Polychlorinated biphenyl and polybrominated diphenyl ether profiles vary with feeding ecology and marine rearing distribution among 10 Chinook salmon (Oncorhynchus tshawytscha) stocks in the North Pacific Ocean.

Chinook salmon (Oncorhynchus tshawytscha) along the west coast of North America have experienced significant declines in abundance and body size over recent decades due to several anthropogenic stressors. Understanding the reasons underlying the relatively high levels of persistent organic pollutants (POPs) in Chinook stocks is an important need, as it informs recovery planning for this foundation species, as well for the Chinook-dependent Resident killer whales (Orcinus orca, RKW) of British Columbia (Canada) and Washington State (USA). We evaluated the influence of stock-related differences in feeding ecology, using stable isotopes, and marine rearing ground on the concentrations and patterns of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Chinook salmon. A principal components analysis (PCA) revealed a clear divergence of PCB and PBDE congener patterns between Chinook with a nearshore rearing distribution ('shelf resident') versus a more offshore distribution. Shelf resident Chinook had 12-fold higher PCB concentrations and 46-fold higher PBDE concentrations relative to offshore stocks. Shelf resident Chinook had PCB and PBDE profiles that were heavier and dominated by more bioaccumulative congeners, respectively. The higher δ13C and δ15N in shelf resident Chinook compared to the offshore rearing stocks, and their different marine distributions explain the large divergence in contaminant levels and profiles, with shelf resident stocks being heavily influenced by land-based sources of industrial contamination. Results provide compelling new insight into the drivers of contaminant accumulation in Chinook salmon, raise important questions about the consequences for their health, and explain a major pathway to the heavily POP-contaminated Resident killer whales that consume them.

Absorbable Sutures and Telemedicine for Patients Undergoing Trigger Finger Release.

Background In the setting of the COVID-19 pandemic, the development of care processes that reduce the need for in-person clinic visits while maintaining low complication rates is needed. The purpose of this study is to assess the outcomes of patients undergoing trigger finger release with various suture and follow-up visit types to assess the feasibility of shifting towards telemedicine-based follow-up protocols. Methods A retrospective review of 329 patients undergoing trigger finger release was performed. Patients were classified based on whether or not they received in-office follow-ups; whether they received absorbable or non-absorbable sutures; and whether they were treated using a telemedicine and absorbable suture protocol or other combination of sutures and follow-ups. Univariate statistics were performed to compare outcomes between groups. Results Patients who did not undergo in-office follow-up were more likely to experience residual stiffness or contracture (11.4% vs. 4.1%; p=0.033) but had no significant differences in 30-day reoperation, emergency department (ED) returns, wound complaints, and Quick DASH (Disabilities of the Arm, Shoulder, and Hand) scores. When comparing chromic absorbable sutures to non-absorbable sutures, those with absorbable sutures were significantly more likely to have telemedicine visits but were also more likely to have wound complaints (17.9% vs. 8.5%; p=0.022). There was no significant difference in two- and six-week pain scores, 30-day reoperation, ED returns, residual symptoms, and Quick DASH scores. When comparing patients treated using the absorbable suture and telemedicine protocol with those receiving any other type of suture and postoperative follow-up, no significant differences in any postoperative clinical outcome measures were observed. Conclusion The results of this study demonstrate that the use of an absorbable suture and telemedicine protocol for patients undergoing trigger finger release yields similar outcomes as traditional methods of care. However, the use of absorbable sutures may result in decreased patient satisfaction with surgical wound healing.

The effects of hypoalbuminemia in obese patients undergoing total joint arthroplasty.

INTRODUCTION: Total joint arthroplasty (TJA) is a highly effective surgery. However, poor nutritional status has been associated with worse outcomes. In orthopedics, nutrition status is commonly evaluated using serum albumin. When albumin levels fall below 3.0 g/dL, wound healing ability becomes impaired. Typically, malnutrition is associated with low BMI, but malnourished patients can also be obese. The goals of this study were to investigate the relationship between malnourishment represented through albumin levels of obese patients and likelihood of postoperative complications. METHODS: A retrospective review of patients undergoing primary TJA from 2016 to 2020 in the American College of Surgeons National Surgical Quality Improvement Program national database was performed. Patients with an albumin of < 3.5 g/dL were considered to have hypoalbuminemia and those with ≥ 3.5 g/dL were considered normal albumin. Univariate analysis was used to determine demographic and comorbidity differences between those with and without hypoalbuminemia. Outcomes of interest included length of stay, resource utilization, discharge disposition, and unplanned readmissions. Multivariate logistic regression examined albumin as a predictor of increased resource utilization and complications after controlling for possible confounding variables. RESULTS: Of the 79,784 patients, 4.96% of patients had low albumin. Those with hypoalbuminemia were nearly 1.5 years older than those with normal albumin, were more likely to be black, female, and had an overall increased comorbidity burden as shown by percent of patients with ASA > 3 (all p < 0.001). After risk adjustment, those with hypoalbuminemia and a BMI of 35 + had greater risk of complications and increased resource utilization. CONCLUSION: Our results demonstrated the prevalence of malnutrition increases as a patient's BMI increases. Further, hypoalbuminemia was associated with increased resource utilization and increased complication rates in all obese patients. We suggest screening albumin levels in obese patients preoperatively to give surgeons the best opportunity to optimize patient nutrition before undergoing surgery.

Racial Disparities in Outcomes of Total Joint Arthroplasty at a Single Institution: Have We Made Progress?

Background: Health disparities disproportionately affect minority groups across the United States with respect to care access, quality, and outcomes. The aim of this study is to examine existing disparities between white and African American (AA) patients regarding postoperative outcomes following total joint arthroplasty and provide insight into disparity trends over a 9-year period. Methods: A retrospective review of 16,779 total joint arthroplasty patients at a single institution between January 2013 and December 2021 was performed. Patients were grouped by race as AA or white. Outcomes of interest included length of stay (LOS), home discharge, 30-day emergency department return, and 30-day readmission. Univariate statistics and multivariate regressions were utilized to analyze results. Results: Significant improvements in LOS and rates of home discharge occurred for both white and AA patients at our institution over a 9-year period, while rates of 30-day emergency department returns and readmissions demonstrated a downward but non-statistically significant trend. Despite these trends, AA patients continued to experience longer lengths of stay, less likelihood of 0- or 1-day LOS, and higher risk of nonhome discharge for most years examined. However, after controlling for demographic and comorbidity differences, the differences between groups narrowed over time resulting in no significant differences in the aforementioned 3 measures by 2021. Conclusions: Although racial disparities in outcomes are still apparent, over time, the differences in resource utilization between AA and white patients have narrowed. Initiatives aimed at creating healthier communities with increased access to care and the ultimate goal of equitable care must continue to be pursued.

Telemedicine Satisfaction and Preferences in an Orthopaedic Spine Clinic.

The use of telemedicine has expanded amid the COVID-19 pandemic and office closures and cancellation of elective surgeries early in the pandemic helped propagated its use. Previous studies have described the feasibility of telemedicine, however, little has been reported on patient perception and preferences within orthopaedics. The objective of this study was to evaluate satisfaction and preferences of telemedicine from the perspective of patients within an orthopaedic spine clinic. A cross-sectional, anonymous survey was implemented as a prospective quality improvement initiative. The survey was sent to patients who had an in-office or telemedicine visit with a provider in our orthopaedic spine clinic. Statistical analysis was performed on the results of the survey. The survey was sent to 1129 patients and a total of 316 patients responded. Twenty-one percent of respondents had a telemedicine appointment. There was no difference in satisfaction among groups (P = .288) and those with telemedicine appointments were more likely to have had a previous experience with this type of visit (P = .004) and were more inclined to use it in the future (P < .001). Patients preferred telemedicine because of the ability to get earlier appointments (P < .001) and the convenience of the visits (P < .001). Patients preferred in-office visits because they received hands-on physical exams (P = .003) or imaging (P = .041). Telemedicine is a viable alternative to in-office appointments for spine patients, as evidenced by similar levels of patient satisfaction. Sooner appointments and convenience are attractive elements of telemedicine visits, while the desire for physical examination remains a barrier to adoption in this population.

Pain After Preoperative Ultrasound Guided Hip Injections for Total Hip Arthroplasty: A Pilot Randomized Controlled Trial.

Introduction. Hip replacement is a frequently performed and highly successful treatment for patients with end stage osteoarthritis. Advances in technique and pain management have allowed for rapid mobilization and early discharge after surgery. We hypothesize that pre-incision intra-articular injection of local anesthetic with epinephrine under image guidance combined with post incision peri-articular injection (PAI) may be more effective than PAI alone. Methods. A prospective, randomized, controlled, comparative investigation at a single institution of 41 patients undergoing THA who received standard 30 mL post-arthrotomy, PAI of ropivacaine with epinephrine under direct visualization after prosthesis implantation before closure or an equivalent dose divided into a 10 mL pre-incision, ultrasound guided intra-articular injection and a 20 mL post-arthrotomy PAI. Results. 42 patients were included in this study before its early conclusion with 22 patients in the treatment group and 20 in the control group. There were no significant differences in age, BMI or ASA scores. Additionally, there were no significant differences noted when comparing groups by postoperative outcome measures including OMME, EBL, OR time, PACU minutes, and first and last PACU pain score. Furthermore, there were no significant differences in the PROMs evaluated. Discussion. The addition of ultrasound guided pre-incision intra-articular injection to the standard PAI had no benefit when compared with standard PAI during a THA. Portable mobile phone based ultrasound devices provide a cost effective way to perform musculoskeletal blocks, and further studies on their use and comparative accuracy is warranted. A novel technique for confirmation of injection location is described.

The Impact of Depression and Anxiety on Perioperative Outcomes and Patient-Reported Outcomes Measurement Information System Physical Function After Thoracolumbar Surgery.

BACKGROUND: Depression and anxiety are common within spine patient populations. The demand for surgical management of degenerative spine conditions and the prevalence of mental disorders are expected to increase as the general population ages. Concurrently, there is increasing pressure to demonstrate high-value care through improved perioperative outcome metrics and patient-reported outcome instruments. The purpose of this study was to evaluate the impact of common mental disorders on perioperative markers of high resource utilization and patient-reported outcomes measurement information system physical function (PROMIS-PF) following thoracolumbar (TL) spine surgery. METHODS: A retrospective review of patients undergoing TL decompression alone or with fusion at a single institution. Data were collected using an administrative database for patient demographics. Outcomes of interest included length of stay, discharge disposition, 90-day return to the emergency department (ED), 90-day hospital readmission, 1-year complication rate, 1-year revision surgery rate, 1-year residual radiculopathy, and PROMIS-PF scores recorded preoperatively, at 0 to 1, 1 to 3, 3 to 6, and 6 to 12 months postoperatively. Univariate analysis and multiple linear regression were utilized to analyze results. RESULTS: A total of 596 patients were included in this study, of whom 205 (34%) had a history of depression or anxiety. Compared with patients with no history of a mental disorder, patients with depression or anxiety who underwent TL decompression alone had higher rates of 90-day ED visits (P = 0.019), 90-day readmissions (P = 0.031), and complications at 1 year (P = 0.012). After risk adjustment, the diagnosis of depression or anxiety had no significant effect on PROMIS-PF improvement from the preoperative to postoperative period. CONCLUSION: Our study suggests that a history of depression or anxiety is common among patients undergoing spine surgery but has no significant impact on PROMIS-PF improvement. Because some patients with depression or anxiety may be at higher risk of postoperative resource utilization, further study and effort are warranted to support at-risk groups and improve overall care value. CLINICAL RELEVANCE: Although patients with depression or anxiety are at risk for increased resource utilization after TL decompression or fusion, they can experience similar levels of functional improvement as patients without these conditions. Therefore depression or anxiety should not be considered contraindications to surgery, but additional attention should be paid to this population during the postoperative recovery period.

Development and validation of a risk-based algorithm for preoperative type and screen testing in spine surgery.

BACKGROUND CONTEXT: With improvements in surgical techniques and perioperative management, transfusion rates after spine surgery have decreased over time. Given this trend, routine preoperative ABO/Rh type and antibody screen (T&S) laboratory testing may not be warranted in all patients undergoing spine surgery. PURPOSE: The aim of the current study is to evaluate risk factors for intra/postoperative transfusion in patients undergoing a variety of spine procedures and to develop an algorithm for selectively ordering preoperative T&S testing in appropriate patients. STUDY DESIGN/SETTING: This is a single institution, retrospective observational study of patients undergoing emergent or elective spine surgery. External validation of the algorithm was performed on a national sample of patients undergoing spine surgery from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) national database. PATIENT SAMPLE: A total of 5,947 surgeries from January 1, 2016 to December 31, 2019 at a single institution, and 166,113 surgeries from the 2016 to 2018 ACS-NSQIP database. OUTCOME MEASURES: The primary outcome measure was performance of intraoperative or postoperative transfusion. METHODS: Using the institutional sample, univariate statistics (chi-square tests, fisher's exact test, 2-sided independent sample tests) were performed to compare demographics, comorbidities, and surgical details (case type, number of levels treated, etc.) between patients who did and did not require intra- or postoperative transfusion. Transfusion rates were calculated and compared across procedure types. Multivariate logistic regression was performed to identify independent predictors of transfusion and the model's accuracy was evaluated using the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. A risk-based algorithm suggesting no preoperative T&S in low transfusion risk procedures, routine preoperative T&S in high-risk procedures, and further assessment in medium risk thoracolumbar fusion procedures was created. The algorithm's sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were evaluated when it was applied to both the institutional and national samples. Potential cost savings from reducing T&S orders were calculated. RESULTS: In the institutional sample, 120 patients (2.0%) required intraoperative or postoperative transfusion. The highest rates of transfusion were found in corpectomy (10.5%) and anterior/posterior cervical fusion (6.9%) procedures. In the multivariate logistic regression model, the presence of a preoperative coagulation defect or hemorrhagic condition (OR: 7.149, p<.001) and 6+ level surgery (OR: 7.511, p<.001) were the strongest predictors of transfusion. Overall, the model generated an AUC of 0.882, indicating excellent predictive accuracy. When applied to the institutional cohort, the risk-based algorithm had a sensitivity of 78.3%, specificity of 80.5%, PPV of 7.6%, and NPV of 99.4% for evaluating likelihood of transfusion. Using the algorithm 4,717 T&S tests would have been eliminated (79.3%), resulting in a cost savings of $179,246. Application of the model to the ACS-NSQIP cohort resulted in a sensitivity of 61.9%, specificity of 84.6%, PPV of 15.6%, and NPV of 98.0%. CONCLUSIONS: The routine use of preoperative ABO/Rh type and antibody screen testing does not appear to be warranted in patients undergoing spine surgery. A risk-based approach to preoperative type and screen testing may eliminate unnecessary tests and generate significant cost savings with minimal disruption to clinical care.

Enhanced Preoperative Education Pathways: A Step Toward Reducing Disparities in Total Joint Arthroplasty Outcomes.

BACKGROUND: Patients with increased comorbidities, lower socioeconomic status, and African American (AA) race have been shown to be at increased risk for suboptimal outcomes after total joint arthroplasty (TJA). Despite the body of evidence highlighting these disparities, few interventions aimed at improving outcomes specifically in high-risk patients have been evaluated. This study evaluates the impact of an enhanced preoperative education pathway (EPrEP) on outcomes after TJA. METHODS: All patients included underwent unilateral primary total hip or knee arthroplasty at a single institution from September 1, 2020 to September 31, 2021. This is a retrospective observational cohort study comparing demographics, comorbidities, and outcomes of patients treated through EPrEP with those receiving routine care. Subgroup analysis of outcome differences by race was performed. RESULTS: In total, 1,716 patients were included in the study: 802 went through the EPrEP and 914 did not. EPrEP patients had a higher comorbidity burden as measured by the Charlson Comorbidity Index (3.54 ± 1.71 vs 3.25 ± 1.75, P < .001). After risk adjustment, there was no significant relationship among EPrEP utilization and length of stay, home discharge, or 30-day readmissions. However, EPrEP patients were less likely to return to the emergency department 30 days postoperatively (odds ratio 0.49, 95% confidence interval 0.27-0.86, P = .016). No significant differences in outcomes between AA and non-AA patients were observed. CONCLUSION: High-risk patients receiving individualized nurse navigator counseling experienced similar outcomes to the broader patient population undergoing TJA. Implementation of EPrEPs may be an effective means of enhancing the equity of care quality across all patients undergoing TJA.

Patients From Medically Underserved Areas Are at Increased Risk for Nonhome Discharge and Emergency Department Return After Total Joint Arthroplasty.

BACKGROUND: Maryland Health Enterprise Zones (MHEZs) were introduced in 2012 and encompass underserved areas and those with reduced access to healthcare providers. Across the United States many underserved and minority populations experience poorer total joint arthroplasty (TJA) outcomes seemingly because they reside in underserved areas. The purpose of this study is to identify and quantify the relationship between living in an MHEZ and TJA outcomes. METHODS: Retrospective review of 11,451 patients undergoing primary TJA at a single institution from July 1, 2014 to June 30, 2020 was conducted. Patients were classified based on whether they resided in an MHEZ. Statistical analyses were used to compare outcomes for TJA patients who live in MHEZ and those who do not. RESULTS: Of the 11,451 patients, 1057 patients lived in MHEZ and 10,394 patients did not. After risk adjustment, patients who live in an MHEZ were more likely to return to the emergency department within 90 days postoperatively and were less likely to be discharged home than those patients who do not live in an MHEZ. CONCLUSION: Total joint arthroplasty patients residing in MHEZ appear to present with poorer overall health as measured by increased American Society of Anesthesiologists and Hierarchical Condition Categories scores, and they are less likely to be discharged home and more likely to return to the emergency department within 90 days. Several factors associated with these findings such as socioeconomic factors, household composition, housing type, disability, and transportation may be modifiable and should be targets of future population health initiatives.

Murine AML12 hepatocytes allow Salmonella Typhimurium T3SS1-independent invasion and intracellular fate.

Numerous studies have demonstrated the key role of the Salmonella Pathogenicity Island 1-encoded type III secretion system (T3SS1) apparatus as well as its associated effectors in the invasion and intracellular fate of Salmonella in the host cell. Several T3SS1 effectors work together to control cytoskeleton networks and induce massive membrane ruffles, allowing pathogen internalization. Salmonella resides in a vacuole whose maturation requires that the activity of T3SS1 subverts early stages of cell signaling. Recently, we identified five cell lines in which Salmonella Typhimurium enters without using its three known invasion factors: T3SS1, Rck and PagN. The present study investigated the intracellular fate of Salmonella Typhimurium in one of these models, the murine hepatocyte cell line AML12. We demonstrated that both wild-type Salmonella and T3SS1-invalidated Salmonella followed a common pathway leading to the formation of a Salmonella containing vacuole (SCV) without classical recruitment of Rho-GTPases. Maturation of the SCV continued through an acidified phase that led to Salmonella multiplication as well as the formation of a tubular network resembling Salmonella induced filaments (SIF). The fact that in the murine AML12 hepatocyte, the T3SS1 mutant induced an intracellular fate resembling to the wild-type strain highlights the fact that Salmonella Typhimurium invasion and intracellular survival can be completely independent of T3SS1.

A large panel of chicken cells are invaded in vivo by Salmonella Typhimurium even when depleted of all known invasion factors.

Poultry are the main source of human infection by Salmonella. As infected poultry are asymptomatic, identifying infected poultry farms is difficult, thus controlling animal infections is of primary importance. As cell tropism is known to govern disease, our aim was therefore to identify infected host-cell types in the organs of chicks known to be involved in Salmonella infection and investigate the role of the three known invasion factors in this process (T3SS-1, Rck and PagN). Chicks were inoculated with wild-type or isogenic fluorescent Salmonella Typhimurium mutants via the intracoelomic route. Our results show that liver, spleen, gall bladder and aortic vessels could be foci of infection, and that phagocytic and non-phagocytic cells, including immune, epithelial and endothelial cells, are invaded in vivo in each organ. Moreover, a mutant defective for the T3SS-1, Rck and PagN remained able to colonize organs like the wild-type strain and invaded non-phagocytic cells in each organ studied. As the infection of the gall bladder had not previously been described in chicks, invasion of gall bladder cells was confirmed by immunohistochemistry and infection was shown to last several weeks after inoculation. Altogether, for the first time these findings provide insights into cell tropism of Salmonella in relevant organs involved in Salmonella infection in chicks and also demonstrate that the known invasion factors are not required for entry into these cell types.

Intraoperative Anaphylaxis in Response to Hemostatic Agents With Protein Derivatives.

Topical hemostatic agents are commonly used in a wide variety of surgical procedures to assist in hemostasis. However, the use of these agents is not without risk as many contain biologically active agents derived from human and animal products that have the potential to cause adverse reactions. This case report covers a 44-year-old man with a history of alpha-gal syndrome who was scheduled for an open reduction and internal fixation of a left distal radius fracture. Alpha-gal syndrome is characterized by an IgE-mediated type 1 hypersensitivity reaction to a mammalian oligosaccharide epitope. Patients with this condition have a history of a past tick bite and subsequent development of an allergic reaction to mammalian protein products, most notably red meat. The patient had concerns about products used during surgery and potential reactions based on his allergy. The intent of this case report is to promote physician awareness of the widespread use of mammalian products in surgical hemostatic agents and potential immunogenic reactions. By increasing awareness of the alpha-gal syndrome, the goal is that medical device companies will actively disclose product components that could potentiate these adverse reactions and continue to develop alternative agents.

Mutations in PHF8 are associated with X linked mental retardation and cleft lip/cleft palate.

Truncating mutations were found in the PHF8 gene (encoding the PHD finger protein 8) in two unrelated families with X linked mental retardation (XLMR) associated with cleft lip/palate (MIM 300263). Expression studies showed that this gene is ubiquitously transcribed, with strong expression of the mouse orthologue Phf8 in embryonic and adult brain structures. The coded PHF8 protein harbours two functional domains, a PHD finger and a JmjC (Jumonji-like C terminus) domain, implicating it in transcriptional regulation and chromatin remodelling. The association of XLMR and cleft lip/palate in these patients with mutations in PHF8 suggests an important function of PHF8 in midline formation and in the development of cognitive abilities, and links this gene to XLMR associated with cleft lip/palate. Further studies will explore the specific mechanisms whereby PHF8 alterations lead to mental retardation and midline defects.

The Gln-Ala repeat transcriptional activator CA150 interacts with huntingtin: neuropathologic and genetic evidence for a role in Huntington's disease pathogenesis.

Huntington's disease (HD) is a neurodegenerative disease caused by polyglutamine expansion in the protein huntingtin (htt). Pathogenesis in HD appears to involve the formation of ubiquitinated neuronal intranuclear inclusions containing N-terminal mutated htt, abnormal protein interactions, and the aggregate sequestration of a variety of proteins (noticeably, transcription factors). To identify novel htt-interacting proteins in a simple model system, we used a yeast two-hybrid screen with a Caenorhabditis elegans activation domain library. We found a predicted WW domain protein (ZK1127.9) that interacts with N-terminal fragments of htt in two-hybrid tests. A human homologue of ZK1127.9 is CA150, a transcriptional coactivator with a N-terminal insertion that contains an imperfect (Gln-Ala)(38) tract encoded by a polymorphic repeat DNA. CA150 interacted in vitro with full-length htt from lymphoblastoid cells. The expression of CA150, measured immunohistochemically, was markedly increased in human HD brain tissue compared with normal age-matched human brain tissue, and CA150 showed aggregate formation with partial colocalization to ubiquitin-positive aggregates. In 432 HD patients, the CA150 repeat length explains a small, but statistically significant, amount of the variability in the onset age. Our data suggest that abnormal expression of CA150, mediated by interaction with polyglutamine-expanded htt, may alter transcription and have a role in HD pathogenesis.

Detection of polyglutamine expansion in a new acidic protein: a candidate for childhood onset schizophrenia?

Polyglutamine expansion (PGE) encoded by a CAG repeat underlies eight inherited neurodegenerative diseases, among which is Huntington's disease. CAG expansion has also been reported in schizophrenia, suggesting a role for PGE. To investigate the potential role of PGE as a candidate for schizophrenia, we searched for PGE in nuclear families comprising a patient affected by childhood onset schizophrenia (COS, a rare and severe form of the disease) as a variation of the candidate gene approach for identifying susceptibility genes. We tested lymphoblastoid cell lines from COS patients (n = 32) by Western blot analysis with 1C2, a monoclonal antibody that specifically recognizes long polyglutamines. Eight of 11 unrelated black American COS patients showed a 60-kDa (approximately) band indicative of PGE. A strong 60-kDa band (suggestive of a large PGE) was detected in two of the eight positive patients. A weaker 60-kDa band (suggestive of a smaller and non pathogenic PGE) was detected in some unaffected parents or sibs of these two COS patients, and in six other black American COS patients. The strong and weak PGE signals were found to correspond to two different proteins. Unrelated black Americans unaffected by COS (n = 38) were negative for the strong 60-kDa PGE signal. Healthy white Americans (n = 53) were negative for both the strong and weak 60-kDa PGE signals. Two-dimensional gel analysis suggested that the strong PGE signal corresponds to an acidic (pI 4 approximately) protein and resulted in a more precise estimation (52-57 kDa) of its relative mass. This protein appeared to be not represented in Genbank, as suggested by the exclusion of several candidate CAG repeats. Our data suggest that this acidic protein might be a candidate for COS.

CAG/CTG and CGG/GCC repeats in human brain reference cDNAs: outcome in searching for new dynamic mutations.

CAG and CGG expansion is associated with 10 inherited neurological diseases and is thought to be involved in other human genetic diseases. To identify new candidate genes, we have undertaken a large-scale screening project for CAG/CTG ([CAG]n) and CGG/GCC ([CGG]n) repeats in human brain reference cDNAs. Here, we present the final classification for 597 cDNAs selected by CAG and CGG hybridization from two libraries (100,128 clones) and the updated characterization of [CAG]n- and [CGG]n-positive cDNAs (repeat polymorphism and cDNA localization). We have selected 124 CAG and 83 CGG hybridization-positive clones representing new genes, from which 49 CAG and 7 CGG repeats could be identified. New [CAG]n and [CGG]n with more than seven to nine units were rare (1/2000), and perfect [CAG]n 9 were more likely polymorphic. Overall, highly polymorphic to monomorphic new [CAG]n > 9 and [CGG]n > 7 were characterized. The comparison of our data with other [CAG]n and [CGG]n resources suggests that the screening of reference cDNAs leads to unique sources of new [CAG]n and [CGG]n and will enhance the study of enlarged triplet repeats in human genetic diseases.

Survey of CAG/CTG repeats in human cDNAs representing new genes: candidates for inherited neurological disorders.

Expansion of polymorphic CAG and CTG repeats in transcripts is the cause of six inherited neurodegenerative or neuromuscular diseases and may be involved in several other genetic disorders of the central nervous system. To identify new candidate genes, we have undertaken a large-scale screening project for CAG and CTG repeats in human reference cDNAs. We screened 100 128 brain cDNAs by hybridization. We also scanned GenBank expressed sequence tags for the presence of long CAG/CTG repeats in the extremities of cDNAs from several human tissues. Of the selected clones, 286 were found to represent new genes, and 72 have thus far been shown to contain CAG/CTG repeats. Our data indicate that CAG/CTG repeated 10 or more times are more likely to be polymorphic, and that new 3'-directed cDNAs with such repeats are very rare (1/2862). Nine new cDNAs containing polymorphic (observed heterozygote frequency: 0.05-0.90) CAG/CTG repeats have been currently identified in cDNAs. All of the cDNAs have been assigned to chromosomes, and six of them could be mapped with YACs to 1q32-q41, 3p14, 4q28, 3p21 and 12q13.3, 13q13.1-q13.2, and 19q13.43. Three of these clones are highly polymorphic and represent the most likely candidate genes for inherited neurodegenerative diseases and, perhaps, neuropsychiatric disorders of multifactorial origin.