Decompressive craniectomy for patients with malignant infarction of the middle cerebral artery: a pooled analysis of two randomized controlled trials

BACKGROUND

Decompressive craniectomy (DC) reduces mortality without increasing the risk of very severe disability among patients with life-threatening massive cerebral infarction. However, its efficacy was demonstrated before the era of endovascular thrombectomy trials. It remains uncertain whether DC improves the prognosis of patients with malignant middle cerebral artery (MCA) infarction receiving endovascular therapy.

METHODS

We pooled data from two trials (DEVT and RESCUE BT studies in China) and patients with malignant MCA infarction were included to assess outcomes and heterogeneity of DC therapy effect. Patients with herniation were dichotomized into DC and conservative groups according to their treatment strategy. The primary outcome was the rate of mortality at 90 days. Secondary outcomes included disability level at 90 days as measured by the modified Rankin Scale score (mRS) and quality-of-life score. The associations of DC with clinical outcomes were performed using multivariable logistic regression.

RESULTS

Of 98 patients with herniation, 37 received DC surgery and 61 received conservative treatment. The median (interquartile range) was 70 (62-76) years and 40.8% of the patients were women. The mortality rate at 90 days was 59.5% in the DC group compared with 85.2% in the conservative group (adjusted odds ratio, 0.31 [95% confidence interval (CI), 0.10-0.94]; P=0.04). There were 21.6% of patients in the DC group and 6.6% in the conservative group who had a mRS score of 4 (moderately severe disability); and 10.8% and 4.9%, respectively, had a score of 5 (severe disability). The quality-of-life score was higher in the DC group (0.00 [0.00-0.14] vs 0.00 [0.00-0.00], P=0.004), but DC treatment was not associated with better quality-of-life score in multivariable analyses (adjusted β Coefficient, 0.02 [95% CI, -0.08-0.11]; p=0.75).

CONCLUSIONS

DC was associated with decreased mortality among patients with malignant MCA infarction who received endovascular therapy. The majority of survivors remained moderately severe disability and required improvement on quality of life.

CLINICAL TRIAL REGISTRATION

The DEVT trial: http://www.chictr.org. Identifier, ChiCTR-IOR-17013568. The RESCUE BT trial: URL: http://www.chictr.org. Identifier, ChiCTR-INR-17014167.

[Infection status and Molecular types of Rhinovirus among Cases of Acute Respiratory Tract Infections in Luohe City, Henan Province, from 2017 to 2022]

Objective: To understand the infection status and molecular types of rhinovirus (RV) among cases of Acute Respiratory Infections (ARIs) in Luohe City, Henan Province, from 2017 to 2022. Methods: From October 2017 to June 2022, clinical and epidemiological data were collected from 2 270 cases of ARIs at Luohe Central Hospital in Henan Province. Throat swab specimens were obtained from these cases. Real-time quantitative polymerase chain reaction (qPCR) was used to screen for RV-positive specimens. Subsequently, the positive samples were subjected to nested reverse transcription polymerase chain reaction (nested RT-PCR) to amplify the full-length VP1 region. Using the MEGA software, along with 169 RV reference strains recommended by the International Committee on Taxonomy of Viruses, a phylogenetic tree was constructed to determine RV types. Results: Among the 2 270 cases of ARIs, there were 1 283 male cases (56.52%). The median age (Q1, Q3) was 3 (1, 6) years, with the population under 5 years old accounting for 68.59% (1 557/2 270). RV was detected in 137 cases (6.04%), of which 68 cases (49.64%) showed co-detection with other viruses, with the most common being co-detection with enterovirus, accounting for 14.60% (20/137). The RV detection rates in the age groups of 0~4 years, 5~14 years, 15~59 years, and≥60 years were 6.42% (100/1 557), 4.69% (21/448), 3.80% (6/158), and 9.35% (10/107), respectively, with no statistically significant differences (χ2=5.310, P=0.150). The overall detection rates of RV before (2017-2019) and during (2020-2022) the COVID-19 pandemic showed no statistically significant difference (χ2=1.823, P=0.177). A total of 109 VP1 sequences were obtained, including 62 types. Among them, RV-A, RV-B, and RV-C had 42, 3, and 17 types respectively. Conclusion: RV is one of the predominant pathogens in ARIs cases in Luohe City, Henan Province, from 2017 to 2022. Multiple types of RV co-circulate without any apparent dominant type.

Electron-rich palladium regulated by cationic vacancies in CoFe layered double hydroxide boosts electrocatalytic hydrodechlorination

Palladium (Pd) is regarded as a promising electrocatalytic hydrodechlorination (EHDC) catalyst for the detoxification of halogenated phenols. Nevertheless, its intrinsic EHDC activity is seriously restricted by the hydrogen evolution reaction (HER), consuming the active hydrogen (H*) for EHDC. Here, we report a defect regulation strategy using cationic vacancies rich CoFeV-LDH with coupling ultrafine Pd nanoparticles that induces optimized electron distribution of Pd to promote EHDC. The experimental and theoretical results reveal that superior EHDC performance of Pd@CoFeV-LDH is attributed to the electron-rich Pd regulated by cationic vacancies in CoFeV-LDH support, driving facile adsorption of halogenated phenols, high water activation ability and H* selectivity for EHDC. Our findings provide a versatile defect-regulating strategy to overcome the challenge in efficiency and selectivity of EHDC process.

WOOD: Wasserstein-Based Out-of-Distribution Detection

The training and testing data for deep-neural-network-based classifiers are usually assumed to be sampled from the same distribution. When part of the testing samples are drawn from a distribution that is sufficiently far away from that of the training samples (a.k.a. out-of-distribution (OOD) samples), the trained neural network has a tendency to make high-confidence predictions for these OOD samples. Detection of the OOD samples is critical when training a neural network used for image classification, object detection, etc. It can enhance the classifier's robustness to irrelevant inputs, and improve the system's resilience and security under different forms of attacks. Detection of OOD samples has three main challenges: (i) the proposed OOD detection method should be compatible with various architectures of classifiers (e.g., DenseNet, ResNet) without significantly increasing the model complexity and requirements on computational resources; (ii) the OOD samples may come from multiple distributions, whose class labels are commonly unavailable; (iii) a score function needs to be defined to effectively separate OOD samples from in-distribution (InD) samples. To overcome these challenges, we propose a Wasserstein-based out-of-distribution detection (WOOD) method. The basic idea is to define a Wasserstein-based score that evaluates the dissimilarity between a test sample and the distribution of InD samples. An optimization problem is then formulated and solved based on the proposed score function. The statistical learning bound of the proposed method is investigated to guarantee that the loss value achieved by the empirical optimizer approximates the global optimum. The comparison study results demonstrate that the proposed WOOD consistently outperforms other existing OOD detection methods.

Self-Scalable Tanh (Stan): Multi-Scale Solutions for Physics-Informed Neural Networks

Differential equations are fundamental in modeling numerous physical systems, including thermal, manufacturing, and meteorological systems. Traditionally, numerical methods often approximate the solutions of complex systems modeled by differential equations. With the advent of modern deep learning, Physics-informed Neural Networks (PINNs) are evolving as a new paradigm for solving differential equations with a pseudo-closed form solution. Unlike numerical methods, the PINNs can solve the differential equations mesh-free, integrate the experimental data, and resolve challenging inverse problems. However, one of the limitations of PINNs is the poor training caused by using the activation functions designed typically for purely data-driven problems. This work proposes a scalable tanh-based activation function for PINNs to improve learning the solutions of differential equations. The proposed Self-scalable tanh (Stan) function is smooth, non-saturating, and has a trainable parameter. It can allow an easy flow of gradients and enable systematic scaling of the input-output mapping during training. Various forward problems to solve differential equations and inverse problems to find the parameters of differential equations demonstrate that the Stan activation function can achieve better training and more accurate predictions than the existing activation functions for PINN in the literature.

Reduction of Biosensor False Responses and Time Delay Using Dynamic Response and Theory-Guided Machine Learning

Here, we provide a new methodology for reducing false results and time delay of biosensors, which are barriers to industrial, healthcare, military, and consumer applications. We show that integrating machine learning with domain knowledge in biosensing can complement and improve the biosensor accuracy and speed relative to the performance achieved by traditional regression analysis of a standard curve based on the biosensor steady-state response. The methodology was validated by rapid and accurate quantification of microRNA across the nanomolar to femtomolar range using the dynamic response of cantilever biosensors. Theory-guided feature engineering improved the performance and efficiency of several classification models relative to the performance achieved using traditional feature engineering methods (TSFRESH). In addition to the entire dynamic response, the technique enabled rapid and accurate quantification of the target analyte concentration and false-positive and false-negative results using the initial transient response, thereby reducing the required data acquisition time (i.e., time delay). We show that model explainability can be achieved by combining theory-guided feature engineering and feature importance analysis. The performance of multiple classifiers using both TSFRESH- and theory-based features from the biosensor's initial transient response was similar to that achieved using the entire dynamic response with data augmentation. We also show that the methodology can guide design of experiments for high-performance biosensing applications, specifically, the selection of data acquisition parameters (e.g., time) based on potential application-dependent performance thresholds. This work provides an example of the opportunities for improving biosensor performance, such as reducing biosensor false results and time delay, using explainable machine learning models supervised by domain knowledge in biosensing.

Rapid inverse design of metamaterials based on prescribed mechanical behavior through machine learning

Designing and printing metamaterials with customizable architectures enables the realization of unprecedented mechanical behaviors that transcend those of their constituent materials. These behaviors are recorded in the form of response curves, with stress-strain curves describing their quasi-static footprint. However, existing inverse design approaches are yet matured to capture the full desired behaviors due to challenges stemmed from multiple design objectives, nonlinear behavior, and process-dependent manufacturing errors. Here, we report a rapid inverse design methodology, leveraging generative machine learning and desktop additive manufacturing, which enables the creation of nearly all possible uniaxial compressive stress‒strain curve cases while accounting for process-dependent errors from printing. Results show that mechanical behavior with full tailorability can be achieved with nearly 90% fidelity between target and experimentally measured results. Our approach represents a starting point to inverse design materials that meet prescribed yet complex behaviors and potentially bypasses iterative design-manufacturing cycles.

[Analysis of safety and factors influencing the surgical efficacy of benign biliary stenosis treated with autologous gastric flap repair with the vascular tip]

Objective: To investigate the complication rate and risk factors associated with using autologous gastric flap tissue with a vascular tip to treat benign biliary strictures. Methods: A retrospective analysis was conducted on clinical data of 92 patients with benign biliary stenosis who applied autologous gastric flap tissue to repair the stenosis at the PLA General Hospital from January 2006 to May 2022. Among them, there were 40 males and 52 females, aged from 25 to 79 (50.5±12.9) years. The perioperative clinical data of the patients were recorded(Body Mass Index、preoperative platelets et.), and a multivariate logistic regression model was used to analyze the factors influencing postoperative complications. Long-term follow-up was conducted to evaluate the long-term efficacy of autologous gastric flap tissue with vascular tissues for benign biliary stenosis surgery. Results: The incidence of recent postoperative complications in patients was 26.1%, and univariate analysis showed that preoperative bile-intestinal anastomosis, positive intraoperative bile bacterial culture, low preoperative hemoglobin, and low preoperative platelet count were significantly associated with the occurrence of postoperative complications after biliary stenosis repair with a vascularized gastric flap (P<0.05). Multifactorial analysis showed that low preoperative platelets (OR=0.990, 95%CI: 0.982-0.998, P=0.015), low preoperative hemoglobin (OR=4.953, 95%CI: 1.405-15.010, P=0.012) and positive intraoperative bile bacterial culture (OR=19.338, 95%CI: 3.618-103.360, P<0.001) were independent risk factors for the development of postoperative complications. The excellent long-term follow-up rate of patients was 92.0%. Conclusions: The procedure of repairing benign biliary stenosis with a vascularized gastric flap preserves the function of the sphincter of Oddi and reconstructs the normal physiological passage of the bile duct. This procedure is safe and feasible and provides a reliable option for the surgical treatment of bile duct injury and bile duct stenosis.

Electrostatic Interaction in Amino Protonated Chitosan-Metal Complex Anion Hydrogels: A Simple Approach to Porous Metal Carbides/N-Doped Carbon Aerogels for Energy Conversion

In the face of the increasingly serious rapid depletion of fossil fuels, exploring alternative energy conversion technologies may be a promising choice to alleviate this crisis. Transition metal carbides (TMCs)/carbon composites are considered as prospective electrocatalysts due to their high catalytic activities and structural stability. In this work, we report the simple synthesis of TMCs/N-doping carbon aerogels (TMCs/NCAs, including Fe₃C/NCA, Mo₃C₂/NCA, and Fe₃C-Mo₂C/NCA) for the oxygen reduction reaction (ORR) using protonated chitosan/metal complex anion-chelated aerogels. Among them, the Fe₃C/NCA composite possesses efficient ORR activity (similar to Pt/C), and the Fe₃C/NCA-assembled Zn-air battery exhibits high power densities of about 250 mW cm^-2. The density functional theory calculation reveals that the presence of graphite-N, pyridine-N, and carbon defects in the carbon framework effectively reduces the free energy of ORR occurring in Fe₃C. This work provides a simple and extensible strategy for the preparation of TMCs from chitosan, which is expected to be extended to other metal carbides.

Quantification of extreme thermal gradients during in situ transmission electron microscope heating experiments

Studies on materials affected by large thermal gradients and rapid thermal cycling are an area of increasing interest, driving the need for real time observations of microstructural evoultion under transient thermal conditions. However, current in situ transmission electron microscope (TEM) heating stages introduce uniform temperature distributions across the material during heating experiments. Here, a methodology is described to generate thermal gradients across a TEM specimen by modifying a commercially available MEMS-based heating stage. It was found that a specimen placed next to the metallic heater, over a window, cut by FIB milling, does not disrupt the overall thermal stability of the device. Infrared thermal imaging (IRTI) experiments were performed on unmodified and modified heating devices, to measure thermal gradients across the device. The mean temperature measured within the central viewing area of the unmodified device was 3-5% lower than the setpoint temperature. Using IRTI data, at setpoint temperatures ranging from 900 to 1,300°C, thermal gradients at the edge of the modified window were calculated to be in the range of 0.6 × 10⁶ to 7.0 × 10⁶ °C/m. Additionally, the Ag nanocube sublimation approach was used, to measure the local temperature across a FIB-cut Si lamella at high spatial resolution inside the TEM, and demonstrate "proof of concept" of the modified MEMS device. The thermal gradient across the Si lamella, measured using the latter approach was found to be 6.3 × 10⁶ °C/m, at a setpoint temperature of 1,000°C. Finally, the applicability of this approach and choice of experimental parameters are critically discussed.

Closed-Loop Controlled Photopolymerization of Hydrogels

Here, we present a closed-loop controlled photopolymerization process for fabrication of hydrogels with controlled storage moduli. Hydrogel crosslinking was associated with a significant change in the phase angle of a piezoelectric cantilever sensor and established the timescale of the photopolymerization process. The composition, structure, and mechanical properties of the fabricated hydrogels were characterized using Raman spectroscopy, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). We found that the storage moduli of photocured poly(ethylene glycol) dimethacrylate (PEGDMA) and poly(N-isopropylacrylamide) (PNIPAm) hydrogels could be controlled using bang-bang and fuzzy logic controllers. Bang-bang controlled photopolymerization resulted in constant overshoot of the storage modulus setpoint for PEGDMA hydrogels, which was mitigated by setpoint correction and fuzzy logic control. SEM and DMA studies showed that the network structure and storage modulus of PEGDMA hydrogels were dependent on the cure time and temporal profile of UV exposure during photopolymerization. This work provides an advance in pulsed and continuous photopolymerization processes for hydrogel engineering based on closed-loop control that enables reproducible fabrication of hydrogels with controlled mechanical properties.

Detecting and Classifying Self-injurious Behavior in Autism Spectrum Disorder Using Machine Learning Techniques

Traditional self-injurious behavior (SIB) management can place compliance demands on the caregiver and have low ecological validity and accuracy. To support an SIB monitoring system for autism spectrum disorder (ASD), we evaluated machine learning methods for detecting and distinguishing diverse SIB types. SIB episodes were captured with body-worn accelerometers from children with ASD and SIB. The highest detection accuracy was found with k-nearest neighbors and support vector machines (up to 99.1% for individuals and 94.6% for grouped participants), and classification efficiency was quite high (offline processing at ~ 0.1 ms/observation). Our results provide an initial step toward creating a continuous and objective smart SIB monitoring system, which could in turn facilitate the future care of a pervasive concern in ASD.

A Spectral Fiedler Field-based Contrast Platform for Imaging of Nanoparticles in Colon Tumor

The temporal and spatial patterns of nanoparticle that ferry both imaging and therapeutic agent in solid tumors is significantly influenced by target tissue movement, low spatial resolution, and inability to accurately define regions of interest (ROI) at certain tissue depths. These combine to limit and define nanoparticle untreated regions in tumors. Utilizing graph and matrix theories, the objective of this project was to develop a novel spectral Fiedler field (SFF) based-computational technology for nanoparticle mapping in tumors. The novelty of SFF lies in the utilization of the changes in the tumor topology from baseline for contrast variation assessment. Data suggest that SFF can enhance the spatiotemporal contrast compared to conventional method by 2–3 folds in tumors. Additionally, the SFF contrast is readily translatable for assessment of tumor drug distribution. Thus, our SFF computational platform has the potential for integration into devices that allow contrast and drug delivery applications.

Effects of different exercise durations on Keap1-Nrf2-ARE pathway activation in mouse skeletal muscle

The purpose of this study was to investigate the effects of acute exercise stress on the nuclear factor-erythroid2 p45-related factor 2 (Nrf2)/antioxidant response element (ARE) transactivation, Kelch-like ECH-associated protein 1 (Keap1) cytosolic protein and Nrf2 nucleoprotein expressions, Nrf2 target genes mRNA expressions, and glutathione redox (GSH/GSSG) ratio level; with a particular focus on the changes in Keap1-Nrf2-ARE pathway activation following different durations of exercise. Wild-type mice (C57BL/6J, two months old) were separated into one-hour and six-hour treadmill running groups, as well as a non-exercise control group (n = 10 in each group). Measurements of Nrf2/ARE transactivation, Nrf2 nucleoprotein expressions, Keap1 cytosolic protein expression, Nrf2 target genes' mRNA expressions (superoxide dismutase-1 [SOD1], superoxide dismutase-2 [SOD2], γ-glutamyl cysteine ligase-modulatory [GCLm], γ-glutamyl cysteine ligase-catalytic [GCLc], glutathione reductase [GR], glutathione peroxidase-1 [Gpx1], catalase [CAT], and hemoxygenase-1 [Ho-1]), and GSH/GSSG ratio were carried out immediately after exercise. The results showed significant increases in Keap1-Nrf2-ARE pathway activation and the mRNA expressions of six measured enzymes in skeletal muscle after six hours of exercise; while in the one-hour exercise group, there was no change in Keap1-Nrf2-ARE pathway activation and only two enzymes' mRNA expressions were increased. It is suggested that the changes in Keap1-Nrf2-ARE pathway activation and its target genes' mRNA expressions were dependent on the exercise duration, with longer duration associated with higher responses.

Effect of Synthetic Pyrethroid Pesticide Exposure During Pregnancy on the Growth and Development of Infants

Antenatal urine of 497 pregnant women was collected in the Department of Gynecology and Obstetrics of a county hospital in Jiaozuo, Henan. The content of the main metabolites of synthetic pyrethroid pesticides in urine were determined. After 1 year, physical development indices of 1-year old infants, such as height, weight, and head and chest circumference, were measured. The neural and mental development of the infants was assessed by the Development Screen Test (DST) scale. We observed that the level of synthetic pyrethroid pesticide exposure was negatively related to the neural and mental development of infants (β = −0.1527, P < 0.05). Therefore, direct or indirect exposure to synthetic pyrethroid pesticides should be avoided during pregnancy.

Treatment of volatile organic compounds in a biotrickling filter under thermophilic conditions

The objectives of this research were to investigate the potential to biologically treat volatile organic compounds emitted by the forest products industry at thermophilic conditions and to examine the microbial community developed at high temperatures. Three biotrickling filters were run in parallel at temperatures ranging from 40 degrees C (mesophilic control) to 70 degrees C. The first phase involved treatment of methanol, for a 3-month run, and the second phase involved a 260-day run on the treatment of alpha-pinene. Methanol removal rates over 100 g m(-3) h(-1) where achieved at temperatures up to 70 degrees C. Alpha-pinene removal was achieved at temperatures up to 60 degrees C with optimal treatment occurring at 55 degrees C at rates up to 60 g m(-3) h(-1). The time for acclimation increased with increasing temperature and was longer for pinene than for methanol. Filter performance was also able to quickly recover from a shutdown period of up to 2 weeks due to the robustness of the microbial communities as determined by DNA fingerprinting analysis. The high-temperature communities treating methanol or pinene were more similar to each other than the mesophilic communities (i.e., 40 degrees C). The mesophilic methanol community had a high degree of functional redundancy, while the mesophilic pinene community was more unique and very distinct from the others. These results show that biofiltration at high temperatures is achievable and opens up a range of possibilities for applying biofiltration to hot gas streams.

Oldest playable musical instruments found at Jiahu early Neolithic site in China

Excavations at the early Neolithic site of Jiahu in Henan Province, China have produced what may be the earliest complete, playable, tightly-dated multinote musical instruments. Jiahu was occupied from 7000 BC to 5700 BC, considerably antedating the well known Peiligang culture. Here we describe six exquisitely made complete flutes which were found in radiocarbon-dated excavation layers, along with fragments of perhaps 30 more. The flutes are made from the ulnae of the red-crowned crane (Grus japonensis Millen) and have 5, 6, 7 and 8 holes. The best preserved flute has been played and tonally analysed. In addition to early musical artefacts, the archaeological record at Jiahu contains important information on the very foundations of Chinese society. We describe the archaeological characteristics of the Jiahu site, details concerning its dating, its place in the prehistory of the Chinese Neolithic, the ethnicity of its population and the results of a tonal analysis of a nearly 9,000-year-old musical instrument found there.

[Analysis of 9 cases of pulmonary tuberculosis complicated with legionnaires disease]

OBJECTIVE

To study the characteristics of pulmonary tuberculosis complicated with legionnaires disease (LD) to avoid misdiagnosis and incorrect treatment.

METHOD

Nine cases of pulmonary tuberculosis complicated with LD were retrospectively analyzed.

RESULT

The clinical and chest X-ray manifestations varied, and no characteristics were found in these cases. Because cross antibodies existed between Legionella pneumophila and other causal bacteria, it was found difficult to differentiate LD, pulmonary tuberculosis and other causal bacteria infection. Efficacy of erythromycin combined with rifampicin, and decrease of serum titres of Legionella pneumophila four times after treatment were found helpful for definite diagnosis of LD.

CONCLUSION

Only paying much attention to LD, and detecting the serum antibody as early as possible can provide evidence for diagnosing of the disease.

[Treatment of congenital glaucoma with trabeculotomy]

OBJECTIVE

To investigate the method of localization of Schlemm's canal during trabeculotomy to evaluate the successful rate of trabeculotomy.

METHOD

The author treated 38 cases (46 eyes) of congenital glaucoma with trabeculotomy. Harms trabeculotomy knife was introduced into the Schlemm's canal through the cutting end of an external collecting channel. The follow-up period was over 6 months in 37 eyes.

RESULTS

The intraocular pressure, C/D ratio were significantly improved after surgery compared to the preoperative ones (P < 0.05). But no significant differences were found in the corneal diameter, the depth of the anterior chamber, the length of ocular axis before and after surgery (P > 0.05). The intraocular pressure of 27 eyes (73.0%) was less than or equal to 2.8 kPa (1 kPa = 7.5 mmHg), showing good control of glaucoma.

CONCLUSION

During trabeculotomy, the trabeculotomy knife introduced in to the Schlemm's canal through an external collecting channel is a better and accurate method of localization of Schlemm's canal. The method is relatively simple, reliable and has certain value in clinical application.

Study on the antimutagenic effect of pine needle extract

The micronucleus test and sister-chromatic exchange (SCE) test were used to research the antimutagenic effect of pine needle extract. The results showed that the mutagenic effect of cyclophosphamide (CP) was inhibited by the pine needle extract. The micronucleus frequencies (MNF) of mouse bone marrow and human lymphocytes from peripheral blood were decreased with the effect of the extract (the dose was 2000 mg/kg or 5 mg/ml); the frequency of SCE in human lymphocytes was also reduced significantly, which indicated that the MNF and the SCE frequencies were negatively correlated with the dose of pine needle extract (r = -0.9782, -0.9587, -0.9765, respectively). This suggested that the pine needle extract was an effective antimutagen and it is important to choose the proper doses of pine needle extract for antitumor effect.

An activated sludge-based biosensor for rapid IC50 estimation and on-line toxicity monitoring

The RODTOX (Rapid Oxygen Demand and TOXicity tester), an activated sludge-based respirographic biosensor, is a device for on-line monitoring of the short-term biochemical oxygen demand (stBOD) and potential toxicity of incoming wastewater on the basis of on-line interpretation of respirograms resulting from pulse additions of either calibration substrate or sample. The principle of toxicity detection is based on the comparison of calibration respirograms before and after receiving a potential toxicant. In this paper, the results of the RODTOX as an on-line toxicity monitor are presented. In addition, a simple and fast procedure to estimate the IC50 of a toxicant has been developed, and its validity and good repeatability demonstrated. The performance of this procedure is compared with that of the Microtox test.

Mitomycin C-induced meiotic crossing-over on the interstitial segments in the Chinese hamster heterozygous for a reciprocal translocation

Using Chinese hamsters heterozygous for T(2;10)3Idr and T(1;3)8Idr reciprocal translocations, the authors studied mitomycin C (MMC)-induced crossing-over on the interstitial segments. Marker chromosomes with unequal-length chromatids resulting from crossing-over were clearly detectable, and the frequencies of such marker chromosomes were constant among individual males which were heterozygous for the same reciprocal translocation. The frequency of MMC-induced crossing-over on the interstitial segments increased roughly with increase in dose. These findings, therefore, indicated that marker chromosomes with unequal-length chromatids in translocation heterozygotes may be a useful indicator for detection of the cytogenetic effects of environmental mutagens on germ cells.