Demonstrating the reliability of in vivo metabolomics based chemical grouping: towards best practice.

While grouping/read-across is widely used to fill data gaps, chemical registration dossiers are often rejected due to weak category justifications based on structural similarity only. Metabolomics provides a route to robust chemical categories via evidence of shared molecular effects across source and target substances. To gain international acceptance, this approach must demonstrate high reliability, and best-practice guidance is required. The MetAbolomics ring Trial for CHemical groupING (MATCHING), comprising six industrial, government and academic ring-trial partners, evaluated inter-laboratory reproducibility and worked towards best-practice. An independent team selected eight substances (WY-14643, 4-chloro-3-nitroaniline, 17α-methyl-testosterone, trenbolone, aniline, dichlorprop-p, 2-chloroaniline, fenofibrate); ring-trial partners were blinded to their identities and modes-of-action. Plasma samples were derived from 28-day rat tests (two doses per substance), aliquoted, and distributed to partners. Each partner applied their preferred liquid chromatography-mass spectrometry (LC-MS) metabolomics workflows to acquire, process, quality assess, statistically analyze and report their grouping results to the European Chemicals Agency, to ensure the blinding conditions of the ring trial. Five of six partners, whose metabolomics datasets passed quality control, correctly identified the grouping of eight test substances into three categories, for both male and female rats. Strikingly, this was achieved even though a range of metabolomics approaches were used. Through assessing intrastudy quality-control samples, the sixth partner observed high technical variation and was unable to group the substances. By comparing workflows, we conclude that some heterogeneity in metabolomics methods is not detrimental to consistent grouping, and that assessing data quality prior to grouping is essential. We recommend development of international guidance for quality-control acceptance criteria. This study demonstrates the reliability of metabolomics for chemical grouping and works towards best-practice.

OCT4 immunohistochemistry may be necessary to identify the real risk of gonadal tumors in patients with Turner syndrome and Y chromosome sequences.

BACKGROUND: The aim of this study was to investigate the frequency of gonadal tumors among patients with Turner syndrome (TS) carrying Y-derivative sequences in their chromosomal constitution. METHODS: Six out of 260 patients with TS were selected based on mosaicism of the entire Y chromosome; 10 were included because Y-derivative sequences have been detected by PCR with specific oligonucleotides (sex-determining region on the Y, testis specific-protein, Y and DYZ3) and further confirmed by FISH. The 16 patients were subjected to bilateral gonadectomy at ages varying from 8.7 to 18.2 years. Both histopathological investigation with hematoxylin and eosin (H&E) and immunohistochemical analysis with anti-octamer-binding transcription factor 4 (OCT4) antibody were performed. RESULTS: Gonadal neoplasia was not detected in any of the 32 gonads evaluated by H&E; however, four gonads (12%) from three patients (19%) had positive OCT4 staining in 50-80% of nuclei, suggesting the existence of germ cell tumors (gonadoblastoma or in situ carcinoma). CONCLUSIONS: Evaluation of the real risk of development of gonadal tumors in TS patients with Y-derivative sequences in their chromosomal constitution may require a specific histopathological study, such as immunohistochemistry with OCT4.

Intraoperative localization of an osteoid-osteoma using a gamma probe.

The purpose of this study was to evaluate whether intraoperative nidus detection with a hand-held gamma probe was efficient enough for use as a routine procedure. Thirty-seven patients with osteoid-osteomas were submitted to surgical treatment. The first group consisted of 19 patients submitted to open nidus resection using a hand-held gamma probe as guide. The control group consisted of 18 patients operated on by conventional technique. The procedures were classified as successful if nidus resection could be confirmed by histology or postoperative imaging studies. Patients in the gamma group were followed for a mean of 13 months; patients in the control group for a mean of 39 months. In the gamma group, 17/19 procedures were successful; in the control group, only 12/18 procedures were successful. The gamma probe helped to locate the osteoid-osteoma nidus, and the same probe could be used in various hospitals.

Primary leiomyosarcoma of bone: report of two cases in extragnathic bones.

Primary leiomyosarcoma of extragnathic bone is rare; fewer than 50 cases are found in the literature. We report on two patients, adult men, with tumors located on the long bones (close to the knee joint). Radiographically, the tumors were shown as purely destructive, osteolytic, and infiltrative lesions. The diagnosis was based on light microscopy, including immunohistochemistry and ultrastructural examination. The tumor cells were uniformly positive for vimentin and muscle actin, but not for desmin. In one case, the cells were also positive for alpha-smooth muscle actin. Electron microscopy showed definitive smooth muscle differentiation, including cytoplasmic filaments with focal densities. Both patients died of pulmonary metastases.

Paracoccidioidomycosis of bones and joints. A clinical, radiologic, and pathologic study of 9 cases.

Paracoccidioidomycosis is a systemic fungal infection endemic to Central and South America. It is associated with a broad spectrum of clinical manifestations and has been classified into acute and chronic forms. The latter is the most common type and usually affects male agricultural workers in rural communities. The disease typically begins in the lungs producing varying degrees of parenchymal damage, and in a significant number of cases the organism spreads through bronchogenic, lymphatic, or hematogenous routes to involve 1 or more organs. Bone and joint infection is relatively uncommon and has not been well described in the English literature. Much of the information on this form of the disease has been derived from radiographic and autopsy studies on patients with severe or fatal infections in whom skeletal involvement was a minor or incidental finding. We describe our experience with 9 cases in which osteoarticular manifestations were the sole or 1 of the few major complications of the disease. All 9 patients were male, from 9 to 49 years of age (mean, 36.6 yr). Six were farmers. Evidence of visceral infection was present in 6 patients, in all of whom the lungs were considered the primary site of disease. The osteoarticular lesions were symptomatic in all cases, with the duration of symptoms ranging from 1 week to 2 years. The lesions were centered in bone in 2 cases: they manifested radiographically as circumscribed areas of lysis with or without a rim of sclerosis. The disease was centered in joints in 7 cases; the associated radiographic changes included evidence of joint effusion, periarticular bony erosions, and narrowing of the joint space. Biopsy of the involved skeletal site revealed compact or loose granulomas containing variable numbers of fungi. Although follow-up information was not available for all patients, those treated with TMP-SMX (and 1 patient who also received amphotericin B) and who were followed had prompt resolution of their signs and symptoms. Our findings substantiate some of what is known about the epidemiology of bone and joint involvement in chronic paracoccidioidomycosis. Our patients exhibited features of skeletal infection that have not been emphasized previously, however, including 1) frequent involvement of large joints or long bones of the extremities, 2) presentation with relatively rapidly developing musculoskeletal symptoms, and 3) manifestation as a solitary joint or bone lesion with or without concurrent clinically detectable pulmonary disease. Bone and joint paracoccidioidomycosis should be considered in the differential diagnosis in patients who have skeletal lesions with or without pulmonary involvement and have either lived in or traveled through endemic areas. Early diagnosis and treatment with antifungal medications can achieve an excellent outcome with limited local sequelae.

Congenital generalized fibromatosis causing spinal cord compression.

An unusual case of congenital generalized fibromatosis in which involvement of the spinal dura mater was accompanied by flaccid paralysis in the lower limbs is presented.