From structure to sequence: Antibody discovery using cryoEM

One of the rate-limiting steps in analyzing immune responses to vaccines or infections is the isolation and characterization of monoclonal antibodies. Here, we present a hybrid structural and bioinformatic approach to directly assign the heavy and light chains, identify complementarity-determining regions, and discover sequences from cryoEM density maps of serum-derived polyclonal antibodies bound to an antigen. When combined with next-generation sequencing of immune repertoires, we were able to specifically identify clonal family members, synthesize the monoclonal antibodies, and confirm that they interact with the antigen in a manner equivalent to the corresponding polyclonal antibodies. This structure-based approach for identification of monoclonal antibodies from polyclonal sera opens new avenues for analysis of immune responses and iterative vaccine design.

pdm_utils: a SEA-PHAGES MySQL phage database management toolkit

SUMMARY

Bacteriophages (phages) are incredibly abundant and genetically diverse. The volume of phage genomics data is rapidly increasing, driven in part by the SEA-PHAGES program, which isolates, sequences and manually annotates hundreds of phage genomes each year. With an ever-expanding genomics dataset, there are many opportunities for generating new biological insights through comparative genomic and bioinformatic analyses. As a result, there is a growing need to be able to store, update, explore and analyze phage genomics data. The package pdm_utils provides a collection of tools for MySQL phage database management designed to meet specific needs in the SEA-PHAGES program and phage genomics generally.

AVAILABILITY AND IMPLEMENTATION

https://pypi.org/project/pdm-utils/.

Structural Definition of a Neutralization-Sensitive Epitope on the MERS-CoV S1-NTD

Middle East respiratory syndrome coronavirus (MERS-CoV) emerged into the human population in 2012 and has caused substantial morbidity and mortality. Potently neutralizing antibodies targeting the receptor-binding domain (RBD) on MERS-CoV spike (S) protein have been characterized, but much less is known about antibodies targeting non-RBD epitopes. Here, we report the structural and functional characterization of G2, a neutralizing antibody targeting the MERS-CoV S1 N-terminal domain (S1-NTD). Structures of G2 alone and in complex with the MERS-CoV S1-NTD define a site of vulnerability comprising two loops, each of which contain a residue mutated in G2-escape variants. Cell-surface binding studies and in vitro competition experiments demonstrate that G2 strongly disrupts the attachment of MERS-CoV S to its receptor, dipeptidyl peptidase-4 (DPP4), with the inhibition requiring the native trimeric S conformation. These results advance our understanding of antibody-mediated neutralization of coronaviruses and should facilitate the development of immunotherapeutics and vaccines against MERS-CoV.

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The epitope for the neutralizing antibody G2 is confined to the apex of the MERS-CoV S1-NTD

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G2 epitope is relatively well conserved

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G2 IgG and Fab both neutralize pseudotyped and authentic MERS-CoV

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G2 neutralizes by preventing the binding of DPP4 to trimeric S protein

Mapping the immunogenic landscape of near-native HIV-1 envelope trimers in non-human primates

The induction of broad and potent immunity by vaccines is the key focus of research efforts aimed at protecting against HIV-1 infection. Soluble native-like HIV-1 envelope glycoproteins have shown promise as vaccine candidates as they can induce potent autologous neutralizing responses in rabbits and non-human primates. In this study, monoclonal antibodies were isolated and characterized from rhesus macaques immunized with the BG505 SOSIP.664 trimer to better understand vaccine-induced antibody responses. Our studies reveal a diverse landscape of antibodies recognizing immunodominant strain-specific epitopes and non-neutralizing neo-epitopes. Additionally, we isolated a subset of mAbs against an epitope cluster at the gp120-gp41 interface that recognize the highly conserved fusion peptide and the glycan at position 88 and have characteristics akin to several human-derived broadly neutralizing antibodies.

Potent anti-influenza H7 human monoclonal antibody induces separation of hemagglutinin receptor-binding head domains

Seasonal influenza virus infections can cause significant morbidity and mortality, but the threat from the emergence of a new pandemic influenza strain might have potentially even more devastating consequences. As such, there is intense interest in isolating and characterizing potent neutralizing antibodies that target the hemagglutinin (HA) viral surface glycoprotein. Here, we use cryo-electron microscopy (cryoEM) to decipher the mechanism of action of a potent HA head-directed monoclonal antibody (mAb) bound to an influenza H7 HA. The epitope of the antibody is not solvent accessible in the compact, prefusion conformation that typifies all HA structures to date. Instead, the antibody binds between HA head protomers to an epitope that must be partly or transiently exposed in the prefusion conformation. The "breathing" of the HA protomers is implied by the exposure of this epitope, which is consistent with metastability of class I fusion proteins. This structure likely therefore represents an early structural intermediate in the viral fusion process. Understanding the extent of transient exposure of conserved neutralizing epitopes also may lead to new opportunities to combat influenza that have not been appreciated previously.

Complete genomic sequences of Propionibacterium freudenreichii phages from Swiss cheese reveal greater diversity than Cutibacterium (formerly Propionibacterium) acnes phages

BACKGROUND

A remarkable exception to the large genetic diversity often observed for bacteriophages infecting a specific bacterial host was found for the Cutibacterium acnes (formerly Propionibacterium acnes) phages, which are highly homogeneous. Phages infecting the related species, which is also a member of the Propionibacteriaceae family, Propionibacterium freudenreichii, a bacterium used in production of Swiss-type cheeses, have also been described and are common contaminants of the cheese manufacturing process. However, little is known about their genetic composition and diversity.

RESULTS

We obtained seven independently isolated bacteriophages that infect P. freudenreichii from Swiss-type cheese samples, and determined their complete genome sequences. These data revealed that all seven phage isolates are of similar genomic length and GC% content, but their genomes are highly diverse, including genes encoding the capsid, tape measure, and tail proteins. In contrast to C. acnes phages, all P. freudenreichii phage genomes encode a putative integrase protein, suggesting they are capable of lysogenic growth. This is supported by the finding of related prophages in some P. freudenreichii strains. The seven phages could further be distinguished as belonging to two distinct genomic types, or 'clusters', based on nucleotide sequences, and host range analyses conducted on a collection of P. freudenreichii strains show a higher degree of host specificity than is observed for the C. acnes phages.

CONCLUSIONS

Overall, our data demonstrate P. freudenreichii bacteriophages are distinct from C. acnes phages, as evidenced by their higher genetic diversity, potential for lysogenic growth, and more restricted host ranges. This suggests substantial differences in the evolution of these related species from the Propionibacteriaceae family and their phages, which is potentially related to their distinct environmental niches.

Time-course, negative-stain electron microscopy-based analysis for investigating protein-protein interactions at the single-molecule level

Several biophysical approaches are available to study protein–protein interactions. Most approaches are conducted in bulk solution, and are therefore limited to an average measurement of the ensemble of molecular interactions. Here, we show how single-particle EM can enrich our understanding of protein–protein interactions at the single-molecule level and potentially capture states that are unobservable with ensemble methods because they are below the limit of detection or not conducted on an appropriate time scale. Using the HIV-1 envelope glycoprotein (Env) and its interaction with receptor CD4-binding site neutralizing antibodies as a model system, we both corroborate ensemble kinetics-derived parameters and demonstrate how time-course EM can further dissect stoichiometric states of complexes that are not readily observable with other methods. Visualization of the kinetics and stoichiometry of Env–antibody complexes demonstrated the applicability of our approach to qualitatively and semi-quantitatively differentiate two highly similar neutralizing antibodies. Furthermore, implementation of machine-learning techniques for sorting class averages of these complexes into discrete subclasses of particles helped reduce human bias. Our data provide proof of concept that single-particle EM can be used to generate a “visual” kinetic profile that should be amenable to studying many other protein–protein interactions, is relatively simple and complementary to well-established biophysical approaches. Moreover, our method provides critical insights into broadly neutralizing antibody recognition of Env, which may inform vaccine immunogen design and immunotherapeutic development.

The investigation of patients with HIV infection: 10 years of progress

The past decade has seen great advances in the management of patients with HIV infection. The introduction of highly active antiretroviral therapy (HAART) has resulted in a decrease in opportunistic infections but the development of new clinical entities such as lipodystrophy and immune reconstitution illnesses. The use of investigations such as lipid profiles and dual energy X-ray absorptiometry (DEXA) scanning to assess lipodystrophy have been necessitated by these changes in the epidemic. Technological advances have resulted in new techniques such as viral resistance assays and single photon emission computed tomography (SPECT) scanning. The appropriate use of these investigations is subject to ongoing assessment.

Extramammary Paget's disease masquerading as lichen sclerosus

A wide range of genital infections and skin conditions may present with vulval pruritus. Lichen sclerosus is one cause. This is often associated with visible skin changes which include atrophy, resorption or fusion of the labia, sclerosis and excoriation. Ulceration may indicate malignant transformation and requires urgent biopsy.

Many experienced clinicians diagnose lichen sclerosus on clinical appearance, however we recommend a low threshold for biopsy, especially for non-responding or odd looking lesions. We report a patient whose vulval skin biopsy for clinically suspected lichen sclerosus revealed extramammary Paget's disease of the vulva. We review the pathology, prognosis and treatment of this condition.

Whole genome comparison of a large collection of mycobacteriophages reveals a continuum of phage genetic diversity

The bacteriophage population is large, dynamic, ancient, and genetically diverse. Limited genomic information shows that phage genomes are mosaic, and the genetic architecture of phage populations remains ill-defined. To understand the population structure of phages infecting a single host strain, we isolated, sequenced, and compared 627 phages of Mycobacterium smegmatis. Their genetic diversity is considerable, and there are 28 distinct genomic types (clusters) with related nucleotide sequences. However, amino acid sequence comparisons show pervasive genomic mosaicism, and quantification of inter-cluster and intra-cluster relatedness reveals a continuum of genetic diversity, albeit with uneven representation of different phages. Furthermore, rarefaction analysis shows that the mycobacteriophage population is not closed, and there is a constant influx of genes from other sources. Phage isolation and analysis was performed by a large consortium of academic institutions, illustrating the substantial benefits of a disseminated, structured program involving large numbers of freshman undergraduates in scientific discovery.

DOI:http://dx.doi.org/10.7554/eLife.06416.001

Viruses are unable to replicate independently. To generate copies of itself, a virus must instead invade a target cell and commandeer that cell's replication machinery. Different viruses are able to invade different types of cell, and a group of viruses known as bacteriophages (or phages for short) replicate within bacteria. The enormous number and diversity of phages in the world means that they play an important role in virtually every ecosystem.

Despite their importance, relatively little is known about how different phage populations are related to each other and how they evolved. Many phages contain their genetic information in the form of strands of DNA. Using genetic sequencing to find out where and how different genes are encoded in the DNA can reveal information about how different viruses are related to each other. These relationships are particularly complicated in phages, as they can exchange genes with other viruses and microbes.

Previous studies comparing the genomes—the complete DNA sequence—of reasonably small numbers of phages that infect the Mycobacterium group of bacteria have found that the phages can be sorted into ‘clusters’ based on similarities in their genes and where these are encoded in their DNA. However, the number of phages investigated so far has been too small to conclude how different clusters are related. Are the clusters separate, or do they form a ‘continuum’ with different genes and DNA sequences shared between different clusters?

Here, Pope, Bowman, Russell et al. compare the individual genomes of 627 bacteriophages that infect the bacterial species Mycobacterium smegmatis. This is by far the largest number of phage genomes analyzed from a single host species. The large number of genomes analyzed allowed a much clearer understanding of the complexity and diversity of these phages to be obtained. The isolation, sequencing and analysis of the hundreds of M. smegmatis bacteriophage genomes was performed by an integrated research and education program, called the Science Education Alliance Phage Hunters Advancing Genomics and Evolutionary Science (SEA-PHAGES) program. This enabled thousands of undergraduate students from different institutions to contribute to the phage discovery and sequencing project, and co-author the report. SEA-PHAGES therefore shows that it is possible to successfully incorporate genuine scientific research into an undergraduate course, and that doing so can benefit both the students and researchers involved.

The results show that while the genomes could be categorized into 28 clusters, the genomes are not completely unrelated. Instead, a spread of diversity is seen, as genes and groups of genes are shared between different clusters. Pope, Bowman, Russell et al. further reveal that the phage population is in a constant state of change, and continuously acquires genes from other microorganisms and viruses.

DOI:http://dx.doi.org/10.7554/eLife.06416.002

Snapshot of haloarchaeal tailed virus genomes

The complete genome sequences of archaeal tailed viruses are currently highly underrepresented in sequence databases. Here, we report the genomic sequences of 10 new tailed viruses infecting different haloarchaeal hosts. Among these, only two viral genomes are closely related to each other and to previously described haloviruses HF1 and HF2. The approximately 760 kb of new genomic sequences in total shows no matches to CRISPR/Cas spacer sequences in haloarchaeal host genomes. Despite their high divergence, we were able to identify virion structural and assembly genes as well as genes coding for DNA and RNA metabolic functions. Interestingly, we identified many genes and genomic features that are shared with tailed bacteriophages, consistent with the hypothesis that haloarchaeal and bacterial tailed viruses share common ancestry, and that a viral lineage containing archaeal viruses, bacteriophages and eukaryotic viruses predates the division of the three major domains of non-viral life. However, as in tailed viruses in general and in haloarchaeal tailed viruses in particular, there are still a considerable number of predicted genes of unknown function.

HIV-1 co-receptor expression and epithelial immune cells of the cervix in asymptomatic women attending a genitourinary medicine clinic

OBJECTIVES

The aim of the study was to qualitatively and semiquantitatively characterize the expression of the principal HIV co-receptors chemokine (C-C motif) receptor 5 (CCR5) and chemokine (C-X-C motif) receptor 4 (CXCR4) on susceptible CD4 T-helper cell, monocyte/macrophage and Langerhans dendritic cell populations within the cervical epithelia of asymptomatic women attending a genitourinary medicine clinic.

METHODS

Of 77 asymptomatic women recruited, 35 were excluded: 21 because they were found to have bacterial vaginosis, eight because they were found to have candida and six for other reasons. Cervical cytobrush samples from 11 women with Chlamydia trachomatis infection and 31 women without any detectable genital infection were stained with fluorescently labelled antibodies specific for cell surface CCR5, CXCR4, CD4, CD3, CD1a and CD19 expression, then analysed by flow cytometry.

RESULTS

CD4/CD3 T-helper cells (84%), CD1a Langerhans dendritic cells (75%) and CD4/CD14 monocytes/macrophages (59%) were detected in the samples. CCR5 and CXCR4 HIV co-receptor expression was observed on 46-86% of the above subsets. CD1a cells exhibited significantly higher CCR5 and CXCR4 positivity and median fluorescence than CD4 cells and higher CXCR4 positivity and median fluorescence than CD14 cells (P < 0.05 or less). Increased detection of CCR5 over CXCR4 was seen in CD14 cells (P < 0.05). No significant differences in CCR5 or CXCR4 expression were found in samples from asymptomatic women with or without chlamydial infection.

CONCLUSIONS

Co-receptor expression confirms the potential for CD1a Langerhans cells, monocytes/macrophages and T-helper cells in the cervix as primary targets for HIV infection. Previously observed selective transmission of CCR5-tropic isolates cannot be accounted for by a lack of CXCR4-expressing CD4 cervical immune cells. We were unable to identify any specific impact of chlamydial infection on co-receptor expression in this study.

An unusual cause of acute obstructive jaundice in an HIV-infected patient

We describe the case of an HIV-1-infected patient presenting with acute obstructive jaundice as the initial manifestation of primary small bowel Burkitt's lymphoma. The biliary obstruction resolved rapidly following chemotherapy without the need for surgical intervention. The prognosis is favourable with appropriate timely treatment.

Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution

Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists.

Comparative genomic analysis of 60 Mycobacteriophage genomes: genome clustering, gene acquisition, and gene size

Mycobacteriophages are viruses that infect mycobacterial hosts. Expansion of a collection of sequenced phage genomes to a total of 60-all infecting a common bacterial host-provides further insight into their diversity and evolution. Of the 60 phage genomes, 55 can be grouped into nine clusters according to their nucleotide sequence similarities, 5 of which can be further divided into subclusters; 5 genomes do not cluster with other phages. The sequence diversity between genomes within a cluster varies greatly; for example, the 6 genomes in Cluster D share more than 97.5% average nucleotide similarity with one another. In contrast, similarity between the 2 genomes in Cluster I is barely detectable by diagonal plot analysis. In total, 6858 predicted open-reading frames have been grouped into 1523 phamilies (phams) of related sequences, 46% of which possess only a single member. Only 18.8% of the phams have sequence similarity to non-mycobacteriophage database entries, and fewer than 10% of all phams can be assigned functions based on database searching or synteny. Genome clustering facilitates the identification of genes that are in greatest genetic flux and are more likely to have been exchanged horizontally in relatively recent evolutionary time. Although mycobacteriophage genes exhibit a smaller average size than genes of their host (205 residues compared with 315), phage genes in higher flux average only 100 amino acids, suggesting that the primary units of genetic exchange correspond to single protein domains.

Pilot study in the development of an interactive multimedia learning environment for sexual health interventions: a focus group approach

In the UK there are high rates of sexually transmitted infections and unintended pregnancies amongst young people. There is limited and contradictory evidence that current sexual health education interventions are effective or that they improve access to appropriate sexual health services. This paper describes the outcome of focus group work with young people that was undertaken to inform the design of an Interactive Multimedia Learning Environment that incorporates message framing, intended for use in sexual health promotion. The focus group work addressed sexual attitudes, behaviour, risk perception, and knowledge of sexual health and sexual health services in Nottingham. The results provided new insights into young peoples' sexual behaviour, and their diversity of knowledge and beliefs. Common themes expressed regarding sexual health services included concerns about confidentiality, lack of confidence to access services and fear of the unknown. The results showed that while the adolescents are reasonably knowledgeable about infection, they do not know as much about the relevant services to treat it. This work emphasizes the need for user involvement throughout the design and development of a sexual health intervention, and will form the basis of the next part of the project.

Imiquimod 5% cream is an acceptable treatment option for external anogenital warts in uncircumcised males

OBJECTIVES

To determine the safety and efficacy of imiquimod (Aldara) 5% cream in the treatment of prepuce-associated warts in uncircumcised males.

METHODS

An open-label study in six UK medical centres with 35 uncircumcised males with prepuce-associated warts treated with imiquimod 5% cream three times per week for up to 16 weeks. Other anogenital warts were also treated.

RESULTS

Three times weekly application of imiquimod was found to be safe, with erythema as the most commonly reported local skin reaction. Forty per cent of patients had complete clearance of anogenital warts within 16 weeks.

CONCLUSIONS

Imiquimod cream at a dosing regimen of three times per week, is effective and has an acceptable safety profile in the treatment of prepuce associated warts and other external anogenital warts in uncircumcised males.

Lung cancer as the presenting feature of AIDS

Several reports have suggested that there is an increased incidence of lung cancer amongst the HIV positive population. All cases of lung cancer reported in this group to date were in patients known previously to be HIV positive. We now report a case of AIDS presenting with small cell lung cancer. Unexpectedly severe pancytopenia and immunosuppression after combination chemotherapy revealed the underlying diagnosis. The prognosis in such cases is very poor, but it is important to establish the correct diagnosis in order for patients to make informed treatment decisions and to allow potentially life-saving treatment of their sexual partners.

The investigation of patients with HIV infection: 10 years of progress

The past decade has seen great advances in the management of patients with HIV infection. The introduction of highly active antiretroviral therapy (HAART) has resulted in a decrease in opportunistic infections but the development of new clinical entities such as lipodystrophy and immune reconstitution illnesses. The use of investigations such as lipid profiles and dual energy X-ray absorptiometry (DEXA) scanning to assess lipodystrophy have been necessitated by these changes in the epidemic. Technological advances have resulted in new techniques such as viral resistance assays and single photon emission computed tomography (SPECT) scanning. The appropriate use of these investigations is subject to ongoing assessment.

Animal propagation and genomic survey of a genotype 1 isolate of Cryptosporidium parvum

Human cryptosporidiosis is attributed to two major Cryptosporidium parvum genotypes of which type 1 appears to be the predominant. Most laboratory investigations however are performed using genotype 2 isolates, the only type which readily infects laboratory animals. So far type 1 has only been identified in humans and primates. A type 1 isolate, obtained from an individual with HIV and cryptosporidiosis, was successfully adapted to propagate in gnotobiotic piglets. Genotypic characterization of oocyst DNA from this isolate using multiple restriction fragment length polymorphisms, a genotype-specific PCR marker, and direct sequence analysis of two polymorphic loci confirmed that this isolate, designated NEMC1, is indeed type 1. No changes in the genetic profile were identified during multiple passages in piglets. In contrast, the time period between infection and onset of fecal oocyst shedding, an indicator of adaptation, decreased with increasing number of passages. Consistent with other type 1 isolates, NEMC1 failed to infect mice. A preliminary survey of the NEMC1 genome covering approximately 2% of the genome and encompassing 200 kb of unique sequence showed an average similarity of approximately 95% between type 1 and 2 sequences. Twenty-four percent of the NEMC1 sequences were homologous to previously determined genotype 2 C. parvum sequences. To our knowledge, this is the first successful serial propagation of genotype 1 in animals, which should facilitate characterization of the unique features of this human pathogen.

Factors in childhood drug and alcohol use: a review of the literature

TOPIC

Drug and alcohol use in children.

PURPOSE

To identify the prevalence of drug and alcohol use in children 12 and younger and the factors associated with this use.

SOURCE

A review of the literature.

CONCLUSIONS

The identified factors include: a) differences in use between boys and girls; b) influence of family members' drug and alcohol use; c) influence of peers; d) the child's self-esteem; and e) the child's knowledge about drug and alcohol use. Awareness by child psychiatric nurses of the identified factors is crucial to prevent, assess, and treat the problem of drug and alcohol use by children.

HIV infection with haemolytic anaemia

Images

The use of radiologically placed gastrostomy tubes in head and neck cancer patients receiving radiotherapy

PURPOSE

Patients undergoing radiotherapy to the head and neck area frequently experience radiation reactions that can markedly restrict oral intake, require hospitalization, and occasionally cause treatment interruptions. The Vancouver Cancer Center (VCC) has recently employed radiologically placed gastrostomy tubes (G-tubes) in the management of this problem. A review of the patients on whom this procedure had been performed is the subject of this review.

METHODS AND MATERIALS

Thirty-four patients had gastrostomy tubes inserted under radiologic guidance. This group is compared to a control group matched for age, sex, irradiated volume, and radiation dose, who did not have gastrostomy tubes. Patients with gastrostomy tubes were divided into two categories: (a) patients who had tubes inserted in anticipation of severe reactions, and (b) patients who developed severe radiation reactions necessitating nutritional support.

RESULTS

The gastrostomy group consisted of 65% males with an average age of 59 years and stage range of II (12%), III (24%), and IV (65%). In both the elective group and the nonelective group, patients maintained their weight at 95 to 97% of the pretreatment weight, at follow-up of 6 weeks and 3 months. This compared with an average weight loss in the control group of 9% at 6 weeks and 12% at 3 months. The length of hospitalization was a mean of 4.9 days in the elective group and 19 days in the nonelective group. Complication were low compared to those documented in the literature, but included two tube migrations, two aspirations, and one gastrointestinal bleed.

CONCLUSIONS

We believe that gastrostomy tubes contribute significantly to the management of patients with head and neck cancer, particularly in maintanence of nutrition, and they may decrease the need for hospitalization.

Evaluation of methods for preparing and thawing cryopreserved CD34+ and CD34- cell lines for use as reagents in flow cytometry of hematopoietic progenitor cells

BACKGROUND

Flow cytometry is used to quantitate CD34+ hematopoietic progenitor cells for transplantation. The present study evaluates methods for preparing and thawing cryopreserved CD34+ and CD34- cell lines for use as flow cytometry reagents.

STUDY DESIGN AND METHODS

The human myeloid leukemic cell lines KG 1 a (CD34+) and K562 (CD34-) were grown in culture under standard conditions and then prepared on ficoll gradients of different densities to determine which gave the component that was most reproducible. After ficoll preparation, the cells were frozen in standard cryopreservation media and four methods of thawing were examined. Determination of the method that gave the cell component that was most reproducible was based on viability, percentage of cell recovery, and maintenance of CD34 antigenicity status.

RESULTS

Ficoll gradient preparation improved the ease of flow cytometry analysis when original viability was low, and it produced a more uniform cell population. However, it resulted in significant cell loss for both cell lines. While the cell recovery for K562 cells was not significantly different with any of the densities of ficoll, recovery was significantly better for KG 1 a cells with ficoll at a specific gravity of 1.077. Of the thawing methods examined, all three that involved a rapid thaw at 37 degrees C were statistically equivalent to each other and were better than thawing at 4 degrees C.

CONCLUSION

With a standardized method of preparing cell lines as reagents for quality control purposes, data comparison among cell processing laboratories may more readily be initiated. Such cell lines could also be useful as a teaching tool for flow cytometry and in proficiency testing.

Physicians' perceived value of international AIDS conferences and attitudes towards patient attendance

OBJECTIVE

To determine the perceived value of attendance at an International AIDS Conference and attitudes towards the effect of patient attendance on the conference.

DESIGN

A confidential, self-administered questionnaire.

PARTICIPANTS

102 physicians from the United Kingdom who attended the VIII International AIDS Conference in Amsterdam.

RESULTS

There was an 84% response rate. 50% reported increased motivation for clinical work and 57% for research. Physicians with a lower HIV positive patient workload found the conference more valuable for finding out the latest information on HIV, compared with those with a higher workload (p = 0.04). Those with a higher patient workload found the conference more useful for increasing motivation for research than those with a lower HIV workload (p = 0.047). Conference attendance was felt to reduce burnout by 48% of respondents. The majority (55%) would prefer a more traditional meeting. Patient attendance was seen as improving the standard of discussion of ethical and political issues but not on medical or scientific issues.

CONCLUSIONS

The International AIDS Conferences are perceived as useful by those UK physicians who attend, but most would prefer a more "traditional" scientific meeting. Whilst patient participation was not seen as useful for medical or scientific discussions, it was felt to improve discussion of ethical and political issues. A smaller more focused conference may be equally useful to UK physicians.

Quality of life, appetite, and weight change in patients receiving dose-intensive chemotherapy

Quality of life was assessed by self-report questionnaires in 30 patients receiving dose-intensive chemotherapy for either non-small-cell lung cancer (20 patients) or recurrent head and neck cancer (10 patients). Megestrol acetate was given daily to try to improve appetite and prevent the weight loss usually associated with this chemotherapy. Appetite did not change significantly overall during the first 4 weeks of chemotherapy, but it did improve in those patients still receiving chemotherapy at 8 weeks. Changes in global quality of life were significantly correlated with changes in appetite, fatigue, energy level, and physical function. Thus, these parameters may have more relevance to patients' perceptions of quality of life than does weight change, and should be used more frequently as endpoints in studies of supportive care and palliative treatment of patients with cancer.

Phase II trial of megestrol in the supportive care of patients receiving dose-intensive chemotherapy

Megestrol acetate was given daily to lung cancer patients undergoing therapy with CODE and to recurrent head and neck cancer patients receiving DEB/M in an attempt to prevent weight loss. The outcomes in this study were compared with the same outcomes in similar groups of patients treated with the same chemotherapy regimens, but in which prednisone was used as the main supportive drug along with co-trimoxazole, ketoconazole, and either cimetidine or sucralfate. Weight loss was less pronounced in the current patients than in the previous ones. Nevertheless, there were several factors that led us to conclude that megestrol is not an adequate substitute for prednisone in patients receiving this kind of chemotherapy.

Meta-diagnosis: towards a hermeneutical perspective in medicine with an emphasis on alcoholism

This essay argues that making a diagnosis in medicine is essentially a hermeneutic enterprise, one in which interpretation skills play a major part in understanding a disease. The clinical encounter is an event comprised of two 'voices'; one is the voice of science which is grounded in empiricism, the other is that of human experience, which is grounded in story-telling and the interpretation of those stories. Using two 'voices', one from the Diagnostic and Statistical Manual of Mental Disorders-III-Revised, which describes 'alcohol abuse' and 'alcohol dependence', and the other, that of Claire, a character in Edward Albee's play, A Delicate Balance, who is conversing with her brother-in-law, Tobias, I apply principles from Hans-Georg Gadamer's hermeneutics to the clinical diagnostic process. The essay will demonstrate that we overlook an enormous amount of information about alcoholism by an over-reliance on 'objective data' and that our hope for understanding alcoholics is in listening to their voices, and sharing the interpretation of their experiences with them.

Small fenestra stapedotomy using a fiberoptic hand-held argon laser in obliterative otosclerosis

Obliterative otosclerosis has been a challenge since the advent of stapes surgery. "Drill-out" procedures have had a generally poorer prognosis than conventional stapes surgery because of excessive bleeding, acoustic trauma from the burr, and reclosure of the oval window by otosclerosis. In this report, we describe our early experience using a hand-held fiberoptic argon laser for small fenestra stapedotomy in 10 cases of obliterative otosclerosis. Closure of the air-bone gap to within 10 dB was seen in 100% of the patients. There was no significant sensorineural hearing loss, vertigo, or facial weakness. Argon-laser stapedotomy using a hand-held fiberoptic system is a safe and effective alternative to drill-out stapedotomy in cases of obliterative otosclerosis.

Surgical therapy of the eyelids in patients with facial paralysis

Patients with facial paralysis have a degree of lagophthalmos and paralytic ectropion. We present our experience in the surgical management of 25 consecutive patients treated for these problems. Paralytic lagophthalmos was corrected using gold weights inserted into the upper eyelid. The advantages and disadvantages of this surgical technique are reviewed. Medial canthoplasty and lateral canthoplasty were performed to rectify paralytic ectropion. Ancillary procedures included browpexy, upper-lid blepharoplasty, and temporalis sling. The results were excellent in 23 of 25 patients and good in the remaining two. After a minimum of 6 months' follow-up, there were no complications. The authors believe that the above procedures will yield consistently excellent cosmetic and functional results in patients with paralysis of the eyelids.

Asymptomatic herpes simplex virus shedding from the genital tract whilst on suppressive doses of oral acyclovir

Forty-eight patients were recruited into a study of continuous oral acyclovir therapy for the suppression of recurrent genital herpes simplex virus (HSV) infection. Seven of these patients were shown to shed HSV in the absence of clinical signs or symptoms whilst on medication. The asymptomatic shedders did not differ significantly from the rest of the group in terms of age, interval from first attack to enrollment or number of recurrences prior to enrollment. Only one patient admitted to poor compliance as a trigger to asymptomatic HSV shedding. Failure to suppress asymptomatic shedding during prophylactic acyclovir therapy may have implications for sexual transmission to partners and vertical transmission to neonates and requires further study.

Effect of phase of menstrual cycle on insulin sensitivity, peripheral blood flow and cardiovascular responses to hyperinsulinaemia in young women with type 1 diabetes

Disturbances of blood glucose control around the time of menstruation are often reported by women with Type 1 diabetes. To investigate the possibility that such changes may be due to alterations in insulin sensitivity or peripheral blood flow we have studied 9 women with Type 1 diabetes during the follicular and luteal phases of the menstrual cycle. Insulin sensitivity was assessed by the glucose clamp technique with insulin doses of 40 (low dose) and 100 (high dose) mU m-2 min-1. Glucose disposal rates were 2.5 +/- 0.3 (mean +/- SE) mg kg-1 min-1 during the follicular phase and 3.2 +/- 0.3 mg kg-1 min-1 in the luteal phase with low dose insulin, and 5.9 +/- 0.4 and 6.4 +/- 0.6 mg kg-1 min-1, respectively, with high dose insulin. These differences were not statistically significant. Forearm blood flow, heart rate, and blood pressure were similar during both phases.

An immunohistochemical study of the endolymphatic sac in patients with acoustic tumors

Intraosseous endolymphatic sacs obtained from patients with acoustic neuromas who had undergone total labyrinthectomy during tumor removal were examined for the presence of T helper/inducer and T suppressor/cytotoxic lymphocytes, B lymphocytes, plasma cells, and macrophages. Immunoperoxidase staining of cryostat sections revealed the presence of T helper/inducer lymphocytes, T suppressor/cytotoxic lymphocytes, and macrophages. The number of B lymphocytes and plasma cells was much smaller than the number of T lymphocytes. The number of T suppressor/cytotoxic lymphocytes was higher than the number of T helper/inducer lymphocytes. This study supports the notion of local immune responsiveness in the human inner ear. This is the first immunohistochemical study to analyze lymphocyte subpopulations; specifically, to provide insight into T-cell function in the endolymphatic sac.

Prostitution in Sheffield: differences between prostitutes

This study to assess differences between street walking prostitutes and sauna girls who attended this clinic in 1986 and 1987 showed that fewer street walkers used barrier methods for disease prevention with clients or accepted tests for antibody to human immunodeficiency virus (HIV) when offered and more street walkers practised their profession in both Sheffield and London. They therefore represent a potential pathway for the heterosexual spread of HIV to the region. Trichomonas vaginalis was the only organism more commonly isolated from street walkers. Other sexually transmitted diseases diagnosed, and the sources of acquisition of gonococcal cervicitis, were similar in both groups of prostitutes. Prostitutes rarely used barrier methods with their regular consorts, who were found to be responsible for most cases of gonorrhoea in both groups. As 11 out of 58 prostitutes attending were found to have dysplasia on routine cervical cytological examination, we suggest that all prostitutes be advised to undergo cytology yearly.

Bilateral adhesive capsulitis, oligoarthritis and proximal myopathy as presentation of hypothyroidism

A patient who presented with bilateral adhesive capsulitis of the shoulder, oligoarthropathy and rapidly progressive proximal myopathy is described. Although clinically euthyroid, autoimmune and biochemical hypothyroidism was the only predisposing factor found. Clinical deterioration after initiation of thyroxine replacement was followed by delayed improvement with reduction in initially elevated ESR and CRP.

Human leukocytic antigens in autoimmune sensorineural hearing loss

Susceptibility to many autoimmune diseases is associated with inheritance of certain Human Leukocytic Antigens (HLA), determinants which have become diagnostic or prognostic markers. In this study of HLA antigen frequencies among patients with autoimmune sensorineural hearing loss, 39 patients with this otologic disorder were typed for HLA-A, B, C, and DR antigens. A significant increase of Cw7 occurred in 51% of patients compared to 21% of 627 matched controls (relative risk, 3.95). Trends towards increased frequencies of Cw4, B35 and reduced frequency of DR4 were also observed. These data suggest a possible immunogenetic predisposition to this otologic disorder. The presence of Cw7 may facilitate the diagnosis of autoimmune sensorineural hearing loss.

Sensorineural hearing loss associated with systemic lupus erythematosus

Because our recent clinical experiences suggested a possible association between hearing loss and systemic lupus erythematosus (SLE), we prospectively studied the hearing of 30 patients hospitalized because of exacerbation of SLE. Twenty-nine of the 30 patients were receiving immunosuppressive therapy at the time of testing. We found an 8% incidence of substantial, previously undetected hearing loss without attributable cause. Hearing loss could not be correlated to age, sex, disease activity, organ-system involvement, laboratory test abnormalities, or duration of symptoms of SLE. Otolaryngologists treating patients with unexplainable hearing loss--particularly if it is sudden, fluctuating, or rapidly progressive--are alerted to the possibility of underlying systemic autoimmunity. We advise physicians who frequently treat patients with SLE to include questions on hearing in the review of systems and to refer the patient with hearing complaints for thorough otologic evaluation.

Otitis media at Canyon Day, Ariz. A 16-year follow-up in Apache Indians

A 16-year follow-up survey of native Americans living in Canyon Day, Ariz, did not show improvement in the 9.3% rate of clinically significant otitis media. However, the manifestations were more benign, especially in children, and included the spectrum of otitis media. A genetically determined eustachian tube difference may explain the high rate of occurrence of otitis media in these Apache Indians. Improvements in living conditions and health care may explain the change to less severe manifestations.

Acute myelogenous leukemia presenting as atypical mastoiditis with facial paralysis

Symptomatic otologic involvement by leukemic infiltration is unusual, most often occurring in the already-diagnosed leukemic patient as postauricular mass, acute hemorrhagic otitis media, mastoiditis, cranial neuropathy, vertigo, hearing loss, or leptomeningitis. We think ours is the first reported patient whose leukemia presented as atypical mastoiditis and facial paralysis due to granulocytic sarcoma (chloroma). At mastoidectomy, tan lobulated rubbery tumor filled the mastoid antrum and middle ear cleft. Complete remission and full return of facial nerve function was achieved with 2500 R local radiation and systemic chemotherapy. We discuss the role and extent of surgery in atypical acute mastoiditis when unsuspected middle ear and mastoid tumor, with inconclusive intra-operative histopathologic data, is found.