In vivo selection of sFv from phage display libraries

The development of phage display technology has facilitated the development of many new and sometimes novel antibody based reagents for scientific research. However, present methods for selection from phage-sFv display libraries are limited to selection against purified antigens or ex vivo cells of known origin and phenotype. Existing methods therefore preclude the isolation of sFv against unknown molecules in their natural environment, where expression is complex and subject to diverse control mechanisms. Since such a complex environment is difficult to mimic in vitro, the development of an in vivo selection procedure would greatly enhance the selection from phage display antibody libraries and lead to the development of reagents against cell surface molecules in their natural environment. This would be particularly advantageous for isolation of sFv against vascular endothelium which can readily change phenotype when cultured and is believed to express molecules in a tissue specific manner and in response to different stimuli. We describe here the development of an in vivo selection procedure in the mouse and demonstrate its potential for the selection of sFv from a phage-sFv library. The target antigen for one sFv is expressed solely on the thymic endothelium, while the second, a 165-170 kDa molecule in present on both thymic endothelium and the perivascular epithelium.

Phage display technology

The development of monoclonal antibody (mAb) technology (1) has had a significant impact on many fields of research, in particular immunology. However, the method has limitations. The use of recombinant DNA technology and demonstration by Smith 1985 (2) that peptides can be expressed on the surface of filamentous bacteriophages have permitted the development of a powerful new methodology for the generation and isolation of novel antibody-based reagents for both research and clinical application.

The gp200-MR6 molecule which is functionally associated with the IL-4 receptor modulates B cell phenotype and is a novel member of the human macrophage mannose receptor family

The human gp200-MR6 molecule has previously been shown to have either an antagonistic or agonistic effect on IL-4 function, demonstrated by inhibition of IL-4-induced proliferation of T cells or mimicking of IL-4-induced maturation of epithelium, respectively. We now show that gp200-MR6 ligation can also mimic IL-4 and have an anti-proliferative pro-maturational influence within the immune system, causing up-regulation of co-stimulatory molecules on B lymphocytes. Biochemical analysis and cDNA cloning reveal that gp200-MR6 belongs to the human macrophage mannose receptor family of multidomain molecules. It comprises 1722 amino acids in toto (mature protein, 1695 amino acids; signal sequence, 27 amino acids) organized into 12 external domains (an N-terminal cysteine-rich domain, a fibronectin type II domain and 10 C-type carbohydrate recognition domains), a transmembrane region and a small cytoplasmic C terminus (31 amino acids) containing a single tyrosine residue (Y1679), but no obvious kinase domain. Strong amino acid sequence identity (77%) suggests that gp200-MR6 is the human homologue of the murine DEC-205, indicating that this molecule has much wider functional activity than its classical endocytic role. We also show that the gp200-MR6 molecule is closely associated with tyrosine kinase activity; the link between gp200-MR6 and the IL-4 receptor may therefore be via intracellular signaling pathways, with multifunctionality residing in its extracellular multidomain structure.

The gp200-MR6 molecule which is functionally associated with the IL-4 receptor modulates B cell phenotype and is a novel member of the human macrophage mannose receptor family

The human gp200-MR6 molecule has previously been shown to have either an antagonistic or agonistic effect on IL-4 function, demonstrated by inhibition of IL-4-induced proliferation of T cells or mimicking of IL-4-induced maturation of epithelium, respectively. We now show that gp200-MR6 ligation can also mimic IL-4 and have an anti-proliferative pro-maturational influence within the immune system, causing up-regulation of co-stimulatory molecules on B lymphocytes. Biochemical analysis and cDNA cloning reveal that gp200-MR6 belongs to the human macrophage mannose receptor family of multidomain molecules. It comprises 1722 amino acids in toto (mature protein, 1695 amino acids; signal sequence, 27 amino acids) organized into 12 external domains (an N-terminal cysteine-rich domain, a fibronectin type II domain and 10 C-type carbohydrate recognition domains), a transmembrane region and a small cytoplasmic C terminus (31 amino acids) containing a single tyrosine residue (Y1679), but no obvious kinase domain. Strong amino acid sequence identity (77%) suggests that gp200-MR6 is the human homologue of the murine DEC-205, indicating that this molecule has much wider functional activity than its classical endocytic role. We also show that the gp200-MR6 molecule is closely associated with tyrosine kinase activity; the link between gp200-MR6 and the IL-4 receptor may therefore be via intracellular signaling pathways, with multifunctionality residing in its extracellular multidomain structure.

Computational and in vivo investigation of optical reflectance from human brain to assist neurosurgery

Parkinson's disease (PD) is a chronic, progressive disease involving the globus pallidus (GP), which is a gray matter mass, surrounded by white matter deep within the brain. During a neurosurgery procedure, a thin probe is inserted into the GP to create a lesion that often relieves the cardinal symptoms of PD. The goal of this study is to develop an optical method to accurately locate the GP border. In theory, Monte Carlo simulations were performed to predict the optical reflectance from brain tissue. In experiment, a portable, real-time display spectrometer with a fiber optic reflectance probe was developed and used during human surgery. Optical reflectance values were recorded at 1 mm intervals to obtain a spatial profile of the tissue as the probe passed through regions of gray and white matter. The simulation and in vivo studies of the reflectance from the brain are in good agreement with one another. The clinical data show that the reflectance from gray matter is approximately 50% or less than that from white matter between 650 and 800 nm. A slope algorithm is developed to distinguish gray and white matter in vivo. This study provides previously unknown optical reflectance of the human brain. © 1998 Society of Photo-Optical Instrumentation Engineers.

Association between interleukin-4-producing T lymphocyte frequencies and reduced risk of graft-versus-host disease

BACKGROUND

We have previously developed and used limiting dilution analysis to measure frequencies of alloreactive cytotoxic T cell precursors (CTLp) and interleukin (IL)-2-producing T helper cells (IL-2/HTLp) to assess the risk of graft-versus-host disease in bone marrow transplantation (BMT). However, no test has been available to measure precursor frequencies of the important IL-4-secreting subset.

METHODS

We have now established a limiting dilution analysis to measure the frequency of IL-4-producing T helper cells (IL-4/HTLp) using the IL-4-responsive indicator cell line CT.h4S and have applied this assay to measure alloreactive IL-4/HTLp frequencies in BMT donor-recipient pairs. These frequencies were then analyzed in the context of clinical data to assess the relationship between the number of donor anti-recipient IL-4-secreting T cells and disease outcome.

RESULTS

Frequencies of IL-4/HTLp have been studied in HLA-identical siblings, HLA-"matched" unrelated, and HLA-mismatched combinations and found to range from approximately 1/500,000 in HLA-identical sibling pairs to -1/2,000 in HLA-DR-mismatched pairs. These frequencies were independent of those for IL-2/HTLp and showed a negative correlation with those for CTLp. Clinical follow-up of 30 patients showed that high IL-4/HTLp frequencies are associated with a reduced risk of severe graft-versus-host disease. High IL-4/HTLp frequencies may also indicate an increased risk of leukemia relapse.

CONCLUSIONS

Our data suggest that measurement of IL-4/HTLp frequencies provides information distinct from that obtained with CTLp and IL-2/HTLp. This new assay provides a valuable additional method for optimizing donor selection in unrelated BMT.

Planning and producing scientific posters

Poster sessions now form an important part of most scientific and medical meetings. Traditionally they have been seen by presenters as the poor relation to the lecture programme and consequently poster preparation has never been given the attention it deserves. This article examines the principles of poster production and describes the contribution the illustrator can make to its production.

Rethinking the assessment of sleepiness

The consequences of dozing off when intending to stay awake, e.g. while driving or at work, are potentially catastrophic. The accurate assessment of this tendency is important, but is currently difficult. Several different methods give disparate results. A way out of this dilemma is suggested that involves modification of existing concepts of sleep and wakefulness to conclude the powerful influence of behaviour on sleep propensity. This propensity at a particular time depends, hypothetically, on a mutually inhibitory interaction between a sleep and a wake drive, not on the magnitude of either drive alone. Measurements of sleep propensity are partly situation-specific, whether measured objectively by laboratory tests or subjectively by a questionnaire such as the Epworth Sleepiness Scale. The latter is believed to measure a general characteristic, the average sleep propensity across a range of specified situations in daily life. Any one situational sleep propensity is not always an accurate predictor of another, even in the same subject. The Multiple Sleep Latency test should not be a gold standard for such measurements. Wider discussion and more research into "sleepiness" is needed.

Synthesis of phosphotyrosine-containing peptides using bis-(2,2,2-trichloro)ethyl groups for phosphate protection

Suitability of bis-(2,2,2-trichloro)ethyl (Tc) groups for protection of phosphate moiety in Boc-mode synthesis of phosphotyrosine peptides is demonstrated Boc-Tyr(PO3Tc2)-OH and Fmoc-Tyr(PO3Tc2)-OH were prepared by acylating H-Tyr(PO3Tc2)-OH with (Boc)2O and Fmoc-ONSu, respectively. Phosphorus introduction was achieved by phosphorylating Boc-Tyr-OBzl with Tc phosphochloride. The Tc-phosphorus protector was found to be incompatible with the Fmoc group because the conditions of Fmoc removal (piperidine treatment) caused dephosphorylation. Complete NMR spectral assignments in the described compounds is presented. (Contribution No. 2398 from the Centre for Food and Animal Research).

Daytime sleepiness and sleep habits of Australian workers

Excessive daytime sleepiness in the general community is a newly recognized problem about which there is little standardized information. Our aim was to measure the levels of daytime sleepiness and the prevalence of excessive daytime sleepiness in a sample of Australian workers and to relate that to their self-reported sleep habits at night and to their age, sex, and obesity. Sixty-five percent of all 507 employees working during the day for a branch of an Australian corporation answered a sleep questionnaire and the Epworth sleepiness scale (ESS) anonymously. Normal sleepers, without any evidence of a sleep disorder, had ESS scores between 0 and 10, with a mean of 4.6 +/- 2.8 (standard deviation). They were clearly separated from the "sleepy" patients suffering from narcolepsy or idiopathic hypersomnia whose ESS scores were in the range 12-24, as described previously. ESS scores > 10 were taken to represent excessive daytime sleepiness, the prevalence of which was 10.9%. This was not related significantly to age (22-59 years), sex, obesity, or the use of hypnotic drugs but was related significantly but weakly to sleep-disordered breathing (frequency of snoring and apneas), the presence of insomnia, and reduced time spent in bed (insufficient sleep).

Curriculum model for associate degree programs in HIM, Part III: Focus on educational outcomes and curricular content

This is the last in a series of three articles that discuss curriculum models for associate and baccalaureate degree programs in health information management (HIM). Part I discussed the development of the models and presented a composite summary of key sections within the models. Part II focused on the baccalaureate degree curriculum model sections, which addressed educational outcomes, curricular content, and clinical experience expectations. Part III addresses these same sections, but in regard to the associate degree curriculum model.

Curriculum model for baccalaureate degrees programs in HIM, Part II: Focus on educational outcomes and curriculum content

This the second in a series of three articles discussing curriculum models for associate and baccalaureate degree programs in health information management (HIM). Part I discussed the development of the models and presented a composite summary of selected key sections within the models. Part II focuses on the educational outcomes, curriculum content, and clinical experience expectations for the baccalaureate degree curriculum model. Part III will do the same for the associate degree curriculum model.

Design for slides

The basic principles of design for projection slides are discussed, with particular reference to the impact of the personal computer and commercial presentation software on the material that is destined to end up on the screen at meetings and in seminar rooms. While modern software can be a boon to the presenter, allowing simple creation of slides, it can also encourage some of the worst excesses. The keynote of the design of slides for educational purposes should be simplicity, and ways of achieving simple but effective results are described.

Customer satisfaction: the case for measurement

The measurement of customer satisfaction is a process that is not commonly undertaken by medical illustration departments. The fact that many departments are now run on a zero-budgeted basis and rely totally on their 'customers' for their income has brought into sharper focus the need to ensure customer satisfaction with the services offered. This article discusses the background to customer satisfaction measurement and some of the techniques used.

Identification of capsule-forming Bacillus anthracis spores with the PCR and a novel dual-probe hybridization format

Anthrax is a fatal infection of humans and livestock that is caused by the gram-positive bacterium Bacillus anthracis. The virulent strains of B. anthracis are encapsulated and toxigenic. In this paper we describe the development of a PCR technique for identifying spores of B. anthracis. Two 20-mer oligonucleotide primers specific for the capB region of 60-MDa plasmid pXO2 were used for amplification. The amplification products were detected by using biotin- and fluorescein-labeled probes in a novel dual-probe hybridization format. Using the combination of PCR amplification and dual-probe hybridization, we detected two copies of the bacterial genome. Because the PCR assay could detect a minimum of 100 unprocessed spores per PCR mixture, we attempted to facilitate the release of DNA by comparing the effect of limited spore germination with the effect of mechanical spore disruption prior to PCR amplification. The two methods were equally effective and allowed us to identify single spores of B. anthracis in PCR mixtures.