尿酶检测早期诊断庆大霉素肾脏损害的动物实验与临床研究

采用犬庆大霉素肾中毒模型,结合临床病例,检测尿丙氨酸氨基肽酶、N-乙酰—β—氨基葡萄糖苷酶、γ-谷氨酰转肽酶、乳酸脱氢酶的变化和犬肾超微结构改变。结果显示,治疗剂量庆大霉素对肾脏具有损害作用,中毒量的损害明显加重;处于亚临床期肾病变者,庆大霉素显著加重其毒性损害。检测尿酶的变化可以早期反映出这种肾毒性损害,是一种灵敏的早期监测指标。     

A comparison of polymerase chain reaction and an infectivity assay for human immunodeficiency virus type 1 titration during virus inactivation of blood components

Three examples of human plasma-derived concentrates, intermediate- purity factors VIII and IX, and fibrinogen were spiked with tissue culture-grown human immunodeficiency virus type 1 (HIV-1) strain RF. All examples were freeze-dried and heated at 80 degrees C for 72 hours by using validated production process models. HIV-1 infectivity was measured by a syncytial infectivity assay in C8166 cells and then compared with levels determined by nested HIV polymerase chain reaction (PCR). The infectivity assay demonstrated a reduction index of at least 4.5 log10, while PCR showed an average 1.7 log10. Large amounts of HIV- 1 RNA (10(5)) were still detectable by PCR in samples in which infectivity assays failed to detect any HIV-1. These data suggest that HIV-1 PCR levels do not parallel HIV-1 infectivity levels during virus- inactivation procedures involved in coagulation factor concentrate production. PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal.     

Isolation of simian virus 40 from rhesus monkeys (Macaca mulatta) with spontaneous progressive multifocal leukoencephalopathy.

Isolates of virus from the brain tissue of two naturally occurring cases of progressive multifocal leukoencephalopathy in rhesus monkeys (Macaca mulatta) have been characterized. Both isolates were demonstrated to be simian virus 40 (SV40) by serological tests and analysis of cleavage fragments of viral deoxyribonucleic acid produced by restriction endonuclease from Haemophilus influenzae. SV40 virions and the nonvirion T antigen were demonstrated in the brain lesions of one monkey by the fluorescent antibody staining technique. SV40 was not demonstrated in the brain of normal rhesus monkeys from the same colony with use of the same methods of viral isolation or demonstration of antigen.     

Cyclic AMP triggers glucagon-like peptide-1 secretion from the GLUTag enteroendocrine cell line

Aims/hypothesis To investigate the pathways by which cyclic AMP (cAMP) stimulates glucagon-like peptide-1 (GLP-1) secretion, using the GLUTag enteroendocrine cell line. Materials and methods GLP-1 release from GLUTag cells was measured in response to agents that increase cAMP, and single cells were studied by fluorescence calcium imaging and electrophysiology to evaluate the underlying pathways. Results Pituitary adenylate cyclase-activating polypeptide increased cAMP levels and stimulated GLP-1 release from GLUTag cells. Agents that increase cAMP levels, including forskolin plus 3-isobutyl-1-methylxanthine (fsk/IBMX), triggered a rise in the intracellular calcium concentration and enhanced the response to glucose by increasing both the number of cells responding to glucose and the magnitude of calcium responses in individual cells. Importantly, fsk/IBMX also stimulated GLP-1 release and intracellular calcium elevation even in the absence of nutrients. fsk/IBMX triggered membrane depolarisation and the firing of action potentials, associated with a +14 mV shift in the voltage-dependence of activation of hyperpolarisation-activated currents and the closure of a background potassium conductance. Conclusions/interpretation We show here that cAMP elevation directly triggers GLP-1 release and enhances the secretory response to other stimuli like glucose, by modulating hyperpolarisation-activated currents and the background potassium current. cAMP-elevating pathways and the cAMP-modulated conductances in L cells present important targets for the development of therapeutic GLP-1 secretagogues. A. K. Simpson and P. S. Ward contributed equally to this study.     

Chronic ankle instability and fatigue create proximal joint alterations during performance of the Star Excursion Balance Test

The combined effects of chronic ankle instability (CAI) and lower extremity fatigue on measures of neuromuscular control have not been well established. The purpose of this study was to investigate the influence of CAI on the performance of a dynamic postural control task, the Star Excursion Balance Test (SEBT), after fatiguing activities. Thirty subjects with (n = 14) or without (n = 16) unilateral CAI completed anterior, medial, and posterior reaching directions of the SEBT performed before and after a lunging fatigue protocol and an open chain ankle isokinetic fatigue protocol. Pre-post fatigue change scores were calculated for sagittal plane kinematics of the stance leg and the normalized reach distances (%MAXD). Using a regression model, group and kinematic data were used to explain between subject differences in %MAXD. For each reaching direction, a separate analysis was completed for the two fatigue conditions. When reaching anteriorly after the lunge fatigue condition, CAI and the changes in knee and hip flexion predicted approximately 49 % of the variance in %MAXD (R2 = .487; p = .001). When reaching medially under lunge fatigue, CAI predicted approximately 20 % of the variance in %MAXD (R2 = .198; p = .014). Isolated ankle fatigue did not cause significantly different responses between groups. For two of the reaching directions, CAI status significantly influenced the variances in %MAXD under the influence of lunge fatigue. Functional fatigue protocols     

Support for a reduction in the number of trials needed for the star excursion balance test

Robinson RH, Gribble PA. Support for a reduction in the number of trials needed for the Star Excursion Balance Test.

Objective

To determine the number of trials necessary to achieve stability in excursion distance and stance leg angular displacement for the 8 directions of the Star Excursion Balance Test (SEBT).

Design

One-way repeated-measures analysis of variance.

Setting

Athletic training laboratory.

Participants

Twenty participants (10 men, 10 women) without any known musculoskeletal injuries or neurologic deficits that could have negatively affected their dynamic balance volunteered for the study.

Intervention

Participants completed 6 practice and 3 test trials in each of the 8 reach directions of the SEBT.

Main Outcome Measures

Excursion distances of the reaching leg normalized to leg length and angular displacement at the hip and knee of the stance leg in all 3 planes of movement were determined.

Results

There were significant increases in excursion distance, hip flexion, and knee flexion for 7, 4, and 5 of the 8 reach directions, respectively.

Conclusions

For the majority of the reach directions, maximum excursion distances and stance leg angular displacement values achieved stability within the first 4 practice trials, thus justifying a reduction in the recommended number of practice trials from 6 to 4 and supporting the trend toward simplifying SEBT administration.     

Detection of circulating tumour DNA after neoadjuvant chemoradiotherapy in patients with locally advanced oesophageal cancer

Active surveillance instead of standard surgery after neoadjuvant chemoradiotherapy (nCRT) has been proposed for patients with oesophageal cancer. Circulating tumour DNA (ctDNA) may be used to facilitate selection of patients for surgery. We show that detection of ctDNA after nCRT seems highly suggestive of major residual disease. Tumour biopsies and blood samples were taken before, and 6 and 12 weeks after, nCRT. Biopsies were analysed with regular targeted next-generation sequencing (NGS). Circulating cell-free DNA (cfDNA) was analysed using targeted NGS with unique molecular identifiers and digital polymerase chain reaction. cfDNA mutations matching pre-treatment biopsy mutations confirmed the presence of ctDNA. In total, 31 patients were included, of whom 24 had a biopsy mutation that was potentially detectable in cfDNA (77%). Pre-treatment ctDNA was detected in nine of 24 patients (38%), four of whom had incurable disease progression before surgery. Pre-treatment ctDNA detection had a sensitivity of 47% (95% CI 24–71) (8/17), specificity of 85% (95% CI 42–99) (6/7), positive predictive value (PPV) of 89% (95% CI 51–99) (8/9), and negative predictive value (NPV) of 40% (95% CI 17–67) (6/15) for detecting major residual disease (>10% residue in the resection specimen or progression before surgery). After nCRT, ctDNA was detected in three patients, two of whom had disease progression. Post-nCRT ctDNA detection had a sensitivity of 21% (95% CI 6–51) (3/14), specificity of 100% (95% CI 56–100) (7/7), PPV of 100% (95% CI 31–100) (3/3), and NPV of 39% (95% CI 18–64) (7/18) for detecting major residual disease. The addition of ctDNA to the current set of diagnostics did not lead to more patients being clinically identified with residual disease. These results indicate that pre-treatment and post-nCRT ctDNA detection may be useful in identifying patients at high risk of disease progression. The addition of ctDNA analysis to the current set of diagnostic modalities may not improve detection of residual disease after nCRT. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.