Explicit state duration HMM for abnormality detection in sequences of human activity

The importance of explicit duration modelling for classification of sequences of human activity and the reliable and timely detection of duration abnormality was highlighted. The normal classes of behavior were designed to highlight the importance of modelling duration given the limitations of the tracking system. It was found that HMM was the weakest model for classification of the unseen normal sequences with 81% accuracy. Long term abnormality was investigated by artificially varying the duration of primary activity in a randomly selected test sequence. The incorporation of duration in models of human behavior is an important consideration for systems seeking to provide cognitive support and to detect deviation in the behavorial patterns.

Towards detecting patterns of human behaviour from image sequences

This paper details research that will explore the analysis of human behaviour via video surveillance. Digital computer images will be obtained from video footage of a real world scene, and positions of people in the scene will be identified and tracked through each frame in the sequence.

The noted positions will build into a pattern of motion that can be examined and classified. It is proposed that specific events, such as panic or fight situations, will have unique, and therefore identifying, characteristics that will enable automatic detection of such events.

It is envisaged that active cameras will be used when a situation of interest occurs, to enable more information to be extracted from the scene (e.g., panning to follow action, or zooming to enhance detail.)

Amyloid formation results in recurrence of hyperglycaemia following transplantation of human IAPP transgenic mouse islets

Aims/hypothesis Islet transplantation is a potential cure for diabetes; however, rates of graft failure remain high. The aim of the present study was to determine whether amyloid deposition is associated with reduced beta cell volume in islet grafts and the recurrence of hyperglycaemia following islet transplantation.

Methods We transplanted a streptozotocin-induced mouse model of diabetes with 100 islets from human IAPP (which encodes islet amyloid polypeptide) transgenic mice that have the propensity to form islet amyloid (n = 8–12) or from non-transgenic mice that do not develop amyloid (n = 6–10) in sets of studies that lasted 1 or 6 weeks.

Results Plasma glucose levels before and for 1 week after transplantation were similar in mice that received transgenic or non-transgenic islets, and at that time amyloid was detected in all transgenic grafts and, as expected, in none of the non-transgenic grafts. However, over the 6 weeks following transplantation, plasma glucose levels increased in transgenic but remained stable in non-transgenic islet graft recipients (p < 0.05). At 6 weeks, amyloid was present in 92% of the transgenic grafts and in none of the non-transgenic grafts. Beta cell volume was reduced by 30% (p < 0.05), beta cell apoptosis was twofold higher (p < 0.05), and beta cell replication was reduced by 50% (p < 0.001) in transgenic vs non-transgenic grafts. In summary, amyloid deposition in islet grafts occurs prior to the recurrence of hyperglycaemia and its accumulation over time is associated with beta cell loss.

Conclusions/interpretation Islet amyloid formation may explain, in part, the non-immune loss of beta cells and recurrence of hyperglycaemia following clinical islet transplantation.

Effects of modifying the tRNA(3Lys) anticodon on the initiation of human immunodeficiency virus type 1 reverse transcription

tRNA(3Lys) is a primer for reverse transcription in human immunodeficiency virus type 1 (HIV-1), and the anticodon of tRNA(3Lys) has been implicated in playing a role in both its placement onto the HIV-1 genome and its interaction with HIV-1 reverse transcriptase (RT). In this work, the anticodon in a tRNA(3Lys) gene was changed from UUU to CUA (tRNA(3Lys)Su+) or, in addition, G-73 was altered to A (tRNA(3Lys)Su+G73A). COS-7 cells were transfected with either wild-type or mutant tRNA(3Lys) genes, and both the wild-type and mutant tRNA(3Lys) produced were purified by using immobilized tRNA-specific hybridization probes. Each mutant tRNA(3Lys) was tested for its ability to prime reverse transcription in vitro, either alone or in competition with wild-type tRNA(3Lys). Short RT extensions of wild-type and mutant tRNALys could be distinguished from each other by their different mobilities in one-dimensional single-stranded conformation polymorphism polyacrylamide gel electrophoresis. These reverse transcription products show that heat-annealed tRNA(3Lys)Su+ has the same ability as heat-annealed wild-type tRNA(3Lys) to prime RT and competes equally well with wild-type tRNA(3Lys) for priming RT. tRNA(3Lys)Su+G73A has 60% of the wild-type ability to prime RT but competes poorly with wild-type tRNA(3Lys) for priming RT. However, the priming abilities of wild-type and mutant tRNA(3) are quite different when in vivo-placed tRNA is examined. HIV-1 produced in COS cells transfected with a plasmid containing both the HIV-1 proviral DNA and DNA coding for tRNA(3Lys)Su+ contains both endogenous, cellular wild-type tRNA(3Lys) and mutant tRNA(3Lys). When total viral RNA is used as the source of primer tRNA placed onto the genomic RNA in vivo, only wild-type tRNA(3Lys) is used as a primer. If the total viral RNA is first heated and exposed to hybridizing conditions, then both the wild-type and mutant tRNA(3Lys) act as primers for RT. These results indicate that the tRNA(3Lys)Su+ packaged into the virions is unable to act as a primer for RT, and a model is proposed to explain the disparate results between heat-annealed and in vivo-placed primer tRNA.

Mutations in the kissing-loop hairpin of human immunodeficiency virus type 1 reduce viral infectivity as well as genomic RNA packaging and dimerization

A stem-loop termed the kissing-loop hairpin is one of the most highly conserved structures within the leader of human immunodeficiency virus type 1 (HIV-1) and chimpanzee immunodeficiency virus genomic RNA. Because it plays a key role in the in vitro dimerization of short HIV-1 RNA transcripts (M. Laughrea and L. Jette, Biochemistry 35:1589-1598, 1996, and references therein; M. Laughrea and L. Jette, Biochemistry 35:9366-9374, 1996, and references therein) and because dimeric RNAs may be preferably encapsidated into the HIV-1 virus, alterations of the kissing-loop hairpin might affect the in vivo dimerization and encapsidation processes. Accordingly, substitution and deletion mutations were introduced into the kissing-loop hairpin of an infectious HIV-1 molecular clone in order to produce viruses by transfection methods. The infectivity of the resulting viruses was decreased by at least 99%, the amount of genomic RNA packaged per virus was decreased by 50 to 75%, and the proportion of dimeric genomic RNA was reduced from >80 to 40 to 50%, but the dissociation temperature of the genomic RNA was unchanged. There is evidence suggesting that the deletion mutations moderately inhibited CAp24 production but had no significant effect on RNA splicing. These results are consistent with the kissing-loop model of HIV-1 RNA dimerization. In fact, because intracellular viral RNAs are probably more concentrated in transfected cells than in cells infected by one virus and because the dimerization and encapsidation processes are concentration dependent, it is likely that much larger dimerization and encapsidation defects would have been manifested within cells infected by no more than one virus.

The dimer initiation sequence stem-loop of human immunodeficiency virus type 1 is dispensable for viral replication in peripheral blood mononuclear cells

Human immunodeficiency virus type 1 (HIV-1) contains two copies of genomic RNA that are noncovalently linked via a palindrome sequence within the dimer initiation site (DIS) stem-loop. In contrast to the current paradigm that the DIS stem or stem-loop is critical for HIV-1 infectivity, which arose from studies using T-cell lines, we demonstrate here that HIV-1 mutants with deletions in the DIS stem-loop are replication competent in peripheral blood mononuclear cells (PBMCs). The DIS mutants contained either the wild-type (5′GCGCGC3′) or an arbitrary (5′ACGCGT3′) palindrome sequence in place of the 39-nucleotide DIS stem-loop (NLCGCGCG and NLACGCGT). These DIS mutants were replication defective in SupT1 cells, concurring with the current model in which DIS mutants are replication defective in T-cell lines. All of the HIV-1 DIS mutants were replication competent in PBMCs over a 40-day infection period and had retained their respective DIS mutations at 40 days postinfection. Although the stability of the virion RNA dimer was not affected by our DIS mutations, the RNA dimers exhibited a diffuse migration profile when compared to the wild type. No defect in protein processing of the Gag and GagProPol precursor proteins was found in the DIS mutants. Our data provide direct evidence that the DIS stem-loop is dispensable for viral replication in PBMCs and that the requirement of the DIS stem-loop in HIV-1 replication is cell type dependent.

Nef binds p6* in gagpol during replication of human immunodeficiency virus type 1

The atypical Nef protein (NefF12) from human immunodeficiency virus type 1 strain F12 (HIV-1F12) interferes with virion production and infectivity via a mysterious mechanism. The correlation of these effects with the unusual perinuclear subcellular localization of NefF12 suggested that the wild-type Nef protein could bind to assembly intermediates in late stages of viral replication. To test this hypothesis, Nef from HIV-1NL4-3 was fused to an endoplasmic reticulum (ER) retention signal (NefKKXX). This mutant NefKKXX protein recapitulated fully the effects of NefF12 on Gag processing and virion production, either alone or as a CD8 fusion protein. Importantly, the mutant NefKKXX protein also localized to the intermediate compartment, between the ER and the trans-Golgi network. Furthermore, Nef bound the GagPol polyprotein in vitro and in vivo. This binding mapped to the C-terminal flexible loop in Nef and the transframe p6* protein in GagPol. The significance of this interaction was demonstrated by a genetic assay in which the release of a mutant HIV-1 provirus lacking the PTAP motif in the late domain that no longer binds Tsg101 was rescued by a Nef.Tsg101 chimera. Importantly, this rescue as well as incorporation of Nef into HIV-1 virions correlated with the ability of Nef to interact with GagPol. Our data demonstrate that the retention of Nef in the intermediate compartment interferes with viral replication and suggest a new role for Nef in the production of HIV-1.

The raft-promoting property of virion-associated cholesterol, but not the presence of virion-associated brij 98 rafts, is a determinant of human immunodeficiency virus type 1 infectivity

Lipid rafts are enriched in cholesterol and sphingomyelin and are isolated on the basis of insolubility in detergents, such as Brij 98 and Triton X-100. Recent work by Holm et al. has shown that rafts insoluble in Brig 98 can be found in human immunodeficiency virus type 1 (HIV-1) virus-like particles, although it is not known whether raft-like structures are present in authentic HIV-1 and it is unclear whether a virion-associated raft-like structure is required for HIV replication. Independently, it was previously reported that virion-associated cholesterol is critical for HIV-1 infectivity, although the specific requirement of virion cholesterol in HIV-1 was not examined. In the present study, we have demonstrated that infectious wild-type HIV-1 contains Brij 98 rafts but only minimal amounts of Triton X-100 rafts. To directly assess the functional requirement of virion-associated rafts and various features of cholesterol on HIV-1 replication, we replaced virion cholesterol with exogenous cholesterol analogues that have demonstrated either raft-promoting or -inhibiting capacity in model membranes. We observed that variable concentrations of exogenous analogues are required to replace a defined amount of virion-associated cholesterol, showing that structurally diverse cholesterol analogues have various affinities toward HIV-1. We found that replacement of 50% of virion cholesterol with these exogenous cholesterol analogues did not eliminate the presence of Brij 98 rafts in HIV-1. However, the infectivity levels of the lipid-modified HIV-1s directly correlate with the raft-promoting capacities of these cholesterol analogues. Our data provide the first direct assessment of virion-associated Brij 98 rafts in retroviral replication and illustrate the importance of the raft-promoting property of virion-associated cholesterol in HIV-1 replication.

Non-invasive collection and examination of human corneal epithelial cells

Purpose. To report the development of a new apparatus for non-invasive collection of human corneal epithelial cells.

Methods. Previous methods of non-invasive, irrigative corneal cell collection resulted in low cell yields limiting potential analysis. A new ocular surface cell collection apparatus (OSCCA) was designed to collect more epithelial cells from direct irrigation of the corneal surface to allow for clinical comparisons. Forty-five samples were obtained (unilateral or bilateral over seven visits) from five human participants. Cell yield, size, phenotype, and corneal staining (prior and post eye wash) were examined.

Results. On average 364 ± 230 epithelial cells were collected from the cornea per eye. Epithelial cell sizes ranged from 8.21 to 51.69 μm in diameter, and 67.30 to 2098.85 μm2 area. The proportion of corneal specific cells collected per sample was 75 ± 14% as determined by positive K3 expression with AE5. On average, 77 ± 0.2% of epithelial cells harvested were nucleated, the remainder were non-nucleated ghost cells. Corneal staining was reduced in the OSCCA-washed vs. contralateral non-washed eyes (p = 0.02).

Conclusions. The OSCCA allows collection of human corneal epithelial cells with significantly higher yields, and greater specificity than previously reported. Reduced corneal staining observed post eye-wash demonstrated the safety of the technique, and its ability to remove cells directly from the corneal surface. The OSCCA could provide an objective non-invasive method of investigating pathological changes, effects of topical therapeutics, and impact of contact lenses and care-solutions of the cells of the ocular surface.

Gender-common and -specific neuroanatomical basis of human anxiety-related personality traits

Exploration of the relationships between regional brain volume and anxiety-related personality traits is important for understanding preexisting vulnerability to depressive and anxiety disorders. However, previous studies on this topic have employed relatively limited sample sizes and/or image processing methodology, and they have not clarified possible gender differences. In the present study, 183 (male/female: 117/66) right-handed healthy individuals in the third and fourth decades of life underwent structural magnetic resonance imaging scans and Temperament and Character Inventory. Neuroanatomical correlates of individual differences in the score of harm avoidance (HA) were examined throughout the entire brain using voxel-based morphometry. We found that higher scores on HA were associated with smaller regional gray matter volume in the right hippocampus, which was common to both genders. In contrast, female-specific correlation was found between higher anxiety-related personality traits and smaller regional brain volume in the left anterior prefrontal cortex. The present findings suggest that smaller right hippocampal volume underlies the basis for higher anxiety-related traits common to both genders, whereas anterior prefrontal volume contributes only in females. The results may have implications for why susceptibility to stress-related disorders such as anxiety disorders and depression shows gender and/or individual differences.

Real estate graduates’ employability skills : the perspective of human resource managers of surveying firms

Purpose – The purpose of this paper is to report further on research funded by the Centre for Education in the Built Environment (CEBE) into real estate programmes of study in UK universities (Poon and Hoxley). The aim of this paper is to identify human resource managers’ view on the employability skills of real estate graduates. It also compares the views on the employability skills of real estate graduates between human resource managers, a large sample of real estate employers and real estate course directors.

Design/methodology/approach – This paper presents the research findings of eight interviews with human resource managers who work in different types of surveying firms. The approach for collecting their view of the employability skills required by real estate graduates was through gathering their opinions on three charts. These charts compare what employers feel graduates require and what they feel graduates demonstrate in 31 knowledge areas, 20 skills and 21 attributes, alongside a list of additional competencies made by graduates and employers which was developed as part of an earlier study.

Findings – The human resource managers identified the key employability skills for real estate graduates as soft skills, in particular report writing skills, communication skills, presentation skills, client care and professional standards. The human resource managers of real estate consultancy firms also voiced their concern regarding graduates’ lack of commercial awareness, which echoed the same view from real estate employers and real estate course directors mentioned in the previous research (Poon, Hoxley and Fuchs). Therefore, it is necessary for universities to embed these soft skills, such as commercial awareness in the curriculum in order to enhance the employability of graduates.

Originality/value – This paper makes an original contribution to existing literature on the identification and discussion of employability skills for real estate graduates. It describes pioneering research focusing on the human resource managers’ perspective of the real estate graduate employability skills.