The relation between major histocompatibility complex (MHC) restriction and the capacity of Ia to bind immunogenic peptides

The capacity of purified I-Ad, I-Ed, I-Ak, and I-Ek to bind to protein derived peptides that have been previously reported to be T cell immunogens has been examined. For each of the 12 peptides studied strong binding to the relevant Ia restriction element was observed. All the peptides bound more than one Ia molecule; however, for 11 of 12 peptides, the dominant binding was to the restriction element, whereas in one instance the dominant binding was to a nonrestriction element. When the peptides were used to inhibit the presentation of antigen by prefixed accessory cells to T cells, an excellent correlation was found between the capacity of a peptide to inhibit the binding of an antigen to purified Ia and the capacity of the peptide to inhibit accessory cell presentation of the antigen. Thus, the binding of peptide to purified Ia is immunologically relevant, and Ia seems to be the only saturable molecule on the surface of the accessory cell involved in antigen presentation. Inhibition analysis also indicated that all peptides restricted to a particular Ia molecule competitively inhibited one another, suggesting that each Ia restriction element has a single binding site for antigen. Cross-linking of labeled peptides to Ia followed by electrophoretic analysis and autoradiography suggested that this single binding site is made up of portions of both alpha and beta chains of Ia.

Structural characteristics of an antigen required for its interaction with Ia and recognition by T cells

A detailed analysis of the residues within an immunogenic peptide that endow it with the capacity to interact with Ia and to be recognized by T cells is presented. Ia interacts with only a few of the peptide residues and overall exhibits a very broad specificity. Some residues appear to interact both with Ia and with T cells, leading to a model in which a peptide antigen is 'sandwiched' between Ia and the T-cell receptor.

Characterization of the first definitive hematopoietic stem cells in the AGM and liver of the mouse embryo

At day 10 in mouse gestation, the intraembryonic aorta-gonads-mesonephros (AGM) region generates the first definitive hematopoietic stem cells (HSCs) of the adult blood system. By 11 days postcoitum, the liver contains such HSCs. While HSCs of the adult bone marrow and late-stage fetal liver have been extensively characterized for cell surface markers, there has been no phenotypic description of the first HSCs during embryo development. We report here the temporal cell surface phenotype of HSCs from the AGM region and early fetal liver and show that all HSCs reside in the c-kit+ population. c-kit+ HSCs from AGM and liver are mainly CD34+ and in the AGM are in both Mac-1+ and Mac-1 fractions. These results demonstrate that during mouse ontogeny the first definitive HSCs are similar in cell surface phenotype to the HSCs of adult bone marrow but that spatial localization and developmental time are critical factors in the phenotypic assessment of this functional cell population.

Prediction of major histocompatibility complex binding regions of protein antigens by sequence pattern analysis

We have previously experimentally analyzed the structural requirements for interaction between peptide antigens and mouse major histocompatibility complex (MHC) molecules of the d haplotype. We describe here two procedures devised to predict specifically the capacity of peptide molecules to interact with these MHC class II molecules (IAd and IEd). The accuracy of these procedures has been tested on a large panel of synthetic peptides of eukaryotic, prokaryotic, and viral origin, and also on a set of overlapping peptides encompassing the entire staphylococcal nuclease molecule. For both sets of peptides, IAd and IEd binding was successfully predicted in approximately 75% of the cases. This suggests that definition of such sequence "motifs" could be of general use in predicting potentially immunogenic peptide regions within proteins.

Significance of popliteal reflux in relation to ambulatory venous pressure and ulceration

Fifty-one patients (55 limbs) who had had deep venous thrombosis (DVT) extending into the femoral or iliofemoral segment three to five years earlier and ten limbs of ten healthy volunteers were studied. The ambulatory venous pressure (AVP) was measured by inserting a needle in a vein on the foot; the presence of reflux in the popliteal vein was determined by a directional Doppler ultrasonic blood velocity detector. All patients had ascending venography. The results suggest that the most important factor in determining the AVP and ulceration in postthrombotic limbs is the condition of the popliteal valves. Ulceration does not occur even in the presence of occlusion if the popliteal valves are competent. The extent of DVT and recanalization or the failure of recanalization is of secondary importance.

Interaction between a "processed" ovalbumin peptide and Ia molecules

The binding of 125I-labeled immunogenic peptides to purified Ia molecules in detergent solution was examined by equilibrium dialysis. We used the chicken ovalbumin peptide ovalbumin-(323-339)-Tyr, which is immunogenic in the BALB/c mouse and restricted to I-Ad. 125I-labeled ovalbumin-(323-339)-Tyr was shown to bind to I-Ad but not to I-Ed, I-Ek, or I-Ak. This binding was inhibited by unlabeled ovalbumin-(323-339) but not by ovalbumin-(329-339), which is the longest N-terminally truncated peptide that fails to stimulate any of the I-Ad-restricted hybridomas that have been raised to ovalbumin-(323-339)-Tyr. As a further specificity control, we also used the chicken egg lysozyme peptide Tyr-(46-61), which has recently been studied by similar methods [Babbitt, B. P., Allen, P. M., Matsueda, G., Haber, E. & Unanue, E. R. (1985) Nature (London) 317, 359-361]. We have confirmed that it bound to I-Ak but not to I-Ek, I-Ad, or I-Ed. Thus, a specific interaction between Ia and antigen that correlates with the major histocompatibility complex restriction was demonstrated, strongly arguing in favor of a determinant selection hypothesis for such restriction.

Privileged access by irrelevant speech to short-term memory: the role of changing state

Memory for visually presented items is impaired by speech that is played as an irrelevant background. The paper presents the view that changing state of the auditory material is an important prerequisite for this disruption. Four experiments studied the effects of sounds varying in complexity in an attempt to establish which features of changing state in the auditory signal lead to diminished recall. Simple unvarying or repetitive speech sounds were not sufficient to induce the irrelevant speech effect (Experiment 1): in addition, simple analogues of speech, possessing regular or irregular envelopes and using a range of carriers, failed to imitate the action of speech (Experiment 2). Variability of between-utterance phonology in the irrelevant stream (Experiment 3) emerged as a crucial factor. Moreover, predictability of the syllable sequence did not reduce the degree of disruption (Experiment 4) suggesting that supra-syllabic characteristics of the speech are of little importance. The results broadly support the idea that disruption of short-term memory only occurs when the speech stream changes in state. It is argued that disruption occurs in memory when cues to serial order based on phonological representations of heard material interfere with the phonological codes of visual origin. It is suggested that cues to changing state of the speech input contaminate those associated with items of visual origin, which are already in a phonological store.

Structure of the carboxy-terminal LIM domain from the cysteine rich protein CRP

The three dimensional solution structure of the carboxy terminal LIM domain of the avian Cysteine Rich Protein (CRP) has been determined by nuclear magnetic resonance spectroscopy. The domain contains two zinc atoms bound independently in CCHC (C = Cys, H = His) and CCCC modules. Both modules contain two orthogonally-arranged antiparallel beta-sheets, and the CCCC module contains an alpha-helix at its C terminus. The modules pack due to hydrophobic interactions forming a novel global fold. The structure of the C-terminal CCCC module is essentially identical to that observed for the DNA-interactive CCCC modules of the GATA-1 and steroid hormone receptor DNA binding domains, raising the possibility that the LIM motif may have a DNA binding function.

A zinc finger truncation of murine WT1 results in the characteristic urogenital abnormalities of Denys-Drash syndrome

The Wilms tumor-suppressor gene, WT1, plays a key role in urogenital development, and WT1 dysfunction is implicated in both neoplastic (Wilms tumor, mesothelioma, leukemias, and breast cancer) and nonneoplastic (glomerulosclerosis) disease. The analysis of diseases linked specifically with WT1 mutations, such as Denys-Drash syndrome (DDS), can provide valuable insight concerning the role of WT1 in development and disease. DDS is a rare childhood disease characterized by a nephropathy involving mesangial sclerosis, XY pseudohermaphroditism, and/or Wilms tumor (WT). DDS patients are constitutionally heterozygous for exonic point mutations in WT1, which include mutations predicted to truncate the protein within the C-terminal zinc finger (ZF) region. We report that heterozygosity for a targeted murine Wt1 allele, Wt1(tmT396), which truncates ZF3 at codon 396, induces mesangial sclerosis characteristic of DDS in adult heterozygous and chimeric mice. Male genital defects also were evident and there was a single case of Wilms tumor in which the transcript of the nontargeted allele showed an exon 9 skipping event, implying a causal link between Wt1 dysfunction and Wilms tumorigenesis in mice. However, the mutant WT1(tmT396) protein accounted for only 5% of WT1 in both heterozygous embryonic stem cells and the WT. This has implications regarding the mechanism by which the mutant allele exerts its effect.

Emergency department contact prior to suicide in mental health patients

OBJECTIVES

To describe attendance at emergency departments (EDs) in the year prior to suicide for a sample of mental health patients. To examine the characteristics of those who attended (particularly those who attended frequently) prior to suicide.

DESIGN

Case review of ED records for 286 individuals who died within 12 months of mental health contact in North West England (2003-2005).

METHOD

Cases identified through the National Confidential Inquiry into Suicide were checked against regional EDs to establish attendance in the year prior to death. Records were examined to establish the number of attendances, reason for the final, non-fatal attendance, treatment offered and outcome.

RESULTS

One hundred and twenty-four (43%) individuals had attended the ED at least once in the year prior to their death, and of these, 35 (28%) had attended the ED on more than three occasions. These frequent attenders died by suicide significantly sooner after their final, non-fatal attendance than other attenders. A clinical history of alcohol misuse was also associated with early death following ED attendance.

CONCLUSIONS

Over 40% of our clinical sample attended an ED in the year prior to death, and some individuals attended particularly frequently. EDs may therefore represent an important additional setting for suicide prevention in mental health patients. The majority of attendances prior to suicide were for self-harm or to request psychiatric help. Clinicians should be alert to the risk associated with such presentations and to the possible association between frequent attendance and suicide.

Drug use and barriers to use of health care services

This paper examines barriers to health care utilization and the correlates associated with these barriers. As part of a larger study of health services utilization, the study sample of 1085 including injection drug users, other chronic users of heroin or cocaine, and a demographically similar group who had used neither heroin nor cocaine, was selected based on the criterion of not having received health care for at least one health problem within the previous 12 months. Both categories of chronic drug users were more likely than non-users not to want health care treatment and to put off seeking needed health care.

Complete sequencing of the Fugu WAGR region from WT1 to PAX6: dramatic compaction and conservation of synteny with human chromosome 11p13

The pufferfish Fugu rubripes has a genome approximately 7.5 times smaller than that of mammals but with a similar number of genes. Although conserved synteny has been demonstrated between pufferfish and mammals across some regions of the genome, there is some controversy as to what extent Fugu will be a useful model for the human genome, e.g., [Gilley, J., Armes, N. & Fried, M. (1997) Nature (London) 385, 305-306]. We report extensive conservation of synteny between a 1.5-Mb region of human chromosome 11 and <100 kb of the Fugu genome in three overlapping cosmids. Our findings support the idea that the majority of DNA in the region of human chromosome 11p13 is intergenic. Comparative analysis of three unrelated genes with quite different roles, WT1, RCN1, and PAX6, has revealed differences in their structural evolution. Whereas the human WT1 gene can generate 16 protein isoforms via a combination of alternative splicing, RNA editing, and alternative start site usage, our data predict that Fugu WT1 is capable of generating only two isoforms. This raises the question of the extent to which the evolution of WT1 isoforms is related to the evolution of the mammalian genitourinary system. In addition, this region of the Fugu genome shows a much greater overall compaction than usual but with significant noncoding homology observed at the PAX6 locus, implying that comparative genomics has identified regulatory elements associated with this gene.

Peptide sequences of T-cell receptor delta and gamma chains are identical to predicted X and gamma proteins

Although most mature peripheral T lymphocytes express a major histocompatibility complex restricted, CD3-associated, antigen receptor (TCR) which has been well characterized, some T cells carry a different CD3-associated heterodimer on their surface. One of the two disulphide-linked chains of this putative second receptor, which in mice has relative molecular mass (Mr) 35,000 (35K), has been identified as a product of the group of gamma genes. The other chain, termed delta (Mr 45K in mice), is not as well characterized. Although gamma/delta-bearing cells are a minor subset among peripheral T lymphocytes, they are the only CD3+ cells in the thymus early in ontogeny. Taking advantage of these kinetics, we have generated gamma/delta-bearing hybridomas, using a new TCR alpha chain-negative variant of the AKR thymoma BW5147 as tumour parent, fetal thymocytes as normal cell partners, and an anti-CD3 monoclonal antibody (mAb) as screening reagent. Gamma and delta chains from one of these hybrids have been purified and partially sequenced. The sequences obtained indicate that delta is indeed identical to the polypeptide encoded by the recently described gene X, as suggested by Chien et al.

Enhancing social functioning in young people at Ultra High Risk (UHR) for psychosis: A pilot study of a novel strengths and mindfulness-based online social therapy

BACKGROUND

Psychological and pharmacological treatments have been shown to reduce rates of transition to psychosis in Ultra High Risk (UHR) young people. However, social functioning deficits have been unresponsive to current treatments.

AIMS

The study aims were to: i) describe the theoretical basis and therapeutic targets of a novel intervention targeting social functioning in UHR young people; and ii) examine its acceptability, safety and preliminary effect on social functioning.

METHODS

An international, multidisciplinary team developed a new intervention (MOMENTUM) to improve social functioning in UHR young people. MOMENTUM blends two novel approaches to social recovery: strengths and mindfulness-based intervention embedded within a social media environment, and application of the self-determination theory of motivation. The acceptability and safety of MOMENTUM were tested through a 2-month pilot study with 14 UHR participants.

RESULTS

System usage was high, with over 70% of users being actively engaged over the trial. All participants reported a positive experience using MOMENTUM, considered it safe and would recommend it to others. 93% reported it to be helpful. There were large, reliable improvements in social functioning (d = 1.83, p < 0.001) and subjective wellbeing (d = 0.75, p = 0.03) at follow-up. There were significant increases in the mechanisms targeted by the intervention including strengths usage (d = 0.70, p = 0.03), mindfulness skills (d = 0.66, p = 0.04) and components of social support. Social functioning improvement was significantly correlated with indicators of system usage.

CONCLUSION

MOMENTUM is engaging and safe. MOMENTUM appeared to engage the hypothesized mechanisms and showed promise as a new avenue to improve social functioning in UHR young people.

An injury prevention program in an urban African-American community

OBJECTIVES

Injury is a major US public health problem, particularly in urban minority communities. This paper evaluates the impact of the Safe Block Project, a comprehensive injury prevention trial, on home hazards and injury prevention knowledge in a poor urban African-American community.

METHODS

Nine census tracts in the community were allocated to either the intervention area or the control area. The intervention, carried out by trained community outreach workers, consisted of (1) home modification for simple prevention measures, (2) home inspection accompanied by information about home hazards, and (3) education about selected injury prevention practices. Approximately 12 months after the intervention, random samples of control and intervention homes were assessed for home hazards and injury prevention knowledge.

RESULTS

A significantly larger proportion of intervention homes than control homes had functioning smoke detectors, syrup of ipecac, safely stored medications, and reduced electrical and tripping hazards. No consistent differences were observed between control and intervention homes on home hazards requiring major effort to correct.

CONCLUSIONS

There was a distinct difference between control and intervention homes with respect to safety knowledge and home hazards requiring minimal to moderate effort to correct. The Safe Block Project could serve as a model for future urban injury prevention efforts.

Estrogen and memory in a transsexual population

The association between administered estrogen and performance on verbal memory and other cognitive tasks was examined. Male-to-female transsexuals undergoing estrogen treatment for sex reassignment (n = 29) scored higher on Paired Associate Learning (PAL) compared to a similar transsexual control group, awaiting estrogen treatment (n = 30) (P < 0.05). No differences between groups receiving and not receiving estrogen were detected on a control memory task (Digit Span) or on other cognitive tasks including Mental Rotations and Controlled Associations. There were no group differences in age. Group differences in mood or in general intellectual ability also did not explain the findings. Results suggest a specific influence of estrogen in men on verbal memory tasks, similar to that seen in prior studies of women. They are discussed in terms of differential processing demands of the two memory tasks and possible differences between estrogenic influences on Mental Rotations and Controlled Associations in men versus women.

Individual differences in reactivity to the rewarding/aversive properties of drugs: assessment by taste and place conditioning

The ability of individual differences in the strength of conditioned taste avoidance (CTA) to predict strength of place conditioning produced by the same drug was assessed. In Phase 1, rats were assigned to High CTA and Low CTA groups on the basis of their intake of saccharin solution previously paired with morphine, amphetamine, lithium, or fenfluramine. In Phase 2, the rats received place conditioning training with the same drug used during Phase 1. The rats that displayed the strongest amphetamine-induced CTA also displayed the strongest amphetamine-induced place preference, suggesting that a common mechanism mediates both effects. On the other hand, the strength of the CTA was unrelated to the strength of the place preference or place aversion produced by morphine, lithium, or fenfluramine.

Risk of acute first myocardial infarction and use of nicotine patches in a general population

OBJECTIVES

To determine if nicotine patches, both as prescribed and used over-the-counter, increase the risk of first myocardial infarction (MI).

BACKGROUND

Although nicotine patches improve smoking cessation rates, case reports have raised the hypothesis that they may increase the risk of MI.

METHODS

A population-based case-control study among 68 hospitals in an eight-county region surrounding Philadelphia was performed to determine if nicotine patches increase the risk of first MI. Cases were smokers (current or within the prior year) admitted to all hospitals in the region with a first MI. Controls were smokers (current or within the prior year) without prior MI selected from the same region using random-digit dialing. Data were collected by telephone interviews and chart reviews. The study had 80% power to detect an odds ratio (OR) of 2.5.

RESULTS

A total of 653 cases and 2,990 controls were interviewed. There was no association between nicotine patches and MI (OR 0.46; 95% CI: 0.09, 1.47), and the confidence interval (CI) excluded an effect from nicotine patches equal to that from cigarette smoking itself (OR < 2.5). Among those who abstained from smoking, the OR for use of nicotine patches was 0.25 (95% CI: 0.01, 1.67); among those who smoked concomitantly, the OR for patch use was 0.83 (95% CI: 0.09, 3.81). Adjustment for confounding did not alter the study's findings (OR adjusted for confounders that could mask a harmful effect of patches: 0.70; 95% CI: 0.20, 2.46).

CONCLUSIONS

Nicotine patches, as used in actual practice, do not appear to be associated with an increased risk of MI.

Expression of the Ly-6E.1 (Sca-1) transgene in adult hematopoietic stem cells and the developing mouse embryo

The mouse hematopoietic marker Sca-1, encoded by the Ly-6E.1 and Ly-6A.2 genes, has been instrumental in the enrichment and characterization of the stem cell for the adult blood system. In the studies reported here, we use Ly-6E.1 genomic fragments to direct expression of a lacZ marker transgene in vivo to study Ly-6E.1 specific regulatory elements in the hematopoietic stem cell and to localize these cells in the developing mouse embryo. We demonstrate that a region approximately 9 kb downstream from the transcriptional start site is required for the distinct, restricted expression pattern of the Ly-6E.1-lacZ transgene within adult hematopoietic stem cells and embryos. We also demonstrate that viable and functional lacZ-expressing hematopoietic stem cells can be enriched by FDG staining and flow cytometric sorting. The Ly-6E.1-lacZ-mediated enrichment of hematopoietic stem cells from adult transgenic bone marrow in combination with the temporal expression pattern of the transgene in the pro/mesonephros suggest an intraembryonic site of development for these cells in the mouse.

The combined effects of occupational health hazards: an experimental investigation of the effects of noise, nightwork and meals

An experimental study of the effects of noise, nightwork and meals showed that these factors influenced different aspects of performance. Speed of performing a low memory load version of a visual search task was influenced by working at night but was unaffected by either noise or meals. A high memory load version of the search task was performed more slowly after consumption of a meal, both during the day and at night, but was not influenced by nightwork. Subjects working in noise produced more errors on the high memory load task than those working in quiet, but neither nightwork nor meals had significant effects on the number of errors. The only evidence of an interaction between factors was obtained in the high memory load search task, where noise reduced the size of the post-meal decline in speed. These results show that the effects of noise, nightwork and meals are largely independent, the exception being the beneficial effect of noise on post-lunch performance. They also demonstrate that the effects of all of these factors depend on the nature of the task being performed, and on whether speed or accuracy is the variable under consideration.

DNA sequence determination of gamma-radiation-induced mutations of the hamster aprt locus

From a collection of 85 independent gamma-radiation hamster aprt- mutants, 27 having no major structural alterations were analysed at the nucleotide level by using the polymerase chain reaction to amplify mutant exons and then directly sequencing the double-stranded products. The majority of these mutations were simple base substitutions of all types, particularly transversions (11/27). Frameshifts and small deletions were also induced. The 'spectrum' of mutations produced by gamma-radiation was not significantly different from that occurring spontaneously at this locus. Differences with respect to the target and structure of frameshifts and small deletions occurring in the two collections were apparent.

Effects of lunch on selective and sustained attention

Post-lunch impairments in performance efficiency have been found in both real-life settings and the laboratory. The first aim of the present experiment was to determine whether post-lunch changes in performance depend on eating a meal, or whether they are also found in subjects who abstain from eating. A second aim was to examine which aspects of performance are most likely to show post-lunch impairments. The results showed that the ability to maintain attention and react quickly to the appearance of a new stimulus was impaired following consumption of the meal. The extent of this effect did not vary with time on task, and was unaltered by changes in the time at which lunch was eaten. In contrast to this, the ability to resist distraction was unaffected by eating lunch. Other types of performance, such as movement time, varied as a function of time of day, but were not impaired by the meal.

Low vision services for vision rehabilitation in the United Kingdom

AIM

Little is known about the distribution and methods of delivery of low vision services across the United Kingdom. The purpose of this study was to determine the type and location of low vision services within the UK.

METHODS

Survey by means of a 29 point postal questionnaire, followed when necessary by a five point telephone questionnaire. All known potential providers of low vision services (n = 2539) including hospitals (n = 277), optician/optometry practices (n = 1683), social services (n = 177), voluntary groups (n = 190), specialist teachers (n = 205), and universities (n = 6) were surveyed. For each service provider, the type, magnitude, and geographical location were determined. The distribution of services across the United Kingdom and the ratio of providers to population density of people with a visual impairment were mapped using the Geographic Information System (GIS).

RESULTS

Data were obtained on 1945 (77%) service providers: 1679 (66%) responded to the postal questionnaire and 266 (11%) to the telephone questionnaire. Of all respondents, 59% (n = 1135) offer some form of help to people with a visual disability, of which 26% (n = 497) only sell magnifiers and 33% (n = 638) provide low vision services. It is estimated that in total just under 155,000 low vision consultations are offered annually, the bulk of which are provided by hospital eye departments. The distribution was geographically uneven and there appears to be scarcity in some areas.

CONCLUSION

When compared to the probable number of people with a visual impairment in the UK there are apparent inadequacies in service provision in terms of distribution, magnitude, and coordination. The results highlight a need to review current services.

The role of the physician as an information source on mammography

PURPOSE

The value of mammography for asymptomatic women younger than 50 years of age has been under debate, and it had been suggested that each woman should decide for herself whether to start having mammograms in her 40s. This decision-making process requires women to have knowledge of screening guidelines. This study reported key determining informational factors that led women age 40 and older to obtain a mammogram.

DESCRIPTION OF STUDY

To examine the relationship between sources of information and utilization of mammography, the authors conducted a communitywide telephone survey, in English and Spanish, of a stratified random sample of 999 white, black, and Hispanic women in Dade County, Florida. The survey was designed to measure knowledge, attitudes, practices, and beliefs about breast cancer, its prevention, and its early detection. Data for 784 women 40 years and older are analyzed and reported here.

RESULTS

The most commonly cited source of information was the media (90.2%). In a logistic regression, having had a checkup in the past year was the strongest predictor of having had a recent mammogram as opposed to a distant one (OR 4.17; 95% CI 2.92-5.95). Women who named their physician as an important source of information about health and prevention were also more likely to have had a recent examination (OR 1.85; 95% CI 1.27-2.69).

CLINICAL IMPLICATIONS

This analysis of the relationship between the source of information and utilization of mammography suggests that physicians, as sources of information, serve to motivate women to obtain a mammogram. This is true even after taking into account the patient's age and utilization of the healthcare system for preventive care in general. For this reason, it is imperative that clinicians be aware of national guidelines for breast cancer screening; of the risks and benefits of screening measures; and of the implications of a positive and negative test result. In addition, clinicians must realize the importance of follow-up to remind the patient to obtain a mammogram or other screening test and should develop strategies to provide this service.