Keratin-Positive Giant Cell-Rich Tumor of Bone Harboring an HMGA2::NCOR2 Fusion: Two Cases, Including a Patient With Metastatic Disease, and Review of the Literature

Giant cell-rich lesions of bone represent a heterogeneous group of entities which classically include giant cell tumor of bone, aneurysmal bone cyst, nonossifying fibroma, and Brown tumor of hyperparathyroidism. A recently described subset of giant cell-rich tumors involving bone and soft tissue has been characterized by recurrent HMGA2::NCOR2 fusions and keratin expression. The overlapping clinical, radiographic, and morphological features of these giant cell-rich lesions provide a unique diagnostic challenge, particularly on biopsy. We present 2 additional cases of keratin-positive giant cell-rich tumor of bone with HMGA2::NCOR2 fusions, including 1 patient who developed metastatic disease.

Current updates in sarcoma biomarker discovery: emphasis on next-generation sequencing-based methods

Soft tissue sarcomas comprise a heterogeneous group of neoplasms. Although soft tissue malignancies make up only 2% of adult cancers, classification based on histomorphology presents a diagnostic challenge. Characterisation of soft tissue sarcomas by molecular analysis is rapidly evolving to improve diagnostic accuracy and develop targeted therapies. This review highlights the advances in molecular techniques, including current next-generation sequencing-based assays (fusion detection by RNA sequencing, targeted/whole exome sequencing, microRNA profiling), as well as emerging methods (liquid biopsies, DNA methylation profiling, single-cell molecular profiling and next-generation immunohistochemistry) for future clinical applications.

Anti-Inflammatory and Therapeutic Effects of a Novel Small-Molecule Inhibitor of Inflammation in a Male C57BL/6J Mouse Model of Obesity-Induced NAFLD/MAFLD

Purpose

Non-alcoholic fatty liver disease (NAFLD), recently renamed metabolic (dysfunction) associated fatty liver disease (MAFLD), is the most common chronic liver disease in the United States. Presently, there is an intense and ongoing effort to identify and develop novel therapeutics for this disease. In this study, we explored the anti-inflammatory activity of a new compound, termed IOI-214, and its therapeutic potential to ameliorate NAFLD/MAFLD in male C57BL/6J mice fed a high fat (HF) diet.

Methods

Murine macrophages and hepatocytes in culture were treated with lipopolysaccharide (LPS) ± IOI-214 or DMSO (vehicle), and RT-qPCR analyses of inflammatory cytokine gene expression were used to assess IOI-214's anti-inflammatory properties in vitro. Male C57BL/6J mice were also placed on a HF diet and treated once daily with IOI-214 or DMSO for 16 weeks. Tissues were collected and analyzed to determine the effects of IOI-214 on HF diet-induced NAFL D/MAFLD. Measurements such as weight, blood glucose, serum cholesterol, liver/serum triglyceride, insulin, and glucose tolerance tests, ELISAs, metabolomics, Western blots, histology, gut microbiome, and serum LPS binding protein analyses were conducted.

Results

IOI-214 inhibited LPS-induced inflammation in macrophages and hepatocytes in culture and abrogated HF diet-induced mesenteric fat accumulation, hepatic inflammation and steatosis/hepatocellular ballooning, as well as fasting hyperglycemia without affecting insulin resistance or fasting insulin, cholesterol or TG levels despite overall obesity in vivo in male C57BL/6J mice. IOI-214 also decreased systemic inflammation in vivo and improved gut microbiota dysbiosis and leaky gut.

Conclusion

Combined, these data indicate that IOI-214 works at multiple levels in parallel to inhibit the inflammation that drives HF diet-induced NAFLD/MAFLD, suggesting that it may have therapeutic potential for NAFLD/MAFLD.

Myoepithelioma, myoepithelioma-like, and chondroid soft-tissue tumors arising at acral sites: a review

Myoepithelial neoplasms comprise a histologically and immunophenotypically diverse spectrum of entities. The following review is a comprehensive summary of acral lesions demonstrating myoepithelial-like and chondroid histomorphology, as well as recently described mimics that are diagnostically challenging to distinguish. The salient clinicopathologic, immunophenotypic, and molecular features of each entity are described.

A novel IRF2BP2::CDX2 Gene fusion in digital intravascular myoepithelioma of soft tissue: An enigma!

Soft tissue myoepitheliomas (STM) are benign myoepithelial neoplasms (of nonsalivary gland origin) arising, most commonly within subcutaneous and deep soft tissues of the extremities and rarely within bones. To the best of our knowledge, the intravascular location of STM as well as the identification of a novel IRF2BP2::CDX2 fusion have not been previously reported. Herein, we report a case of spindle cell myoepithelioma arising within the intravascular space of the right index finger in a 52-year-old male of more than 20 years duration. Histopathology demonstrated an intravascular tumefactive lesion composed of predominantly plump banal spindle cells in a fascicular arrangement within a mixed collagenous and chondromyxoid stroma colliding with papillary endothelial hyperplasia (Masson tumor). By immunohistochemistry, the lesional cells were positive for keratin-AE1/3, epithelial membrane antigen, S100, SOX10, glial fibrillary acid protein, calponin and negative for CD34, smooth muscle actin, desmin, p63, and ERG. Fluorescence in situ hybridization for EWSR1 gene rearrangement was negative. Next-generation sequencing detected a novel IRF2BP2::CDX2 fusion involving Exon 1 of the IRF2BP2 gene and Exon 2 of the CDX2 gene confirmed by reverse transcriptase polymerase chain reaction and Sanger sequencing. Further, clinical evaluation for a salivary gland mass in the head and neck region and magnetic resonance imaging (MRI) of the chest, abdomen, and pelvis was performed with no evidence of tumor elsewhere. Taken together, the overall features were considered diagnostic of STM. Our current case underscores the novelty of the IRF2BP2::CDX2 gene fusion in STM and its exceptionally rare intravascular location.

Metastatic sporadic paraganglioma with EWSR1::CREM gene fusion: A unique molecular profile that expands the phenotypic diversity of the molecular landscape of the EWSR1::CREM gene fusion positive tumors

Chromosomal translocations with gene fusions are uniquely rare events in paraganglioma, mostly involving UBTF::MAML3 gene fusion. Precedent literature suggests that tumors involving MAML3 gene fusion correlate with poor clinical outcomes. Herein, we report a case of metastatic sporadic paraganglioma harboring EWSR1::CREM gene fusion in a 36-year-old male, that has not been previously described. The patient presented with large paraspinal mass that was resected the same year. Tumor recurred 3-years later and on further work-up, patient was found to have metastases involving both lungs. Histopathologic evaluation of the original primary tumor showed tightly packed irregular nests and cords of cells containing palely eosinophilic cytoplasm. Features considered atypical included: areas of solid growth pattern, coagulative tumor necrosis, focal cellular atypia and angiolymphatic invasion were also identified. By immunohistochemistry, the tumor cells were positive for synaptophysin and chromogranin and negative for keratin. The S100 stain highlights the sustentacular cells and the Ki-67 proliferation index of 15%. The recurrence specimen was similar but showed increased cellularity, atypia, necrosis, and proliferative activity (Ki-67 proliferation index of 35%). CT guided biopsy of the right lung lesion was consistent with metastasis. Next generation sequencing identified EWSR1::CREM fusion. The breakpoints were found in chromosome 22: 29683123 for EWSR1 exon 7 (NM_005243.3) and at chromosome 10:35495823 for CREM exon 6 (NM_001267562.1). Fluorescence in situ hybridization for EWSR1 gene rearrangement was positive. In summary, we report a case of metastatic paraganglioma with EWSR1::CREM gene fusion, not previously described in this entity, and expands on the phenotypic diversity within the genetic landscape of EWSR1::CREM gene fusion positive tumors.

Paratesticular Dedifferentiated Liposarcoma with Epithelioid Features: A Diagnostic Pitfall

Well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS) represent a significant number of sarcomas arising within the paratesticular region. DDLPS is notorious for a broad histologic spectrum, but epithelioid morphology is rare. Herein, we describe a unique case of paratesticular DDLPS with prominent epithelioid features and molecular confirmation. The patient is 71-year-old-male who presented with multiple paratesticular masses. Morphologic review of the resection specimen revealed a biphasic adipocytic neoplasm consistent with DDLPS. Additionally, epithelioid foci with acinar and nested architecture and focal keratin expression were noted. These areas raised the possibility of a secondary neoplasm including sex cord stromal tumor, germ cell tumor, and paraganglioma. However, MDM2 immunohistochemistry and FISH showed these areas to express MDM2 and exhibit MDM2 amplification, respectively, confirming that they represented a component of DDLPS. This case further highlights the morphologic diversity of DDLPS as well as the utility of MDM2 studies.

A SS18::NEDD4 Cutaneous Spindled and Epithelioid Sarcoma: A Hitherto Unclassified Cutaneous Sarcoma, Resembling Epithelioid Sarcoma with Aggressive Clinical Behavior

SS18::SSX gene fusions as a result of t(X,18)(p11;q11) have only been described in synovial sarcoma (SS). Recently, an SS18::NEDD4 gene fusion was identified in a single case of primary renal SS exhibiting a hypocellular and myxoid morphology. Herein, we report a case of an unclassified malignant cutaneous spindled and epithelioid neoplasm in a 60‐year‐old female that resembled an epithelioid sarcoma (ES) and harbored a rare SS18::NEDD4 gene fusion. Briefly, the patient presented with a progressively growing cutaneous mass involving the volar aspect of right hand, warranting an amputation. Histologic sections revealed a cutaneous ulcerative neoplasm composed of spindled and epithelioid cells, bearing a certain semblance to ES, with diffuse invasion into the subcutis and skeletal muscle. Coagulation tumor necrosis and mitotic figures were present. By immunohistochemistry, the tumor cells were positive for keratins (AE1/3 and cam5.2), vimentin, CMYC, BCL2, p53, smooth muscle actin (focal), and TLE1 (multifocal) and negative for p40, p63, CK5/6, CK7, CK20, CD56, CD31, CD34, ERG, desmin, SMMS, H‐Caldesmon, myogenin, and S‐100. Expression of INI1 stain was retained. The unusual histomorphology and inconclusive immunophenotypic profile lead to next‐generation sequencing identifying an SS18::NEDD4 gene fusion with genomic coordinates 5′‐SS18 (ex1‐9 NM_005637)‐NEDD4 (ex14‐29 NM_006154). Fluorescence in situ hybridization confirmed SS18 gene rearrangement. Within 2 years, the patient developed widespread metastatic disease. Despite aggressive multimodality treatment, the patient succumbed to disease. In summary, we report a unique case of previously unclassified cytokeratin positive malignant cutaneous spindled and epithelioid sarcoma with aggressive behavior, harboring an SS18::NEDD4 fusion.

Influenza A virus modulates ACE2 expression and SARS-CoV-2 infectivity in human cardiomyocytes

Influenza A virus (IAV) and SARS-CoV-2 are both acute respiratory viruses currently circulating in the human population. Prior IAV infection enhances SARS-CoV-2 infectivity and lung pathogenesis in mice; however, underlying mechanisms and the extent that co-infection leads to involvement of other organs in disease severity remains unknown. Herein, we investigated the impact of prior IAV infection on SARS-CoV-2 pathogenesis and cardiomyocyte function. IAV infection induces the expression of ACE2 in human lung epithelial cells, lung fibroblasts, macrophages, cardiac fibroblasts (HCFs), and hiPSC-Cardiomyocytes (CMs). Interestingly, we detected poorly glycosylated ACE2 in lung epithelial cells and cardiac fibroblasts. In contrast, expression of a heavily glycosylated form of ACE2 is induced by IAV in CMs. In all cell types, IAV infection enhances SARS-CoV-2 viral entry. However, efficient SARS-CoV-2 replication was uniquely inhibited in CMs. Glycosylation of ACE2 correlated with enzymatic conversion of its substrate Angiotension II, induction of eNOS and nitric oxide production, providing a mechanistic underpinning for restricted viral replication in CMs. Our results indicate that IAV-mediated induction of ACE2 is double-edged, providing increased risk for SARS-CoV-2 coinfection in epithelial cells and HCFs, while limiting SARS-CoV-2 replication in CMs. We conclude that differential glycosylation of ACE2 may be a molecular determinant, not of SARS-CoV-2 infection, but of replication.

Funding: NIH grants R01-AI 146252, R21-AI 146690

Funding:  NIH grants R01-AI 146252, R21-AI 146690

Intraneural Nodular Fasciitis of the Femoral Nerve with A Unique CTNNB1::USP6 Gene Fusion: Apropos of a Case and Review of Literature

Nodular fasciitis (NF) is a benign proliferation of fibroblasts and myofibroblasts occurring most commonly in the upper extremities that can mimic a variety of mesenchymal tumors including sarcoma. Although reported in almost all anatomic locations, only 7 cases of intraneural nodular fasciitis have been reported in English literature. The CTNNB1::USP6 gene fusion has not been previously reported in intraneural nodular fasciitis, although it has been reported in three entities including aneurysmal bone cyst, nodular fasciitis, and intravascular fasciitis. We report a case of a 29-year-old female with a 6-month history of left leg weakness, myalgia, and paresthesia of the left foot prompting a clinical diagnosis of a peripheral nerve sheath tumor. Surgical resection was performed, and histologic sections revealed a circumscribed lesion composed of banal spindle cells with variable interstitial collagen and occasional mitotic figures. By immunohistochemistry, the lesional cells were positive for smooth muscle actin, smooth muscle heavy chain myosin, p16, and H-caldesmon and negative for desmin, S-100, SOX10, HMB45, CD34, and beta-catenin. Fluorescence in Situ Hybridization for USP6 gene rearrangement was positive and consistent with the diagnosis of nodular fasciitis. Next-generation sequencing uncovered the presence of a CTNNB1::USP6 gene fusion involving CTNNB1 gene in exon 1 at the genomic position chr3:41241161 and the USP6 gene in exon 1 at the genomic position chr17:5033231. This gene fusion was confirmed by Sanger sequencing. Herein, we report a case that underscores the rare incidence of intraneural nodular fasciitis and highlights the pitfalls associated with the clinical differential diagnoses of intraneural tumors.

Primary Intranodal Epithelioid Hemangioendothelioma with Molecular Confirmation

Epithelioid hemangioendothelioma (EHE) is a rare low-grade malignant vascular tumor with indolent biology, characterized by reciprocal t(1;3)(p36.6;q25) with resultant WWTR1::CAMTA1 gene fusion in the vast majority of cases, regardless of anatomic location. Only a small subset, exhibiting well formed vasoformative features will contain YAP1::TFE3 gene fusion. Primary intranodal EHE is exquisitely rare. We report a case in a 54-year-old male with persistent left groin mass with discomfort for nine months. A CT of the abdomen and pelvis showed a minimally enlarged left inguinal lymph node measuring 2.8 cm with no other masses or lymphadenopathy. PET/CT and MRI imaging of the abdomen showed no evidence of disease elsewhere. Sections showed an epithelioid vasoformative neoplasm, centrally necrotic and involving a lymph node. The cells were arranged in anastomosing cords with intracytoplasmic lumens, resembling "signet ring cells". By immunohistochemistry, the tumor cells were positive for vimentin, CD31, CD34, ERG and CAMTA1; and negative for AE1/3, CAM 5.2, KRT7, KRT20, desmin, actin, HMB-45 and S-100. Ki-67 proliferation index was estimated at <1%. Molecular studies including next generation sequencing (NGS) revealed the presence of WWTR1::CAMTA1 gene fusion, and fluorescence in situ hybridization for CAMTA1 (1p36.23) and WWTR1 (3p25.1) showed fusion signals, diagnostic of EHE. We highlight a rare occurrence of EHE in a lymph node exhibiting morphologic mimicry with metastatic carcinoma.

A YAP1::TFE3 cutaneous low-grade fibromyxoid neoplasm: A novel entity!

Cutaneous fibromyxoid neoplasms (CFMN) comprise a vast category of benign and malignant tumors that include, but are not limited to, low-grade fibromyxoid sarcoma, myxofibrosarcoma, myxoid dermatofibrosarcoma protuberans, myxoid solitary fibrous tumor, and myxoid neurofibroma with differing implications for treatment and prognosis. Herein, a case of CFMN arising as a painless, slow-growing, flesh-colored forearm mass in a 53-year-old female is presented. The neoplasm comprised of copious myxoid material with banal spindle cells, exhibiting mild hyperchromasia, dissecting the dermal collagen table. Focal perivascular accentuation of spindle cells was identified in the absence of vasoformative features. Immunohistochemically, lesional cells were strongly and diffusely positive for CD34 and multifocally for Factor XIIIa and epithelial membrane antigen while negative for CD31, ERG, FLI-1, D2-40, smooth muscle actin, Desmin, S100, HMB-45, STAT6, MUC4, and keratins. RNA- and DNA-sequencing identified a YAP1::TFE3 fusion transcript that were subsequently corroborated by fluorescence in situ hybridization and immunohistochemistry for TFE3 (Xp11.23) locus rearrangement and strong, diffuse TFE3 immunoreactivity, respectively. To date, the YAP1::TFE3 fusion has only been identified in a subset of epithelioid hemangioendotheliomas and clear cell stromal tumors of the lung. This is the first report of a CFMN featuring a YAP1::TFE3 fusion (YAP1 Exon 1 and TFE3 Exon 4). The morphologic findings are unlike those previously described for epithelioid hemangioendothelioma and suggest that this neoplasm may represent a yet unclassified or novel CFMN entity. Although the patient is 1-year status postsurgical excision with no evidence of clinical recurrence, the clinical behavior of this novel entity remains to be fully characterized.

An unexpected paradox: wall shear stress in the aorta is less in patients with severe atherosclerosis regardless of obesity

BACKGROUND

Obesity is a widespread condition that is more prevalent in Western countries compared to others. Aortic atherosclerosis (AA) is a condition that frequently has been associated with obesity. An obesity paradox, where morbidly obese decedents had either no or minimal AA compared to nonobese decedents, recently has been described by some of us. The explanation for this almost counterintuitive paradox has yet to be determined, but a number of hypotheses were advanced, including hemodynamic factors producing aortic wall shear stress (WSS). The purpose of the present study was to determine if there was a relationship between AA and WSS, as determined by postmortem measurement of aortic wall diameters.

METHODS

Circumferences of the aorta at the levels of the ascending, thoracic and abdominal aorta were measured in 274 consecutive autopsies over 2-year period of time. AA was assessed using a previously described grading scale as either mild or severe. Circumferences were mathematically converted to diameters and WSS was calculated using the Hagen-Poiseuille formula. Two different methods to estimate cardiac output were used, both based on literature methods, one of which was body mass index (BMI) dependent, and the other BMI independent. Univariate and multivariable analyses of the relationship between WSS, age, BMI, gender, race and severity of AA were performed.

RESULTS

Of the 274 decedents, 140 had mild and 134 had moderate to severe AA. BMI <35 was associated with moderate to severe AA. WSS was inversely correlated with AA in all these segments of the aorta in each BMI subgroup with the exception of the ascending aorta for decedents with BMI ≤35 kg/m². Contrary to what we had hypothesized, WSS was not a determinant of the obesity paradox. However, among all the variables analyzed, a history of hypertension, diabetes mellitus and age were significant factors for developing AA (relative risk [RR] 0.35, P = .039; RR 1.51, P = .0006, RR 1.19, P = .0001, respectively).

CONCLUSIONS

Our data demonstrate that WSS was unexpectedly lower in decedents with moderate and severe AA as compared to those with mild AA. This observation, which requires further investigations, was seen in all BMI ranges and was confirmed by 2 methods to calculate WSS.

SUN-095 Attenuation of Inflammation by a Novel Small Molecule Prevents High Fat Diet-Induced Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of both metabolic and inflammatory diseases, and it has become pervasive worldwide. Inflammation, including inflammation resulting from free fatty acid (FFA) activation of toll-like receptor (TLR) signaling, has been suggested to be an essential component of the pathophysiology of both insulin resistance and NAFLD. High fat (HF) diets promote an increased uptake and storage of FFAs and triglycerides in hepatocytes, which initiates inflammation and steatosis that induces lipotoxicity and an exacerbation of inflammation. In previous studies, we have established the efficacy of phenylmethimazole, a TLR3/4 inhibitor, to prevent and reverse HF diet-induced NAFLD, inflammation, and insulin resistance. A new library of small molecule compounds, including COB-214, was generated to identify even more potent inhibitors of inflammation. The objectives of this study were to evaluate the efficacy of COB-214 to delay and/or prevent hepatic steatosis, inflammation, and insulin resistance in a HF diet-induced model of NAFLD. C57BL/6J male mice were fed a HF diet (60 % fat, 20% protein, 70% carbohydrate) and divided into 3 groups (N=8 for each group): sham injection (stress control), DMSO (vehicle control), COB-214. Each treatment was administered once daily at a dosage of 1mg/kg for 16 weeks. Histological examination of liver sections from these mice using hematoxylin and eosin (H&E) revealed less hepatic lipid accumulation in mice treated with COB-214 when compared to mice in the sham- and DMSO-treated groups. Transcription of pro-inflammatory cytokines was down-regulated in both liver and mesenteric adipose tissue isolated from COB-214-treated mice when compared to sham- and DMSO-treated mice. Treatment with COB-214 prevented HF diet-induced insulin resistance measured by a 3-hour intraperitoneal glucose tolerance test (IPGTT) and 1.5-hour intraperitoneal insulin tolerance test (IPITT). Future directions include determining the efficacy of COB-214 to reverse HF diet-induced NAFLD, inflammation, and insulin resistance. At the conclusion of this study, we hope to have established the role of a novel class of small molecule inhibitors of inflammation in the treatment and prevention of NAFLD.

Phenylmethimazole abrogates diet-induced inflammation, glucose intolerance and NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of both metabolic and inflammatory diseases and has become the leading chronic liver disease worldwide. High-fat (HF) diets promote an increased uptake and storage of free fatty acids (FFAs) and triglycerides (TGs) in hepatocytes, which initiates steatosis and induces lipotoxicity, inflammation and insulin resistance. Activation and signaling of Toll-like receptor 4 (TLR4) by FFAs induces inflammation evident in NAFLD and insulin resistance. Currently, there are no effective treatments to specifically target inflammation associated with this disease. We have established the efficacy of phenylmethimazole (C10) to prevent lipopolysaccharide and palmitate-induced TLR4 signaling. Because TLR4 is a key mediator in pro-inflammatory responses, it is a potential therapeutic target for NAFLD. Here, we show that treatment with C10 inhibits HF diet-induced inflammation in both liver and mesenteric adipose tissue measured by a decrease in mRNA levels of pro-inflammatory cytokines. Additionally, C10 treatment improves glucose tolerance and hepatic steatosis despite the development of obesity due to HF diet feeding. Administration of C10 after 16 weeks of HF diet feeding reversed glucose intolerance, hepatic inflammation, and improved hepatic steatosis. Thus, our findings establish C10 as a potential therapeutic for the treatment of NAFLD.

Impact of Fibroblast Growth Factors 19 and 21 in Bariatric Metabolism

BACKGROUND

Bariatric surgery is a popular and effective therapeutic intervention for obesity, which is an abnormal health condition that is prevalent worldwide. Metabolic improvements that precede weight loss after bariatric surgery may be mediated, in part, through the fibroblast growth factor (FGF) 15/19 and FGF21 signaling pathways. Both FGF15/19 and FGF21 are hormone-like members of the FGF family and exert their metabolic effects in an endocrine manner. Enhanced bile acid recycling after bariatric surgery leads to increased circulating levels of FGF15/19 in the distal small intestine. Synthesis of FGF21 is upregulated predominately in the fasting state through peroxisome proliferator-activated receptor pathways and to a lesser extent by FGF15/19. Key Messages: The biological functions of FGF15/19 and FGF21 are diverse and complicated. The tissue targeted effects of FGF15/19 and FGF21 of importance after bariatric surgery include the regulation of hepatic bile acid biosynthesis and ketogenesis as well as thermogenesis in adipose tissue, respectively. Furthermore, FGF15/19 and FGF21 function to regulate carbohydrate and lipid metabolism.

CONCLUSION

The long-term effects of bariatric surgery on weight loss are undisputable. However, the mechanism for improvements in glucose and lipid homeostasis observed shortly after bariatric surgery is less understood. This review article attempts to describe the known metabolic effects of FGF15/19 and FGF21 that may potentiate these improvements after bariatric surgery.

Variability and misclassification of worker estimated hand force

Ergonomic studies often use worker estimated hand force reproduced on a dynamometer to quantify force exposures but this method has not been well-studied in real work settings. This study evaluated the validity of worker estimates of hand force in a field study and determined the misclassification of worker estimated hand force exposures compared to directly measured forces. Eight experienced sheet metal assemblers completed ¼-inch diameter fastener installations using 6 different pneumatic tools. Grip forces were recorded by a pressure mat and were compared to worker estimated forces demonstrated on a dynamometer. Directly measured and worker estimated readings showed moderate correlations (0.53-0.67) for four installation tools and fair to moderate for two tools. The coefficient for variation of force estimates was 65% within repeated subject trials and 78% between averaged subject trials but 69% between subject trials during actual tool installations. Misclassification of worker estimated exposures varied by two cut-points: 29% using 4.0 kg and 49% using 6.0 kg. The force match procedure may provide adequate differentiation of high and low exposures in some settings, but is likely to result in substantial misclassification in other settings.

Intraoperative sonography-guided removal of radiolucent foreign bodies

This article reports our use of intraoperative sonography to guide in real time, the removal of radiolucent foreign bodies from five patients. Two of these patients had undergone previous unsuccessful attempts at surgical removal in the operating room. The technique is cost effective, readily available, and can be very helpful in locating difficult-to-find radiolucent foreign bodies at the time of surgery.

Amyloid beta precursor protein and ubiquitin epitopes in human and experimental dystrophic axons. Ultrastructural localization

Dystrophic axons (DA) represent a major pathological feature of several neurodegenerative disorders, including infantile neuroaxonal dystrophy (INAD) and Alzheimer disease. We have previously presented evidence that amyloid beta precursor protein (BPP) and ubiquitin (Ub) are present in DA of different origin. We have now characterized the immunoreactivity of DA experimentally induced in rat by the administration of parabromophenylacetylurea (BPAU) and examined the subcellular localization of Ub and BPP in BPAU-induced DA and in DA present in subjects affected by INAD. BPAU-induced DA strongly immunoreacted with antisera to Ub and to COOH- and NH2-terminal regions of BPP. Immunoblots of DA-enriched brain regions were consistent with an increase in the amount of Ub and BPP in DA. Moreover, BPAU-induced DA immunoreacted with antibodies to PGP 9.5, a neuronal-specific Ub COOH-terminal hydrolase, and to the inducible heat shock protein 70. Antigenic characterization also indicated that the tubulovesicular membranes within DA derived largely from the smooth endoplasmic reticulum rather than from the Golgi system or the synaptic vesicles. Subcellular immunolocalization of Ub and BPP in both INAD- and BPAU-induced DA revealed that Ub and BPP colocalize in granulovesicular material in both conditions. In INAD DA intense Ub immunoreactivity was also detected in nonmembranous electron dense structures that were present only in these DA, probably because of the chronic course of INAD. Although BPP immunostaining may be related to accumulation of BPP-containing membranes in DA, Ub immunostaining is likely to result from activation of the Ub system by the neuron in the attempt to remove excessive and possibly abnormal proteins. A similar pathogenesis can be postulated for DA of Alzheimer disease.

Primary hypothyroidism with intracranial hypertension and pituitary hyperplasia

A 12-year-old girl presented with primary hypothyroidism, secondary pituitary hyperplasia, and intracranial hypertension. Cranial computed tomography revealed a sellar mass with suprasellar extension. She responded to medical treatment. Intracranial hypertension may be associated with primary hypothyroidism prior to thyroxine treatment. Because significant pituitary hyperplasia can be associated with primary hypothyroidism, it is vital to have endocrine investigation prior to consideration of surgical removal of an apparent pituitary tumor.

Amyloid precursor protein and ubiquitin immunoreactivity in dystrophic axons is not unique to Alzheimer's disease

A distinctive feature of Alzheimer's disease (AD) is the presence of dystrophic neurites that immunoreact with antibodies to amyloid precursor protein (APP) and ubiquitin (Ub). The authors examined dystrophic axons (DA) present in other chronic conditions such as familial infantile neuroaxonal dystrophy (INAD), aging, cystic fibrosis, and biliary obstruction as well as in conditions of shorter duration such as human immunodeficiency virus (HIV) leucoencephalopathy, infarction and radiation therapy to determine whether APP and Ub immunoreactivity was unique to the DA of AD. A large number of DA immunoreacted with antibodies to the A4, C- and N-terminal regions of APP as well as to Ub. Ub and APP immunoreactivities often, but not always, colocalized. "Acute" DA generally reacted more intensely and in larger number with antibodies to APP than to Ub, whereas the reverse was true for "chronic" DA. Structureless DA immunostained diffusely. In DA with cores or granules, the Ub immunoreaction was occasionally limited to these structures, whereas reaction with antibodies to APP was more diffuse. In view of the contention that impairment of proteolysis is the common pathogenetic step in the formation of DA, Ub immunoreactivity in all DA may indicate a vicarious attempt to degrade accumulated components through an activation of the Ub system. The role of APP in the formation of DA remains to be determined.

Axonal transport of two major components of the ubiquitin system: free ubiquitin and ubiquitin carboxyl-terminal hydrolase PGP 9.5

Ubiquitin (Ub), a stress protein thought to target abnormal proteins for degradation, is present in abnormal structures that occur in neuronal perikarya and axons of degenerative diseases including Alzheimer disease. To begin to assess the role of the Ub system in the axon, we studied expression and axonal transport of Ub and other stress proteins, as well as of Ub carboxyl-terminal hydrolase PGP 9.5, in the rat visual system in normal conditions and following heat-shock (HS). In the retina, both the constitutive and inducible forms of HSPs 70 were expressed under normal conditions, while in the superior colliculus the inducible form was detected only following HS. Ub, PGP 9.5 and HSPs 70 were transported in the axon exclusively with the slow component b (SCb), known to carry cytoskeletal and cytoplasmic proteins. The exceedingly long time needed for stress proteins to reach distant axonal locales at the rate of SCb (approximately 3 mm/day) makes it unlikely that they could contribute significantly to the stress response at those sites.

Giant axonopathy characterized by intermediate location of axonal enlargements and acceleration of neurofilament transport

It has previously been shown that 2,5-hexanedione (2,5-HD) and its 3,4-dimethyl derivative (3,4-DMHD) induce neurofilamentous accumulations at prenodal sites in distal and proximal, respectively, regions of peripheral axons. For 2,5-HD, neurofilament (NF) transport is accelerated and this is thought to be directly related to the appearance of the axonal enlargements. For 3,4-DMHD, however, the rate of NF transport cannot be assessed owing to the very proximal position of NF accumulation. In the present study, it is shown that administration to rats of 3-methyl-2,5-hexanedione, the structural 'average' of 2,5-HD and 3,4-DMHD, induces NF accumulations at midway axonal positions of the sciatic and optic systems, and results in acceleration of NF in the sections of optic axons proximal to the enlargements. These results suggest that a common mechanism underlies all gamma-diketone neuropathies, and that the proximodistal pattern of axonal enlargements represents pharmacokinetic variables rather than differences in mode of action. The neurotoxicity of gamma-diketones probably arises from pyrrolation of lysine epsilon-amino groups in crucial regions of NF or related proteins responsible for maintaining the proper supramolecular organization of the cytoskeleton. Acceleration of NF transport appears to be a common characteristic of chemically induced axonopathies, regardless of location, and this is contrary to the theory that gamma-diketone-induced NF accumulation results primarily from a progressive cross-linking of NF occurring subsequent to pyrrole formation.

Axonal transport of neurofilament is accelerated in peripheral nerve during 2,5-hexanedione intoxication

The neurotoxic compound 2,5-hexanedione (2,5-HD) causes an axonopathy characterized by the presence of neurofilament (NF)-containing enlargements in the preterminal segments of central and peripheral axons. The 2,5-HD axonopathy is a good model for human acquired and inherited giant axonal neuropathies. Recently, we reported that following 2,5-HD administration, axonal transport of NF is markedly and selectively accelerated in the primary visual system. We have now studied slow axonal transport in the sciatic system of rats intoxicated with 0.5% 2,5-HD in drinking water. Following radiolabeling, transported proteins were examined after polyacrylamide gel electrophoresis and fluorography. The bulk of radiolabeled NF subunits was located 30-50 mm from the spinal cord in 2,5-HD treated animals and 10-25 mm in controls. The rate of transport of the three NF subunits was 0.7 mm/day in controls and 1.2 mm/day in 2,5-HD treated animals. The rate of transport of tubulin was not significantly changed. Electrophysiological studies of soleus nerve and muscle showed no evidence of denervation after 6 weeks of intoxication. It is concluded that, following 2,5-HD administration, transport of NF is preferentially accelerated in both central and peripheral axons. A pathogenetic mechanism based on the acceleration of NF transport is proposed, which may explain the formation and the distal or proximal location of NF-containing axonal enlargements in giant axonopathies.

Muscarinic receptors: relationships among phosphoinositide breakdown, adenylate cyclase inhibition, in vitro detrusor muscle contractions and in vivo cystometrogram studies in guinea pig bladder

The relationships between activation of muscarinic receptors in guinea pig bladder measured as carbachol-stimulated inositol phosphate (IP) accumulation, oxotremorine-induced adenylate cyclase (AC) inhibition and bladder detrusor smooth muscle contraction determined in vitro as well as in vivo in the slow filling cystometrogram (CMG), were analyzed from the potencies of a number of muscarinic antagonists to block these responses. Significant positive linear correlations were found among the inhibitory potencies of 10 muscarinic antagonists to inhibit phosphoinositide (PI) turnover and both detrusor muscle contraction in vitro, as well as peak intravesical bladder pressure in vivo in the CMG (r = 0.8, P less than .01). In contrast, there was no significant correlation between the potency of antagonists to block the AC inhibitory response and either in vitro or in vivo guinea pig bladder contractions (P greater than .05). Muscarinic agonists inhibited basal AC activity to a maximum of 20% in a GTP-dependent, Na+-sensitive manner and dose dependently stimulated both PI breakdown (3- to 4-fold) and isolated detrusor contractions. Again, a significant correlation (r = 0.9, P less than .01) was calculated among the potencies of seven muscarinic agonists to elicit PI turnover and in vitro muscle contraction, whereas no significant correlation was observed between their potencies to inhibit AC activity and contractile responses in vitro. Collectively, the data suggest that IP accumulation and presumably IP-induced Ca++ release may function as the transducing mechanism for cholinergic contraction of the urinary bladder.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of high carbohydrate diets on endurance running performance

The purpose of the present study was to examine the influence of high carbohydrate (CHO) diets on recovery of endurance capacity following a treadmill run to exhaustion. Two high CHO diets were used, one in which the normal diet was supplemented with complex carbohydrates and the other in which supplementation was achieved with simple carbohydrates. The thirty recreational runners who took part in this study (fifteen men and fifteen women) completed weighed food intake diaries two to three weeks before the start of the study. From an analysis of this information each subject's 'normal diet' was prescribed before Trial 1 and then a supplemented diet before Trial 2. The aim was to achieve an increase in carbohydrate content to 70% in the diets of the two high CHO groups and an equivalent increase in energy intake by the Control group. The subjects were required to run to exhaustion on a treadmill at a speed equivalent to 70% VO2max on two occasions separated by 3 days. After Trial 1 the subjects were divided into three equal groups. The Complex CHO group (301 +/- 86 mg vs 507 +/- 120 mg) and Simple CHO group (265 +/- 45 mg vs 462 +/- 81 mg) increased their CHO intake by approximately 70% (p less than 0.05) during the 3 days before Trial 2 whereas the Control group increased their energy intake with additional protein and fat so as to match the energy intakes of the two CHO groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The metabolic challenge of the marathon

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