Phase contrast X-ray imaging of mice and rabbit lungs: a comparative study

The significant degree of X-ray phase contrast created by air-tissue interfaces, coupled with the poor radiographic contrast of conventional chest radiographs, makes the inflated lung an ideal candidate for investigating the potential diagnostic improvement afforded by phase contrast X-ray imaging. In small animals these methods highlight the lung airways and lobe boundaries and reveal the lung tissue as a speckled intensity pattern not seen in other soft tissues. We have compared analyser-based and propagation-based phase contrast imaging modalities, together with conventional radiographic imaging, to ascertain which technique shows the greatest image enhancement for various lung sizes. The conventional radiographic image of a mouse was obtained on a Siemens Nova 3000 mammography system, whilst phase contrast images of mice and rabbit chests were acquired at the medical imaging beamline (20B2) at the SPring-8 synchrotron radiation research facility in Japan. For mice aged 1 day, 1 week and 1 month old it was determined that analyser-based imaging showed the greatest overall image contrast, however, for an adult rabbit both techniques yielded excellent contrast. The success of these methods in creating high quality images for rabbit lungs raises the possibility of improving human lung imaging using phase contrast techniques.

Dynamic imaging of the lungs using x-ray phase contrast

High quality real-time imaging of lungs in vivo presents considerable challenges. We demonstrate here that phase contrast x-ray imaging is capable of dynamically imaging the lungs. It retains many of the advantages of simple x-ray imaging, whilst also being able to map weakly absorbing soft tissues based on refractive index differences. Preliminary results reported herein show that this novel imaging technique can identify and locate airway liquid and allows lung aeration in newborn rabbit pups to be dynamically visualized.

Distal symmetric polyneuropathy: a definition for clinical research: report of the American Academy of Neurology, the American Association of Electrodiagnostic Medicine, and the American Academy of Physical Medicine and Rehabilitation

The objective of this report was to develop a case definition of distal symmetric polyneuropathy to standardize and facilitate clinical research and epidemiologic studies. A formalized consensus process was employed to reach agreement after a systematic review and classification of evidence from the literature. The literature indicates that symptoms alone have relatively poor diagnostic accuracy in predicting the presence of polyneuropathy; signs are better predictors of polyneuropathy than symptoms; and single abnormalities on examination are less sensitive than multiple abnormalities in predicting the presence of polyneuropathy. The combination of neuropathic symptoms, signs, and electrodiagnostic findings provides the most accurate diagnosis of distal symmetric polyneuropathy. A set of case definitions was rank ordered by likelihood of disease. The highest likelihood of polyneuropathy (useful for clinical trials) occurs with a combination of multiple symptoms, multiple signs, and abnormal electrodiagnostic studies. A modest likelihood of polyneuropathy (useful for field or epidemiologic studies) occurs with a combination of multiple symptoms and multiple signs when the results of electrodiagnostic studies are not available. A lower likelihood of polyneuropathy occurs when electrodiagnostic studies and signs are discordant. For research purposes, the best approach to defining distal symmetric polyneuropathy is a set of case definitions rank ordered by estimated likelihood of disease. The inclusion of this formalized case definition in clinical and epidemiologic research studies will ensure greater consistency of case selection.

On the origin of speckle in x-ray phase contrast images of lung tissue

Phase contrast x-ray imaging of small animal lungs reveals a speckled intensity pattern not seen in other tissues, making the lungs highly visible in comparison to other organs. Although bearing a superficial resemblance to alveoli, the cause of this speckle has not been established. With a view to determining the mechanism for the formation of speckle, this paper details the results of propagation-based phase contrast experiments performed on mice lungs, together with packed glass microspheres used to emulate lung tissue. These experimental studies are compared to numerical simulations, based on wave propagation techniques. We find that speckle arises from focusing effects, with multiple alveoli acting as aberrated compound refractive lenses. Both experiments and modelling suggest that this speckle-formation phenomenon may lead to better screening methods for human lungs than conventional radiography.

Medical phase contrast x-ray imaging: current status and future prospects

The exploitation of phase contrast appears to offer the tantalising possibility of creating the biggest change in medical x-ray imaging since the invention of computed tomography. A considerable number of experiments performed by researchers across four continents have produced some extraordinary images. These images have demonstrated greatly enhanced contrast over conventional methods revealing soft tissue discrimination at micron scale resolutions. Contrast improvements can be achieved at doses rather less than those required by conventional x-ray imaging. The use of synchrotrons has revealed the possibilities offered by these techniques but unfortunately the application of these ideas in a clinical context requires that technology be pushed to its limits in a number of areas including x-ray sources, optics and detectors. The current state of the art is reviewed.

Medical phase contrast x-ray imaging: current status and future prospects

The exploitation of phase contrast appears to offer the tantalising possibility of creating the biggest change in medical x-ray imaging since the invention of computed tomography. A considerable number of experiments performed by researchers across four continents have produced some extraordinary images. These images have demonstrated greatly enhanced contrast over conventional methods revealing soft tissue discrimination at micron scale resolutions. Contrast improvements can be achieved at doses rather less than those required by conventional x-ray imaging. The use of synchrotrons has revealed the possibilities offered by these techniques but unfortunately the application of these ideas in a clinical context requires that technology be pushed to its limits in a number of areas including x-ray sources, optics and detectors. The current state of the art is reviewed.

Self-assembled uniaxial and biaxial multilayer structures in chiral smectic liquid crystals frustrated between ferro- and antiferroelectricity

With a view to obtain a molecular model for the subphases produced by the frustration between ferro- and antiferroelectricity in chiral smectic liquid crystals, we report results on two compounds and observe (i) the staircase character of uniaxial Sm C(*)(alpha) itself in the bulk and (ii) the multipeaked characteristic reflection bands due to the modulated helical structures just above the Sm C(*)(A) temperature range. We suggest the emergence of several uniaxial and biaxial subphases. The results show that both types of subphases can be specified by q(T) = [F] / ( [A] + [F] ) in the zero-order approximation; [A] and [F] are the numbers of antiferroelectric and ferroelectric orderings in the unit cell. We consider the basis of both types of subphases, particularly the description of the short-pitch helical structure of Sm C(*)(alpha), in terms of the molecular models so far proposed and emphasize the important role played by the discrete flexoelectric polarization.

Genotyping microarray (gene chip) for the ABCR (ABCA4) gene

Genetic variation in the ABCR (ABCA4) gene has been associated with five distinct retinal phenotypes, including Stargardt disease/fundus flavimaculatus (STGD/FFM), cone-rod dystrophy (CRD), and age-related macular degeneration (AMD). Comparative genetic analyses of ABCR variation and diagnostics have been complicated by substantial allelic heterogeneity and by differences in screening methods. To overcome these limitations, we designed a genotyping microarray (gene chip) for ABCR that includes all approximately 400 disease-associated and other variants currently described, enabling simultaneous detection of all known ABCR variants. The ABCR genotyping microarray (the ABCR400 chip) was constructed by the arrayed primer extension (APEX) technology. Each sequence change in ABCR was included on the chip by synthesis and application of sequence-specific oligonucleotides. We validated the chip by screening 136 confirmed STGD patients and 96 healthy controls, each of whom we had analyzed previously by single strand conformation polymorphism (SSCP) technology and/or heteroduplex analysis. The microarray was >98% effective in determining the existing genetic variation and was comparable to direct sequencing in that it yielded many sequence changes undetected by SSCP. In STGD patient cohorts, the efficiency of the array to detect disease-associated alleles was between 54% and 78%, depending on the ethnic composition and degree of clinical and molecular characterization of a cohort. In addition, chip analysis suggested a high carrier frequency (up to 1:10) of ABCR variants in the general population. The ABCR genotyping microarray is a robust, cost-effective, and comprehensive screening tool for variation in one gene in which mutations are responsible for a substantial fraction of retinal disease. The ABCR chip is a prototype for the next generation of screening and diagnostic tools in ophthalmic genetics, bridging clinical and scientific research.

Outcomes of systematic screening for optic pathway tumors in children with Neurofibromatosis Type 1

Optic pathway tumors (OPT) occur in about 15% of individuals with Neurofibromatosis Type 1 (NF1) and may effect substantial visual loss. Because their growth is not predictable at the time of discovery, neuroimaging for OPT in asymptomatic NF1 patients remains controversial. We evaluated the outcomes of systematic screening by both MRI and ophthalmic examinations for OPT in young children with NF1 seen at multi-disciplinary clinics for Neurofibromatosis and Genetics at one institution between 1996 and 2001. We report on 84 children who presented with NF1 under age 6 years, of whom 13 children presented with either known OPT or abnormal MRI findings and 11 children had OPTs identified by neuroimaging, including two children with abnormal eye examinations at presentation (one with strabismus and one with optic atrophy). Nine OPTs were detected in asymptomatic subjects with normal ophthalmic examinations. Three children with chiasmal lesions enlarging on subsequent MRI were treated with carboplatin and vincristine. After treatment, the vision in each involved eye was intact. In contrast, the 13 children with OPT diagnosed outside of screening guidelines included five children with substantial visual loss. Our observations suggest that early recognition of NF1 promotes appropriate surveillance and allows early intervention to reduce complications of OPT. This analysis supports prospective studies to compare the outcomes of systematic screening with neuroimaging to screening with ophthalmic examinations alone in children with NF1.

Distal symmetrical polyneuropathy: Definition for clinical research

The objective of this report was to develop a case definition of "distal symmetrical polyneuropathy" to standardize and facilitate clinical research and epidemiological studies. A formalized consensus process was employed to reach agreement after a systematic review and classification of evidence from the literature. The literature indicates that symptoms alone have relatively poor diagnostic accuracy in predicting the presence of polyneuropathy; signs are better predictors of polyneuropathy than symptoms; and single abnormalities on examination are less sensitive than multiple abnormalities in predicting the presence of polyneuropathy. The combination of neuropathic symptoms, signs, and electrodiagnostic findings provides the most accurate diagnosis of distal symmetrical polyneuropathy. A set of case definitions was rank ordered by likelihood of disease. The highest likelihood of polyneuropathy (useful for clinical trials) occurs with a combination of multiple symptoms, multiple signs, and abnormal electrodiagnostic studies. A modest likelihood of polyneuropathy (useful for field or epidemiological studies) occurs with a combination of multiple symptoms and multiple signs when the results of electrodiagnostic studies are not available. A lower likelihood of polyneuropathy occurs when electrodiagnostic studies and signs are discordant. For research purposes, the best approach for defining distal symmetrical polyneuropathy is a set of case definitions rank ordered by estimated likelihood of disease. The inclusion of this formalized case definition in clinical and epidemiological research studies will ensure greater consistency of case selection.

Molecular orientation and the infrared dichroism of a chiral smectic liquid crystal in a homogeneously aligned cell at different temperature and bias fields

The molecular orientation and the dichroic behavior of the vibrational bands of a homogeneously aligned helical cell containing chiral smectic liquid crystal (R)-(-)-1-methylheptyl 4-(4(')-dodecyloxybiphenyl-4-ylcarbonyloxy)-3-fluorobenzoate are studied at various temperatures as a function of the bias field. These temperatures correspond to the various phase states of the sample at zero field. For those bands that exhibit significant dichroism, the field dependencies of the dichroic parameters (the dichroic ratio and the polarization angle of maximum absorbance) are found to be dependent on temperature, phase state, and helical unwinding. For the SmA* and SmC(*)(alpha) phases, the phenyl band dichroic ratio and the corresponding orientational order parameter are found to be almost independent of the bias field. The temperature dependence of the orientational order for zero field is discussed by taking into account the structures of the phases and the molecular tilt angles. The field dependencies of the phenyl band dichroic parameters for the SmC(*)(A) and SmC(*)(gamma) phases yield results about the distribution of directors in the layers of their unit cells and the state of helical unwinding. The azimuthal orientational distribution function of the carbonyl transition moments with respect to the long molecular axis has been determined. It is found that the degrees of the polar and quadrupolar biasing increase with decrease in temperature and the azimuthal biasing angle for the chiral carbonyl group increases significantly with a reduction in temperature.

X-ray refraction effects: application to the imaging of biological tissues

The purpose of this study was to explore the potential of refraction contrast X-ray imaging of biological tissues. Images of dissected mouse lungs, heart, liver and legs were produced using the medical beamline at the Elettra Synchrotron at Trieste, Italy. The technique used was diffraction enhanced imaging. This utilizes a silicon crystal positioned between the tissue sample and the detector to separate refracted X-rays from transmitted and scattered radiation by Bragg diffraction. The contrast in the images produced is related to changes in the X-ray refractive index of the tissues, resulting in remarkable clarity compared with conventional X-ray images based on absorption effects. These changes were greatest at the boundaries between different tissues, giving a marked edge enhancement effect and three-dimensional appearance to the images. The technique provides a way of imaging a property of biological tissues not yet exploited, and further studies are planned to identify specific applications in medical imaging.

Diagnostic DNA testing for X-linked ocular albinism (OA1) with a hierarchical mutation screening protocol

Albinism is a group of inherited conditions in which affected individuals have less than normal pigment in the eyes, skin, and hair compared to others of the same race and ethnic background. The prevalence of all types of albinism in the United States is estimated at 1 in 20,000, based on poor epidemiological data. X-linked Nettleship-Falls ocular albinism (XLOA, OA1) affects approximately 1/150,000 males in the population. XLOA effects reduce visual acuity and nystagmus, result in a mild skin and hair phenotype, and occur mostly in XY males. Female carriers of XLOA have normal visual acuity, but often show iris punctate transillumination and a classic pattern of mosaic retinal pigmentation, coarse and grainy in the macula and becoming increasingly reticular into the periphery of the retinal pigment epithelium. Studies of OA1 have shown linkage of a single gene to markers at Xp22.3-p22.2. About 48% of the reported mutations in the OA1 gene are intragenic deletions and about 43% are point mutations. We present a hierarchical strategy for mutation screening for diagnostic testing for OA1 that comprises two tiers: first, multiplex PCR to detect intragenic deletions in the OA1 gene with denaturing high-performance liquid chromatography (dHPLC), and, second, heteroduplex analysis with dHPLC to scan for mutations, with subsequent sequencing of variants to confirm putative mutations in the OA1 gene. Prenatal diagnosis can be provided for families when the mutation has been firmly identified. We have validated this procedure with positive controls that were identified in patients by Southern blot, single-stranded conformation polymorphism (SSCP), and sequencing. In this hierarchical strategy, these procedures have an analytical sensitivity of > 99%.

A prospective, open-label treatment trial to compare the effect of IFNbeta-1a (Avonex), IFNbeta-1b (Betaseron), and glatiramer acetate (Copaxone) on the relapse rate in relapsing--remitting multiple sclerosis: results after 18 months of therapy

We previously reported results of a 12 month prospective, non-randomized, open-label treatment trial of immunomodulatory therapy in patients with relapsing-remitting multiple sclerosis (RRMS). We now report the results after 18 months of follow-up. Our primary objective was to compare the effect of IFNbeta-1a (Avonex), IFNbeta-1b (Betaseron), and Glatiramer Acetate (GA, Copaxone) to no treatment on the relapse rate in patients with RRMS. One hundred and fifty-six consecutive patients with clinically definite RRMS with a Kurtzke scale (EDSS) score of 4 or less were followed for 18 months. Prior 2-year relapse history and available chart information was carefully reviewed at the time of enrollment Thirty-three of 156 elected no treatment at enrollment; 40 elected IFNbeta-1a, 41 IFNbeta-1b, and 42 chose GA. There were no statistically significant differences among the four groups at enrollment. After 18 months of treatment 122 patients remained in their original treatment group. Compared to the untreated group (1.02), mean annualized number of relapses was significantly reduced only in the GA (0.49, P>0.0001) and IFNbeta-1b groups (0.55, P=0.001) in contrast to the IFNbeta-1a treated patients (0.81, P=0.106) who did not show a significant reduction. Despite limitations of the study design, the results provide helpful clinical information regarding the relative efficacy of each therapy in mildly affected treatment naive RRMS patients.

Evaluation of the ELOVL4 gene in patients with age-related macular degeneration

Stargardt-like macular degeneration (STGD(3)) and autosomal dominant macular degeneration (adMD) share phenotypic characters with atrophic age-related macular degeneration (AMD). Mutations in a photoreceptor cell-specific factor involved in the elongation of very long chain fatty acids (ELOVL(4)) were shown to be associated with STGD(3), adMD, and pattern dystrophy. We screened 778 patients with AMD and 551 age-matched controls to define the role of sequence variants in the ELOVL(4) gene in age-related macular degeneration. We detected three sequence variants in the non-coding region and eight variants in the coding region. No statistically significant association was observed between sequence variants in the ELOVL(4) gene and susceptibility to AMD. However, for the detection of modest effects of multiple alleles in a complex disease, the analysis of larger cohorts of patients may be required.

Survival of male patients with incontinentia pigmenti carrying a lethal mutation can be explained by somatic mosaicism or Klinefelter syndrome

Incontinentia pigmenti (IP), or "Bloch-Sulzberger syndrome," is an X-linked dominant disorder characterized by abnormalities of skin, teeth, hair, and eyes; skewed X-inactivation; and recurrent miscarriages of male fetuses. IP results from mutations in the gene for NF-kappaB essential modulator (NEMO), with deletion of exons 4-10 of NEMO accounting for >80% of new mutations. Male fetuses inheriting this mutation and other "null" mutations of NEMO usually die in utero. Less deleterious mutations can result in survival of males subjects, but with ectodermal dysplasia and immunodeficiency. Male patients with skin, dental, and ocular abnormalities typical of those seen in female patients with IP (without immunodeficiency) are rare. We investigated four male patients with clinical hallmarks of IP. All four were found to carry the deletion normally associated with male lethality in utero. Survival in one patient is explained by a 47,XXY karyotype and skewed X inactivation. Three other patients possess a normal 46,XY karyotype. We demonstrate that these patients have both wild-type and deleted copies of the NEMO gene and are therefore mosaic for the common mutation. Therefore, the repeat-mediated rearrangement leading to the common deletion does not require meiotic division. Hypomorphic alleles, a 47,XXY karyotype, and somatic mosaicism therefore represent three mechanisms for survival of males carrying a NEMO mutation.

Null missense ABCR (ABCA4) mutations in a family with stargardt disease and retinitis pigmentosa

PURPOSE

To determine the type of ABCR mutations that segregate in a family that manifests both Stargardt disease (STGD) and retinitis pigmentosa (RP), and the functional consequences of the underlying mutations.

METHODS

Direct sequencing of all 50 exons and flanking intronic regions of ABCR was performed for the STGD- and RP-affected relatives. RNA hybridization, Western blot analysis, and azido-adenosine triphosphate (ATP) labeling was used to determine the effect of disease-associated ABCR mutations in an in vitro assay system.

RESULTS

Compound heterozygous missense mutations were identified in patients with STGD and RP. STGD-affected individual AR682-03 was compound heterozygous for the mutation 2588G-->C and a complex allele, [W1408R; R1640W]. RP-affected individuals AR682-04 and-05 were compound heterozygous for the complex allele [W1408R; R1640W] and the missense mutation V767D. Functional analysis of the mutation V767D by Western blot and ATP binding revealed a severe reduction in protein expression. In vitro analysis of ABCR protein with the mutations W1408R and R1640W showed a moderate effect of these individual mutations on expression and ATP-binding; the complex allele [W1408R; R1640W] caused a severe reduction in protein expression.

CONCLUSIONS

These data reveal that missense ABCR mutations may be associated with RP. Functional analysis reveals that the RP-associated missense ABCR mutations are likely to be functionally null. These studies of the complex allele W1408R; R1640W suggest a synergistic effect of the individual mutations. These data are congruent with a model in which RP is associated with homozygous null mutations and with the notion that severity of retinal disease is inversely related to residual ABCR activity.

Cosegregation and functional analysis of mutant ABCR (ABCA4) alleles in families that manifest both Stargardt disease and age-related macular degeneration

Mutations in ABCR (ABCA4) have been reported to cause a spectrum of autosomal recessively inherited retinopathies, including Stargardt disease (STGD), cone-rod dystrophy and retinitis pigmentosa. Individuals heterozygous for ABCR mutations may be predisposed to develop the multifactorial disorder age-related macular degeneration (AMD). We hypothesized that some carriers of STGD alleles have an increased risk to develop AMD. We tested this hypothesis in a cohort of families that manifest both STGD and AMD. With a direct-sequencing mutation detection strategy, we found that AMD-affected relatives of STGD patients are more likely to be carriers of pathogenic STGD alleles than predicted based on chance alone. We further investigated the role of AMD-associated ABCR mutations by testing for expression and ATP-binding defects in an in vitro biochemical assay. We found that mutations associated with AMD have a range of assayable defects ranging from no detectable defect to apparent null alleles. Of the 21 missense ABCR mutations reported in patients with AMD, 16 (76%) show abnormalities in protein expression, ATP-binding or ATPase activity. We infer that carrier relatives of STGD patients are predisposed to develop AMD.

Triallelic inheritance in Bardet-Biedl syndrome, a Mendelian recessive disorder

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder characterized by multiple clinical features that include pigmentary retinal dystrophy, polydactyly, obesity, developmental delay, and renal defects. BBS is considered an autosomal recessive disorder, and recent positional cloning efforts have identified two BBS genes (BBS2 and BBS6). We screened our cohort of 163 BBS families for mutations in both BBS2 and BBS6 and report the presence of three mutant alleles in affected individuals in four pedigrees. In addition, we detected unaffected individuals in two pedigrees who carry two BBS2 mutations but not a BBS6 mutation. We therefore propose that BBS may not be a single-gene recessive disease but a complex trait requiring three mutant alleles to manifest the phenotype. This triallelic model of disease transmission may be important in the study of both Mendelian and multifactorial disorders.

Increasing informed uptake and non-uptake of screening: evidence from a systematic review

OBJECTIVE

To report data relating to the informed uptake of screening tests.

SEARCH STRATEGY

Electronic databases, bibliographies and experts were used to identify relevant published and unpublished studies up until August 2000.

INCLUSION CRITERIA

RCTs, quasi-RCTs and controlled trials of interventions aimed at increasing the informed uptake of screening. All participants were eligible as defined by the entry criteria of individual programmes. Studies had to report actual uptake and meet three out of four criteria used to define informed uptake.

DATA EXTRACTION AND SYNTHESIS

Relevant studies were identified, data extracted and their validity assessed by two reviewers independently. Outcome data included screening uptake, knowledge, informed decision-making and attitudes to screening. A random-effects model was used to calculate individual relative risks and 95% confidence intervals.

MAIN RESULTS

Six controlled trials (five RCTs and one quasi-RCT), focusing on antenatal and prostate specific antigen screening, were included. All reported risks/benefits of screening and assessed knowledge. Two also assessed decision-making. Two reported risks/benefits to all randomized groups and evaluated different ways of presenting information. Neither found that interventions such as videos, information leaflets with decision trees, or touch screen computers conveyed any additional benefits over well-prepared leaflets.

CONCLUSIONS

There is some evidence to suggest that changing the format of informed choice interventions in screening does not alter knowledge, satisfaction or decisions about screening. It is not clear whether informed choice in screening affects uptake. More well-designed RCTs are required and further research should also be directed towards the development of a valid instrument for measuring all components of informed choice in screening.

A recurrent deletion in the ubiquitously expressed NEMO (IKK-gamma) gene accounts for the vast majority of incontinentia pigmenti mutations

Incontinentia pigmenti (IP) is an X-linked dominant disorder characterized by abnormal skin pigmentation, retinal detachment, anodontia, alopecia, nail dystrophy and central nervous system defects. This disorder segregates as a male lethal disorder and causes skewed X-inactivation in female patients. IP is caused by mutations in a gene called NEMO, which encodes a regulatory component of the IkappaB kinase complex required to activate the NF-kappaB pathway. Here we report the identification of 277 mutations in 357 unrelated IP patients. An identical genomic deletion within NEMO accounted for 90% of the identified mutations. The remaining mutations were small duplications, substitutions and deletions. Nearly all NEMO mutations caused frameshift and premature protein truncation, which are predicted to eliminate NEMO function and cause cell lethality. Examination of families transmitting the recurrent deletion revealed that the rearrangement occurred in the paternal germline in most cases, indicating that it arises predominantly by intrachromosomal misalignment during meiosis. Expression analysis of human and mouse NEMO/Nemo showed that the gene becomes active early during embryogenesis and is expressed ubiquitously. These data confirm the involvement of NEMO in IP and will help elucidate the mechanism underlying the manifestation of this disorder and the in vivo function of NEMO. Based on these and other recent findings, we propose a model to explain the pathogenesis of this complex disorder.

Outpatient shoulder surgery: a prospective analysis of a perioperative protocol

During a 10-month period, 106 consecutive outpatient shoulder procedures were done in 102 patients who were followed up prospectively for a minimum of 6 months. The procedures included arthroscopic surgery alone (60%) and open surgeries with or without associated arthroscopy (40%). The anesthetic protocol included propofol and nitrous oxide, without scalene block augmentation, and local 0.5% bupivacaine. Patients were discharged with oral analgesics. Ninety-five percent of the patients successfully underwent their procedure as an outpatient; only 5% required admission on the day of surgery, and none required readmission. There were no short- or long-term postoperative complications attributable to the protocol. Ninety-six percent of the patients were satisfied with their pain management, and all patients were satisfied with their overall experience.

Evaluation of the G protein coupled receptor-75 (GPR75) in age related macular degeneration

BACKGROUND

A long term project was initiated to identify and to characterise genes that are expressed exclusively or preferentially in the retina as candidates for a genetic susceptibility to age related macular degeneration (AMD). A transcript represented by a cluster of five human expressed sequence tags (ESTs) derived exclusively from retinal cDNA libraries was identified.

METHODS

Northern blot and RT-PCR analyses confirmed preferential retinal expression of the gene, which encodes a G protein coupled receptor, GPR75. Following isolation of the full length cDNA and determination of the genomic organisation, the coding sequence of GPR75 was screened for mutations in 535 AMD patients and 252 controls from Germany, the United States, and Italy. Employed methods included single stranded conformational polymorphism (SSCP) analysis, denaturing high performance liquid chromatography (DHPLC), and direct sequencing.

RESULTS

Nine different sequence variations were identified in patients and control individuals. Three of these (-30A>C, 150G>A, and 346G>A) likely represent polymorphic variants. Each of six alterations (-4G>A, N78K, P99L, S108T, T135P, and Q234X) were found once in single AMD patients and were considered variants that could affect the protein function and potentially cause retinal pathology.

CONCLUSION

The presence of six potential pathogenic variants in a cohort of 535 AMD patients alone does not provide statistically significant evidence for the association of sequence variation in GPR75 with genetic predisposition to AMD. However, a possible connection between the variants and age related retinal pathology cannot be discarded. Functional studies are needed to clarify the role of GPR75 in retinal physiology.

Clinical manifestations in a cohort of 41 Rothmund-Thomson syndrome patients

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive genodermatosis characterized by a poikilodermatous rash starting in infancy, small stature, skeletal abnormalities, juvenile cataracts, and predisposition to specific cancers. We have identified a contemporary cohort of 41 patients to better define the clinical profile, diagnostic criteria, and management of patients with RTS. Patients with the diagnosis of RTS were ascertained by referrals from dermatology, ophthalmology, genetics, and oncology or from direct contact with the patient's family. Medical information was obtained from interviews with physicians, patients, and their parents and a review of medical records. The age range at ascertainment was 9 months to 42 years (28 males and 13 females; M:F, 2:1). All subjects displayed a characteristic rash. Thirteen subjects had osteosarcoma (OS) (32%), eight had radial defects (20%), seven had gastrointestinal findings (17%), two had cataracts (6%), and one had skin cancer (2%). Twenty-two of 28 patients without OS were less than 15 years old and thus remain at significant risk for this tumor. This case-series study reveals a clinical profile of RTS that includes a higher prevalence of OS and fewer cataracts, compared with historical reports. These differences may reflect either allelic or genetic heterogeneity. This study documents the frequency of clinical anomalies in a contemporary cohort of RTS patients and revises guidelines for diagnosis and management of RTS.