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Many Gram‐negative bacteria pathogenic to plants and animals deploy the type III secretion system (T3SS) to inject virulence factors into their hosts. All bacteria that rely on the T3SS to cause infectious diseases in humans have developed antibiotic resistance. The T3SS is an attractive target for developing new antibiotics because it is essential in virulence, and part of its structural component is exposed on the bacterial surface. The structural component of the T3SS is the needle apparatus, which is assembled from over 20 different proteins and consists of a base, an extracellular needle, a tip, and a translocon. This review summarizes the current knowledge on the structure and assembly of the needle, tip, and translocon.  相似文献   

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Fine needle aspiration (FNA) is a diagnostic technique that has become widely used. The procedure may be performed by interventional radiologists, endoscopists, pathologists and cytotechnologists; diagnostic interpretation of FNA samples is performed by pathologists and cytotechnologists. I provide here an introduction to the technique and applications of FNA with a review of current practice parameters and recent developments in the molecular application of FNA.  相似文献   

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To evaluate the effects of air pollution on the decline of Pinus densiflora forests, various research has been conducted around Mt. Gokurakuji (34° 23N, 132° 19E, 693 m a.s.l.) north of the Seto Inland Sea, west Japan. To investigate the mechanisms responsible for decreases in photosynthesis (Pn) and stomatal conductance (gl), 13C of needles and seasonal changes in the water content (WC) and abscisic acid concentration (ABA) of needles were measured in various stands. The 13C values were less negative in declining stands and younger needles. ABA and WC were not correlated with each other. WC decreased consistently with needle age while the ABA showed a minimum in August and a smaller content in older needles. Monthly precipitation and the daily maximum vapor pressure were not correlated with ABA and WC. In declining stands, WC and ABA tended to be higher and lower, respectively, than in nondeclining stands. These results suggest that the trees in declining stands received less water stress than those in nondeclining stands and the differences in gl and 13C are not caused by the difference in water stress. The possibilities of the effects of air pollution and the infection of pine-wood nematode on the physiological decline on the pine needles are discussed.  相似文献   

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OBJECTIVE: To investigate whether fine needle capillary (FNC) sampling gives quantitatively and qualitatively superior cytologic material as compared to the conventional technique of fine needle aspiration (FNA) when performed by a single aspirator. STUDY DESIGN: Cross-sectional diagnostic test evaluation study. FNA and FNC were performed by a single operator on 200 diffuse and nodular thyroid lesions. RESULTS: A statistically significant difference in favor of FNC was observed for the parameter amount of cellular material. For the rest of the parameters--background blood or clot, degree of cellular degeneration, degree of cellular trauma and retention of architecture--the average score favored FNC but was not statistically significant--i.e., smears prepared from FNC displayed cellular material that was more concentrated, less damaged and less likely to be obscured by blood. CONCLUSION: Although FNC sampling was diagnostic in a greater number of cases than FNA sampling, this study did not prove a clear superiority of FNC over FNA. Until greater experience shows clear sampling superiority of FNC alone, rather than performing only FNA in diffuse or nodular thyroid lesions, incorporating FNC into the second puncture will definitely improve the quality and quantity of material at the patient's first visit.  相似文献   

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Influence of season and needle age on the yield and composition of the Pinus ponderosa needle oil was investigated. Oil yields throughout the year averaged 0·13% on the basis of tissue green weight. The average composition was 11·9% -pinene, 70·2% β-pinene, 8·0% 3-carene, 5·0% myrcene, 1·8% limonene, 2·2% β-phellandrene and 6·4% methyl chavicol (total MONOTERPENES = 100%). The amount of methyl chavicol and total monoterpenoids was highest in summer, lower in juvenile than in mature firstyear needles, and decreasing thereafter with needle age. A significant increase in 3-carene and decrease in β-pinene was apparent in juvenile needles. The most important step towards decreasing the seasonal and age variability of needle samples in ecological or chemotaxonomic studies was found to involve exclusion of sample collections during a period between the initial appearance of young needles and the time that they reach maximum length.  相似文献   

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Percutaneous nephrostomy is a simple technique for temporary drainage of an obstructed kidney. Under local anaesthesia a ureteric catheter is passed through a Vim–Silverman needle into the renal pelvis and is connected to a drainage bag. Seven cases (six successful) in which this method was used are described and the indications are discussed. It has been free from complications, is acceptable to patients, and is felt to represent a useful addition to the methods available for the treatment of obstruction of the upper urinary tract.  相似文献   

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《Cytopathology》1990,1(2):57-58
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Pine needle (Pinus densiflora Sieb. et Zucc.) extract has been used to improve cardiovascular disorders, detoxification of nicotine, the infirmities of age and curing diseases of unidentified symptoms in folk medicine. To determine the facts behind the traditional belief, we tried to investigate the effects of fresh and self-fermented pine needle extracts of different aging. Fibrinolytic activities of the extract indicated that activity depends on time and also with aging of the product. It was also found that the extract can lower the blood plasma cholesterol and triglyceride in cholesterol fed rat. Also, Self-Fermented Pine Needle Extracts 7 years old (SFPE 7) (200 μg/mL) reduce the frequency and amplitude of pacemaker currents in Interstitial Cells of Cajal (ICC) of murine small intestine by modulating ATP-sensitive potassium channels. Therefore, the investigation indicated that self-fermentation improves efficacy of the pine needle extracts reducing risk of cardio-vascular related disorders and would be an important source in nutraceutics.  相似文献   

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OBJECTIVE: To evaluate the diagnostic efficacy of fine needle aspiration cytology (FNAC) in gallbladder mass lesions and to explore the possibility of overlooking malignancy in coexistent adenocarcinoma with xanthogranulomatous cholecystitis (XGC) on fine needle aspiration smears. STUDY DESIGN: In a retrospective, seven-year study, ultrasound-guided needle aspirates from 25 histologically proven cases of gallbladder adenocarcinoma, 11 cases of gallbladder adenocarcinoma associated with XGC and 20 cases of XGC were evaluated for the presence of mesotheliumlike, foam, inflammatory and multinucleate giant cells; pink, granular background; bile; and degenerated cells, along with atypical or frankly malignant cells. Detailed clinical findings were retrieved from the records. RESULTS: The overall sensitivity of detecting carcinoma was 90.63% and specificity 94.74%. The sensitivity of detecting malignancy was 80% when adenocarcinoma was associated with XGC. CONCLUSION: FNAC plays an important role in making the preoperative diagnosis of adenocarcinoma, XGC and coexistent lesions. The probability of detecting malignancy is greater than with XGC in coexistent lesions. Thus, a preoperative FNAC diagnosis would help in determining the urgency of treatment and in planning for the surgical procedure in gallbladder lesions.  相似文献   

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The aim of this study was to examine the diversity of, and differentiation between, 41 natural populations representing Juniperus phoenicea complex within their geographic range using the morphological characteristics of cones, seeds, and sprouts with leaves. Seven populations of J. phoenicea s.s., 25 J. turbinata and nine J. canariensis, each represented by ~20–30 individuals, were studied. The characteristics describing the size of cones and seeds and their proportions were different between J. phoenicea s.s., J. turbinata, and J. canariensis, and were useful in distinguishing between these three taxa. The populations of J. canariensis had a significantly higher percentage of trimerous cones, a higher number of cone scales, but a lower number of seeds, which were also larger than the seeds from other taxa. Juniperus phoenicea s.s., J. turbinata, and J. canariensis revealed a high level of multivariate differentiation, but there were no single characteristics which allowed one to distinguish between these alone. We detected significant differences between populations of J. turbinata from Europe and Africa, which supports the role of the Gibraltar Straight in the structuring of conifer species. Significant differences were also detected between European and Asiatic populations in several characters examined, indicating the important role of the Aegean Sea in the structuring of this taxon.  相似文献   

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OBJECTIVE: To evaluate the usefulness of fine needle aspiration (FNA) study of lymph nodes in HIV-positive patients. STUDY DESIGN: The study was conducted at Kasturba Medical College, Mangalore, India. Samples from lymph nodes of 48 HIV-positive patients were taken and air dried, and wet smears were made. After staining with routine cytologic stains and special stains, detailed cytomorphologic study was conducted. RESULTS: Tuberculosis accounted for nearly half (48%) the cases,followed by HIV lymphadenitis (36%), lymphoma (10%), suppurative lymphadenitis (2%), Mycobacterium avium-intracellulare lymphadenitis (2%) and metastases (2%), in descending order of their frequency. A suppurative picture, which was found in 13% of cases of tuberculous lymphadenitis in AIDS patients, occasionally was misleading without the help of acid fast bacilli stain. CONCLUSION: FNA is a useful tool in the diagnosis of lymphadenopathy in HIV-positive patients provided that proper safety measures are taken to avoid contracting the infection.  相似文献   

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Eleven fine needle aspiration (FNA) biopsies were performed on seven children with neuroblastoma, including one patient with a congenital neuroblastoma and another with a peripheral neuroblastoma of the thoracopulmonary region. FNA cytology made the primary diagnosis of neuroblastoma in four of the seven cases. The other biopsies documented local recurrences and metastases to liver, lymph nodes, orbit and breast. The cytologic features included varying numbers of small primitive cells with scanty cytoplasm, poorly to well-formed pseudorosettes, cell processes, a fibrillary matrix and multinucleated ganglion cells. Five of the seven patients had electron microscopic (EM) examination of the FNA specimen, which in all cases confirmed the diagnosis. Batteries of immunoperoxidase stains were performed on all 11 aspirates with variable results. Staining for neuron-specific enolase was positive in four of the five neoplasms tested, although strongly positive in only three of the cases. Staining for neurofilament markers was positive in only two of five tumors. Studies for cytokeratin markers (AE1/3), low-molecular-weight cytokeratin (35BH11), hematopoietic markers (T29/33), immunoglobulin light chains and myoglobin were negative. One case was positive for vimentin. This study attests to the value of FNA cytology in suggesting a correct diagnosis of either primary, recurrent or metastatic neuroblastoma in children. Selective use of immunoperoxidase stains and EM on the aspirates may be of value.  相似文献   

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