Positive Needle Research Articles

Bronchoscopic and Roentgenographic Correlates of a Positive Transbronchial Needle Aspiration in the Staging of Lung Cancer

A study was conducted to determine the bronchoscopic and chest roentgenographic findings associated with a positive TBNA. One hundred fifty-seven of 465 patients who were diagnosed for the first time as having carcinoma of the lung had a positive aspirate. Bronchoscopic findings associated with a positive TBNA of N2 nodes were carinal widening and endobronchial disease, especially of the right upper lobe. Mediastinal adenopathy noted on chest roentgenograms and subcarinal nodes on CAT scans were associated with a positive aspirate as well. In 34 of 465 patients, TBNA was the only means of establishing the diagnosis of pulmonary malignancy. A useful, simple and safe procedure, TBNA can be used to stage the mediastinum in patients with lung cancer and is most likely to be positive with endobronchial and nodal disease. It can also facilitate therapeutic decision-making in patients whose surgical candidacy is marginal.

Breakdown of gas-liquid composite in divergent fields

Artificial gas bubbles about 1 mm in diameter were generated and attached to a needle tip in n-hexane. Breakdown voltage was reduced by the presence of the bubble. Gas discharges which could be detected by a photomultiplier occurred inside the bubble. The motion of the bubble was observed by a high-speed camera. Before breakdown, a bubble moved to the plane electrode, leaving the negative needle, while the bubble never left the positive needle. The breakdown mechanism of a gas bubble n-hexane composite is discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Electric Discharges in Ultrasonic Field –Relationship between Particle Velocity of Sound and Spread Width of Discharge–

This paper deals with the effect of ultrasonic field on electric discharge phenomena. An electrode of a positive needle to a disc gap was located at an antinode of particle velocity in a standing wave field. Both the intensity of sound and the applied voltage were varied. Results showed that the luminous part of the bridged-over corona discharge and spark discharges was changed from a linear to a fan-like shape by sound waves, and the spread width of the luminous part of discharges was proportional to the displacement of sound.

The Optimum Use of Needle Aspiration in the Bacteriologic Diagnosis of Cellulitis in Adults

Twenty-five adult inpatients with cellulitis were prospectively studied to determine if distinctive predisposing factors, characteristic clinical findings, or specific laboratory features were predictive of isolating a pathogen from needle aspiration cultures of the leading edges of their lesions. In the univariate analysis, age, underlying disease, temperature, and white blood cell count at admission to the hospital correlated with a positive needle aspiration culture. A series of logistic regressions were performed to determine if each of these variables was independently associated with a positive needle aspiration culture. The final model demonstrated that underlying disease and body temperature were independent predictors of obtaining a positive needle aspiration culture. Consequently, the addition of white blood cell count and age failed to enhance the model's predictability. For most patients this procedure will not be helpful [corrected] in establishing a bacteriologic diagnosis. On the basis of these results, the needle aspiration technique will most likely yield pathogens in patients with underlying disease that predisposes to the acquisition of cellulitis. These patients may also fail to mount a febrile response to infection.

Diagnosis of Cellulitis in the Immunocompromised Host

A prospective study of diagnostic techniques in cellulitis was performed on 28 patients with malignancy. Twenty-two (78%) of the fine needle aspiration cultures and 10 (35%) of the blood cultures were positive in this immunocompromised population. The incidence of positive fine needle aspiration cultures (P<0.005) or bacteremia (P<0.0005) was significantly higher than results obtained in an immunocompetent population with cellulitis at the same institution. Staphylococci or streptococci were recovered in 59% of positive cultures, while aerobic Gram-negative bacilli grew in 33%. This study indicates that in the immunocompromised population with cellulitis, fine needle aspiration and blood cultures should be obtained, and the antibiotic regimen should cover Gram-positive cocci and Gram-negative bacilli pending the results of cultures.

Visual observation of electrical discharges in a standing sound wave field

There are many papers reporting the effects of electrical discharge, such as in atmospheric pressure, gaseous mediums, and the shape and geometry of an electrode. However, in spite of the fact that an electrical discharge phenomenon accompanies sound waves, there are very few reports regarding the influence of sound waves on the discharge phenomenon. In this paper, it is visually confirmed that discharging phenomena are influenced by sound waves irradiating the electrical discharge. Discharging cells with both positive and negative needle electrodes were located at a sound‐pressure node in a standing wave field. As a result, the luminous part of the electrical discharge changed to a leaflike shape, and the starting voltage of the discharge also changed.

Breakdown Characteristics of SF6-N2 Mixture in High Nonuniform Field Gap under Pulse Voltage

The corona and breakdown characteristics of gas mixtures were investigated in a positive needle gap, using µs pulse voltage with various rise times. The breakdown voltage reached a maximum value as the rise time increased, and reduced at longer rise times. An extremely high breakdown voltage was obtained with the addition of a very small percentage of SF6 to N2.

Behavior of Electric Discharge in Ultrasonic Field

This paper deals with the influence of ultrasonic field on electric discharge phenomenon, i.e., spark and high-pressure glow discharge. An electrostatic unit having a positive needle electrode and a negative plate electrode was located at the sound pressure node in a standing sound wave field; the sound pressure level and the applied voltage were varied. As a result, the shape of the electric discharge was changed to an open fan-like shape, and the starting voltage for spark and high-pressure glow discharge could be varied by the sound.

TRU-CUT needle biopsy of the breast. An analysis of its specificity and sensitivity.

One hundred fifty needle core biopsies of the breast, performed with the use of the Travenol TRU-CUT disposable needle, were done from January 1980 to November 1984. There were 112 diagnoses of breast cancer and 33 diagnoses of normal breast tissue or nonneoplastic breast disease, including 2 diagnoses of marked atypia. In five biopsy specimens, no breast tissue or tumor could be identified. Fourteen cases of malignancy were not diagnosed by TRU-CUT biopsy specimens. There were no false-positive diagnoses. Sensitivity for the diagnoses of breast cancer was 89% overall and 94% for lesions greater than 2.5 cm in diameter. The histopathologic correlation between the core biopsy specimen and the excised specimen is excellent. The core biopsy specimen permits the pathologist to accurately classify the mammary carcinoma. The overall specificity for the TRU-CUT needle biopsy is 100%, and the overall predictive value of a positive needle biopsy is 100%. A factor not apparent in all reports, whether they be fine needle aspiration or core biopsy, is the ability of the individual obtaining the tissue and the cytopathologist or pathologist interpreting the material.

Behavior of Bridged-over Corona in High-intensity Sound Field

This paper deals with the discharging phenomena experienced in the region of corona discharge with an acoustic field. An electrostatic unit having positive needle electrode and negative plate electrode was located at the sound pressure node, and the sound pressure level and frequency were varied. As a result, the form of bridged-over corona was changed to fanwise, and the starting voltage for corona discharge phenomena could be varied by the sound pressure level and the frequency.

The role of fine needle aspiration in the management of the thyroid nodule

The role of fine needle aspiration (FNA) in the management of the patient with a thyroid nodule continues to be controversial. We present a retrospective study of 69 patients who underwent FNA for thyroid nodules over a two-year period. No false positive or false negative fine needle aspirations are reported in 22 patients who underwent surgery. From the results of this study and other studies in the literature, we feel that ultrasonography and thyroid scans are of minimal additional benefit in determining whether a nodule is benign or malignant. It is our opinion that FNA, along with clinical assessment, should be the diagnostic test to determine the management of the thyroid nodule in centers with personnel experienced in FNA.

Dielectric Breakdown of Liquid Helium and Influence of Electrode Coating

Polarity and conditioning effects of breakdown in liquid helium and the influence of electrode coating by solid insulator are studied. The breakdown strength under positive needle condition decreases with repeating breakdown events. However, it increases under negative needle condition, which can be explained in terms of severe damage of the cathode surface and its influence on electron emission from the cathode. The breakdown strength with coated cathode is found to indicate higher values than that with the coated anode, which is also discussed in terms of the electron emission. The breakdown strength of insulating polymer film in liquid helium is lower than that in liquid nitrogen, but becomes comparable by covering of the sample and electrodes with 3-methylpentane, which can be explained by the environmental effect in liquid helium. The barrier effect in liquid helium is also studied.

Pre-Breakdown Current and Light Emission in Transformer Oil

Prebreakdown current, photo current, and light emission are measured simultaneously in transformer oil under nonuniform fields. For a negative needle point, the light emission is divided into two patterns. They change from a bush-type to a tree-type as the applied voltage or the oil pressure increase. In the case of the tree-type, they are cau-sed by the streamer only at the initial stage. In the case of the bush-type, the light is emitted intermittently within a few hundred us. The initial one is caused by a tiny streamer but those that follow seem to occur within bubbles created by the initial one. For a positive needle point, positive streamers emanate from the point radially. When they reach the cathode, a few bright spots are formed on the cathode from which negative streamers start.

Reliability of aspiration biopsy in thyroid nodes: study of 2190 operated patients.

The cytologic finding was negative in 1841 patients; accurate in 1763 (95.8%). Suspicious cytology proved malignant in 82 of 252 patients (32.5%). Positive cytology was accurate in 88 out of 97 cases (90.7%). In 1942 benign goiters, cytology was accurate in 90.8% of patients, false suspicious in 8.7% and false positive in 0.5%; the highest percentage of misdiagnosis was in adenomas (15.8%) and thyroiditis (19.0). In 248 malignant goiters, cytology was accurate in 35.5% of patients, suspicious in 33.1%, and false negative in 31.4%. False-negative cytology was found in 44% of follicular cancers, 22.2% of papillary and medullary, and 12.9% anaplastic. The most frequent false-negative cytologic diagnosis was the adenomatous goiter. The accuracy of cytology was statistically higher in papillary cancers than in follicular (77.8% vs 56.0%), in undifferentiated tumors than in differentiated (83.7% vs 65.0%), and in adenomatous nontoxic goiters than in adenomas, thyroiditis and toxic goiters (80.3% vs 42.7%), 20.1% and 13.4%). Positive preoperative fine needle aspiration biopsy cytology is a worthwhile and reliable finding; it fails in less than 10% of patients. Negative cytology, however, does not exclude malignancy in thyroid nodes; it is false negative in more than 30% of cancers.

Conditioning Effect of Dielectric Breakdown in Liquid Helium

In a non-uniform field with a needle-plane electrode system, the breakdown voltage Vb of a positive needle decreases as the number of breakdown events N increases, but that of a negative needle increases slightly with N. In a uniform field, the breakdown voltage decreases with increasing N. However, when the polarity of the voltage pulse is reversed after many breakdown events, Vb increases suddenly and then again decreases slightly with increasing N, tending to saturate. These conditioning effects can be explained by the increase of the electron injection from the cathode due to the formation of a rough surface by the previous breakdown events.

Dependence of polarity effect of dielectric breakdown on molecular structure of liquids

In liquid hydrocarbon, at short electrode distance, the negative needle indicates lower strength than that of positive needle and it reverses at longer electrode distance. The critical distance of this polarity reversal is very short for liquids with large electron mobility like neopentane. In perfluorocarbon liquids, the difference of breakdown voltage for both polarities is much less than that of hydrocarbon liquids. In liq.N 2, the polarity effect of breakdown is similar to that of hydrocarbons and strongly dependent on pulse width, applied pressure. The polarity effect in liq.He is completely different from other liquids and due to the unique behaviour of electrons in liq.He. The polarity effect in liq.Ne is similar to liq.He. These polarity effects in various liquids seem to have some correlation with the mobility in these liquids and are discussed in terms of bubble process and electronic processes like streamer.

Pressure Dependence of Dielectric Breakdown in Liquid Nitrogen

Breakdown voltage characteristics in liquid nitrogen (liq.N2) have been studied in the pressure range between 1 and 15 atm. For constant gap length, the breakdown voltage increases with increasing pressure and saturates at around 10 atm. For shorter pulse width, the increase in breakdown voltage with pressure becomes less remarkable. In a non-uniform field of a plane-needle electrodes system, the breakdown voltage of the negative needle configuration increases remarkably with increasing pressure but that of the positive needle is almost insensitive to the pressure. These results can be interpreted in terms of the suppression of the formation and the development of a gaseous bubble in the breakdown of liq.N2 under high pressure and at short pulse width. The positive streamer seems to play an important role in initiating total breakdown under high pressure and at short pulse width.

A Semiquantitative Culture Technic for Identifying Infection Due to Steel Needles Used for Intravenous Therapy

Using steel intravneous needles obtained from patients with hematologic malignancies, the authors evaluated the efficacy of a semiquantitative method for culturing vascular cannulas on solid medium, comparing it with conventional broth culture. Of 148 needles studied, 140 (95%) were negative on semiquantitative culture (less than 15 colonies on the plate) although 38 produced growth in broth or on the plate; none of these needles caused septicemia. Eight needles were positive on semiquantitative culture (greater than or equal to 15 colonies), and two of these caused septicemia (P = .002). Positive semiquantitative cultures were associated with local inflammation (P = .02). Semiquantitative culturing was equal to the broth method in sensitivity (100%) in the diagnosis of needle-related septicemia; specificity (96% vs. 92%) and the predictive value of a positive needle culture (25% vs. 14%) were both enhanced with the semiquantitative method. The semiquantitative technic differentiates infection from contamination and offers other major advantages compared with the broth method, and is recommended for culturing steel needles as well as plastic catheters.

Anomalous polarity effect of dielectric breakdown voltages in liquid helium

The polarity effect of the dielectric breakdown voltage in liquid He is studied. The breakdown voltage for a positive needle is higher than that for a negative needle and even than that for uniform field. The field strength on the cathode surface at breakdown threshold for a positive needle is calculated with a simple hyperboloid approximation of field distribution, and agrees approximately with the breakdown field in the uniform field condition. The breakdown strength also depends on the work function of the cathode metal but not that of the anode metal. Therefore, breakdown threshold in liquid He seems to be determined by the field strength at the cathode.

Electrical breakdown in cryogenic liquids

Both the statistical time lag T s and the formative time lag T f of the breakdown in cryogenic liquids (Liq.Ar, N 2 and He) are evaluated from the Laue plots of the breakdown time lag induced by a voltage pulse having a 100-ns pulse width. In the case of Liq.Ar, both T s and T f become shorter with increasing applied voltage, and T f increases with increasing electrode distance under the constant electric field. Therefore, these experimental results are interpreted in terms of a single avalanche mechanism. On the other hand, in the case of Liq.N 2, T s decreases with increasing electric field, but T f does not depend strongly on the electric field. In Liq.He at both 4.2 K and 2.1 K, T s and T f show a similar tendency as with Liq.Ar. In Li He, the threshold breakdown field decreases with increasing electrode distance and voltage pulse width. The carrier mobility, estimated from T f by assuming a single avalanche breakdown, is nearly the same as that obtained by the time-of-flight method in Liq.Ar. In Liq.He, however, the former is larger than the latter obtained at low fields. Under the non-uniform electric field (plane-needle electrode configuration), the breakdown strength at negative needle configuration is much higher than that at positive needle in Liq.Ar. On the contrary, in Liq.He the former is much lower than the latter. These experimental results can be interpreted by taking into consideration the different mobilities of negative and positive carriers in these liquids.