regulating the marine ecosystem by controlling cyanobacteria community organization and mediating lateral gene transfer. Here we visualize the maturation process of cyanophage Syn5 inside its host cell, Synechococcus, using Zernike Phase Contrast (ZPC) electron cryo-tomography (cryoET)1,2. This imaging modality yields significant enhancement of image contrast over conventional cryoET and thus facilitates the direct identification of subcellular components, including thylakoid membranes, carboxysomes and polyribosomes, as well as phages, inside the congested cytosol of the infected cell. By correlating the structural features and relative abundance of viral progeny within cells at different stages of infection, we identified distinct Syn5 assembly intermediates. Our results suggest that the procapsid releases scaffolding proteins and expands its volume at an early stage of genome packaging. Later in assembly, we detected full particles with a tail either with or without an additional horn. The morphogenetic pathway we describe herein is highly conserved and was probably established long before that of double stranded DNA (dsDNA) viruses infecting higher life forms.
To eliminate blinding trachoma, the World Health Organization emphasizes implementing the SAFE strategy, which includes annual mass drug administration (MDA) with azithromycin to the whole population of endemic districts. Prevalence surveys to assess impact at the district level are recommended after at least 3 years of intervention. The decision to stop MDA is based on a prevalence of trachomatous inflammation follicular (TF) among children aged 1–9 years below 5% at the sub-district level, as determined by an additional round of surveys limited within districts where TF prevalence is below 10%. We conducted impact surveys powered to estimate prevalence simultaneously at the sub-district and district in two zones of Amhara, Ethiopia to determine whether MDA could be stopped.
Seventy-two separate population-based, sub-district surveys were conducted in 25 districts. In each survey all residents from 10 randomly selected clusters were screened for clinical signs of trachoma. Data were weighted according to selection probabilities and adjusted for correlation due to clustering.
Overall, 89,735 residents were registered from 21,327 households of whom 72,452 people (80.7%) were examined. The prevalence of TF in children aged 1–9 years was below 5% in six sub-districts and two districts. Sub-district level prevalence of TF in children aged 1–9 years ranged from 0.9–76.9% and district-level from 0.9–67.0%. In only one district was the prevalence of trichiasis below 0.1%.
The experience from these zones in Ethiopia demonstrates that impact assessments designed to give a prevalence estimate of TF at sub-district level are possible, although the scale of the work was challenging. Given the assessed district-level prevalence of TF, sub-district-level surveys would have been warranted in only five districts. Interpretation was not as simple as stopping MDA in sub-districts below 5% given programmatic challenges of exempting sub-districts from a highly regarded program and the proximity of hyper-endemic sub-districts.
Trachoma, the leading cause of preventable blindness, is targeted for “elimination as a public health problem” by the year 2020. National programs are implementing the recommended strategy of surgery, antibiotics, facial cleanliness, and environmental improvements (SAFE) to meet this target. Many programs are currently facing the decision of when to scale down interventions, particularly mass drug administration (MDA) of azithromycin. We implemented large population-based surveys in two different zones of the Amhara National Regional State of Ethiopia. Rather than conducting an impact assessment first at the district level, followed by additional sub-district-level surveys, we took a novel approach to measure the prevalence of trachoma at sub-district level to be able to make an immediate decision of whether to stop MDA. Over 72,000 people in 714 communities in 72 sub-districts were examined for clinical signs of trachoma. We identified only six sub-districts that met criteria for being able to stop MDA. Our work demonstrates that determining the prevalence of trachoma at sub-district level is feasible but requires significant resources. In this hyper-endemic setting, sub-district-level surveys were not needed in the majority of districts. Overall, the clinical data suggest some decline in trachoma within these areas since the SAFE strategy was implemented.
Cognition is 1 of 4 domains measured by the NIH Toolbox for the Assessment of Neurological and Behavioral Function (NIH-TB), and complements modules testing motor function, sensation, and emotion. On the basis of expert panels, the cognition subdomains identified as most important for health, success in school and work, and independence in daily functioning were Executive Function, Episodic Memory, Language, Processing Speed, Working Memory, and Attention. Seven measures were designed to tap constructs within these subdomains. The instruments were validated in English, in a sample of 476 participants ranging in age from 3 to 85 years, with representation from both sexes, 3 racial/ethnic categories, and 3 levels of education. This report describes the development of the Cognition Battery and presents results on test-retest reliability, age effects on performance, and convergent and discriminant construct validity. The NIH-TB Cognition Battery is intended to serve as a brief, convenient set of measures to supplement other outcome measures in epidemiologic and longitudinal research and clinical trials. With a computerized format and national standardization, this battery will provide a “common currency” among researchers for comparisons across a wide range of studies and populations.
Preventive chemotherapy with praziquantel is recommended in adults by the World Health Organization when prevalence of schistosomiasis in school-aged children (SAC) is ≥ 50%. This study ascertained the value of this threshold in predicting prevalence and intensity of Schistosoma hematobium (SH) infection in adults in central Nigeria. We evaluated urogenital schistosomiasis prevalence in 1,164 adults: 659 adults in 12 communities where mean hematuria among SAC in 2008 was 26.6% and 505 adults in 7 communities where the mean hematuria among SAC in 2008 was 70.4%. No statistically significant differences were found between the two groups of adults in prevalence of hematuria, prevalence of SH eggs, or intensity of infections. We conclude that, in this setting, the SAC threshold is not useful for treatment decisions in adults. Given the increased risk of subtle morbidity or urogenital schistosomiasis as a risk factor for human immunodeficiency virus (HIV), more liberal treatment of adults with praziquantel is warranted.
The flavonoid quercetin holds promise as an anti-tumor agent in several preclinical animal models. However, the efficacy of oral administration of quercetin in a pancreatic cancer mouse model is unknown.
The anti-proliferative effects of quercetin alone or in combination with gemcitabine were tested in two human pancreatic cancer cell lines using cell count and MTT assays. Apoptosis was evaluated by flow cytometry. Tumor growth in vivo was investigated in an orthotopic pancreatic cancer animal model using bioluminescence. Quercetin was administered orally in the diet.
Quercetin inhibited the growth of pancreatic cancer cell lines, which was caused by an induction of apoptosis. In addition, dietary supplementation of quercetin attenuated the growth of orthotopically transplanted pancreatic xenografts. The combination of gemcitabine and quercetin had no additional effect compared to quercetin alone. In vivo quercetin caused significant apoptosis and reduced tumor cell proliferation.
Our data provide evidence that oral administration of quercetin was capable of inhibiting growth of orthotopic pancreatic tumors in a nude mouse model. These data suggest a possible benefit of quercetin in patients with pancreatic cancer.
Pancreatic cancer; apoptosis; quercetin; orthotopic animal model; bioluminescence
Giant abdominal wall hernias represent a major challenge to the hernia surgeon in practice today. Of the common abdominal wall hernias, those located in the subcostal region are among the most difficult to repair, and have historically been plagued by higher recurrence rates than other locations, such as the midline. No technique has been identified as the clearly superior choice for hernias of this type.
We report a successful repair of a giant, multiply recurrent subcostal hernia with loss of domain in a 45-year-old obese Caucasian man. This was accomplished in a novel fashion, using a porcine acellular dermal matrix (Strattice™) as the floor of the repair, which was fixed to the costal margin using orthopedic bone anchors (Mitek™), then covered with a pedicled omental flap to eliminate dead space and facilitate a more rapid revascularization of the porcine acellular dermal matrix implant.
This case emphasizes the need for a thorough understanding of the challenges of the specific type of hernia defect encountered, as well as knowledge of any available techniques that may be adjunctively employed to enhance the chances of achieving a successful result.
Subcostal; Hernia; Omental flap; Porcine acellular dermal matrix; Strattice
Retroperitoneal angiomyolipoma is a rare tumour that is difficult to diagnose preoperatively. We present a case of retroperitoneal angiomyolipoma that highlights its diagnostic dilemma. We also performed a literature review and present a review of retroperitoneal angiomyolipoma.
Tobacco-derived carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, NNK, activates β-adrenergic receptor (β-AR) signaling through Src/focal adhesion kinases (FAK)/MAPK to modulate proliferation, migration and survival. Apigenin (4′, 5, 7-trihydroxyflavone) is reported to attenuate proliferation and migration of cancer cells. This study was designed to determine the effects of apigenin on NNK-induced pro-carcinogenesis using human pancreatic cancer cells BxPC-3 and MIA PaCa-2 that express β-AR.
Proliferation and migration were assessed by standard MTT and scratch assays. β-AR, FAK/MAPK and ERK expression and activation were assessed by Western blotting and real time PCR.
NNK caused a dose- and time-dependent increase in BxPC-3 and MIA PaCa-2 cell proliferation that was inhibited by propranolol or apigenin. NNK also stimulated a time-dependent increase in FAK and ERK activation that was suppressed by propranolol or apigenin. NNK-enhanced gap closure at 24 hr was prevented by either propranolol or apigenin.
Apigenin suppressed the effects of NNK on pancreatic cancer cell proliferation and migration that are mediated through the β-AR and its downstream signals FAK and ERK activation. These findings suggest a therapeutic role for this natural phytochemical in attenuating the pro-carcinogenic effects of NNK on pancreatic cancer proliferation and migration.
apigenin; propranolol; NNK; FAK; smoking; pancreatic cancer
Large cross-sectional household surveys are common for measuring indicators of neglected tropical disease control programs. As an alternative to standard paper-based data collection, we utilized novel paperless technology to collect data electronically from over 12,000 households in Ethiopia.
We conducted a needs assessment to design an Android-based electronic data collection and management system. We then evaluated the system by reporting results of a pilot trial and from comparisons of two, large-scale surveys; one with traditional paper questionnaires and the other with tablet computers, including accuracy, person-time days, and costs incurred.
The electronic data collection system met core functions in household surveys and overcame constraints identified in the needs assessment. Pilot data recorders took 264 (standard deviation (SD) 152 sec) and 260 sec (SD 122 sec) per person registered to complete household surveys using paper and tablets, respectively (P = 0.77). Data recorders felt a lack of connection with the interviewee during the first days using electronic devices, but preferred to collect data electronically in future surveys. Electronic data collection saved time by giving results immediately, obviating the need for double data entry and cross-correcting. The proportion of identified data entry errors in disease classification did not differ between the two data collection methods. Geographic coordinates collected using the tablets were more accurate than coordinates transcribed on a paper form. Costs of the equipment required for electronic data collection was approximately the same cost incurred for data entry of questionnaires, whereas repeated use of the electronic equipment may increase cost savings.
Conducting a needs assessment and pilot testing allowed the design to specifically match the functionality required for surveys. Electronic data collection using an Android-based technology was suitable for a large-scale health survey, saved time, provided more accurate geo-coordinates, and was preferred by recorders over standard paper-based questionnaires.
Archaeal and eukaryotic cytosols contain group II chaperonins, which have a double-barrel structure and fold proteins inside a cavity in an ATP-dependent manner. The most complex of the chaperonins, the eukaryotic TCP-1 ring complex (TRiC), has eight different subunits, chaperone containing TCP-1 (CCT1–8), that are arranged so that there is one of each subunit per ring. Aspects of the structure and function of the bovine and yeast TRiC have been characterized, but studies of human TRiC have been limited. We have isolated and purified endogenous human TRiC from HeLa suspension cells. This purified human TRiC contained all eight CCT subunits organized into double-barrel rings, consistent with what has been found for bovine and yeast TRiC. The purified human TRiC is active as demonstrated by the luciferase refolding assay. As a more stringent test, the ability of human TRiC to suppress the aggregation of human γD-crystallin was examined. In addition to suppressing off-pathway aggregation, TRiC was able to assist the refolding of the crystallin molecules, an activity not found with the lens chaperone, α-crystallin. Additionally, we show that human TRiC from HeLa cell lysate is associated with the heat shock protein 70 and heat shock protein 90 chaperones. Purification of human endogenous TRiC from HeLa cells will enable further characterization of this key chaperonin, required for the reproduction of all human cells.
TRiC; CCT; Chaperonin; Crystallin; Protein folding
An average of six annual rounds of ivermectin and albendazole were distributed in Plateau and Nasarawa States, Nigeria, to eliminate lymphatic filariasis. From 2007 to 2008, population-based surveys were implemented in all 30 local government areas (LGAs) of the two states to determine the prevalence of Wuchereria bancrofti antigenemia to assess which LGA mass drug administration (MDA) could be halted. In total, 36,681 persons from 7,819 households were examined for filarial antigen as determined by immunochromatographic card tests. Overall antigen prevalence was 3.05% (exact upper 95% confidence interval [CI] = 3.41%) with an upper 95% CI range by LGA of 0.50–19.3%. Among 3,233 children 6–7 years of age, overall antigen prevalence was 1.71% (exact upper 95% CI = 2.19%), too high to recommend generally halting MDA in the two-state area. However, based on criteria of < 2% antigenemia among persons > 2 years of age, stopping MDA was recommended for 10 LGAs.
Cataract affects 1 in 6 Americans over the age of 40, and is considered a global health problem. Cataract is caused by the aggregation of unfolded or damaged proteins in the lens, which accumulate as an individual ages. Currently, surgery is the only available treatment for cataract, however, small molecules have been suggested as potential preventative therapies. In this work, we study the effect of sodium citrate on the stability of Human γD Crystallin (HγD-Crys), a structural protein of the eye lens, and two cataract-related mutants, L5S HγD-Crys and I90F HγD-Crys. In equilibrium unfolding-refolding studies, the presence of 250 mM sodium citrate increased the transition midpoint of the N-td of WT HγD-Crys and L5S HγD-Crys by 0.3 M GuHCl, the C-td by 0.6M GuHCl, and the single transition of I90F HγD-Crys by 0.4M GuHCl. In kinetic unfolding reactions, sodium citrate demonstrates a measurable stabilization effect only for the mutant I90F HγD-Crys. In the presence of citrate, a kinetic unfolding intermediate of I90F HγD-Crys can be observed, which was not observed in the absence of citrate. Rate of aggregation was measured using solution turbidity, and sodium citrate demonstrates negligible effect on rate of aggregation of WT HγD-Crys, but considerably slows the rate of aggregation of both L5S HγD-Crys and I90F HγD-Crys. The presence of sodium citrate dramatically slows refolding of WT HγD-Crys and I90F HγD-Crys, but has a significantly smaller effect on the refolding of L5S HγD-Crys. The differential stabilizing effect of sodium citrate suggests that the ion is binding to a partially unfolded conformation of the C-td, but a solution-based Hofmeister effect cannot be eliminated as a possible explanation for the effects observed. These results suggest that sodium citrate may be a potential preventative agent for cataract.
crystallin; protein folding; aggregation; citrate; stability
Systematic cognitive training produces long-term improvement in cognitive function and less difficulty in performing activities of daily living. We examined whether cognitive training was associated with reduced rate of incident dementia. Participants were from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (n=2,802). Incident dementia was defined using a combination of interview- and performance-based methods. Survival analysis was used to determine if ACTIVE treatment affected the rate of incident dementia during 5 years of follow-up. A total of 189 participants met criteria for incident dementia. Baseline factors predictive of incident dementia were older age, male gender, African American race, fewer years of education, relationship other than married, no alcohol use, worse MMSE< worse SF-36 physical functioning, higher depressive symptomatology, diabetes, and stroke (all p<.05). A multivariable model with significant predictors of incident dementia and training group revealed that cognitive training was not associated with a lower rate of incident dementia. Cognitive training did not affect rates of incident dementia after 5 years of follow-up. Longer follow-up or enhanced training may be needed to fully explore the preventive capacity of cognitive training in forestalling onset of dementia.
Cognitive training; Intervention; Aging; Dementia; Prevention; Cognition
Surgery to correct trachomatous trichiasis (TT) is recommended to prevent blindness caused by trachoma. This study evaluated the outcomes of community-based trichiasis surgery with absorbable sutures, conductd in Amhara Regional State, Ethiopia.
A simple random sample of 431 patients was selected from surgical campaign records of which 363 (84.2%) were traced and enrolled into the study. Participants were interviewed and examined for trichiasis recurrence, complications of TT surgery and corneal opacity. Multilevel logistic regression models were used to explore the associations between trichiasis recurrence, corneal opacity and explanatory variables at the eye level.
The prevalence of trichiasis recurrence was 9.4% (95% Confidence Interval [CI] 6.6–12.8) and corneal opacity was found in 14.3% (95% CI 10.9–18.3) of the study participants. The proportion of participants with complications of TT surgery was: granuloma 0.6% (95% CI 0.1–2.0); lid closure defects 5.5% (95% CI 3.4–8.4) and lid notching 16.8% (95% CI 13.1–21.1). No factors were identified for trichiasis recurrence. Corneal opacity was associated with increased age (Ptrend=0.001), more than 12 months post surgery (OR=2.7; 95%CI 1.3–5.6), trichiasis surgery complications (OR=2.9; 95%CI 1.4–5.9) and trichiasis recurrence (OR=2.5; 95%CI 1.0–6.3).
Prevalence of recurrent trichiasis and granuloma were lower than expected but higher for lid closure defects and lid notching. The majority of the participants reported satisfaction with the trichiasis surgery they had undergone. The findings suggest that recurrence of trichiasis impacts on the patients' risk of developing corneal opacity but longitudinal studies are required to confirm this.
Corneal opacity; Trichiasis; Trichiasis recurrence; Ethiopia
The SAFE strategy aims to reduce transmission of Chlamydia trachomatis through antibiotics, improved hygiene, and sanitation. We integrated assessment of intestinal parasites into large-scale trachoma impact surveys to determine whether documented environmental improvements promoted by a trachoma program had collateral impact on intestinal parasites.
We surveyed 99 communities for both trachoma and intestinal parasites (soil-transmitted helminths, Schistosoma mansoni, and intestinal protozoa) in South Gondar, Ethiopia. One child aged 2–15 years per household was randomly selected to provide a stool sample of which about 1 g was fixed in sodium acetate-acetic acid-formalin, concentrated with ether, and examined under a microscope by experienced laboratory technicians.
A total of 2,338 stool specimens were provided, processed, and linked to survey data from 2,657 randomly selected children (88% response). The zonal-level prevalence of Ascaris lumbricoides, hookworm, and Trichuris trichiura was 9.9% (95% confidence interval (CI) 7.2–12.7%), 9.7% (5.9–13.4%), and 2.6% (1.6–3.7%), respectively. The prevalence of S. mansoni was 2.9% (95% CI 0.2–5.5%) but infection was highly focal (range by community from 0–52.4%). The prevalence of any of these helminth infections was 24.2% (95% CI 17.6–30.9%) compared to 48.5% as found in a previous study in 1995 using the Kato-Katz technique. The pathogenic intestinal protozoa Giardia intestinalis and Entamoeba histolytica/E. dispar were found in 23.0% (95% CI 20.3–25.6%) and 11.1% (95% CI 8.9–13.2%) of the surveyed children, respectively. We found statistically significant increases in household latrine ownership, use of an improved water source, access to water, and face washing behavior over the past 7 years.
Improvements in hygiene and sanitation promoted both by the SAFE strategy for trachoma and health extension program combined with preventive chemotherapy during enhanced outreach services are plausible explanations for the changing patterns of intestinal parasite prevalence. The extent of intestinal protozoa infections suggests poor water quality or unsanitary water collection and storage practices and warrants targeted intervention.
Part of the SAFE strategy (surgery, antibiotics, facial cleanliness, and environmental improvement) to eliminate blinding trachoma involves improving access to, and use of, water and sanitation. We combined the assessment of parasitic worm and intestinal protozoa infections with surveys of trachoma in an area of Ethiopia where the SAFE strategy, together with enhanced outreach services and the health extension program, had been implemented for more than 5 years. We compared our findings with results from a survey conducted in the mid-1990s. We documented significant increases in household access and use of latrines and clean water: the F and E components of the SAFE strategy as promoted by the health extension program. We found considerably lower levels of parasitic worm infections than those reported previously. Moreover, we documented, for the first time in this zone, pathogenic intestinal protozoa infections, which indicate poor water quality and unhygienic water collection and storage practices in the communities surveyed. A plausible hypothesis for the decline in parasitic worm infections might be the combined impact of ongoing simultaneous health programs: SAFE strategy for trachoma control alongside the health extension program and regular deworming of preschool-aged children.