High resolution solid-state 29si nmr spectroscopy of silicone gels used to fill breast prostheses

We have used ²⁹Si solid-state nuclear magnetic resonance (NMR) spectroscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses. Despite evidences of alteration in the morphological appearance of the silicone gel inside the breast prosthesis, our results do not reveal changes in the chemical nature and structure of the silicone gels after implantation. In addition to the main ²⁹Si resonance peak at ?22.26 ppm that corresponds to the resonance frequency of the D repeat unit of the polysiloxane chains, the high sensitivity of our NMR technique allows the detection of very low concentrations of silicone compounds. Within our experimental detection limit of 0.2%, no signal between ?90 ppm and ?150 ppm are observed. This indicates that no silica products are present inside the gel of the prostheses. Furthermore, our ²⁹Si NMR spectra indicate differences in the chemical compositions of the silicone gels from different manufacturers.     

Hypercalcemia associated with dysregulation of 1,25-dihydroxyvitamin D in arthritis.

We describe an elderly man who presented with hypercalcemia associated with suppressed intact parathyroid hormone (PTH) levels. Despite renal insufficiency the circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) was in the upper part of the normal range. Known causes of hypercalcemia were absent and mild hypercalcemia with suppression of intact PTH persisted until after bilateral hip replacement for severe arthritis (1 year after presentation). After hip replacement the ionized calcium normalized, intact PTH normalized, and 1,25(OH)2D decreased markedly. We believe the abnormalities in mineral homeostasis were related to production of 1,25(OH)2D by inflammatory mononuclear cells associated with arthritis.     

Down-Regulation of Estrogen Receptor Immunoreactivity by 17β-estradiol in the Guinea Pig Forebrain

Low amplitude pulses of estradiol-17β (E₂-17β) are more effective than large single bolus injections or constant exposure to E₂-17β in inducing progesterone-facilitated sex behavior in female rats and guinea pigs. The present study examined whether the increased responsiveness to E₂-17β is due to an increase in the number of estrogen receptors in the estrogen receptor rich areas of the hypothalamus and amygdala. Initial studies examined the rapid effects (20 min) of a high dose of E₂-17β (50 μg) on estrogen receptor immunostaining using either the H222 antibody or the ER 21 antiserum. ER 21 immunostaining was not affected by the E₂-17β treatment suggesting that it binds to both occupied and unoccupied estrogen receptors. Therefore the ER 21 antiserum was used to characterize the regulation of estrogen receptor immunoreactivity (ER-IR) by E₂-17β. ER-IR was examined for 48 h and serum E₂-17β for 24 h following a 2 μg s.c. injection of E₂-17β (a dose similar to that used in multiple pulse paradigms). Serum E₂-17β peaked 15 to 30 min following the injection and returned to baseline values by 1 h. In all but one area maximal suppression of ER-IR occurred at 12 h. In summary, 1) decreases in estrogen receptor immunoreactivity following E₂-17β are consistent with studies in which estrogen receptors were assayed by binding assays and estrogen receptor mRNA was determined by in situ hybridization; 2) the ER 21 antiserum is able to detect both occupied and unoccupied estrogen receptors and 3) H222 immunoreactivity is influenced by the presence of E₂-17β, so that the level of H222-IR is a reflection of ligand/receptor binding dynamics. The data suggest that up-regulation of estrogen receptors does not account for the increase in behavioral sensitivity which is observed following multiple pulses of E₂-17β.     

Fine-needle aspiration cytology of sarcomatoid renal cell carcinoma: A morphologic and immunocytochemical study of 15 cases

Sarcomatoid renal cell carcinoma (SRCC), which accounts for 5% of all renal cell carcinomas (RCC), has a worse prognosis than conventional nonsarcomatoid RCC. making accurate diagnosis important. This study reports on the morphologic and immunocytochemical features of 15 cases of SRCC (9 primary tumors and 6 metastases) diagnosed by fine-needle aspiration (FNA) biopsy. All but three cases showed a dimorphic cell population consisting of varying proportions of a high-grade epithelial component, either clear or granular-cell type and a spindle cell (sarcomatoid) component, of either fibrosarcomatous, malignant fibrous histiocytoma (MFH), or unclassified types. The sarcomatoid component in the biphasic and monophasic tumors stained positively for cytokeratin in 12 of 14 (85%) cases, for vimentin in 10 of 11 (91 %) cases, and for muscle-specific action in 4 of 11 (36%) cases. Of note, the three cases that demonstrated a purely sarcomatoid morphology stained positively for cytokeratin. Unlike in studies performed on surgically resected specimens, neither the proportion of the sarcomatoid component nor the presence of necrosis had prognostic significance, the discrepancy most likely being related to the sampling. We conclude that SRCC, both primary and metastatic, can be accurately diagnosed by FNA when cytologic features are evaluated in conjunction with immunocytochemical findings.     

Unsuspected intrathyroidal parathyroid adenoma: mimic of lymphocytic thyroiditis in fine-needle aspiration specimens-a case report.

Fine-needle aspirations (FNAs) of parathyroid adenomas (PA) are infrequently encountered, but the scant literature on this topic emphasizes the difficulties in distinguishing them from thyroid neoplasms. We report on a case of an unsuspected intrathyroidal PA whose two FNA specimens mimicked almost perfectly the features of lymphocytic thyroiditis (LT). The smears from two FNAs of a "thyroid nodule" in a 22-yr-old woman were received with a clinical diagnosis of "LT." The cytological features of both specimens were similar and consisted of groups of epithelial cells in a background of numerous "naked" nuclei, interpreted as Hurthle cells and lymphocytes respectively, and leading to a cytological diagnosis of LT. Subsequent surgical excision of the "nodule" revealed a large intrathyroidal PA. The oxyphil cells and chief cells (the latter devoid of cytoplasm) present in the PA resembled Hurthle cells and lymphocytes respectively, in the FNA specimens. In conclusion, PA can give a cytological picture almost identical to that of LT in FNA material. Important clues to the diagnosis of PA in FNA specimens include the presence of prominent capillaries and the knowledge of a clinical history of hyperparathyroidism. Diagn. Cytopathol. 1999;21:276-279.     

Human epithelial thymic tumours: heterogeneity in immunostaining of epithelial cell markers and thymic hormones.

Different hormones (thymulin, thymosin alpha 1, vasopressin), antigenic markers of cortical and subcapsular/medullary thymic areas and tumour associated antigens were studied on paraffin or frozen section and cultures of human epithelial thymic tumours ('thymomas'). Thymulin, thymosin alpha 1 and for the first time vasopressin are found in most tumours. The epithelial cells of five 'thymomas' had markers of both cortical (TE3) and subcapsular/medullary thymic regions (A2B5 and/or TE4 and/or anti-p19). Leu-7, a marker of subcapsular epithelial cells was positive only in two tumours. The histological classification into cortical and medullary tumours does not correspond to our immunofluorescence results. The presence of these markers does not support the theory of different embryologic origin of the cortical and subcapsular/medullary epithelial cells. Transferrin receptors were detected on only some epithelial cells of thymic 'carcinomas'. Adenocarcinoma related antigen and carcino embryonic antigen only stained a few epithelial cells of all the tumours. There is no expected correlation between the presence of epidermal growth factor receptors on cell membranes and the number of proliferative cells stained by the anti-Ki67 antibodies. Immunostainings were heterogeneous according to the epithelial thymic tumours, independent of histological classification and not yet useful for prognosis.     

Immunoreactivity of aqueous extracts of rat and mouse tissue with anti-thymosin alpha 1, anti-bovine thymopoietin and anti-thymulin antibodies. Studies using immunoblotting

Anti-thymosin alpha 1 monoclonal antibodies recognized, on immunoblots, 1 to 2 bands corresponding to molecules of 34 and 35 Kd when using aqueous extracts of thymus, spleen, kidney, liver, brain, pituitary and adrenal glands from rats or mice. Anti-bovine thymopoietin polyclonal antibodies, in the same conditions, labelled analogous 34, 35 and 35.5 Kd molecules in brain and thymus extracts but also a 40 Kd molecules in thymus and a 90 Kd in brain extracts. Anti-synthetic thymulin monoclonal antibodies recognized irregularly and poorly a 52 Kd molecule from thymus and brain extracts. These results suggest that thymopoietin, thymulin and specially Thymosin alpha 1 are first synthesized in large precursors. Finally, other organs seem capable of synthesizing thymosin alpha 1 and probably thymopoietin, but for thymulin, the results are too irregular to conclude.     

Human cytomegalovirus causes productive infection and neuronal injury in differentiating fetal human central nervous system neuroepithelial precursor cells

OBJECTIVES: To study the effect of cell differentiation on the vulnerability of human neural cell types to human cytomegalovirus (HCMV) infection. STUDY DESIGN/METHODS: Primary cultures of human fetal neuroepithelial stem cells and differentiating neuroepithelial precursor cells were infected with HCMV strain AD169. Infectious virus production, apoptosis, and viral-associated cytopathic effects then were examined over a 5-day period. RESULTS: HCMV established productive infection in these cells, generating 10-fold amplification of infectious virus. There was no significant difference in the percentage of apoptotic cells in HCMV-infected versus mock-infected cultures. HCMV antigen and specific cytopathic effects were observed in differentiating astrocytes and neurons, although HCMV antigen was 2-fold more frequent among postmitotic neurons. CONCLUSIONS: Neuroepithelial precursor cells and differentiating astrocytes and neurons are permissive to cytopathic HCMV infection, suggesting that the fetal human central nervous system is vulnerable to HCMV-induced neuronal injury at its earliest stages of development.     

Quality of mobility measures among individuals with acquired brain injury: an umbrella review

Quality of Life Research - While several mobility measures exist, there is large variability across measures in how mobility is conceptualized, the source of information and the measurement...