Optimized determination of T cell epitope responses

Pools of overlapping peptides corresponding to specific antigens are frequently used to identify T cell immune responses to vaccines or pathogens. While the response to the entire pool of peptides provides important information, it is often desirable to also know to which individual peptides within the pool the immune responses are directed. In this report, we analyzed various ways of deconvoluting an immune response to a pool of peptides to determine the number of different peptides to which the T cells are responding. We used a Monte Carlo simulation to optimize the construction of peptide pools that could identify responses to individual peptides using the fewest numbers of assays and patient material. We find that the number of assays required to deconvolute a pool increases by the logarithm of the number of peptides within the pool; however, the optimum configuration of pools changes dramatically according to the number of responses to individual peptides that are expected to be in the sample. Our simulation will help in the design of clinical trials in which the breadth of the response is being measured, by allowing a calculation for the minimum amount of blood that needs to be collected. In addition, our results guide the design and implementation of the experiments to deconvolute the responses to individual peptide epitopes.     

Should donors have the right to decide who receives their gametes?

A continuing feature of gamete donation is the scarcity of availabledonors. A strategy to improve the meagre supply of gametes wouldbe to adjust the donation procedure to the wishes and desiresof the donors. However, giving donors the right to direct theirgametes to certain groups of recipients goes against the generalrule that donors relinquish all rights and duties. Moreover,allocation by the donor might very well run counter to the rulesof distributional justice. On the other hand, the allocationright can be supported by the principle of autonomy and by thedonor's interest in and contribution to the process. The positionis taken that the donors should have the right to direct theirgametes to categories accepted as relevant by the moral andreligious communities in their society. They should not be giventhe right to add their own categories to the exclusion list.If donors are not allowed to allocate their gift, they shouldat least be informed as to which categories of recipient aretreated by the hospital to enable them to decide whether theywant to donate gametes.     

53例慢性髓系白血病细胞遗传学和bcr/abl融合基因检测

目的了解我院慢性粒细胞白血病(慢粒)染色体变异及融合基因表达与临床诊断和分期间的关系。方法染色体制备采用骨髓或外周血短期培养法,G显带,分析核型;融合基因检测则用逆转录-聚合酶链反应法(PCR法)。结果发现慢粒急变期的染色体,除具典型的Ph染色体外,还有 8、 9、i(16)q、i(17)q、-18等其它染色体改变。bcr/ab l融合基因显示慢粒急变期的患者,同时具有165bp和90bp扩增带。结论我们宜将细胞遗传学和PCR法结合,对慢粒白血病进行检测,即有助于对其诊断、预测急变、判断疗效及预后情况的深入了解。     

Immunotherapy for neurological diseases

The burden of neurological diseases in western societies has accentuated the need to develop effective therapies to stop the progression of chronic neurological diseases. Recent discoveries regarding the role of the immune system in brain damage coupled with the development of new technologies to manipulate the immune response make immunotherapies an attractive possibility to treat neurological diseases. The wide repertoire of immune responses and the possibility to engineer such responses, as well as their capacity to promote tissue repair, indicates that immunotherapy might offer benefits in the treatment of neurological diseases, similar to the benefits that are being associated with the treatment of cancer and autoimmune diseases. However, before applying such strategies to patients it is necessary to better understand the pathologies to be targeted, as well as how individual subjects may respond to immunotherapies, either in isolation or in combination. Due to the powerful effects of the immune system, one priority is to avoid tissue damage due to the activity of the immune system, particularly considering that the nervous system does not tolerate even the smallest amount of tissue damage.     

Essentially Winnicott: Creating Psychic Health

The authors of this paper recognize the paradox of identifying with the body of work of D. W. Winnicott as it was essential to his view that each analyst has to become the analyst s/he is or can be. This is to avoid the dead hand of conformity and falsity. Nevertheless his work continues to inspire creative use with its concern with health and those conditions for its development. Both authors find themselves committed to history taking, to needing and taking time, to a willingness to wait before interpreting, to a recognition that the self derives originally from a bodily state of unintegration, that the body remains significant for the expression of self‐states, to an understanding of aggression as not primarily associated with destructiveness, to attending to the state of mind in the analyst that encourages the establishment and maintenance of the analytic setting. Clinically their intention is to maintain a continuity within which psychic change can be facilitated, through an attention to the ongoing exchanges between both parties of the analytic relation. Several clinical examples are given from different settings to illustrate the presence of these tenets in their work.     

Saliva-binding region of Streptococcus mutans surface protein antigen.

A 190-kDa surface protein antigen (PAc) of Streptococcus mutans binds to human salivary components. For detection of specific binding of the PAc protein to human salivary components, a simple sandwich assay was used. Microtiter plates precoated with recombinant PAc (rPAc), PAc fragments, or S. mutans whole cells were allowed to react with human whole saliva and then were incubated with biotinylated rPAc. The biotinylated rPAc bound to salivary components was detected by use of alkaline phosphatase-conjugated streptavidin and p-nitrophenylphosphate. In this assay, the binding of whole cells of S. mutans and purified rPAc to salivary components was confirmed. For determination of a saliva-binding region of the PAc molecule, 14 truncated PAc fragments were constructed by use of the polymerase chain reaction and an expression vector, pAX4a+. The binding of these truncated PAc fragments to human salivary components was determined by the sandwich assay. Among the truncated PAc fragments, fragments corresponding to residues 39 to 864 and residues 39 to 1000 of PAc showed a high ability to bind to salivary components. Shorter recombinant fragments corresponding to residues 39 to 217, residues 200 to 481, residues 470 to 749, and residues 688 to 864 did not exhibit any binding ability. The fragment that corresponds to a proline-rich repeating region (residues 828 to 1000) bound directly to the PAc protein. These results suggest that residues 39 864 of the PAc molecule are important in the binding of the surface protein to human salivary components, and the proline-rich repeating region of the PAc protein may contribute to spontaneous self-aggregation of the PAc protein.     

A Proposed Feedback Method For Studying the Inhibition of EEG Responses to Visual Stimuli

A new method for studying inhibition of an electroencephalographic component of the OR to visual stimuli is described. The EEG response is suppression of the occipital alpha following visual stimulation. By a controlled feedback contingency, two stimuli are made to occur in sequence with a controlled time delay after the onset of alpha in the EEG. Inhibition is defined as a lack of EEG response to the first stimulus followed by a response to the second, delayed stimulus. Because the stimuli are feedback with regard to the occurrence of alpha, the dynamics of the alpha - alpha suppression system are different when a response is made to the first stimulus (elicitation of OR to first stimulus) compared to not responding to the first stimulus but responding to the second delayed stimulus (inhibition of OR to the first stimulus).     

Production of antihaptene antisera. Comparison of methods of immunisation (author's transl)]

Five immunogenic substances were injected to rabbits. The method of immunisation by the intradermal route at 30 to 50 different points, with low doses of immunogen, without booster, does not seem to lead to production of antiserum of great specificity. The choice of the dose of immunogen to be injected is difficult, owing to our ignorance of the immunogenic dose for a given immunogen. The method of immunisation by the subcutaneous route with high doses followed by a booster, leads to more constant results, comparable to those obtained by the first method to which one may associate boosters by the subcutaneous route. The titers, affinities and specificities of the antisera thus produced are sufficient for the development of radio-immunoassay. The characteristics of the antisera obtained, related to the quality of the immunogen, do not seem to depend on the method of immunisation.     

Soluble CD14 enhances membrane CD14-mediated responses to peptidoglycan: structural requirements differ from those for responses to lipopolysaccharide

The purpose of this study was to identify the functional significance of the binding of soluble CD14 (sCD14) to bacterial peptidoglycan (PGN) and to compare the structural requirements of sCD14 for the binding to PGN and lipopolysaccharide (LPS) and for sCD14-mediated enhancement of PGN- and LPS-induced cell responses. sCD14 did not facilitate the responses of membrane CD14 (mCD14)-negative pre-B 70Z/3 cells to PGN, although it facilitated the responses of these cells to LPS and although mCD14 facilitated the responses of 70Z/3 cells to PGN. sCD14 enhanced mCD14-mediated cell activation by both PGN and LPS, but only the responses to LPS, and not to PGN, were enhanced by LPS-binding protein. Four 4- or 5-amino-acid-long sequences within the 65-amino-acid N-terminal region of sCD14 were needed for binding to both PGN and LPS and for enhancement of cell activation by both PGN and LPS. However, deletions of individual sequences had different effects on the ability of sCD14 to bind to PGN and to LPS and on the ability to enhance the responses to PGN and to LPS. Thus, there are different structural requirements of sCD14 for binding to PGN and to LPS and for the enhancement of PGN- and LPS-induced cell activation.     

The ramification and connections of retinal fibres in layer 7 of the domestic chick optic tectum: a Golgi impregnation, anterograde tracer and GABA-immunogold study

Layer 7 is one of the retinorecipient layers of the avian optic tectum. However, little information is available about the neuronal organization of this layer and its implications for visual function. Golgi impregnation was used to investigate the retinal input to and the neuronal architecture of layer 7 of the chick optic tectum, which forms a narrow band between the two cell‐dense layers 6 and 8. Anterograde tracers were also used to investigate the afferent and efferent connections of layer 7, in both the light and the electron microscope, together with GABA immunogold labelling. Three types of radial neuron were defined according to the origin and course of their axons. The perikarya of these neurons were situated in tectal layers 10–11. The principal dendrites of these radial neurons ascended to the tectal surface and gave rise to dendritic side‐branches in layer 7. These dendritic side‐branches received asymmetric synapses from the terminations of retinal fibre arborisations. Type 2 radial neurons, whose axons arose from the deep pole of the perikaryon or occasionally from a basal dendrite, were shown to project to the nucleus isthmi pars magnocellularis, which has previously been demonstrated to be GABAergic and to project to glomerulus‐like complexes in tectal layers 4–5. In these layers, the dendritic branches of layer 13 neurons that project to the nucleus rotundus have previously been shown to receive retinal fibre input. Therefore, the retinal input to layer 7 may be able to modulate the transmission of information to the visual thalamus, by way of a feedback loop to layers 4–5 of the tectum involving the nucleus isthmi pars magnocellularis.     

Evidence of Different Cell Populations in the Mouse Thymus Releasing and Responding to Mitogenic Factor

The thymocyte population of mice treated with cortisone was examined at various times with respect to its relative capacity to be triggered to DNA synthesis by soluble phytomitogens or mitogenic factors (MF) released by lymph node cells exposed to phytomitogens. The capacity of the thymocyte population to produce MF in response to phytomitogen exposure was also examined. We found that the relative blastogenic activity of both phytomitogens and MF on thymocytes increased as the cell number of the thymus was reduced by the cortisone treatment. However, the reactivity to phytomitogens increased to a higher extent. During the subsequent regeneration of the organ the stimulability of the cells by phytomitogen decreased far below that of MF. The relative capacity of thymocytes to produce MF seemed to parallel their phytomitogen reactivities One possible explanation of the results is that there exists one subpopulation of cells in the thymus more responsive to phytomitogens than to MF and another more responsive to MF than to phytomitogen. It is possible that the cells that are phytomitogen-responsive are those that can produce MF.     

A rapid procedure for initial drug evaluation.

The overall aim of this work is to develop computer simulations to aid in the selection of proposed medicines and identify those most likely to succeed. One important feature is a systems approach to simulate both the target area with which the drug is designed to interact as well as the surrounding areas where feedback mechanisms may alter the expected effect. The simulation must be rapid if it is to be used to evaluate large numbers of potential drugs. Thus the procedure simplifies many of the known complex phenomena to provide a general framework and feedback mechanisms. An example of the use of the simulation to study a drug used to treat hypertension is given. A possible use of the technique is shown using the example of the effect of varying the drug dosage on the contraction of the arteriole muscle.     

Antimicrobial susceptibility testing of Streptococcus pneumoniae: quality assessment results.

Six strains of Streptococcus pneumoniae were distributed to 405 United Kingdom laboratories who were asked to test the susceptibility of the strains to penicillin, tetracycline, chloramphenicol and erythromycin and to provide details of methodology to test the standards of susceptibility testing. High error rates were seen only in failure to detect moderate resistance to penicillin (12%) and resistance to chloramphenicol (16%). Increased error rates were associated with several methods or practices. These included the use of certain culture media; failure to standardise the inoculum; inoculation by loop rather than by swab; failure to use control organisms; failure to measure zone sizes; the use of discs containing a high content of penicillin to test susceptibility to penicillin, and the use of high content discs for testing erythromycin, tetracycline, and chloramphenicol.     

Resistance of Escherichia coli to osmotically introduced complement component C9.

Investigation into the action of osmotically introduced C9 in Escherichia coli (in the absence of any other complement components) revealed that C9 could inhibit inner membrane respiration and cause a decrease in the viability of cells that were normally complement sensitive. This effect is analogous to the loss of inner membrane function and viability due to the assembly of the C5b-9 complex on these cells. Complement-resistant cells showed no such inhibition of respiration or loss of viability when subjected to the osmotic introduction of C9. The reason for this failure of C9 to affect complement-resistant cells was explored to determine whether this resistance to C9 was due to an inability of proteins in general to be osmotically introduced into the complement-resistant cells. The protein toxins melittin and colicin E1 were showed to be able to kill these complement-resistant cells (as well as complement-sensitive cells) when osmotically introduced into the periplasm. Therefore, cellular resistance to osmotically introduced C9 is not due to an inability of proteins to be introduced into the cells and may be related to a mechanism of cellular resistance to the C5b-9 complex.     

A specific form of cognitive rigidity following excitotoxic lesions of the basal forebrain in marmosets.

The effects of N-methyl-D-aspartate-induced lesions of the basal forebrain were studied on performance of a series of visual discrimination tests that examined a range of cognitive functions in the marmoset. These included the ability to attend to the various dimensional properties of stimuli and to use just one of these properties in order to solve a discrimination (intra-dimensional shift); to switch attention from one dimension to another (extra-dimensional shift); to learn the reinforcement value of specific exemplars within a dimension (new learning); and to relearn their reinforcement value following reversal of the reward contingencies (serial reversals). Lesions of the basal forebrain did not impair the ability either to attend selectively to the dimensional properties of the stimuli or to switch attention from one dimension to the other. However, the lesion did affect various aspects of associative learning including a transient impairment of new learning and a marked disruption of serial reversal learning. The reversal deficit could be characterised as a tendency to perseverate on the previously correct stimulus and as a failure to to show the formation of a reversal learning set. In addition, the lesion prevented disruption of performance of a well-learned discrimination when novel exemplars from the irrelevant dimension were introduced (probe test). It is suggested that the functional effects of the basal forebrain lesion reflect impaired learning of stimulus-reward associations and behavioural rigidity. The finding, however, that there was no effect of the lesion on attentional set-shifting suggests that any loss of inhibitory control was specific to the level of stimulus-response or stimulus-reward associations, inhibitory control at the level of attentional selection remaining intact. The similarity of the effects of damage to the basal forebrain to those seen following damage to the orbitofrontal cortex and the amygdala are discussed in the context of the close anatomical and functional relationships that exist among these three structures.     

Kinetic analysis of pepsin digestion of chicken egg white ovomucoid and allergenic potential of pepsin fragments

BACKGROUND: The allergenic potential of chicken egg white ovomucoid (OVM) is thought to depend on its stability to heat treatment and digestion. Pepsin-digested fragments have been speculated to continue to exert an allergenic potential. OVM was digested in simulated gastric fluid (SGF) to examine the reactivity of the resulting fragments to IgE in sera from allergic patients. METHODS: OVM was digested in SGF and subjected to SDS-PAGE. The detected fragments were then subjected to N-terminal sequencing and liquid chromatography/mass spectrometry/mass spectrometry analysis to confirm the cleavage sites and partial amino acid sequences. The reactivity of the fragments to IgE antibodies in serum samples from patients allergic to egg white was then determined using Western blotting (n=24). RESULTS: The rate of OVM digestion depended on the pepsin/OVM ratio in the SGF. OVM was first cleaved near the end of the first domain, and the resulting fragments were then further digested into smaller fragments. In the Western blot analysis, 93% of the OVM-reactive sera also bound to the 23.5- to 28.5-kDa fragments, and 21% reacted with the smaller 7- and 4.5-kDa fragments. CONCLUSION: When the digestion of OVM in SGF was kinetically analyzed, 21% of the examined patients retained their IgE-binding capacity to the small 4.5-kDa fragment. Patients with a positive reaction to this small peptide fragment were thought to be unlikely to outgrow their egg white allergy. The combination of SGF-digestibility studies and human IgE-binding experiments seems to be useful for the elucidation and diagnosis of the allergenic potential of OVM.     

An Upsurge in early childhood mortality in Kenya: A search for explanations

This study seeks to document recent trends in early childhood mortality in the country and to offer some plausible explanations for the upsurge in the trends. Data and information from various sources are used in this paper to achieve this purpose. The results obtained show that infant, child and under-five mortality rates had declined in the 1960s and 1970s but were taking an upward trend since early 1990s. This situation is attributable to a combination of factors, including increased poverty, adverse effects of economic hardships and cost recovery programs associated with structural adjustment programs, increased childhood malnutrition, decreased use of certain maternity care services, decline in the coverage of child immunisations, inability of the public health system to provide services, and the HIV / AIDS epidemic and the recent ethnic clashes that rocked some parts of the Rift Valley, Coast, Nyanza and Western province. In order to reverse the upward trend in mortality, there is an urgent need to intensify efforts to reduce poverty, to enable most people to have adequate food supply, improve the public health sector so that it can deliver health care to all people; to make greater efforts to raise the living standards of rural populations and improve the quality of housing, sanitary and sewerage conditions in urban slums. In addition, concerted efforts must continue to be made to contain the spread of HIV/AIDS, to assist Aids orphans and to eliminate completely and to avoid recurrence of ethnic clashes and cattle rustling.     

Modeling the development of acquired clinical immunity to Plasmodium falciparum malaria

Individuals living in regions where malaria is endemic develop an acquired immunity to malaria which enables them to remain asymptomatic while still carrying parasites. Field studies indicate that cumulative exposure to a variety of diverse Plasmodium parasites is required for the transition from symptomatic to asymptomatic malaria. This study used a simulation model of the within-host dynamics of P. falciparum to investigate the development of acquired clinical immunity under different transmission conditions and levels of parasite diversity. Antibodies developed to P. falciparum erythrocyte membrane protein 1 (PfEMP1), a clonally variant molecule, were assumed to be a key human immunological response to P. falciparum infection, along with responses to clonally conserved but polymorphic antigens. The time to the development of clinical immunity was found to be proportional to parasite diversity and inversely proportional to transmission intensity. The effect of early termination of symptomatic infections by chemotherapy was investigated and found not to inhibit the host's ability to develop acquired immunity. However, the time required to achieve this state was approximately double that compared to when no treatment was administered. This study demonstrates that an immune response primarily targeted against PfEMP1 has the ability to reduce clinical symptoms of infections irrespective of whether treatment is administered, supporting its role in the development of acquired clinical immunity. The results also illustrate a novel use for simulation models of P. falciparum infections, investigation of the influence of intervention strategies on the development of naturally acquired clinical immunity.     

To What Does the Terminal Orienting Response Respond?

Previous authors suggested that the electrodermal orienting response to stimulus onset (OR) reflects cognitive processes related to the content of a stimulus while responses to stimulus offset (TOR) reflect processes related to stimulus duration. Experiment 1 tested the hypothesis that the OR and TOR are special cases of Ss responding to whatever part of the stimulus contains information necessary to make the requested judgment. The results clearly supported this alternative hypothesis. The Ss responded to stimulus onset when asked to judge the pitch (content) of a constant tone and to stimulus offset when asked to judge the terminal pitch of a varying tone. They responded to both the onset and offset of a stimulus when asked to compare the onset and offset pitch and when asked to judge stimulus duration. Experiment 2 partially replicated Experiment 1 in an attempt to assess the OR-TOR phenomenon in a second sensory modality (vision) and with a second dependent measure. The patterns of both electrodermal and heart rate responses were similar to those of Experiment 1 and to those observed by other authors.     

Modal profiles for the Luria-Nebraska Neuropsychological Battery.

Modal Profile Analysis was used to cluster subjects on the clinical scales of the Luria-Nebraska Neuropsychological Battery, Form I (LNNB). The analysis produced 22 modal profile types, of which seven were replicated in multiple samples of subjects with single criterion diagnoses. Subjects who had been assigned to modal types according to their correlations with the modal profiles were more similar to the modal profile of their assigned groups than to other modal profiles. Assigned subjects were more likely to belong to their assigned group than to other groups and were more similar to other subjects who had been assigned to the same group than to subjects assigned to other groups. Eighty-two percent of subjects in the derivation sample were assigned empirically to a modal profile group; 77% of subjects in a cross-validation sample were assigned to a modal profile group. The discussion focuses on the potential research and clinical use of the modal LNNB profiles.