Measurement of the internal magnetic fluctuation by the transport of runaways on J-TEXT.

The measurement of internal magnetic fluctuation is important for the study of transport in tokamak plasmas. The runaway electron transport induced by the sawtooth crash can be used to obtain the internal magnetic fluctuation. Inversed sawtooth-like activities on hard x-ray (HXR) fluxes following sawtooth activities were observed after the application of electrode biasing on J-TEXT tokamak. The runaway diffusion coefficient Dr is deduced to be about 30 m2/s according to the time delay of HXR flux peaks to the sawtooth crashes. The averaged value of normalized magnetic fluctuation in the discharges with electrode biasing was increased to the order of 1 × 10-4.

Measurement of the electron and ion temperatures by the x-ray imaging crystal spectrometer on joint Texas experimental tokamak.

An x-ray imaging crystal spectrometer has been developed on joint Texas experimental tokamak for the measurement of electron and ion temperatures from the Kα spectra of helium-like argon and its satellite lines. A two-dimensional multi-wire proportional counter has been applied to detect the spectra. The electron and ion temperatures have been obtained from the Voigt fitting with the spectra of helium-like argon ions. The profiles of electron and ion temperatures show the dependence on electron density in ohmic plasmas.

Designing of the massive gas injection valve for the joint Texas experimental tokamak.

In order to mitigate the negative effects of the plasma disruption a massive gas injection (MGI) valve is designed for the joint Texas experimental tokamak. The MGI valve is based on the eddy-current repulsion mechanism. It has a fueling volume of 30 ml. The piston of the MGI valve is made by non-ferromagnetic material, so it can be installed close to the vacuum vessel which has a strong toroidal magnetic field. A diode is use to prevent current oscillation in the discharge circuit. The drive coil of the valve is installed outside the gas chamber. The opening characteristics and the gas flow of the MGI valve have been tested by a 60 l vacuum chamber. Owing to the large electromagnetic force the reaction time of the valve is shorter than 0.3 ms. Duration for the opening of the MGI valve is in the order of 10 ms.

Fracture risk after thiazide-associated hyponatraemia.

BACKGROUND/AIM: Although thiazide-type diuretics can promote a positive calcium balance, thiazide can be associated with hyponatraemia, which is recently linked with heightened fracture risk. We examine the chance of developing fracture in patients with and without hyponatraemia after taking thiazide diuretics. METHODS: In this single-centre retrospective study, we followed up a previously published cohort of patients with (n= 223) and without (n= 216) thiazide-induced hyponatraemia. RESULTS: A total of 61 osteoporotic fractures was recorded during a mean follow-up period of 82 months. Using univariate regression analysis, the hazard ratio of thiazide-induced hyponatraemia was 1.78 (95% confidence interval (CI), 1.05-3.03; P= 0.033). Cox proportional hazards regression analysis, however, showed that age, body mass index and diabetes mellitus were the only independent predictors of osteoporotic fractures. No association of a history of thiazide-induced hyponatraemia and risk of fracture was evident in the final model. CONCLUSION: Since a history of thiazide-induced hyponatraemia is associated with osteoporotic fracture in univariate but not multivariate analyses, an alternative explanation is that confounding factors of older age and low body mass index accounted for the apparently increased risk of osteoporotic fracture in patients with thiazide-induced hyponatraemia.

Fine needle aspiration cytology of papillary lesions of the breast: how accurate is the diagnosis?

BACKGROUND: Cytological diagnosis of mammary papillary lesions is difficult. AIM: To review the previous cytology diagnosis of 23 papillomas and 11 papillary carcinomas and specific cytological features that may assist in differentiating these entities. METHODS: The cytology preparations were reviewed for: (i) overall cellularity; (ii) epithelial cell ball devoid of fibrovascular cores; (iii) background single cells; and (iv) papillary fragments and their morphology. RESULTS: The overall diagnostic accuracy was 59%, atypical rate was 24%, and the error (combined false positive and negative) rate was 17%. For overall cellularity, 6, 14 and 3 cases of papillomas, and 6, 3 and 2 cases of papillary carcinomas showed low, moderate and high cellularity, respectively. Cell balls were present in mild to moderate number in 20 papillomas and 10 papillary carcinomas. The background single cells were absent, or present in low or moderate to high numbers in 7, 10 and 6 papillomas, and 3, 3 and 5 papillary carcinomas, respectively. Papillary fragments were absent, or present in small, moderate or large quantities in 9, 4, 8 and 2 papillomas, and 6, 3, 1 and 1 papillary carcinomas, respectively. There was no demonstrable quantitative difference between papilloma and papillary carcinoma for all these parameters. Qualitatively, the cell balls and single cells showed a higher degree of atypia in papillary carcinoma, and the papillary fragments were more elaborate and slender. CONCLUSION: Cytological diagnosis of papillary lesions shows a significant error rate with overlapping features. Cellular atypia and fragments with long and slender papillae with ramifying edges favour papillary carcinoma.

The role of immunohistochemistry for smooth-muscle actin, p63, CD10 and cytokeratin 14 in the differential diagnosis of papillary lesions of the breast.

BACKGROUND: Histological differentiation of mammary papillary lesions can be difficult. The evaluation of myoepithelial cells can be helpful, with benign papilloma showing a continuous myoepithelial cell layer, which becomes attenuated or absent in malignant papillary lesions. METHODS: A large series of 100 papillomas (28 papillomas with florid epithelial hyperplasia) and 68 papillary carcinomas (9 invasive, 44 in situ, and 15 ductal carcinomas in situ (DCIS) involving papillomas) of the breast were stained for myoepithelial cells by immunohistochemistry using antibodies to smooth-muscle actin (SMA), p63, CD10 and cytokeratin (CK) 14. RESULTS: In the papillomas, using these four antibodies, myoepithelial cells were positive in 88%, 99%, 91% and 95% of cases, respectively, with SMA showing marked stromal component cell staining and CD10 showing epithelial and stromal staining. CK14 also showed epithelial staining in 71% of papillomas and 96% of papillomas with florid epithelial hyperplasia. In the papillary carcinomas, 36 (53%) cases showed staining of myoepithelial cells that were scattered, discontinuous and diminished in number and the remaining 32 (47%) cases did not show myoepithelial cells. Invasive papillary carcinoma has the lowest proportion (33%) with myoepithelial cells, and DCIS involving papillomas had the highest proportion (87%). CONCLUSIONS: p63 had the highest sensitivity and did not cross-react with stromal cells and only rarely with epithelial cells. CK14 has the added ability to distinguish between florid epithelial hyperplasia involving papilloma and DCIS involving papillomas. CK14 and p63 may be used as an adjunct in assessing difficult papillary lesions of the breast.

Role of radiologic features in the management of papillary lesions of the breast.

OBJECTIVE: The purpose of our study was to assess the role of imaging and core biopsy in the management of patients with papillary lesions of the breast. MATERIALS AND METHODS: Clinical records and mammographic and sonographic findings of 40 women with papillary lesions in the breast were retrieved. The imaging features and cytologic findings were correlated with histologic findings. RESULTS: Fifty-six papillary lesions in 40 patients underwent either mastectomy, segmental duct resection, or excision biopsy. There were three papillary carcinomas, 13 papillaryal lesions with carcinoma in situ, one atypical papilloma, four sclerosed papillomata, and 35 papillomata. Of these lesions, 37.5% (21/56) and 82.1% (46/56) could be detected on mammography and sonography, respectively. Galactography and dilated ducts helped to suggest the papillary nature of the lesions. However, mammography and sonography were not able to predict malignancy (sensitivity, 69% and 56%, respectively; specificity, 25% and 90%; positive predictive value [PPV], 60% and 75%; and negative predictive value [NPV], 33% and 90%). Combined interpretation of mammography and sonography gave a sensitivity of 61%, specificity of 33%, PPV of 85%, and NPV of 13%. Fine-needle aspiration gave a sensitivity of 44%, specificity of 68%, PPV of 31%, and NPV of 79%, whereas core biopsy gave a sensitivity of 82%, specificity of 100%, PPV of 100%, and NPV of 83% in the diagnosis of malignancy. CONCLUSION: Radiologic features are not sufficiently sensitive or specific to differentiate benign from malignant papillary lesions. Fine-needle aspiration and core biopsy have pitfalls, and the need for surgical excision of all papillary lesions should be revisited.

CD44s is useful in the differentiation of benign and malignant papillary lesions of the breast.

BACKGROUND/AIMS: CD44s, the standard form of CD44, has been shown to be downregulated during malignant transformation of breast cancers. It has also been reported recently to be a useful marker in differentiating between benign and malignant papillary lesions of the breast, with high expression in the former. CD44s expression in benign and malignant papillary lesions was evaluated. METHODS: CD44s expression was assessed by immunohistochemistry in 101 benign papillomas and 59 papillary carcinomas (seven invasive papillary carcinomas, 41 papillary ductal carcinomas in situ, and 11 ductal carcinomas involving papillomas). RESULTS: Patients' age and tumour size were significantly different between the papilloma and papillary carcinoma groups (p < 0.0001). CD44s showed positive staining in 45 papillomas (45%) and five papillary carcinomas (8%), and the difference was significant (p < 0.0001). The myoepithelial cells, when present, were also positive for CD44s in both groups, with no observable differences. Using CD44s positive staining to differentiate between benign and malignant papillary lesions gives a sensitivity, specificity, and accuracy of 45%, 92%, and 62%, respectively. CONCLUSIONS: CD44s may be useful as an adjunct in the evaluation of morphologically problematic cases of papillary lesion of the breast.

BRAF and NRAS mutations are uncommon in melanomas arising in diverse internal organs.

BACKGROUND: Malignant melanoma arising from different body compartments may be associated with differing aetiological factors and clinical behaviour, and may manifest diverse molecular genetic profiles. Although many studies have focused on cutaneous melanoma, little is known of mucosal and other types of melanoma. In particular, malignant melanoma of soft parts is different from other melanomas in many respects, yet manifests a common melanocytic differentiation. Mutation of BRAF is now known to be common in cutaneous melanomas, and raises possible new therapeutic options of anti-RAF treatment for these patients. Few data are available for non-cutaneous melanomas. AIMS: To study the incidence of BRAF and NRAS mutations in melanomas arising in diverse internal organs. METHODS: Fifty one melanomas from various internal organs were investigated for BRAF and NRAS mutation by direct DNA sequencing. RESULTS: BRAF and NRAS mutations were found in two and five mucosal melanomas arising from the aerodigestive and female genital tracts (n = 36). Their occurrence is mutually exclusive, giving a combined mutation incidence rate of 19.4% in mucosal melanomas. Both BRAF and NRAS mutations were absent in malignant melanoma of soft parts (n = 7). BRAF mutation was also absent in uveal melanoma (n = 6), but was seen in two of five cutaneous melanomas. The incidence of BRAF or combined BRAF/NRAS mutations in all non-cutaneous groups was significantly lower than published rates for cutaneous melanomas. CONCLUSION: Each melanoma subtype may have a unique oncogenetic pathway of tumour development, and only a small fraction of non-cutaneous melanomas may benefit from anti-RAF treatment.

Sonographic appearance of mucinous carcinoma of the breast.

OBJECTIVE: The aim of this study was to evaluate the sonographic and mammographic features of mucinous carcinoma and to correlate the imaging features with two histologic classifications. MATERIALS AND METHODS: Two radiologists analyzed the mammographic and sonographic features of 33 mucinous carcinomas. Mammographic features according to the Breast Imaging Reporting and Data System (BI-RADS) and sonographic features were recorded and analyzed. The imaging features of the mass were correlated with the nuclear grade and mucin content of these 33 mucinous carcinomas. The incidence of axillary lymph nodes metastasis in different histologic grades and their detection by imaging were also assessed. RESULTS: As many as 21.2% (7/33) of mucinous carcinomas could not be detected mammographically. When they were detected mammographically, more than 92% of the tumors presented as a mass, either oval or lobular. Microlobulations were present in 38.5% of these lesions. The margin of the lesion as seen on mammography can be used to predict the histologic grade. A circumscribed margin was associated with a favorable histologic grade (p = 0.01), whereas an indistinct margin was more commonly associated with the mixed type of lesion (p = 0.05). Sonographically, mixed cystic and solid components, distal enhancement, and microlobulated margins were commonly found in mucinous carcinomas, with an incidence of 37.5%, 43.8%, and 56.3%, respectively. Homogeneity on sonography was associated with the pure type of mucinous carcinoma and hence a better prognosis. Sonography showed a sensitivity of 50%, specificity of 89%, positive predictive value of 60%, negative predictive value of 84%, and accuracy of 79.2% in the detection of axillary lymph node metastasis. CONCLUSION: Both sonographic and mammographic assessments are important in the correct diagnosis of mucinous carcinoma, the prediction of histologic grade, and the prognosis of the tumors.

Sputum cytology of patients with severe acute respiratory syndrome (SARS).

BACKGROUND: Severe acute respiratory syndrome (SARS) is a newly described form of atypical pneumonia linked to a novel coronavirus. AIMS: To review the sputum cytology of 15 patients who fulfilled the World Health Organisation clinical criteria for SARS in an attempt to evaluate whether early diagnosis is feasible with routine sputum examination. METHODS: All sputum samples from patients with SARS from the four major hospitals in Hong Kong were reviewed; abnormalities were sought in the cellular component, including abnormal numbers and morphology of the component cells compared with those from age matched controls taken over the same period one year ago. RESULTS: Fifteen sputum samples from patients were compared with 25 control samples. In the patients with SARS, loose aggregates of macrophages were seen more frequently in the sputum. These macrophages frequently showed morphological changes, such as cytoplasmic foaminess, vacuole formation, and nuclear changes (including multinucleation and a ground glass appearance) when compared with the control samples. CONCLUSIONS: The cytological features of SARS are non-specific, but the observation of any of the described features should prompt further investigations, especially in patients with suspicious clinical features.

Fine needle aspiration cytology of granulomatous mastitis.

AIMS: Granulomatous mastitis (GM) is an uncommon breast lesion that mimics carcinoma. The fine needle aspiration cytological (FNAC) features of GM have rarely been discussed in the literature. These features are reported in eight histologically confirmed cases of GM. METHODS: A retrospective study was undertaken in which a diagnosis of GM had been made on histopathology, and the FNAC slides were reviewed and assessed for the presence of granulomas, necrosis, multinucleated giant cells, and inflammatory background cells. Polymerase chain reaction (PCR) for Mycobacterium tuberculosis was performed on the histological material to exclude tuberculosis. RESULTS: All cases were confirmed histologically and PCR for mycobacterial DNA was negative. In the FNACs, varying numbers of granulomas composed of epithelioid histiocytes were present in four cases. The same four cases showed giant cells of either foreign body or Langhan's type. No necrosis was noted. Six cases showed many histiocytes, some plump and others epithelioid, in the background. The number of epithelioid histiocytes corresponded to the presence of granulomas. Neutrophils were the predominant background inflammatory cells in most cases (six). CONCLUSIONS: The cytological diagnosis of GM is difficult because the features overlap with other aetiologies, including tuberculosis. Specific features are absent. The absence of necrosis and a predominantly neutrophilic infiltrate in the background favour a diagnosis of GM. This diagnosis should also be considered when abundant epithelioid histiocytes are seen in smears, even in the absence of granulomas. However, the definitive diagnosis of GM depends on histology from fine needle biopsies and negative microbiological investigations.

Hamartoma of the breast: a clinicopathological review.

AIMS: To review 25 cases of breast hamartoma and discuss the pathological criteria, and the usefulness of imaging modalities, fine needle aspiration cytology (FNAC), and needle core biopsy in the diagnosis. METHODS: The hamartomas were assessed for interlobular fibrotic stroma, stromal adipose tissue content, pseudo-angiomatous stromal hyperplasia, and epithelial changes (hyperplasia, adenosis or apocrine metaplasia, and cyst formation). All imagings, previous FNACs, and biopsies were also reviewed. RESULTS: Imaging (mammography, ultrasound, and magnetic resonance imaging) was performed in 18 cases, and mostly showed encapsulated masses with a heterogeneous appearance. Microscopically, all hamartomas demonstrated good demarcation with fibrous tissue condensation. Adipose tissue was noted in all cases (5-90%; mean, 31%), and interlobular fibrosis in 21 cases. Benign epithelial hyperplasia occurred in 10 cases, and pseudo-angiomatous stromal hyperplasia or cystic ducts in eight cases each. Apocrine metaplasia, calcification, stromal giant cells, and adenosis occurred in four cases or less. Two cases showed coexisting ductal carcinoma in situ limited to within the hamartoma. Needle core biopsies (four cases) and FNAC (14 cases) were largely insufficient, inconclusive, or non-specific. CONCLUSIONS: Hamartomas do not possess specific diagnostic histological features. The role of FNAC and needle core biopsy in making the diagnosis is limited, and requires clinical and radiological correlation to avoid underdiagnosis.

Increased microvessel density in malignant and borderline mammary phyllodes tumours.

AIMS: Tumour vascularity is considered a prognostic indicator in breast carcinoma, but its utility in mammary phyllodes tumour has not been explored. The authors report the correlation between intratumoral microvessel density and the histological grade of phyllodes tumour. METHODS AND RESULTS: Forty cases of phyllodes tumour were reviewed for stromal cellularity, overgrowth, cytological pleomorphism, mitotic count and margin pattern. Using established criteria, these were diagnosed as benign (n=28), borderline (n=10) and malignant (n=2). Microvessel density was counted on CD31-stained slides as the number of vessels per high power field. For benign phyllodes tumour, the range was 7-26.2 (mean 13.1); for borderline phyllodes tumour the range was 17.2-32.5 (mean 22.4); for malignant phyllodes tumour the range was 25.9-33.3 (mean 29.6). The difference between the benign and borderline groups was significant (P < 0.0001) but that between the borderline and malignant groups was not, due to the small number of malignant cases. CONCLUSIONS: There is a significant difference in stromal microvessel density between benign and borderline phyllodes tumour. Although the small number of cases of malignant phyllodes tumour limits further interpretation, we believe that microvessel density can be used as an additional objective histological parameter in the evaluation of phyllodes tumour.

Fine-needle aspiration cytology of breast carcinoma with endocrine differentiation.

BACKGROUND: The value of fine-needle aspiration (FNA) in atypical proliferative to in situ to low grade invasive breast lesions remains limited due to the overlapping cytologic features of these entities. In the current study the authors review the FNA cytology of endocrine carcinoma and identify common cytologic features that allow for the diagnosis of this uncommon, low grade subtype of mammary malignancy. METHODS: The histopathology files from the medical practices of both authors were searched between January 1996 and May 1999 and yielded six cases of endocrine carcinoma. The clinical history and all previous FNA smears were reviewed. RESULTS: All six patients were elderly women (mean age of 72 years). Four patients presented with breast masses, one patient presented with nipple discharge, and one patient presented with both a breast mass and nipple discharge. All six surgical specimens showed endocrine ductal carcinoma in situ (E-DCIS), with four specimens showing invasive endocrine carcinoma, two of which were labeled as mucinous carcinoma. All invasive components showed the same histomorphologic and immunohistochemical profiles as the in situ components. Cytology demonstrated common features of the cellular smears with clusters and single, monomorphic plasmacytoid tumor cells that possessed moderate amounts of eosinophilic, granular cytoplasm and eccentric nuclei with fine chromatin and inconspicuous nucleoli. In four cases, additional fragments of fine and elaborate papillary fronds also were present. CONCLUSIONS: The cytologic smear diagnosis of endocrine carcinoma is assisted by the presence of plasmacytoid tumor cells and arborizing papillary fronds.

Peripheral chemoreceptors in congenital central hypoventilation syndrome.

Congenital central hypoventilation syndrome (CCHS) is a rare disorder of unknown etiology, characterized by failure of the autonomic control of respiration. The primary defect is believed to involve central respiratory control; however, no specific lesion has been identified. We report two cases of CCHS (one female, 3 mo of age and one male 2 yr of age) in which there was detailed examination of the neural, muscular, and chemoreceptor components of respiratory control. Although no specific abnormalities were identified in the central nervous system (CNS) or muscles of respiration, striking changes were observed in arterial chemoreceptors, carotid bodies (CB), and airway chemoreceptors, neuroepithelial bodies (NEB). In both cases, CB were small (< 50% of control), with a marked decrease in the number of glomus cells identified by immunostaining for tyrosine hydroxylase and serotonin. Ultrastructural analysis of glomus cells in Case 1 showed a marked decrease in the frequency of dense core vesicles (< 20% of control), the storage site of amine and peptide neurotransmitters. Immunostaining for S100 protein, a marker of sustentacular or Type II cells, was increased up to twofold compared with controls. In the lung, the frequency and size of NEB immunostained for bombesin was increased twofold in both cases, suggesting compensatory hyperplasia of airway chemoreceptors. Since intact peripheral chemoreceptors are essential for respiratory control, especially the response to hypoxia, abnormalities in CB and NEB may contribute to the pathophysiology of CCHS and related conditions such as sudden infant death syndrome (SIDS).

Spontaneous rupture of thoracic aorta through an atheromatous plaque: case report and literature review.

Spontaneous rupture of thoracic aorta without aneurysm formation is extremely rare. A case of spontaneous rupture through an atheromatous plaque in an 82-year-old woman is reported. She presented with atypical chest pain, and chest radiography revealed no evidence of aneurysm. She died suddenly in the hospital within 24 h after admission. At autopsy, there was an intimal tear and rupture of the descending aorta through an atheromatous plaque, resulting in massive hemothorax. The previous reported cases of spontaneous aortic rupture were reviewed. The pathology of spontaneous aortic rupture are discussed with emphasis on the dating of the rupture, which may have significant medicolegal importance.

Narcolepsy secondary to fourth ventricular subependymoma.

BACKGROUND: Secondary (symptomatic) narcolepsy is rare. We report a subependymoma of the fourth ventricle associated with narcolepsy. The patient was a 50-year old woman with a long history of narcolepsy who died of colonic carcinoma with no cerebral metastasis. She was positive for HLA-DR2. At autopsy there was a tumour dorsal to the fourth ventricle which involved the midbrain tectum and rostral pons. Histologic examination of the tumour confirmed it to be a subependymoma. METHODS: Review of the previous cases of secondary narcolepsy was made with particular reference to the anatomical location of the lesions. RESULTS: Most of the lesions were found around the third ventricle and rostral brainstem. CONCLUSIONS: Knowing the anatomical localization of the pathological changes in secondary narcolepsy could be important in improving our understanding of its pathogenesis.