Multipath artifacts enable angular contrast in multimodal endoscopic optical coherence tomography

Multipath artifacts are inherent to double-clad fiber based optical coherence tomography (OCT), appearing as ghost images blurred in the A-line direction. They result from the excitation of higher-order inner-cladding modes in the OCT sample arm which cross-couple into the fundamental mode at discontinuities and thus are detected in single-mode fiber-based interferometers. Historically, multipath artifacts have been regarded as a drawback in single fiber endoscopic multimodal OCT systems as they degrade OCT quality. In this work, we reveal that multipath artifacts can be projected into high-quality two-dimensional en face images which encode high angle backscattering features. Using a combination of experiment and simulation, we characterize the coupling of Mie-range scatterers into the fundamental image (LP01 mode) and higher-order image (multipath artifact). This is validated experimentally through imaging of microspheres with an endoscopic multimodal OCT system. The angular dependence of the fundamental image and higher order image generated by the multipath artifact lays the basis for multipath contrast, a ratiometric measurement of differential coupling which provides information regarding the angular diversity of a sample. Multipath contrast images can be generated from OCT data where multipath artifacts are present, meaning that a wealth of clinical data can be retrospectively examined.

Triple-clad W-type fiber mitigates multipath artifacts in multimodal optical coherence tomography

Multimodal endoscopic optical coherence tomography (OCT) can be implemented with double-clad fiber by using the presumed single-mode core for OCT and the higher numerical aperture cladding for a secondary modality. However, the quality of OCT in double-clad fiber (DCF) based systems is compromised by the introduction of multipath artifacts that are nt present in single-mode fiber OCT systems. Herein, the mechanisms for multipath artifacts in DCF are linked to its modal contents using a commercial software package and experimental measurement. A triple-clad W-type fiber is proposed as a method for achieving multimodal imaging with single-mode quality OCT in an endoscopic system. Simulations of the modal contents of a W-type fiber are compared to DCF and single-mode fiber. Finally, a W-Type fiber rotary catheter is used in a DCF-based endoscopic OCT and autofluorescence imaging (AFI) system to demonstrate multipath artifact free OCT and AFI of a human fingertip.

Clinical burden of illness in patients with phenylketonuria (PKU) and associated comorbidities - a retrospective study of German health insurance claims data

BACKGROUND

Phenylketonuria (PKU) is an inherited deficiency in the enzyme phenylalanine hydroxylase (PAH), which, when poorly-managed, is associated with clinical features including deficient growth, microcephaly, seizures, and intellectual impairment. The management of PKU should start as soon as possible after diagnosis to prevent irreversible damage and be maintained throughout life. The aim of this study was to assess the burden of illness in PKU patients in general and in PKU patients born before and after the introduction of newborn screening in Germany.

METHODS

This retrospective matched cohort analysis used the Institut für angewandte Gesundheitsforschung Berlin (InGef) research database containing anonymized healthcare claims of approximately 4 million covered lives. PKU patients were compared with matched controls from the general population within the same database (1:10 ratio via direct, exact matching on age and gender without replacement). PKU patients were included if they were aged ≥18 years on 01/01/15 and were continuously enrolled from 01/01/10 to 31/12/15. The 50 most commonly reported comorbidities and 50 most commonly prescribed medications in the PKU population were analyzed. Differences between groups were tested using 95% confidence interval (CI) of prevalence ratio (PR) values.

RESULTS

The analysis included 377 adult PKU patients (< 5 of which were receiving sapropterin dihydrochloride) and 3,770 matched controls. Of the 50 most common comorbidities in the PKU population, those with a statistically significant PR > 1.5 vs controls included major depressive disorders (PR = 2.3), chronic ischemic heart disease (PR = 1.7), asthma (PR = 1.7), dizziness and giddiness (PR = 1.8), unspecified diabetes mellitus (PR = 1.7), infectious gastroenteritis and colitis (PR = 1.7), and reaction to severe stress and adjustment disorders (PR = 1.6). The most commonly prescribed Anatomical Therapeutic Chemical (ATC) subcodes among PKU patients (vs the control population) are for systemic antibacterials (34.7% vs 32.8%), anti-inflammatory and antirheumatic (29.4% vs 27.5%), renin-angiotensin agents (30.0% vs 27.0%), acid-related disorders (29.4% vs 20.2%), and beta-blockers (24.9% vs 19.9%).

CONCLUSION

The overall clinical burden on patients with PKU is exacerbated by a significantly higher risk of numerous comorbidities and hence, prescribing of the requisite medication, both for recognized (e.g. major depressive disorders) and more unexpected comorbidities (e.g. ischemic heart disease).

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Case report: a troublesome ophthalmic artery aneurysm

Objective and Importance When treating large unruptured ophthalmic artery (OA) aneurysms causing progressive blindness, surgical clipping is still the preferred method because aneurysm sac decompression may relieve optic nerve compression. However, endovascular treatment of OA aneurysms has made important progress with the introduction of stents. Although this development is welcomed, it also makes the choice of treatment strategy less straightforward than in the past, with the potential of missteps.

Clinical Presentation A 56-year-old woman presented with a long history of progressive unilateral visual loss and magnetic resonance imaging showing a 20-mm left-sided OA aneurysm.

Intervention Because of her long history of very poor visual acuity, we considered her left eye to be irredeemable and opted for endovascular therapy. The OA aneurysms was treated with stent and coils but continued to grow, threatening the contralateral eye. Because she failed internal carotid artery (ICA) balloon test occlusion, we performed a high-flow extracranial-intracranial bypass with proximal ICA occlusion in the neck. However, aneurysm growth continued due to persistent circulation through reversed blood flow in distal ICA down to the OA and the cavernous portion of the ICA. Due to progressive loss of her right eye vision, we surgically occluded the ICA proximal to the posterior communicating artery and excised the coiled, now giant, OA aneurysm. This improved her right eye vision, but her left eye was permanently blind.

Conclusion This case report illustrates complications of the endovascular and surgical treatment of a large unruptured OA aneurysm.

Ex vivo confocal imaging with contrast agents for the detection of oral potentially malignant lesions

OBJECTIVES

We investigated the potential use of real-time confocal microscopy in the non-invasive detection of occult oral potentially malignant lesions. Our objectives were to select the best fluorescence contrast agent for cellular morphology enhancement, to build an atlas of confocal microscopic images of normal human oral mucosa, and to determine the accuracy of confocal microscopy to recognize oral high-grade dysplasia lesions on live human tissue.

MATERIALS AND METHODS

Five clinically used fluorescent contrast agents were tested in vitro on cultured human cells and validated ex vivo on human oral mucosa. Images acquired ex vivo from normal and diseased human oral biopsies with bench-top fluorescent confocal microscope were compared to conventional histology. Image analyzer software was used as an adjunct tool to objectively compare high-grade dysplasia versus low-grade dysplasia and normal epithelium.

RESULTS

Acriflavine Hydrochloride provided the best cellular contrast by preferentially staining the nuclei of the epithelium. Using topical application of Acriflavine Hydrochloride followed by confocal microscopy, we could define morphological characteristics of each cellular layer of the normal human oral mucosa, building an atlas of histology-like images. Applying this technique to diseased oral tissue specimen, we were also able to accurately diagnose the presence of high-grade dysplasia through the increased cellularity and changes in nuclear morphological features. Objective measurement of cellular density by quantitative image analysis was a strong discriminant to differentiate between high-grade dysplasia and low-grade dysplasia lesions.

CONCLUSIONS

Pending clinical investigation, real-time confocal microscopy may become a useful adjunct to detect precancerous lesions that are at high risk of cancer progression, direct biopsy and delineate excision margins.

Lymphoid tissue inducer cells: architects of CD4 immune responses in mice and men

In this review, we summarize the current understanding of the multiple functions of the mouse lymphoid tissue inducer (LTi) cells in: (i) the development of organized lymphoid tissue, (ii) the generation and maintenance of CD4-dependent immunity in adult lymphoid tissues; and (iii) the regulation of central tolerance in thymus. By contrast with mouse LTi cells, which have been well described, the human equivalent is only just beginning to be characterized. Human LTi-like cells expressing interleukin (IL)-22 have been identified recently and found to differentiate into natural killer (NK) cells. The relationship of LTi cells to NK cells is discussed in the light of several studies reporting a close relationship in the mouse between LTi cells and transcription factor retinoid-related orphan receptor gammat-dependent IL-22 producing NK cells in the gut. We also outline our data suggesting that these cells are present in adult human lymphoid tissues.

Effect of myeloablative bone marrow transplantation on growth in children with sickle cell anaemia: results of the multicenter study of haematopoietic cell transplantation for sickle cell anaemia

Although haematopoietic cell transplantation (HCT) is curative for sickle cell anaemia (SCA), concerns about its short- and long-term toxicities limit its application. A potential toxicity is an adverse effect on growth. To identify an HCT growth effect, serial height and weight measurements from 53 children and adolescents with SCA after receiving a transplant were compared to historical controls. Hierarchical Linear Models for longitudinal data were used for analysis. In general growth was not impaired by HCT for SCA in young children; however, diminished growth may occur if HCT is carried out near or during the adolescent growth spurt.

Long-term clearance of patch-stage mycosis fungoides with the 308-nm laser

In order to investigate the effectiveness of the 308-nm xenon chloride laser in the treatment of patch-stage mycosis fungoides that is refractory to topical steroids, we conducted a prospective, histologically controlled, open-label pilot study. Eight patients with stage 1A or 1B cutaneous T-cell lymphoma that was unresponsive to application of potent topical steroids received 20 treatments with the laser over 10 weeks and were then followed up for a minimum of 30 months. Three patients had a complete clinical and histological response and remained free of disease after 30 months A further three patients had complete clinical and histological clearance of disease, but experienced relapse within the 30 months follow-up period. One patient withdrew from the study and one had a partial response. Further research to establish the role of the 308-nm laser in the treatment of MF appears justified.

The emergency department approach to violently injured patient care: a regional survey

OBJECTIVE

Since the early 1990s public health workers have challenged healthcare practitioners to take an active role in violence prevention with patients aged 10-24 years. Emergency department (ED) clinicians are uniquely positioned to identify, assess, and refer youth involved in violent events. The objective of this study was to describe ED directors' estimate of the number of violently injured youth seen, the presence of established protocols or guidelines for handling youth violence, and the type of training programs offered to ED physicians regarding this issue.

METHODS

The authors conducted a survey of EDs (n = 64) in the Philadelphia metropolitan region to determine the standard of ED care for violently injured youths. Half of the EDs were in urban areas and half in suburban.

RESULTS

A total of 41 out of 64 (64.1%) ED directors completed and returned the written questionnaire. In addition to treating the specific injuries sustained, ED responses to youth violence primarily involved talking with patients about the events surrounding the injury. The estimated number of violently injured youth seen per month varied considerably. Twenty four directors (58.5%) estimated that their institution treated fewer than 10 per month; 10 (24.4%) reported 11-30, and seven (17.1%) mostly large urban hospitals, saw more than 30 per month. Although most hospitals reported that the staff counsels patients about safety concerns, only 17% offered their staff formal training programs on youth violence.

CONCLUSIONS

To address the prevention of youth violence, EDs need specific training programs for ED staff, as well as systematic risk assessment and referral resources for structured intervention and follow up.

Nodular regenerative hyperplasia of the liver and coeliac disease: potential role of IgA anticardiolipin antibody

Nodular regenerative hyperplasia (NRH) of the liver is a rare disorder that is often associated with connective tissue disorders, haematological malignancy, or drugs, and is a cause of non-cirrhotic portal hypertension. We describe two cases of NRH in individuals with adult coeliac disease and IgA anticardiolipin antibodies. We discuss the potential impact of this observation on the understanding of the pathogenesis of NRH.

Improvement of a mammalian cell culture process by adaptive, model-based dialysis fed-batch cultivation and suppression of apoptosis

Both conventional and genetic engineering techniques can significantly improve the performance of animal cell cultures for the large-scale production of pharmaceutical products. In this paper, the effect of such techniques on cell yield and antibody production of two NS0 cell lines is presented. On the one hand, the effect of fed-batch cultivation using dialysis is compared to cultivation without dialysis. Maximum cell density could be increased by a factor of approximately 5-7 by dialysis fed-batch cultivation. On the other hand, suppression of apoptosis in the NS0 cell line 6A1 bcl-2 resulted in a prolonged growth phase and a higher viability and maximum cell density in fed-batch cultivation in contrast to the control cell line 6A1 (100)3. These factors resulted in more product formation (by a factor of approximately 2). Finally, the adaptive model-based OLFO controller, developed as a general tool for cell culture fed-batch processes, was able to control the fed-batch and dialysis fed-batch cultivations of both cell lines.

Factors influencing the access of severely injured children and elderly patients involved in motor vehicle collisions to trauma center care

This study was undertaken to determine factors that influence the access to trauma center care of pediatric and geriatric patients injured in motor vehicle collisions (MVC). Hospital discharge records for 1997 were obtained from the Pennsylvania Health Care Cost Containment Council and were analyzed. Of cases with an Injury Severity Score of > 15, 52.6% of elderly cases and 48.6% of pediatric cases were transported to and received their care in non-trauma center hospitals. These very high "mis-triage" rates could not be explained by differences in injury severity, body region or population density. In order to assess potential out-of-hospital factors, a file containing matched records from Emergency Medical Services (EMS) calls and hospital discharges from MVC cases across Pennsylvania for the year 1996 was constructed and analyzed. There were no significant vital signs differences between trauma center and non-trauma center cases, with the single exception of the Glasgow Coma Scale score, for both the pediatric and geriatric age groups. A reevaluation of out-of-hospital trauma triage is needed.

High-density miniaturized thermal shift assays as a general strategy for drug discovery

More general and universally applicable drug discovery assay technologies are needed in order to keep pace with the recent advances in combinatorial chemistry and genomics-based target generation. Ligand-induced conformational stabilization of proteins is a well-understood phenomenon in which substrates, inhibitors, cofactors, and even other proteins provide enhanced stability to proteins on binding. This phenomenon is based on the energetic coupling of the ligand-binding and protein-melting reactions. In an attempt to harness these biophysical properties for drug discovery, fully automated instrumentation was designed and implemented to perform miniaturized fluorescence-based thermal shift assays in a microplate format for the high throughput screening of compound libraries. Validation of this process and instrumentation was achieved by investigating ligand binding to more than 100 protein targets. The general applicability of the thermal shift screening strategy was found to be an important advantage because it circumvents the need to design and retool new assays with each new therapeutic target. Moreover, the miniaturized thermal shift assay methodology does not require any prior knowledge of a therapeutic target's function, making it ideally suited for the quantitative high throughput drug screening and evaluation of targets derived from genomics.

Cloning, pharmacology, and tissue distribution of G-protein-coupled receptor GPR105 (KIAA0001) rodent orthologs

It has recently been shown that UDP-glucose is a potent agonist of the orphan G-protein-coupled receptor (GPCR) KIAA0001. Here we report cloning and analysis of the rat and mouse orthologs of this receptor. In accordance with GPCR nomenclature, we have renamed the cDNA clone, KIAA0001, and its orthologs GPR105 to reflect their functionality as G-protein-coupled receptors. The rat and mouse orthologs show 80% and 83% amino acid identity, respectively, to the human GPR105 protein. We demonstrate by genomic Southern blot analysis that there are no genes in the mouse or rat genomes with higher sequence similarity. Chromosomal mapping shows that the mouse and human genes are located on syntenic regions of chromosome 3. Further analyses of the rat and mouse GPR105 proteins show that they are activated by the same agonists as the human receptor, responding to UDP-glucose and closely related molecules with similar affinities. The mouse and rat receptors are widely expressed, as is the human receptor. Thus we conclude that we have identified the rat and mouse orthologs of the human gene GPR105.

S-nitrosylation is emerging as a specific and fundamental posttranslational protein modification: head-to-head comparison with O-phosphorylation

Nitric oxide (NO) is a free-radical product of mammalian cell metabolism that plays diverse and important roles in the regulation of cell function. Biological actions of NO arise as a direct consequence of chemical reactions between NO or NO-derived species and protein targets. Reactions of NO with transition metals in target proteins have garnered the most attention to date as the principal mechanism of NO signaling; nonetheless, S-nitrosylation of protein Cys residues is rapidly moving to center stage in importance. In general, however, there has been a delay in adequate appreciation of the role of S-nitrosylation in biological signaling by NO. This lag is attributed to a poor understanding of the basis for selective targeting of NO to particular thiols, and methodological limitations in accurately quantifying this modification--recent breakthroughs in concepts and methods diminish these barriers. Here, we consider the wheres and whys of protein S-nitrosylation and its basis for specificity. Protein S-nitrosylation potentially represents a ubiquitous and fundamental mechanism for posttranslational control of protein activity on a par with that of O-phosphorylation.

Supporting GPs whose performance gives cause for concern: the North Trent experience

BACKGROUND

The North Trent scheme to address the problem of GPs whose performance gives cause for concern was implemented in 1997. This paper describes the structure and process of the scheme and evaluates the main outcomes.

METHODS

We used non-participant observation and semi-structured interviews with representatives of the seven Health Authorities (HAs) of North Trent including medical and prescribing advisors and senior primary care managers. Twenty-one GPs who were members of the Performance Review Quartets (PRQs) were also interviewed. Qualitative data were analysed using a constant comparative method to identify emergent themes.

RESULTS

Performance indicators were agreed between HAs and the profession in the seven North Trent localities. The scheme identified 18 GPs whose performance gave cause for concern, of whom 15 GPs in six practices received a formal visit. Educational plans were agreed and implemented with three GPs. The remaining 12 received administrative and clinical support. Three of the 18 GPs initially refused to co-operate with the scheme. Two of these have since agreed a practice visit following a visit by a senior local medical committee representative. The performance indicators used in the scheme have not been specific to individual GPs except those in single-handed practices. Some indicators used by PRQs related to cost effectiveness rather than quality of care for individual patients. Current resources were adequate for the small number of underperforming GPs identified by the scheme.

CONCLUSIONS

The North Trent scheme has identified a number of underperforming GPs, 83% of whom have been willing to participate in a supportive intervention. The scheme will need some modification with the advent of primary care trusts and the proposed assessment and support centres.

Interleukin 1 induces hypoxia-inducible factor 1 in human gingival and synovial fibroblasts

Rheumatoid arthritis and periodontitis are inflammatory diseases modulated by proinflammatory cytokines [e.g. interleukin (IL-1) 1 and tumour necrosis factor alpha], which activate local fibroblasts to do the following: (1) proliferate, (2) induce gene expression and (3) produce destructive metalloproteinases. Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor (composed of HIF-1alpha and HIF-1beta/aryl hydrocarbon receptor nuclear transporter) that is modulated by hypoxia. HIF-1 binds to and induces several genes containing an HIF-1 consensus-binding site, including vascular endothelial growth factor and several glycolytic enzymes. Through differential screening of a human synovial fibroblast cDNA library, we identified HIF-1alpha as a clone up-regulated by IL-1. The mRNA for HIF-1alpha subunit was increased 3-4-fold by Northern blot analysis after cells had been incubated for 3 h in the presence of IL-1. In addition, IL-1 increased the binding of the heterodimer HIF-1 to the HIF consensus sequence. These results suggest that HIF-1 might have a role in inflammation, possibly in attempting to re-establish homoeostasis.

[Actinic prurigo. An assessment of current status]

BACKGROUND AND OBJECTIVE

Actinic prurigo (AP) is a hereditary photodermatoses with typical symptoms and is quite common in North- and South-America. The key genetic factor appears to be a Native American background. In Europeans this type of AP is extremely rare; some dispute if this disease exists in Caucasians. Some newer publications postulate that these patients share HLA markers with the Native Americans. The most important differential diagnosis for AP is polymorphic light eruption which can be excluded relatively accurately by the clinical picture, typical histology and HLA pattern.

PATIENTS/METHODS

The case of a female patient of Mayan ancestry living in Germany is presented.

CONCLUSIONS

Since in literature sometimes cases from Europe are diagnosed as AP this is a problem of naming the disease. It would be helpful to integrate the terms hereditary or hereditaria into the name of the disease in indians.

A competency model for general practice: implications for selection, training, and development

BACKGROUND

The role of the general practitioner (GP) has changed significantly over the past decade. This problem is compounded by growing concern over postgraduate attrition rates from medicine, with current estimates as high as 19%.

AIM

To define a comprehensive model of the competencies required for the job role of GP.

METHOD

Three independent studies were conducted to define GP competencies including (1) critical incidents focus groups with GPs, (2) behavioural coding of GP-patient consultations, and (3) critical incidents interviews with patients. Study 1 was conducted with GPs (n = 35) from the Trent region. Study 2 involved observation of GP-patient consultations (n = 33 consultations), and Study 3 was conducted with patients (n = 21), all from a Midlands-based medical practice.

RESULTS

The data collected from the three studies provided strong evidence for a competency model comprising 11 categories with a summary of the associated behavioural descriptions. Example competencies included empathy and sensitivity, communication skills, clinical knowledge and expertise, conceptual thinking, and coping with pressure.

CONCLUSIONS

Triangulation of results was achieved from three independent studies. The competencies derived imply that a greater account of personal attributes needs to be considered in recruitment and training, rather than focusing on academic and clinical competency alone. The model could be employed for future research in design of selection techniques for the role of GP.

The autoinhibitory control element and calmodulin conspire to provide physiological modulation of endothelial and neuronal nitric oxide synthase activity

NO production by the endothelial and neuronal isoforms of nitric oxide synthase (cNOS) is regulated on a moment-to-moment basis by calmodulin binding, triggered by transient elevations in intracellular-free calcium levels. Nonetheless, additional modes of cNOS regulation are implicit in the discoveries of stimuli that elicit a sustained increase in cNOS activity despite undetectable or transient increases in intracellular Ca2+ in endothelial cells; such stimuli include shear-stress, oestrogen, insulin or insulin-like growth factor treatment of endothelial cells. Recently, we identified a peptide insertion within the FMN-binding domain of mammalian NOSs that is unique to calcium-dependent isoforms, and not shared with inducible NOS or ancestral flavoproteins. Evidence suggests that this insertion serves as a fundamental control element, analogous to intrinsic autoinhibitory peptides that have been demonstrated to regulate activity of other calmodulin-dependent enzymes. Thus, the peptide insertion of cNOSs appears to function as structural element that is displaced upon calmodulin binding, resulting in dysinhibition of NO synthesis. Once displaced, the peptide may also be subject to transient chemical modifications and protein-protein interactions that modulate autoinhibitory function. Herein we summarize our present knowledge and speculate on mechanisms by which calmodulin and the autoinhibitory peptide conspire to regulate cNOS activity.

Mice transgenic for a soluble form of murine cytotoxic T lymphocyte antigen 4 are refractory to murine acquired immune deficiency sydrome development

Interactions between B and CD4+ T cells are central to the pathogenesis of retrovirus-induced murine acquired immune deficiency virus (MAIDS). Prompted by previous work showing that treatment with cytotoxic T lymphocyte antigen 4 immunoglobulin (CTLA4Ig) partly inhibited the disease, we studied the course of infection in mice deficient for CD28-B7 interactions (mCTLA4-Hgamma1 transgenic mice). Despite a relative viral load identical to that of non-transgenic mice, the transgenic mice did not develop any of the major MAIDS symptoms (i.e. lymphoproliferation and immune anergy). The mCTLA4-Hgamma1 did not however, completely inhibit B-cell activation as indicated by a slight hypergammaglobulinaemia and microscopic blastic transformation. Absence of MAIDS in transgenic mice was associated with much lower levels of both interleukin-4 and interferon-gamma transcripts following viral infection. These results support the theory that the CD28/B7 costimulatory pathway is a critical determinant to MAIDS development.

The Wisdom Project: virtual education in primary care

This article examines the development of the Wisdom Project, a pilot for the teaching of informatics to primary health care professionals, using an original educational model based on e-mail and Web pages. The article begins by placing the development of the Wisdom Project in the context of changes in medical education and training. The aims and objectives of Wisdom are outlined, and the methodologies for setting up and evaluating the project are described. The article then presents the results of the evaluation, including the identification of significant improvements in knowledge of CD ROMs (P = 0.01), e-mail (P = 0.03), Medline (P = 0.02), operating systems (P = 0.02), Web browsers (P = 0.003) and word processing (P = 0.03). Improvements in evidence-based practice (EBP) did not reach significance. Finally, a number of conclusions are presented, considering the lessons learnt for the future development of such projects.

The WISDOM project: training primary care professionals in informatics in a collaborative 'virtual classroom'

OBJECTIVES

The WISDOM project applies Internet technologies to create a virtual classroom in health informatics for primary care professionals. Participants use a facilitated E-mail discussion list supported by a web site which provides on-line resources and an archive of teaching materials.

DESIGN

The project took an adult-learning model in which participants identify their learning needs, emphasized using informatics skills in practice, and focused on skills likely to enhance evidence-based practice. The paper describes the project and an evaluation of the first programme which ran in 1997 with 28 participants. Pre- and post-intervention questionnaires were used to assess perceived skills in informatics and evidence-based practice.

SETTING

University of Sheffield.

SUBJECTS

Primary care professionals.

RESULTS

Participants reported statistically significant increases in eight informatics skills. There were no significant changes in evidence-based practice skills. The web-site, seminar programme and discussion list were highly rated as useful in delivering informatics training.

CONCLUSIONS

The WISDOM approach is effective for the delivery of informatics training to primary care professionals, and may be used more widely for other subjects and professional groups. There is a need for further research into facilitating virtual classrooms.

CD4 T cell traffic control: in vivo evidence that ligation of OX40 on CD4 T cells by OX40-ligand expressed on dendritic cells leads to the accumulation of CD4 T cells in B follicles

We report here that CD40- but not lipopolysaccharide (LPS)-activated murine dendritic cells (DC) express OX40-ligand (OX40L) as has been reported in humans. To understand how OX40 ligation affects differentiation of CD4 T cells at the time of priming, we constitutively expressed OX40L on DC using the DC-specific promoter of CD11c. Transgenic mice showed greatly increased numbers of CD4 but not CD8 T cells in their B cell areas. This effect was to a great extent immunization dependent, as spleen and lymphoid tissue with no germinal center reactions from mice which had not been deliberately immunized did not show marked CD4 T cell accumulation. The increased numbers of CD4+ CD62low cells in transgenic mice suggest that it is activated CD4 T cells that accumulate within B cell follicles. These data are consistent with the notion that physiological engagement of OX40 (CD134) on activated CD4 T cells either initiates their migration into or causes them to be retained in B follicles. In contrast, LPS-treated CD did not up-regulate OX40L expression. This dichotomy provides a molecular explanation of how DC might integrate environmental and accessory signals to control cytokine differentiation and migration in CD4 effector cells.

Cell signaling by nitric oxide

Appreciation of the role of nitric oxide (NO) in mammalian cell biology has toppled the paradigm that biological signaling is initiated exclusively by noncovalent, lock-and-key-type interactions with receptor proteins. Remarkably, nitric oxide is a free radical that signals by chemical reaction with its protein targets, resulting in covalent modifications and a stable alteration in protein structure and function. Although most proteins may be coerced to react with NO in vitro, the specific proteins that are functionally modified by NO within cells will depend on the concentration of NO and the composition of the intracellular milieu. A further level of complexity is introduced into NO signaling by the fact that reactions can occur with NO directly, or secondarily with NO-derived species. Much to the surprise of those who thought that reactive molecules are generated and act only under pathophysiological conditions (e.g., ischemia-reperfusion injury), NO has emerged as a prototype molecule that signals by chemistry in normal physiology. The unique attributes and importance of NO were recently recognized by the Nobel Prize Committee, with their decision to award the 1998 Prize in Medicine to Drs Furchgott, Ignarro, and Murad, pioneers in NO biology. This review surveys what we believe to be the most important mechanisms and targets of signaling by NO.

Development and testing of the Resistiveness to Care Scale

A conceptual model and objective scale for measuring resistiveness to care in individuals with advanced dementia of the Alzheimer type (DAT) were empirically generated from the perspective of nursing staff caregivers and through observation of residents with DAT. The resistiveness to care scale (RTC-DAT) was judged to have content validity and reduced to 13 items. Quantifiable scoring procedures and methods for rating videotapes and conducting clinical observations were developed. The RTC-DAT was tested with 68 subjects at three sites. The RTC has a range of 0-156. Initial testing provided reliability estimates of .82-.87 for internal consistency and good to excellent kappas. Criterion-related validity with observed discomfort and construct validity by factor analysis support the RTC-DAT. Measurement issues and recommendations for use in research are discussed.

CD4 T cell cytokine differentiation: the B cell activation molecule, OX40 ligand, instructs CD4 T cells to express interleukin 4 and upregulates expression of the chemokine receptor, Blr-1

This report investigates the role of OX40 ligand (OX40L) and its receptor, OX40, expressed on activated B and T cells, respectively, in promoting the differentiation of T helper type 2 (Th2) CD4 T cells. These molecules are expressed in vivo by day 2 after priming with T cell- dependent antigens. Their expression coincides with the appearance of immunoglobulin (Ig)G switch transcripts and mRNA for interleukin (IL)-4 and interferon (IFN)-gamma, suggesting that this molecular interaction plays a role in early cognate interactions between B and T cells. In vitro, we report that costimulation of naive, CD62Lhigh CD4 T cells through OX40 promotes IL-4 expression and upregulates mRNA for the chemokine receptor, blr-1, whose ligand is expressed in B follicles and attracts lymphocytes to this location. Furthermore, T cell stimulation through OX40 inhibits IFN-gamma expression in both CD8 T cells and IL-12-stimulated CD4 T cells. Although this signal initiates IL-4 expression, IL-4 itself is strongly synergistic. Our data suggest that OX40L on antigen-activated B cells instructs naive T cells to differentiate into Th2 cells and migrate into B follicles, where T cell-dependent germinal centers develop.

Requirements for B7-CD28 costimulation in mucosal IgA responses: paradoxes observed in CTLA4-H gamma 1 transgenic mice

The block in the CD80/CD86-CD28/CTLA-4 pathway in CTLA4-H gamma 1 transgenic (Tg) mice results in strongly impaired systemic IgG immunity and failure to develop germinal center reactions. By contrast, here we report that mucosal immunity and IgA B cell differentiation are not affected by this block. We found abundant germinal centers and evidence of IgA switch differentiation in Peyer's patches, normal total IgA levels, and normal numbers of IgA-labeling cells in the gut mucosa. The distribution of B-1 and B-2 cells and the relative contribution of B-1 cells to the total IgA B cells were similar in Tg and wild-type mice. Despite this, oral immunizations with keyhole limpet hemocyanin plus cholera toxin adjuvant failed to stimulate Ag-specific mucosal IgA responses in CTLA4-H gamma 1 Tg mice. This was not due to a lack of adjuvant activity of cholera toxin in Tg mice, nor was this secondary to an inability to take up Ag from the gut lumen. Rather, CD4+ T cells stimulated by oral immunization in Tg mice appeared to be inappropriately primed, as evidenced by a significantly reduced level of CD40 ligand and CD44 expression and an increased expression of CD95 compared to those in wild-type mice. This study reveals a paradox in the regulation of mucosal IgA responses.

An autoinhibitory control element defines calcium-regulated isoforms of nitric oxide synthase

Nitric oxide synthases (NOSs) are classified functionally, based on whether calmodulin binding is Ca2+-dependent (cNOS) or Ca2+-independent (iNOS). This key dichotomy has not been defined at the molecular level. Here we show that cNOS isoforms contain a unique polypeptide insert in their FMN binding domains which is not shared with iNOS or other related flavoproteins. Previously identified autoinhibitory domains in calmodulin-regulated enzymes raise the possibility that the polypeptide insert is the autoinhibitory domain of cNOSs. Consistent with this possibility, three-dimensional molecular modeling suggested that the insert originates from a site immediately adjacent to the calmodulin binding sequence. Synthetic peptides derived from the 45-amino acid insert of endothelial NOS were found to potently inhibit binding of calmodulin and activation of cNOS isoforms. This inhibition was associated with peptide binding to NOS, rather than free calmodulin, and inhibition could be reversed by increasing calmodulin concentration. In contrast, insert-derived peptides did not interfere with the arginine site of cNOS, as assessed from [3H]NG-nitro-L-arginine binding, nor did they potently effect iNOS activity. Limited proteolysis studies showed that calmodulin's ability to gate electron flow through cNOSs is associated with displacement of the insert polypeptide; this is the first specific calmodulin-induced change in NOS conformation to be identified. Together, our findings strongly suggest that the insert is an autoinhibitory control element, docking with a site on cNOSs which impedes calmodulin binding and enzymatic activation. The autoinhibitory control element molecularly defines cNOSs and offers a unique target for developing novel NOS activators and inhibitors.

Creating an education model for cardiac patients

Patient education is important in reducing the risk of recurrence of myocardial infarction. Education should be specific to patients' individual needs. Patients need motivating to achieve the required behaviour changes. A multidisciplinary, multifactorial approach to education is most effective.

Cardiac electrophysiology studies and ablation procedures: a literature review

This literature review is focused on issues related to the development and usefulness of cardiac electrophysiology studies and ablation procedures. During the past decade, the efficacy of these developments has been proven. The resultant emergence of specialists trained as electrophysiologists represents an important milestone in the advancement of cardiology departments internationally. The majority of research papers on the subject have been published within the past 5 years. Most of the research has evolved from North America and Britain. On searching the literature, it was found that many gaps remain. There is a striking dearth of documented data regarding electrophysiology studies and ablation therapy within the Irish medical and nursing literature, and no previous literature review on the topic was found in a wider search. This paper provides an overview of the strengths and weaknesses associated with these procedures.