Shoulder Rotator Cuff Disorders: A Systematic Review of Clinical Practice Guidelines and Semantic Analyses of Recommendations

OBJECTIVES

To perform a systematic review of clinical practice guidelines (CPGs) and semantic analysis of specific clinical recommendations for the management of rotator cuff disorders in adults.

DATA SOURCES

A systematic bibliographic search was conducted up until May 2018 in Medline, Embase, and Physiotherapy Evidence Database, or PEDro, databases, in addition to 12 clinical guidelines search engines listed on the Appraisal of Guidelines for Research and Evaluation (AGREE) website.

STUDY SELECTION

Nine CPGs on the management of rotator cuff disorders in adults or workers, available in English or French, and published from January 2008 onward, were included and screened by 2 independent reviewers.

DATA EXTRACTION

CPG methodology was assessed with the AGREE II checklist. A semantic analysis was performed to compare the strength of similar recommendations based on their formulation. The recommendations were categorized in a standardized manner considering the following 4 levels: "essential," "recommended," "may be recommended," and "not recommended."

DATA SYNTHESIS

Methodological quality was considered high for 3 CPGs and low for 6. All CPGs recommended active treatment modalities, such as an exercise program in the management of rotator cuff disorders. Acetaminophen or nonsteroidal anti-inflammatory drug prescriptions and corticosteroid injections were presented as modalities that may be recommended to decrease pain. Recommendations related to medical imagery and surgical opinion varied among the guidelines. The most commonly recommended return-to-work strategies included intervening early, use of a multidisciplinary approach, and adaptation of work organization.

CONCLUSIONS

Only 3 CPGs were of high quality. The development of more rigorous CPGs is warranted.

[Autism spectrum disorder and evaluation of perceived stress parents and professionals: Study of the psychometric properties of a French adaptation of the Appraisal of Life Event Scale (ALES-vf)]

INTRODUCTION

Autism and related disorders are grouped into the category of « Autism Spectrum Disorder » (ASD) in the DSM-5. This appellation reflects the idea of a dimensional representation of autism that combines symptoms and characteristics that vary in severity and intensity. Despite common characteristics, there are varying degrees in intensity and in the onset of symptoms, ranging from a disability that can be very heavy with a total lack of communication and major disorders associated with the existence of a relative autonomy associated, sometimes, with extraordinary intellectual abilities. Parents are faced with several difficult situations, such as sleep disturbances, agitation, shouting, hetero violence, self-harm, learning difficulties, stereotyping, lack of social and emotional reciprocity, inappropriate behavior, etc. They can feel helpless and may experience stress related to these developmental and behavioral difficulties. The heterogeneity of symptoms, the presence of behavioral problems, the lack of reciprocity and autonomy also represent a challenge for practitioners in institutions and teachers at school. The objective of this research is to present the validation of a French translation of the Appraisal of Life Events Scale (ALES-vf) from Ferguson, Matthex and Cox, specifically adapted to the context of ASD. ALES was originally developed to operationalize the three dimensions of perceived stress (threat, loss and challenge) described by Lazarus and Folkman.

METHODOLOGY

ALES-vf was initially translated into French and adapted to the situation of parents of children with ASD. It was subsequently administered to 343 parents, 150 paramedical professionals involved with people with ASD, and 155 teachers from an ordinary school environment and from specialized schools, welcoming in their classroom at least one child with ASD.

RESULTS

An exploratory factor analysis performed on data from 170 parents highlighted two exploratory models with four and three factors, slightly different from the original three-factor model of Ferguson and his collaborators. Confirmatory analyzes were conducted on data from 173 other parents to test two exploratory models and the original model of Ferguson. It has also been tested on data from 305 professionals (paramedical professionals and teachers) and on the whole sample (parents and professionals). The results suggest a better match of the original three-factor model. In addition, Cronbach's alpha coefficients and inter-item correlations showed a good internal consistency for these three factors. Finally, variance analysis and regressions were performed to test the effect of the nationality of the parents, the child's level of autonomy, the child's level of communication, and on the perceived stress by experienced professionals.

CONCLUSION

ALES-vf, after our adaptation has good psychometric properties for use not only with parents but also with professionals (teachers, educators, psychologists) working with children with ASD. Our analyses showed that the nationality of the parents does not significantly influence the subscales « threat » and « challenge » of ALES-vf, which makes it usable in other Francophone countries. Specificities in the subscales were identified based on group membership (parents and professionals). For example parents get higher average scores on subscales « loss » and « threat » and a lower average score on the subscale « challenge », compared to professionals. Finally, regarding the specifics found among professionals, the results show that the years of experience have an effect on perceived stress. Specifically, teachers and educators who have more experience perceive their work with children with ASD as a challenge. This is consistent with the results of studies showing that teachers who have had experience with children with ASD had less difficulty in their interventions.

Clinical Utility of Amyloid Imaging in a Complex Case of Corticobasal Syndrome Presenting with Psychiatric Symptoms

Clinical indications of amyloid imaging in atypical dementia remain unclear. We report a 68-year-old female without past psychiatric history who was hospitalized for auditory hallucinations and persecutory delusions associated with cognitive and motor deficits. Although psychotic symptoms resolved with antipsychotic treatment, cognitive and motor impairments remained. She further showed severe visuoconstructive and executive deficits, ideomotor apraxia, elements of Gerstmann’s syndrome, bilateral agraphesthesia and discrete asymmetric motor deficits. Blood tests were unremarkable. Structural brain imaging revealed diffuse fronto-temporo-parietal atrophy, which was most severe in the parietal regions. Meanwhile, FDG-PET suggested asymmetrical fronto-temporo-parietal hypometabolism, with sparing of the posterior cingulate gyrus. A diagnosis of possible corticobasal syndrome (CBS) was made. Amyloid-PET using the novel tracer NAV4694 was ordered, and revealed significant deposition of fibrillar amyloid (SUVR 2.05). The primary diagnosis was CBS with underlying Alzheimer pathology and treatment with a cholinesterase inhibitor was initiated. Determination of underlying pathological CBS subtype is not simple even when based on extensive investigation including clinical presentation, atrophy patterns on MRI, and regional hypometabolism on FDG-PET. By contrast, amyloid imaging quickly confirmed Alzheimer pathology, and allowed rapid initiation of treatment in this complex case with early psychiatric symptoms. This case study illustrates the clinical utility of amyloid imaging in the setting of atypical cases seen in a tertiary memory clinic.

A Thapsigargin Prodrug Produces Sustained Growth Inhibition and Substantial Regression of Human Breast Cancers In Vivo with Minimal Host Toxicity

Background: Thapsigargin (TG) is a cytotoxic natural product isolated in high yields from the plant Thapsia garganica. In the NCI 60 Cancer Cell Line screen, TG has a GI50 of ∼10-10 M which compares favorably with agents such as paclitaxel (10-8 M) and doxorubicin (10-7 M) in this assay. TG is a non-cell type specific cytotoxin that kills cells in a proliferation independent manner via its potent inhibition of a critical intracellular protein, the Sarcoplasmic/Endoplasmic Reticulum Calcium ATPase (SERCA) pump. Sustained inhibition of the SERCA pump by TG produces an elevation of intracellular calcium to micromolar levels which induces apoptosis via activation of the ER stress response and release of apoptotic factors from the mitochondria. TG has no therapeutic index in vivo with an LD100 of 0.2 mg/kg.Methods: In order to create a theraputic index that would allow for sytemic therapy of human breast cancer we generated prodrugs by coupling water soluble acidic amino acid containing peptides to a potent analog of thapsigargin, (12Aminododecanoyl)-8-O debutanoylthapsigargin (12ADT). In addition to solubilization, the peptide also serves to mask the cytotoxicity of the TG analog until it is released by specific active proteases present within tumor sites. One of these prodrugs (G202) was selected for further in vivo evaluation based on its solubility and ability to be hydrolyzed by the carboxypeptidase Prostate-Specific Membrane Antigen (PSMA). PSMA is membrane protein that is highly expressed by normal and malignant prostate epithelial cells. PSMA, however, is also expressed by the neovasculature within most solid tumors, but not by normal tissue vasculature. In this study we evaluated the toxicity and efficacy of this PSMA-activated thapsigargin prodrug against human MCF-7 breast cancer xenografts.Results: In preliminary studies with prostate cancer xenografts we determined that a single intravenous dose of 56 mg/kg G202 formulated in propylene glycol/Solutol could be administered safely without acute toxicity. Mice bearing MCF-7 xenografts were thus treated with one, two or three doses of 56 mg/kg G202. Three doses produced significant tumor regressions and prolonged growth inhibition but was associated with toxicity whereas a single dose of G202 had no discernible toxicity but produced only transient growth inhibition. In contrast, two consecutive doses of G202 produced only transient weight loss and resulted in significant tumor regression and sustained growth inhibition, with complete responses observed in a subset of animals. High levels (∼5 μM) of the active drug 12ADT-Asp were measurable in the tumor tissue 96 hrs post injection while negligible hydrolysis of G202 was observed in plasma. Discussion: The effectiveness of G202 against a panel of ER positive and negative breast cancer xenografts is currently being evaluated. On the basis of this encouraging preliminary data continued clinical development of G202 as therapy for metastatic breast cancer appears warranted.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5074.

An interdisciplinary clinical practice model for the management of low-back pain in primary care: the CLIP project

BACKGROUND

Low-back pain is responsible for significant disability and costs in industrialized countries. Only a minority of subjects suffering from low-back pain will develop persistent disability. However, this minority is responsible for the majority of costs and has the poorest health outcomes. The objective of the Clinic on Low-back pain in Interdisciplinary Practice (CLIP) project was to develop a primary care interdisciplinary practice model for the clinical management of low-back pain and the prevention of persistent disability.

METHODS

Using previously published guidelines, systematic reviews and meta-analyses, a clinical management model for low-back pain was developed by the project team. A structured process facilitating discussions on this model among researchers, stakeholders and clinicians was created. The model was revised following these exchanges, without deviating from the evidence.

RESULTS

A model consisting of nine elements on clinical management of low-back pain and prevention of persistent disability was developed. The model's two core elements for the prevention of persistent disability are the following: 1) the evaluation of the prognosis at the fourth week of disability, and of key modifiable barriers to return to usual activities if the prognosis is unfavourable; 2) the evaluation of the patient's perceived disability every four weeks, with the evaluation and management of barriers to return to usual activities if perceived disability has not sufficiently improved.

CONCLUSION

A primary care interdisciplinary model aimed at improving quality and continuity of care for patients with low-back pain was developed. The effectiveness, efficiency and applicability of the CLIP model in preventing persistent disability in patients suffering from low-back pain should be assessed.

An interdisciplinary guideline development process: the Clinic on Low-back pain in Interdisciplinary Practice (CLIP) low-back pain guidelines

Background

Evaluation of low-back pain guidelines using Appraisal of Guidelines Research and Evaluation (AGREE) criteria has shown weaknesses, particularly in stakeholder involvement and applicability of recommendations. The objectives of this project were to: 1) develop a primary care interdisciplinary clinical practice guideline aimed at preventing prolonged disability from low-back pain, using a community of practice approach, and 2) assess the participants' impressions with the process, and evaluate the relationship between participant characteristics and their participation.

Methods

Ten stakeholder representatives recruited 136 clinicians to participate in this community of practice. Clinicians were drawn from the following professions: physiotherapists (46%), occupational therapists (37%), and family physicians (17%). Using previously published guidelines, systematic reviews, and meta-analyses, a first draft of the guidelines was presented to the community of practice. Four communication tools were provided for discussion and exchanges with experts: a web-based discussion forum, an anonymous comment form, meetings, and a symposium. Participants were prompted for comments on interpretation, clarity, and applicability of the recommendations. Clinical management recommendations were revised following these exchanges. At the end of the project, a questionnaire was sent to the participants to assess satisfaction towards the guidelines and the development process.

Results

Twelve clinical management recommendations on management of low-back pain and persistent disability were initially developed. These were discussed through 188 comments posted on the discussion forum and 103 commentary forms submitted. All recommendations were modified following input of the participants. A clinical algorithm summarizing the guidelines was also developed. A response rate of 75% was obtained for the satisfaction questionnaire. The majority of respondents appreciated the development process and agreed with the guideline content. Most participants thought recommendations improved between versions, and that participant comments contributed to this improvement. All stakeholders officially endorsed the guidelines.

Conclusion

The community of practice approach was a successful method to develop guidelines on low-back pain, with participants providing information to improve guideline recommendations. The information technology infrastructure that was developed remains for continuous interdisciplinary exchanges and updating of the guidelines.

Training the next generation of researchers in work disability prevention: the Canadian Work Disability Prevention CIHR Strategic Training Program

INTRODUCTION

There is a need to create, disseminate, and implement new knowledge in the work disability prevention (WDP) field. Training programs attracting high-quality applicants and taking into account the complexity of this emerging field are urgently needed.

METHODS

An advanced training program, funded by the Canadian Institutes of Health Research (CIHR), was developed by 24 mentors affiliated with nine different universities. The main objective of this program is to develop transdisciplinary knowledge, skills, and attitudes regarding WDP. This program has been developed for PhD students or post-doctoral fellows already registered full-time in a Canadian or recognized foreign university whose main interest is WDP, regardless of the health problem.

RESULTS

Since its implementation, the program received two successive cohorts of 10 students. They were registered in 13 universities in five countries and trained in nine different disciplines. CONCLUSIONS AND SIGNIFICANCES: Appropriate WDP research may save major societal costs attributable to prolonged work disability. The proposed training program will contribute to developing tomorrow's research workforce.

Effect of CEP-751 (KT-6587) on neuroblastoma xenografts expressing TrkB

BACKGROUND

The compound CEP-751 (KT-6587), a potent and selective inhibitor of the Trk family of tyrosine kinases, has been shown to inhibit the growth of human neuroblastoma (NB) xenografts in nude mice [1].

PROCEDURE

To address its mechanism of action, we studied SY5Y, a human NB cell line with no detectable Trk expression, and two subclones transfected with TrkB. The transfected clones, SY5Y (G8) and SY5Y (G12), expressed moderate and high levels, respectively, of TrkB mRNA and protein. These TrkB-expressing subclones and the parental line were then grown as xenografts in nude mice, and CEP-751 was used to inhibit TrkB tyrosine kinase activity in these xenografts. Animals were treated twice a day with CEP-751 (21 mg/kg), or with the carrier vehicle as a control. TrkB expression in the resultant tumors was examined by quantitative RT-PCR. The effect of CEP-751 on TrkB activation by BDNF was examined in G12 cells in culture by immunoprecipitation with antipan Trk antiserum, followed by Western blot analysis using antiphosphotyrosine antibodies. To determine if CEP-751 was causing apoptosis, the TUNEL assay was used.

RESULTS

CEP-751 had little effect on the growth of SY5Y tumors, but did slow the growth rate of the C8 and G12 tumors. The daily growth rate of the treated tumors was 0.16, 0.13, and 0.10 cm3, respectively, for the SY5Y, G8, and G12 tumors. RT PCR analysis confirmed the expression of TrkB in G8 and G12, but not in SY5Y tumors. Activation of TrkB by BDNF in G12 cells was inhibited by CEP-751 in a dose dependent fashion. The treated tumors showed marked evidence of apoptosis.

CONCLUSIONS

These data suggest that the effect of CEP-751 is due, at least in part, to its inhibition of TrkB kinase, and that CEP-751 may become a useful therapeutic tool for the treatment of aggressive neuroblastomas, which often express TrkB.

[Validation of a measurement instrument to evaluate computer access in people with physical disabilities]

The aim of this study was to develop an instrument to measure performance in computer tasks for persons with physical impairments. The objectives were to assure the content validity and the internal consistency of the test as well as the reliability of each task. The first step was to determine the mouse and keyboard actions necessary to use a computer. Resulting from these actions, 15 standardized computer tasks were designed as part of the test. To measure reliability and internal consistency, the test was administered twice to 19 persons without disabilities and 17 persons with disabilities. Reliability was established for most of the tasks and the test showed good internal consistency. This instrument could contribute to the improvement of occupational therapy interventions regarding computer access.

Formal education and back-related disability. In search of an explanation

STUDY DESIGN

The present study is a 2-year prospective study with repeated measurements.

OBJECTIVES

To examine the association of education with back-related disability along with four sets of variables that might explain this relationship: clinical, behavioral, and environmental factors; occupational variables; health care use; and interactions between stressful events and coping strategies.

SUMMARY OF BACKGROUND DATA

Although education has been found to be associated with back-related disability in previous reports, this relationship remains to be explained. Examination of this association may yield a better understanding of the causes and natural history of disability resulting from back pain.

METHODS

Subjects were 1213 enrollees of a Health Maintenance Organization (HMO) who consulted a primary care physician for back pain in 1989-1990, completed a baseline telephone interview, and had a follow-up evaluation after 1 and 2 years, using a modified version of the Roland-Morris Scale to measure disability.

RESULTS

Subjects who completed 13 years or more of schooling had less disability and a greater decline in their disability over time than those who completed less schooling. Occupational characteristics and somatization were among the strongest explanatory factors. Cigarette smoking contributed to the explanation of the cross-sectional association.

CONCLUSIONS

Education is associated cross-sectionally and longitudinally with disability resulting from back pain. A wide range of variables may mediate the education-back-related disability association, including a propensity to report diffuse physical symptoms (somatization), lifestyle (e.g., cigarette smoking), and occupational factors.

Expression of a Trk high affinity nerve growth factor receptor in the human prostate

Nerve growth factor-beta (NGF beta) and a NGF beta-immunoreactive protein derived from human prostatic stromal cell secretory protein (hPS) have been shown to stimulate the growth of prostate epithelial cells. An NGF beta-immunoreactive protein has been localized to the stroma of human prostate tissues, and a low affinity NGF receptor (gp75NGFR) has been localized to the adjacent epithelia, consistent with the paracrine regulation of prostate growth. Interestingly, gp75NGFR is progressively lost during neoplastic progression of the human prostate. In this report we have characterized the expression of the signal-transducing component of the NGF receptor, the Trk tyrosine receptor kinase, in prostate epithelial cells that bind exogenous NGF beta and an endogenous NGF beta-immunoreactive protein in hPS. In this context, a pan-Trk antibody that recognizes all of the members of the Trk receptor family (TrkA, TrkB, and TrkC) specifically localized expression of the Trk receptor to the epithelial component of normal prostate tissue, benign prostatic hyperplasia, and adenocarcinoma tissue. The binding of [125I]NGF beta to the surface of primary cultures of human prostate epithelia and the TSU-pr1 human metastatic prostate tumor cell line was displaced with either excess cold NGF beta or hPS, whereas binding was not displaced by epidermal growth factor or platelet-derived growth factor. Scatchard plot analysis of [125I]NGF beta binding to these cells identified a low affinity binding site (Kd = 1.9 x 10(-9) M) and a high affinity binding site (Kd = 1.8 x 10(-11) M) on the primary prostate epithelia, whereas only a high affinity binding site (Kd = 1.3 x 10(-11) M) was observed on the TSU-pr1 tumor cells. Stimulation of TSU-pr1 cells with either NGF beta or hPS induced tyrosine phosphorylation of Trk proteins, whereas no phosphorylation was evident in untreated cells, cells treated with hPS immunoprecipitated with anti-NGF beta antibody, or brain-derived neurotrophic factor- and neurotrophin-3-treated cells. The Trk protein was also observed in these cells by immunoblot analysis with pan-Trk antibody. These results demonstrate a functional Trk receptor in the epithelia of the human prostate that is responsive to exogenous NGF beta and an endogenous NGF beta-immunoreactive protein in hPS, thereby supporting the concept of the paracrine regulation of growth in the human prostate via a stromal neurotrophin-epithelial Trk receptor interaction.

Postnatal expression of nerve growth factor receptors in the rat testis

Because nerve growth factor beta (NGF beta) and its corresponding receptors have been implicated in the paracrine regulation of spermatogenesis, we examined the postnatal developmental expression of the low- and high-affinity NGF receptors in the rat testis, and localized their expression to specific testicular cell types. The neurotropin receptors consist of a low-affinity p75 nerve growth factor receptor (LNGFR) and a family of high-affinity tyrosine receptor kinases (trk). Both the p75 LNGFR gene product and the trk receptor gene product were detected in immature rat testes, with maximal expression in 10- and 20-day-old rats. Expression of the testicular p75 LNGFR and the trk receptor progressively declined in older animals so that they were barely detectable in 90-day-old adult rats. The 75-kDa LNGFR was detected in membrane fractions of Sertoli cells, whereas the p75 LNGFR was not detected by Western blot in membrane fractions of round spermatids and primary spermatocytes. Interestingly, microsomal fractions of peritubular myoid cells were immunoreactive for a 65-kDa band on Western blots with the p75 LNGFR monoclonal antibody. Immunoblot analysis of the trk receptor in cell lysates of isolated cell types was inconclusive. Excess NGF beta and round spermatid protein, which is known to contain a NGF-like protein, were both capable of displacing the binding of 125I-NGF beta from the surface of Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Genealogy and regional distribution of lipoprotein lipase deficiency in French-Canadians of Quebec

Lipoprotein lipase (LPL) deficiency, an autosomal recessive disorder causing chylomicronemia, has a high prevalence in the French-Canadian population of Quebec. The molecular basis of LPL deficiency has been defined, and two major mutations have been shown to have an uneven geographic distribution. Two mutations, one at residue 188 (M-188) and the other at residue 207 (M-207), are described here; they account for 95% of the mutant alleles. The carrier rate of M-188 was highest in western Quebec (1/326) but that of M-207 was much higher in the eastern part of the province (1/85). Genealogical reconstruction has revealed that both mutations were introduced to the French-Canadian population by migrants from France in the seventeenth century. M-188 is likely to have a Scottish ancestor, whereas M-207 appears to be of French origin.

Geographic distribution and genealogy of mutation 207 of the lipoprotein lipase gene in the French Canadian population of Québec

Mutations in the lipoprotein lipase (LPL) gene, leading to partial or total inactivation of the enzyme, result in a hereditary clinical syndrome called familial LPL deficiency. The French Canadian population, which is primarily and historically located in the province of Québec, has the highest worldwide frequency of LPL-deficient patients. We have analyzed the prevalence, spatial distribution, and genealogy in the Québec population of a LPL gene mutation, M-207 (P207L in conventional notation), which changes the amino acid proline to leucine in position 207 of the LPL protein and inactivates the enzyme. Our results show that M-207 is the most prevalent LPL gene mutation among French Canadians and accounts for the largest proportion of LPL-deficient patients in this population. Genealogical reconstruction of French Canadian LPL-deficient patients point to 16 founders of M-207, all of whom migrated to Québec in the early seventeenth century from the north-western part of France, especially from the region of Perche. Most of the carriers of M-207 are, at present, found in Charlevoix, Saguenay-Lac-St-Jean regions of eastern Québec. On the basis of the number of homozygote M-207 LPL-deficient patients so far identified, we estimate that there are at least 31,000 carriers of this mutation in the province of Québec. This constitutes a large pool of individuals at risk for atherosclerosis and other lipid-related diseases, since LPL deficiency is considered to be a significant contributing factor in the etiology and development of these diseases.

Coping with low-back pain: Remaining disabilities 5 years after multidisciplinary rehabilitation

The health status of 106 persons once affected with a chronic low back pain episode was compared to that of 115 referent subjects, category matched on sex, age, and time of episode about 5 years after their admission to a multidisciplinary treatment program in rehabilitation. The current health status of both groups was assessed with the Sickness Impact Profile (SIP). Results show that cases reported significantly more functional limitations in areas related to ambulation, body care and movements, home management activities, and employment. These limitations increased with age. The current distress of cases seemed comparable to that of patients with severely restricting diseases such as end-stage renal disease. This study underlines the duration and burden of personal suffering among workers with chronic low back pain.

Prevalence, geographical distribution and genealogical investigations of mutation 188 of lipoprotein lipase gene in the French Canadian population of Québec

Familial lipoprotein lipase deficiency (FLD) is of particular interest to the French Canadian population of Québec since the largest concentration of homozygotes and carriers of this genetic disease in the world resides in this area. We have previously described a missense mutation (M-188) in the lipoprotein lipase (LPL) gene which was present in FLD patients belonging to different ancestries, including a number of French Canadians (Monsalve MV et al. J Clin Invest 1990: 86: 728-734). In the present report, we show that this mutation, although found in largest absolute numbers among French Canadians as compared to other groups in the world, accounts for only a small proportion (24%) of all the LPL mutant alleles in this population. The M-188 occurs either in the homozygote state or as a compound heterozygote with another LPL mutation. Analysis of geographic distribution indicates that the M-188 is more prevalent in western Québec, with the highest carrier rate in the Mauricie region. Genealogical reconstruction leads to the recognition of four founders for M-188, all emigrants from France to Québec in the 17th century.

The mRNAs encoding acidic FGF, basic FGF and FGF receptor are coordinately downregulated during myogenic differentiation

Acidic and basic fibroblast growth factors (FGFs) are members of a family of proteins that exert pleiotropic effects in a range of cell types including skeletal myocytes. Previous studies demonstrate that exogenously supplied FGFs stimulate proliferation of myoblasts and inhibit their differentiation in culture, but little information is available concerning endogenous expression of FGFs by skeletal myocytes. In this study acidic and basic FGF mRNAs were found to be expressed in murine and rat skeletal muscle, and expression was demonstrated to vary with the tissue and species examined. Myogenic cell lines were then analyzed to determine if FGFs are expressed in myoblasts, and if so, whether expression is regulated during myogenic differentiation. Murine Sol 8 and rat L6 myoblasts were found to express acidic and basic FGF mRNAs, and the expression of both growth factors was downregulated at the transcriptional level during myogenic differentiation. A decrease in expression of the mouse homologue of the human FGF receptor paralleled the decrease in acidic and basic FGF mRNAs in Sol 8 cells, indicating that the decrease in FGF receptor abundance previously observed during myogenic differentiation is regulated at the mRNA level. The results of this study suggest that a coordinate decrease in endogenously produced acidic and basic FGFs and their cognate receptor may participate in the regulation of myogenic differentiation. Furthermore, the observation that expression of a myogenic determination gene, myogenin, increases as FGF transcripts decline, together with previous data demonstrating suppression of myogenin expression by FGF, suggest a mechanism whereby endogenously produced FGFs may exert their effect on differentiation.

Founder effect in familial hyperchylomicronemia among French Canadians of Quebec

Familial hyperchylomicronemia has reached a high prevalence in the French Canadian population of eastern Quebec. The birth places of 58 carriers identified through the birth of one affected child clustered in three regions. The genealogies of these 58 individuals showed that no founder was common to all of them. Three sets of founders were found, one for each region, with little overlapping between two regions. These results strongly suggest that more than one mutation, introduced by the French migrants in the 17th century, are segregating in the French Canadian population. Perche, a region situated between Paris and Normandy, appeared to be the most likely putative center of diffusion of at least one mutation in the lipoprotein lipase gene segregating in the modern-day French Canadian population of Quebec.

Receptor for acidic fibroblast growth factor is related to the tyrosine kinase encoded by the fms-like gene (FLG)

We have previously isolated a human gene from an endothelial cell cDNA library encoding a putative tyrosine kinase; we have designated this gene the fms-like gene (FLG). To analyze the gene product(s) of FLG, we have generated rabbit polyclonal antibodies directed against a synthetic peptide from FLG and used it to immunoprecipitate biosynthetically labeled FLG protein from a variety of human cell lines. These antibodies specifically recognized glycoprotein(s) of 100, 120, and 135 kDa with protein cores of 90 and 110 kDa. Acidic fibroblast growth factor (aFGF) stimulated tyrosine kinase activity of FLG in vitro and in living cells, suggesting that FLG encodes the membrane receptor for aFGF. Further supporting evidence came from cross-linking experiments on intact cells with the covalent cross-linking agent disuccinimidyl suberate and 125I-labeled aFGF as a specific probe. The cross-linked 125I-labeled aFGF-aFGF receptor complex was specifically immunoprecipitated with FLG antipeptide antibodies. It appears, therefore, that the receptor(s) for aFGF is related to the FLG gene product.

[A demographic analysis of multiple contingencies]

Using the multidimensional model developed by Andrei Rogers, the authors formulate a method for analyzing the interaction between and the multiplicity of certain behavior patterns such as migration. "The present article attempts to present a conceptual approach which extends classical demographic analysis to multiple phenomena or which adapts the analysis of mobility to demographic methods." (summary in ENG, SPA)

The distance between S1, S21, and the 3' end of 16S RNA in 30S ribosomal subunits. The effect of poly(uridylic acid) and 50S subunits on these distances

The apparent distances between probes covalently attached to the cysteine thiols of S1 or S21 and the 3' end of 16S RNA in Escherichia coli 30S ribosomal subunits were determined by non-radiative energy transfer to be: S21-16S RNA, 5.1 nm; S21-S1, 6.9 nm; S1-16S RNA, 6.8 nm. Binding of poly(uridylic acid) to 30S subunits causes the apparent distances between S1 and 16S RNA or S21 and 16S RNA to increase by more than 1.2 nm and 0.5 nm, respectively, but has little or no effect on the S1-S21 distance. Binding of 50S subunits causes an apparent increase in the S21-16S RNA and S21-S1 distances by 1.0 nm and 0.8 nm, respectively, but has little or no effect on the S1-16S-RNA distance.