High Nil Research Articles

Growth of high school NIL impacts college athletics

Growth of high school NIL impacts college athletics

Factors Influencing the Indeterminate Results in a T-SPOT.TB test: A Matched Case-control Study.

Objective A T-SPOT.TB can yield indeterminate results under two test observation conditions: a high response to the nil in negative control wells (high nil-control) or a low response to the mitogen in positive control wells (low mitogen-control). The most strongly influential factors for these indeterminate results, however, have yet to be identified. Methods From June 1, 2015, to June 30, 2021, we conducted a 1:1 matched case-control, retrospective study. Patients Patients who underwent a T-SPOT.TB test at Chiba University Hospital. Results The study included 5,956 participants. Indeterminate results were found in 63 participants (1.1%), including high nil-control in 37 and low mitogen-control in 26. Human T-cell leukemia virus type 1 (HTLV-1) positivity was the only influencing factor associated with high nil-control (adjusted odds ratio=98.5, 95% confidence interval: 6.59-1480). Conclusion Regarding the indeterminate results, all HTLV-1 positive participants had a high nil response and no low mitogen response. It was suspected that abnormally produced interferon γ caused a nonspecific reaction to the negative control well, resulting in a high nil response. Low mitogen-control, conversely, did not appear to have any statistically significant influential factors.

Exploration and improvement of QuantiFERON-TB assay in patients with indeterminate results in clinical practice: A head-to-head study

BackgroundWe implemented the QuantiFERON-TB Gold In-Tube (QFT-GIT) based on peripheral blood mononuclear cells (QFT-PBMCs) and QFT Gold Plus (QFT-Plus) in patients with indeterminate results, and use Mit-Nil value to identify false negatives and impaired cellular immunity. MethodsOne hundred seventy-one out of 2480 patients who had a QFT-GIT test were prospectively recruited and classified as high Nil (n = 35), low Mit (n = 75) and control (n = 61) cohorts. Head-to-head comparisons, i.e., QFT-PBMCs vs. QFT-GIT in high Nil cohort, QFT-Plus vs. QFT-GIT in low Mit cohort, and QFT-PBMCs vs. QFT-GIT in controls, were performed. Lymphocyte subsets counts were conducted in low Mit and control cohorts. ResultsA significant reduction of positive rate only occurred in Mit-Nil < 6 IU/ml (p < 0.001). QFT-PBMCs yielded 100 % valid results and had a significant Nil decline in high Nil cohort (0.98 ± 1.06 vs. 9.55 ± 0.64 IU/ml, p < 0.0001), while correlated well with QFT-GIT for qualitative (Cohen’s k = 0.93) and quantitative (TB–Ag [R2 = 0.91] and Mit [R2 = 0.94]) analyses. QFT-Plus produced 61.3 % valid results and had a significant Mit increase in low Mit cohort (0.82 ± 0.95 vs. 0.17 ± 0.11 IU/ml, p < 0.0001). Mit-Nil value significantly correlated with lymphocyte subsets counts (R:0.49–0.56, p < 0.0001), separately corresponding to thresholds of 4.26, 5.33, 5.55 and 5.81 IU/ml for predicting decreased total lymphocyte, T lymphocyte, CD4+ and CD8+ cells. ConclusionsQFT that replacing whole blood with PBMCs should be recommended to handle high Nil samples, and QFT-Plus can declined the frequency of low Mit results. In addition, Mit-Nil < 6 and 5.81 IU/ml are potential thresholds to identify the risk of false negatives and impaired cellular immunity, respectively.

Selective generation of nitrate and nitrite in plasma activated water and its physicochemical parameters analysis

In this work, a surface dielectric barrier discharge-based cold plasma source is reported with the selective generation of Nitrate and Nitrite in the Plasma Activated Water (PAW). The physicochemical properties of the generated PAW have been analyzed on different process parameters such as applied voltage, frequency, treatment time, and volume of water. The generated PAW has a low pH value, with high conductivity, nitrite concentration, nitrate concentration, and nil concentration of hydrogen peroxide. It is inferred that the PAW is enriched with Nitrate and Nitrite, once hydrogen peroxide is nil in the activated water. This type of PAW can be highly useful for agricultural applications.

CD69 flow cytometry to complement interferon-γ release assay for active tuberculosis.

The interferon-γ (IFN-γ) release assay (IGRA) is widely used to diagnose tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb). However, indeterminate IGRA results due to "high Nil" or "low PHA" responses limit its clinical utility. We developed a novel assay using CD69 flow cytometry (FC) to complement IGRA. CD69 FC measures the surface CD69 expression on T cells prior to centrifugation to harvest the plasma for IGRA. T cell responses against Mtb antigen 1 (Ag1) or Ag2 were measured using three-color FC (CD3, CD4, and CD69) in TB (n=140) and non-TB groups (n=117). The cutoff values of Δ%CD69bright cells (stimulated minus unstimulated) for CD4+ and CD4- T cells were established based on healthy individuals (n=63). The assay performances of CD69 FC and IGRA were compared. In subjects with determinate IGRA results ("positive" or "negative"; n=216), the diagnostic accuracies of CD69 FC (90.3%) and IGRA (87.0%) were not significantly different (p=0.31). For indeterminate IGRA results (n=40), CD69 FC attained a diagnostic accuracy of 92.5%. The CD4+ /CD4- ratio within CD69bright T cells measured by CD69 FC was significantly higher (p < 0.05) in the active TB group (6.39 ± 132.05; n=72) than in other CD69 FC-positive subjects (2.84 ± 15.36; n=63) (p < 0.05), whereas CD8 responses expected by IGRA (difference of IFN-γ levels between Mtb Ag tubes) did not differ significantly (0.00 ± 9.18 and 0.00 ± 4.25, respectively, IU/ml; p=0.58). We demonstrated the potential of CD69 FC as a simple, rapid assay for clarifying indeterminate IGRA results and identifying active TB. With further improvements, CD69 FC may complement the IGRA to enhance TB risk stratification in the routine diagnostic workup.

Indeterminate results of QuantiFERON-TB Gold in-tube due to high nil concentration and methodological exploration and improvement

BackgroundThe features of indeterminate results (ITRs) due to high interferon gamma (IFN-γ > 8.0 IU/mL) concentrations in Nil tubes of QuantiFERON-TB Gold in-Tube (QFT-GIT) have not been well studied. Therefore, this study aimed at investigating the features of ITRs and optimization alternatives for this method. MethodsWe used the plasma exchange method to reduce the ITR rate due to high Nil concentrations (Nil > 8.0 IU/mL) between March 2020 and September 2021 at Xiangya Hospital of Central South University in China. One hundred and eleven out of 28,193 patient samples were considered ITRs due to Nil > 8.0 IU/mL. Of these 111, blood was re-sampled from 82 patients (pretreated group) who received the plasma exchange. Moreover, 40 out of 82 (blood volume ≥ 5 mL) received pretreated QFT-GIT and standard QFT-GIT (untreated group) simultaneously, while the remaining 42 received pretreated QFT-GIT only. The statistical difference between groups was evaluated. Cohen’s kappa coefficient was used to assess the level of agreement between the pretreated and untreated group. ResultsOf the 28,193 subjects, 1,083 (3.8%) had ITRs, and 111 (0.4%) had ITRs due to Nil > 8.0 IU/mL. The population studied had a mean age of 52.9 years, and 70.3% were men, which is a larger proportion than that in patients with ITR and the overall population. Significantly decreased IFN-γ levels in Nil tubes were detected using the pretreated QFT-GIT compared with standard QFT-GIT (p < 0.01). The determinate results rate in the pretreated group was significantly higher than that of the untreated group (80% (32/40) vs 57.5%, (23/40), p = 0.03). Further comparison revealed that the pretreated group was consistent with the untreated group in 17/20 (85%) positive tests, 3/3 (100%) negative tests, and 6/17 (35.3%) ITRs. The overall agreement rate was 26/40 (65%) among all 40 subjects, and the κ value was 0.39 (minimal agreement). The majority of results obtained after pretreatment were positive (71.2%, 59/82) and the agreement rate between clinical diagnosis and pretreated QFT-GIT was at least 61.0% (39/59). ConclusionPlasma exchange pretreated QFT-GIT yields more reliable results than untreated QFT-GIT when processing high Nil concentrations.

Prevalence and influencing factors of the high nil-control spot count in T-SPOT.TB: A matched case-control study

BackgroundT-SPOT.TB may yield indeterminate results, including high nil responses and insufficient mitogen responses. We explored the incidence and risk factors of high nil responses. MethodsA 1:1 matched case-control study of patients who underwent T-SPOT.TB tests in Peking Union Medical College Hospital from Jan 1, 2015 to Apr 30, 2017 was conducted. High nil responses were defined as >10 spots in negative control wells. Cases and controls were matched based on when the tests were performed. Demographic, clinical and laboratory data were obtained from the Medical Record System. ResultsA total of 644 out of 36,316 (1.76%, 95% CI: 1.63%–1.90%) patients presented with high nil responses (280 cases and 280 controls were enrolled). Multivariate analysis revealed that male (OR = 1.882, 95% CI: 1.222–2.899), Behcet's disease (OR = 7.764, 95% CI: 1.714–35.167), heavy use of corticosteroids within a month (OR = 0.357, 95% CI: 0.138–0.921, for >1000 mg group) and hypoalbuminemia (OR = 0.385, 95% CI: 0.241–0.615) are significantly associated with high nil responses. ConclusionsHigh nil responses in T-SPOT.TB assays are quite rare. Male gender and Behcet's disease are suggested as independent risk factors, while recent excessive use of corticosteroids and hypoalbuminemia seem to be independent protective factors.

Indeterminate T-SPOT.TBTest Results in Patients with Suspected Extrapulmonary Tuberculosis in Routine Clinical Practice

BackgroundThe two interferon-γ release assays such as QuantiFERON-TB Gold / In-Tube (QFT-TB) and T-SPOT.TB-are useful tools for the rapid diagnosis of tuberculosis (TB) but can yield indeterminate test results (ITRs). While some studies have identified risk factors for ITRs in the QFT-TB test, there have been few such studies for the T-SPOT.TB test. The aim of this study was to investigate the risk factors associated with ITRs in the T-SPOT.TB test.Materials and MethodsFrom April 2008 to August 2010, all patients with suspected extrapulmonary tuberculosis (E-TB) were enrolled in a tertiary hospital in Korea. ITR was defined as < 20 spots in the positive control well or > 10 spots in the negative control well.ResultsOut of a total of 368 patients, 32 (8.7%, 95% CI, 6.0% to 11.7%) had ITRs in their T-SPOT.TB tests. The ITRs were due to a low mitogen response in 13 (40.6%) patients and to a high nil response in the other 19 (59.4%) patients. Statistical analysis revealed that old age, underlying diseases, immunosuppressive treatment, lymphopenia, and clinical manifestations of E-TB were not significantly associated with ITRs.ConclusionsIndeterminate results in the T-SPOT.TB test are not affected by age, underlying disease, immunosuppressive treatment, lymphopenia, or clinical manifestations of E-TB, which are known risk factors for indeterminate results in the QFT-TB test.

Indeterminate QuantiFERON® -TB Gold results in a public health clinic setting

Public chest clinics, New York City. To evaluate the association between patient characteristics and indeterminate QuantiFERON ® TB Gold (QFT-G) results and describe follow-up testing. Retrospective cross-sectional multivariate logistic regression analyses of patients receiving QFT-G from October 2006 to June 2008. Analyses were performed separately depending on whether the indeterminate result was due to positive (low mitogen) or negative (high nil) control failure. Of 28 864 individuals tested, 2058 (7%) tested positive, 26 284 (91%) negative, and 522 (2%) were indeterminate (low mitogen, n = 264; high nil, n = 258). Low mitogen results were more frequent among those aged < 10 years (OR(adj) 3.7, 95%CI 2.4-5.9), females (OR(adj) 1.4, 95%CI 1.1-1.8), Asians (OR(adj) 2.1, 95%CI 1.3-3.4) and the US-born (OR(adj) 1.9, 95%CI 1.4-2.6) and less frequent among Hispanics (OR(adj) 0.6, 95%CI 0.4-1.0). High nil results were more frequent among Hispanics (OR(adj) 1.7, 95%CI 1.0-2.8) and less frequent among the US-born (OR(adj) 0.6, 95%CI 0.5- 0.8). Among patients who received a repeat QFT-G (n = 137), 4% tested positive, 64% negative and 32% had a second indeterminate result, always of the same type. Age, race/ethnicity and sex were associated with indeterminate QFT-G results. Most follow-up tests were negative, although a modest proportion were repeatedly indeterminate. Further studies evaluating the mechanisms of QFT-G indeterminate results are needed.

Application of Wavelet Analysis in the DPIV Information Processing for the River Model Test

It’s important to measure the horizontal distribution of the 2D velocity field for model verification and scheme selection at model test in the tidal estuary. Digital particle image velocimetry (DPIV) has become an accepted technique for the measurement of two- and three component planar velocities in a wide variety of fluid flows, which has advantages of high speed and nil interference. However, sometimes DPIV images are overexposure, uneven distribution of the gray values, and obscurity on the edges of the particles, which will affect the accuracy of flow data by inversion. Wavelet transform has good characteristics in time-frequency localization, and it has been widely used for image preprocessing, image compression, image restoration, image feature extraction and pattern recognition. A wavelet-based multi-resolution technique was applied to analyze the 2D measurement results of a DPIV system in this paper. In the different stages: boundary treatment, noise reduction, identification and elimination of the error vector, which are applicable to the processing of the DPIV information for getting the velocity vectors with higher resolution and precision through the continuous wavelet transform of velocity data.

Adapted T Cell Interferon-Gamma Release Assay for the Diagnosis of Pleural Tuberculosis

Background: Better and more rapid tests are needed for the diagnosis of tuberculous pleural effusion (TPE), given the known limitations of conventional diagnostic tests. Objectives: To estimate diagnostic accuracy of the QuantiFERON-TB Gold In-Tube (QFT-GIT) test (and its components) using data-derived cutoffs in pleural fluid. Methods: The QFT-GIT test was performed on whole blood and pleural fluid from 43 patients with TPE and 29 control subjects (non-TPE). To achieve the objective, QFT-GIT test, estimating likelihood ratios and receiver operating curve analysis were performed. Results: The sensitivity and specificity using the QFT-GIT for the diagnosis of TPE were 48.8% and 79.3%, respectively, in pleural fluid. The best cutoff points for tuberculosis (TB) antigen, nil and TB antigen minus nil results were estimated at 0.70, 0.90 and 0.30 IU/ml, respectively. Area under the curve of TB antigen IFN-γ response was 0.86 (CI: 0.76–0.93), nil tube was 0.80 (CI: 0.69–0.89) and TB antigen minus nil tube was 0.82 (CI: 0.72–0.90). When the best cutoff scores of the nil tubes were set at this value, the results of a likelihood ratio of a positive and a negative test were 9.44 (7.4–12.0) and 0.37 (0.09–1.5), respectively. The percentages of indeterminate results in pleural fluid among the TPE cases were 42% (most of them caused by high nil IFN-γ values) using the QFT-GIT test. Conclusion: QFT-GIT test or its components have poor accuracy in the diagnosis of TPE, largely because of a high number of indeterminate results due to high background IFN-γ production in the TPE.

Indeterminate Interferon-γ Release Assay Results in Children

Indeterminate Interferon-γ Release Assay Results in Children

Multi-layer alignment control of a large area nano-imprinting stage

An XYθ stage for large area UV Nano-Imprinting Lithography (UV-NIL), which consists of linear actuators, translational/revolute joints, etc., has been modeled as flexible bodies. Multi-layer alignment control for the translation and angle offset cancellation has been performed in a virtual simulation environment using both ADAMS/Control and Matlab/SIMULINK. Furthermore, the vertical motions of three and four axis stages during the control action have been analyzed and compared to each other. The performed analysis can provide useful information for a high precision NIL stage development in the future.

Evaluation of immune responses in HIV infected patients with pleural tuberculosis by the QuantiFERON®TB-Gold interferon-gamma assay

BackgroundDiagnosis of tuberculous (TB) pleuritis is difficult and better diagnostic tools are needed. New blood based interferon-gamma (IFN-γ) tests are promising, but sensitivity could be low in HIV positive patients. The IFN-γ tests have not yet been validated for use in pleural fluid, a compartment with higher level of immune activation than in blood.MethodsThe QuantiFERON TB®-Gold (QFT-TB) test was analysed in blood and pleural fluid from 34 patients presenting with clinically suspected pleural TB. Clinical data, HIV status and CD4 cell counts were recorded. Adenosine deaminase activity (ADA) analysis and TB culture were performed on pleural fluid.ResultsThe patients were categorised as 'confirmed TB' (n = 12), 'probable TB' (n = 16) and 'non-TB' pleuritis (n = 6) based on TB culture results and clinical and biochemical criteria. The majority of the TB patients were HIV infected (82%). The QFT-TB in pleural fluid was positive in 27% and 56% of the 'confirmed TB' and 'probable TB' cases, respectively, whereas the corresponding sensitivities in blood were 58% and 83%. Indeterminate results in blood (25%) were caused by low phytohemagglutinin (PHA = positive control) IFN-γ responses, significantly lower in the TB patients as compared to the 'non-TB' cases (p = 0.02). Blood PHA responses correlated with CD4 cell count (r = 0.600, p = 0.028). In contrast, in pleural fluid indeterminate results (52%) were caused by high Nil (negative control) IFN-γ responses in both TB groups. Still, the Nil IFN-γ responses were lower than the TB antigen responses (p < 0.01), offering a conclusive test for half of the patients. We did not find any correlation between blood CD4 cell count and IFN-γ responses in pleural fluid.ConclusionThe QFT-TB test in blood could contribute to the diagnosis of TB pleuritis in the HIV positive population. Still, the number of inconclusive results is too high to recommend the commercial QFT-TB test for routine use in pleural fluid in a TB/HIV endemic resource-limited setting.

Supply-Side Analysis of Growth of Bacillus subtilis on Glucose-Citrate Medium: Feasible Network Alternatives and Yield Optimality

Our prior work revealed that compared to the case for glucose metabolism, increased carbon yield and nil acid formation result when Bacillus subtilis grows on glucose medium containing citrate. To scrutinize further how citrate addition may alter metabolic flux regulation and the degree that the observed carbon yield corresponds to the maximal value, experimental (by least-squares analysis) and optimal (by linear programming) fluxes and yields were contrasted. Networks with differing reaction routes, directionality constraints, and transhydrogenase activities were examined. To attain an elevated carbon yield, citrate-glucose utilization need not alleviate any stoichiometric constraints that can sometimes interfere with the attainment of network objectives. Rather, the high carbon yield and nil acid formation attained may be linked to restriction of glycolytic capacity, particularly at the level of pyruvate kinase, which is consistent with a hypothesized effect of coupled metal-citrate uptake. Allowing for malic enzyme activity, hexose monophosphate pathway cycling, and transhydrogenase activity may also lead to the flux distributions underlying the high carbon yield observed. Finally, the observed carbon yield corresponded well to the maximum yield provided by all the network alternatives examined. Collectively, these results suggest that (i) the observed carbon yield is essentially equal to the maximal values associated with plausible networks and (ii), as suggested by others, nonoptimal flux regulation may contribute significantly to apparent cellular maintenance requirements.

Studies in Stomatal Behaviour

An experiment was carried out to investigate stomatal responses in wheat to four ‘closing treatments’, viz. high carbon dioxide concentration, darkness, dry air and nil, each given under both aerobic and anaerobic conditions. Thus the effect of lack of oxygen on the closing (or opening) tendency was estimated. Changes in (conductance)3 calculated from resistance porometer readings were used as data and reasons are given for thinking this is the best available measure for investigating stomatal dynamics in wheat. Williams's hypothesis demands that lack of oxygen should cause stomatal opening or prevent closure; the present experiment shows that anaerobic conditions significantly increase the closing tendency when ‘closing treatments’ are first applied. There is also some suggestion that oxygen-lack itself tends to cause closure in the absence of any other ‘closing treatment’. Williams's hypothesis in its original form is thus disproved (for wheat) but the present results would be consistent with an ‘active’ uptake of water by the guard cells contributing to stomatal opening. A nearly significant interaction between carbon dioxide and oxygen suggests that under anaerobic conditions a ‘closing substance’ may perhaps be formed, for example, by the union of some intermediate in glycolysis with carbon dioxide.