Citric acid-based deep eutectic solvent (CA-DES) as a new soil detergent for the removal of cadmium from coking sites

In order to solve the problem of soil pollution caused by excess heavy metals, cadmium (Cd), a novel soil-washing agent organic chelating acid-based deep eutectic solvent (OCA-DES), was investigated for the removal of Cd from the contaminated soil of coking plant. Four kinds of OCA-DES were prepared by mixing choline chloride (Ch-Cl) with four organic chelating acids (citric acid, oxalic acid, tartaric acid, and malic acid), respectively, to compare their washing efficiency of Cd from soil. The effects of washing operation conditions on the Cd removal efficiency were investigated. Side effects of citric acid-based deep eutectic solvent (CA-DES) on soil were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). The results showed that CA-DES had the best Cd removal efficiency and could reach as high as 93.75%, under ideal conditions. CA-DES mainly washed extractable and reducible Cd. The CA-DES washing process has less side effects on soil and hardly eroded the soil or changed the mineral structure of the soil. The main roles of CA-DES washing Cd include (1) hydrogen bonds capturing Cd; (2) the carboxyl group(-COOH) forming soluble chelate with Cd; and (3) releasing H⁺ ions in exchange for Cd. This study demonstrates that CA-DES, a novel soil-washing agent, has excellent removal of cadmium from soil and is environment-friendly.

Gender differences in the relationships between housework and metabolic markers: a longitudinal cohort study in China

Background

Metabolic syndrome has become a major health threat throughout the world, but there are few studies that focus on the effects of housework on human metabolism. This study explores the association between housework and metabolic markers and examines whether there are gender differences in the relationship of housework intensity on these markers.

Methods

We obtained data for 2,624 participants from the China Health and Nutrition Survey and used binary logistic regression to analyze the association between housework and metabolic markers (triglycerides, high- and low-density lipoprotein cholesterol, hemoglobin, blood glucose, cholesterol, and blood pressure).

Results

We observed no association between housework and metabolic markers for men. However, we find that women who engaged in housework had a higher risk of triglycerides than those who did not (OR=1.16, 95% CI: 1.16, 4.25). Compared with low-intensity, we also find that women who performed moderate- and high-housework intensity had a higher risk of triglycerides (moderate-intensity: OR=1.78, 95% CI: 1.14, 2.78; high-intensity: OR=1.91, 95% CI: 1.22, 2.98), MetS (OR=1.54, 95% CI: 0.98, 2.43; OR=1.68, 95% CI: 1.07, 2.66), pre-hypertension (OR=1.68, 95% CI: 1.08, 2.62; OR=1.63, 95% CI: 1.04, 2.55), and obesity (OR=1.65, 95% CI: 1.01, 2.70; OR=1.66, 95% CI: 1.01, 2.72).

Conclusion

In women, we find that housework is positively associated with the metabolic markers, triglycerides, MetS, and pre-hypertension. However, we did not find evidence that this relationship exists in men, f or any biomarkers we considered. One possible explanation is that people who engage in high-intensity housework are more stressed and sleep less, which could be a mechanism by which housework becomes associated with metabolic disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12566-6.

Direct observation of the topological spin configurations mediated by the substitution of rare-earth element Y in MnNiGa alloy

The evolution of topological magnetic domains microscopically correlates the dynamic behavior of memory units in spintronic application. Nanometric bubbles with variation of spin configurations have been directly observed in a centrosymmetric hexagonal magnet (Mn_0.5Ni_0.5)₆₅(Ga_1-yY_y)₃₅ (y = 0.01) using Lorentz transmission electron microscopy. Magnetic bubbles instead of biskyrmions are generated due to the enhancement of quality factor Q caused by the substitution of rare-earth element Y. Furthermore, the bubble density and diversified spin configurations are systematically manipulated via combining the electric current with perpendicular magnetic fields. The magnetic bubble lattice at zero field is achieved after the optimized manipulation.

A pinhole camera for ultrahigh-intensity laser plasma experiments

A pinhole camera is an important instrument for the detection of radiation in laser plasmas. It can monitor the laser focus directly and assist in the analysis of the experimental data. However, conventional pinhole cameras are difficult to use when the target is irradiated by an ultrahigh-power laser because of the high background of hard X-ray emission generated in the laser/target region. Therefore, an improved pinhole camera has been developed that uses a grazing-incidence mirror that enables soft X-ray imaging while avoiding the effect of hard X-ray from hot dense plasmas.

Oxygen defect engineering by the current effect assisted with temperature cycling in a perovskite-type La0.7Sr0.3CoO3 film

Introducing and modulating the oxygen deficiency concentration have been received as an effective way to obtain high catalytic activity in perovskite oxides. However, it is difficult to control the oxygen vacancy in conventional oxygen defect engineering due to harsh reaction conditions at elevated temperatures and the reducing atmosphere, which make it impractical for many technological applications. Herein, we report a new approach to oxygen defect engineering based on the combination of the current effect and temperature cycling at low temperature. Our investigations revealed that the electrical conductivity of the (011)-La_0.7Sr_0.3CoO₃/PMN-PT film changes continuously from metallicity to insulativity under repeated transport measurements below room temperature, which indicates the transformation of the Co⁴⁺ state to Co³⁺ in the film. Further experiments and analysis revealed that oxygen vacancies can be well regulated by the combined current effect and temperature cycling in repeated measurements, which results in a decrease of Co⁴⁺/Co³⁺ and thus the remarkable variation of conductive properties of the film. Our work provides a simple and highly efficient method to engineer oxygen vacancies in perovskite-type oxides and brings new opportunities in designing high-efficiency oxidation catalysts.

Evaluation of Hsp47 expression in heat-stressed rat myocardial cells in vitro and in vivo

The aim of the present study was to identify the correlation between expression of heat shock protein 47 (Hsp47) and stress injury in heat-stressed myocardial cells and to compare variations in Hsp47 expression in rat myocardial cells exposed to different heat stress for varying periods in vitro and in vivo. Exposure to heat stress at 42°C resulted in similar induction patterns of the heart damage-related enzyme aspartate aminotransferase in the supernatants of H9c2 cells and in the serum of rats. Histological analysis revealed that both H9c2 cells and heart tissues displayed cellular degeneration in response to different periods of heat stress. Hsp47 was constitutively expressed in the cytoplasm of H9c2 cells at all time points during heat stress, which was consistent with observations in heart fibers in vivo. Immunoblotting analysis revealed no significant difference between the expression of Hsp47 in H9c2 cells and heart tissue. However, the expression of hsp47 mRNA in response to heat stress was significantly increased in H9c2 cells at 60 min (P < 0.01) and 100 min (P < 0.01), which was comparable to that at 100 min (P < 0.01) in the rat heart. Thus, Hsp47 was elevated significantly after hyperthermia at the mRNA level but not at the protein level both in vitro and in vivo. The results suggest that Hsp47 turnover may increase during heat stress or that Hsp47 consumption exceeds its production.

Association of Hsp60 expression with damage to rat myocardial cells exposed to heat stress in vivo and in vitro

To investigate the protective role of Hsp60 against stress damage and its role in the sudden death of stressed animals, changes in the levels of Hsp60 protein and hsp60 mRNA of myocardial cells in vivo and in vitro were studied. In addition, the relationship between Hsp60 expression and heat-induced damage was also studied. Rats were exposed to a temperature of 42° ± 1°C for 0, 20, 40, 60, 80, or 100 min. More than 50% of the rats died suddenly within 100 min. With increasing heat stress duration, hsp60 mRNA levels significantly increased in both in vivo and in vitro rat myocardial cells; however, a similar trend was not observed for Hsp60 protein levels. Although the changes observed in Hsp60 expression in myocardial cells in vitro were inconsistent with those of rat heart tissues in vivo, Hsp60 expression levels were consistent with the histopathological damage observed in myocardial cells both in vivo and in vitro. Differences in Hsp60 expression may reflect the degree of injury sustained by myocardial cells in vivo and in vitro. As a mitochondrial protein, Hsp60 represents a potential biomarker of heat stress, and may protect against heat stress induced myocardial cellular damage both in vivo and in vitro.

Gradual electroforming and memristive switching in Pt/CuO(x)/Si/Pt systems

We report a memristive switching effect in Pt/CuOx/Si/Pt devices prepared by the rf sputtering technique at room temperature. Differently from other Cu-based metal filament switching systems, a gradual electroforming process, marked by a gradual increase of the device resistance and a gradual decrease of the device capacitance, was observed in the current-voltage and capacitance characteristics. After the gradual electroforming, the devices show a uniform memristive switching behavior. By Auger electron spectroscopy analysis, a model based on the thickness change of the SiOx layer at the CuOx/Si interface and Cu ion migration is proposed for the gradual electroforming and uniform memristive switching, respectively. This work should be meaningful for the preparation of forming-free and homogeneous memristive devices.

Expression of beclin 1, an autophagy-related protein, in human cervical carcinoma and its clinical significance

PURPOSE

To investigate the impact of beclin 1 on prognosis of cervical cancer, we determined the expression of beclin 1 in cervical cancer, cervical intraepithelial neoplasia (CIN) and normal cervical tissues.

METHODS

A total of 122 cases of cervical cancer, 35 cases with CIN and 31 cases with uterine fibroids were collected at the Cancer Center of Sun Yat University to determine the expression of beclin 1.

RESULTS

Beclin 1 positive rate in normal cervical tissues, CIN tissues and cervical cancers was 83.9%, 74.3% and 53.3%, respectively, and it was significantly different between the three groups (p < 0.01). Beclin 1 expression was negatively correlated with cervical cancer differentiation, lymph node metastasis, recurrence and death (p < 0.05). The negative expression is the risk factor affecting overall survival (p < 0.05) and progression-free survival (PFS) (p < 0.05). Multivariate analysis showed that beclin 1 negative expression was an independent risk factor of PFS time.

CONCLUSIONS

Beclin 1 may play a role in the occurrence and development of cervical cancer. Beclin 1 positive expression in patients indicates a better prognosis.

Prediction model of pelvic lymph node metastasis in early stage cervical cancer and its clinical value

AIM

This study was designed to investigate the risk factors of pelvic lymph node metastasis in early stage cervical cancer in order to establish a prediction model for this metastasis and to explore the feasibility of conservative surgery.

METHODS

The records of 207 stage IB-IIA cervical cancer patients were retrospectivly analyzed. The risk factors of pelvic lymph node metastasis were analyzed using univariate and multivariate methods. The prediction model for pelvic lymph node metastasis was established by logistic regression.

RESULTS

Without preoperative adjuvant therapy, the metastatic rate of pelvic lymph node in stage IB-IIA cervical cancer was 25.1%. The serum SCCAg, the tumor diameter, the depth of cervical stroma invasion, and the cervical canal involvement were revealed as the risk factors of pelvic lymph node metastasis by univariate analysis (P<0.05). Multivariate analysis showed that the serum SCCAg and the depth of cervical stroma invasion were the independent risk factors of pelvic lymph node metastasis (P<0.05, OR = 6.917, 2.227). The patients were divided into three groups according to different independent risk factors: the low-risk group, the medium-risk group, and the high-risk group, which showed metastatic rates of pelvic lymph node of 5.7%, 16.9%, and 48.7%, respectively (P<0.001). A prediction model for pelvic lymph node metastasis was established as follows: Logti(P) = -2.534 + serum SCCAg×1.934 + depth of cervical stroma invasion×0.801. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of this prediction model were 53.8%, 83.9 %, 52.8%, 84.4%, and 76.3%, respectively.

CONCLUSION

The serum SCCAg and the depth of cervical stroma invasion were the independent risk factors of pelvic lymph node metastasis in early stage cervical cancer. The proposed prediction model may help to improve the conservative surgery for early stage cervical cancer.

Large anisotropy in colossal magnetoresistance of charge orbital ordered epitaxial Sm(0.5)Ca(0.5)MnO(3) films

We investigated the structure and magnetotransport properties of Sm(0.5)Ca(0.5)MnO(3) (SCMO) films epitaxially grown on (011)-oriented SrTiO(3) substrates, which exhibited clear charge/orbital ordering transition. A significant anisotropy of ∼1000 in the colossal magnetoresistance (CMR) effect was observed in the films with a thickness between 50 and 80 nm, which was distinctly different from the basically isotropic CMR effect in bulk SCMO. The large anisotropy in the CMR can be ascribed to the intrinsic asymmetric strain in the film, which plays an important role in tuning the spin-orbit coupling in manganite films. The origin of the peculiar CMR effect is discussed.

Phase coexistence and metastability in polycrystalline Pr(0.2)La(0.8)Fe(11.4)Al(1.6) compound

Electrical resistivity, dc magnetization, ac magnetic susceptibility, and magnetic relaxation studies of polycrystalline Pr(0.2)La(0.8)Fe(11.4)Al(1.6) compound have been carried out. On the basis of the measurements of isofield magnetization and ac magnetic susceptibility, we provide evidence for phase coexistence (the appearance of the ferromagnetic phase in the antiferromagnetic matrix) rather than a spin glass, resulting in a cusp observed at ∼70 K in the zero-field-cooled thermal magnetization curve under low fields. The ferromagnetic clusters or nuclei appear randomly in the antiferromagnetic matrix according to the electrical resistivity results. An excellent magnetic-resistive correspondence is observed under medium fields. Under these fields large relaxation effects are presented in the vicinity of the phase transition temperature. Nonuniform variation of the relaxation rate with temperature gives a clear picture of the nucleation and growth of phases. Distinct metastable behavior is shown during the phase transition, which brings about the step-like behavior in the various magnetization curves.

Molecular pathways that modify tumor radiation response

Aberrant expression of signal transduction molecules in pathways controlling cell survival, proliferation, death, or differentiation are a common feature of all tumors. The identification of the molecules that are involved allows the development of novel tumor-specific strategies. Not surprisingly, targeting these pathways often also results in radiosensitization. The efficacy of such directed therapies may, however, be limited by the heterogeneity and the multiple mutations that are associated with the cancerous state. A more robust alternative may be to target global mechanisms of cellular control. The ubiquitin/proteasome degradation pathway is one candidate for such therapeutic intervention. This pathway is the main posttranscriptional mechanism that controls levels of many short-lived proteins involved in regulation of cell cycle progression, DNA transcription, DNA repair, and apoptosis. Many of these proteins are involved in various malignancies and/or radiation responses. In recent years, proteasome inhibitors have gained interest as a promising new group of antitumor drugs. PS-341, a reversible inhibitor of proteasome chymotryptic activity, is currently being tested in phase I clinical trials. In this study, we show that proteasome inhibition by PS-341 can alter cellular radiosensitivity in vitro and in vivo, in addition to having direct antitumor effects.

An indicator cell assay for detection of human cytomegalovirus based on enhanced green fluorescent protein

An indicator cell line (ML-UL54-EGFP) for the detection of human cytomegalovirus (HCMV) by a simple and direct method was developed. The stable line was constructed by introducing into mink lung cells an expression cassette that contains the enhanced green fluorescent protein (EGFP) reporter gene under the control of an HCMV-inducible promoter. The promoter was from the upstream region of the HCMV UL54 (pol) gene, an early gene promoter that is activated in the early phase of HCMV infection. Following infection with HCMV for 48 h, the stable line expressed well detectable level of the EGFP as observed under a fluorescence microscope. The sensitivity of the indicator cell assay is at least comparable with that of a plaque assay as assessed with a panel of HCMV strains. There were no detectable fluorescent cells after inoculations with several viruses other than HCMV, indicating high specificity. Analysis with flow cytometry revealed that the induced fluorescence from the infected cells was proportional to the titer of HCMV inoculated, making it possible to quantify HCMV infectious particles. In summary, the EGFP-based indicator cell line is of potential use for rapid detection and quantification of HCMV in clinical specimens.

[Altered behaviour and expression of Fos in rats born in hypergravity and their re-adaptation to the normal gravity]

Changes in behaviour relevant to the vestibular system were studied in Long-Evans rats which were fertilized, born and housed in 2 acceleration of gravity for 4 months and thereafter exposed to 1 acceleration of gravity, and expression of Fos protein in the brain stem was examined. Data from the hypergravity rats were compared respectively with those from the rotation group and the labyrinthectomized group. Static and locomotion modes of the hypergravity rats were changed, tension of extensor was enhanced and the abilities in locomotion equalization and orientation in swimming and air-righting response were reduced. The adaptation process varied with different behaviours. The time for recovery of the ability of orientating in swimming was the longest, taking more than 1 month. The Fos protein expression provides a useful tool for mapping brain functional activities after sensory stimulation, showing a low basal level in normal and labyrinthectomized groups. The hypergravity rats, on the other hand, exhibited more Fos-positive cells in the superior colliculus, inferior colliculus, periaqueductal gray, raphe dorsal nucleus and solitary nucleus. In contrast, the inferior olivary nuclei, locus coeruleus and vestibular nuclei were not strongly labeled. These spatial patterns of Fos expression suggest that a decrease in gravity-inertial force may activate a neural pathway different from the vestibulo-olivar pathways activated by an increase in gravity-inertial force.

[Enhancement of GAP-43 mRNA expression in the rat medial vestibular nucleus by labyrinthectomy]

Vestibular compensation is the most extensively investigated model for neuroplasticity. Growth-associated protein (GAP-43) mRNA plays a significant role in nerve regeneration and synaptic remodeling. Using in situ hybridization with DIG (digoxigenin)-labeled GAP-43 cDNA probe, changes of GAP-43 mRNA expression in the medial vestibular nucleus in the labyrinthectomized rats at 5, 12, 20 and 30th day after operation were investigated. The results clearly demonstrated that labyrinthectomy increased GAP-43 mRNA expression to different extents and amplitudes in bilateral medial vestibular nuclei. This finding suggests that upregulation of GAP-43 mRNA expression is related to regenerative sprouting, synaptic remodeling and neuroplasticity in vestibular compensation.

[Vestibular compensation: a privileged model for the study on plasticity of central nervous system]

Vestibular compensation is now considered as a privileged model for the study of the underlying mechanisms of restitution and substitution of functions after nervous system lesions. This model is ubiquitously suited for the research of plasticity of central nervous system and recuperation of functions. This review focuses on the latest progress of the research on vestibular compensation in the aspects of electrophysiology, biochemistry and molecular neurobiology as well as the expression of growth-associated protein (GAP-43), and the pharmacological effects of extract of Ginkgo biloba(EGb 761) during the course of vestibular compensation are specially discussed.

[Effect of norepinephrine on the thermosensitive neurons in preoptic area of hypothalamus tissue slices in cold acclimatized rats]

In this work, single unit firing activities were recorded in the preoptic anterior hypothalamus (POAH) brain slices of cold acclimatized and room-temperature housed rats (CR and RR) and the effects of NE on the neuronal discharges were observed. The neurons of POAH in CR became much more sensitive to NE than that in RR (the threshold concentration of NE of CR became significantly lowered). In comparison with RR, the percentage of warm sensitive neurons that could be excited by NE was decreased and some of them even showed inhibitory responses. On the other hand, the percentage of cold sensitive neurons that could be inhibited by NE was decreased and some of them even showed excitatory responses. The percentage of thermo-insensitive neurons that could be either excited or inhibited by NE were increased.

Induction of c-fos and junB mRNA following in vivo brain irradiation

Although radiotherapy is a front line treatment for brain tumors, little is known about the in vivo molecular responses of brain to irradiation. In this study, expression of c-fos, c-jun and junB immediate-early genes were followed in mouse brain after irradiation. C-fos and junB, but not c-jun, mRNA was induced within 15 min in unanesthetized irradiated mice. Induction was transient and lasted < 4 h. The response was dose-dependent with increases in c-fos and junB mRNA levels after dose of > or = 2 and 7 Gy, respectively. Anesthesia of mice with pentobarbitol delayed the increases in mRNA expression and the response was attenuated. Pre-treatment of mice with dexamethasone, in a schedule which suppressed acute-phase gene expression after brain irradiation, did not significantly change c-fos and junB induction. Our results show that c-fos and junB responses occur in the brain in response to irradiation and that they can be modified by pentobarbital treatment but suggest that there is no direct correlation between the level of mRNA expression and later expression of cytokines or other acute-phase response genes.

Delayed molecular responses to brain irradiation

The chance of life-threatening complications occurring late after brain irradiation limits the efficacy of this form of cancer therapy. The molecular and cellular events that trigger radiation-induced brain damage are still unknown, but since they have the potential to serve as valuable targets for therapeutic intervention they are worth delineating. In this murine study, the effect of irradiation on the expression of molecules which are known to contribute to brain damage in other model systems was examined. Expression of genes encoding cytokines (TNF-alpha/beta, IL-1 alpha/beta, IL-2, IL-3, IL-4, IL-5, IL-6 and IFN-gamma), cytokine receptors (TNF-Rp55 and p75, IL-1R- p60 and p80, IFN-gamma R, and IL-6R), the cell adhesion molecule (ICAM-1), inducible nitric oxide synthetase (iNOS), anti-chymotrypsin (EB22/5.3), and the gliotic marker (GFAP) was evaluated over a 6-month period using a sensitive RNase protection assay (RPA). We had previously demonstrated that within 24 h of brain irradiation there is an acute transitory molecular response involving TNF-alpha, IL-1, ICAM-1, EB22/5.3 and GFAP. This study shows re-elevation of TNF-alpha, EB22/5.3 and GFAP mRNA levels at 2-3 months, but only TNF-alpha mRNA was overexpressed at 6 months. These time points are when neurological abnormalities are seen after higher doses. The data suggest that TNF-alpha may be involved in late brain responses to irradiation and could contribute to clinical symptoms.

[Changes and compensation in the locomotor pattern of unilateral vestibular neurectomized cats]

In the present study the locomotor activity of unilateral vestibular neurectomized cats while crossing over a rotating beam along its longitudinal axis at different speeds was investigated. The kinematics of the body movement was recorded by means of a motion analysis system, with an optical automatic TV-image processor (E. L. I. T. E system) allowing a computer reconstruction of the 3 dimensional motion. Analysis was focused on the locomotion pattern as defined by several parameters including step length, step frequency and velocity, and an estimate of the height of the body gravity center. The results obtained with non-rotating beam showed that unilateral vestibular neurectomy induced significant changes in locomotor activity of the lesioned cats. Animals crossed over the beam with very slow locomotion speed and they typically exhibited a strong reduction in step length associated with a decrease in frequency. In addition, the gravity center of the walking cats was lower than the normal. The analysis performed with the rotating beam revealed different strategies of compensation, with cats moving either faster or slower as compared to their preoperative performance. Such strategies in locomotion speed regulation avoided falling from the rotating beam. Recovery to a nearly normal locomotor pattern was observed thereafter with a time delay comparable to that found in other behavioral studies dealing with the vestibular compensation process in the cat.

[Adaptive changes of preoptic thermosensitive neurons in hypothalamic tissue slices of rats after long-term exposure to cold environmental temperature]

In the present work, thermosensitivity and spontaneous firing rate of 86 preoptic neurons in hypothalamic tissue slices from 20 cold acclimated rats (CR, at 5 +/- 1 degrees C for more than 3 weeks) and 127 neurons from 35 warm acclimated rats (WR, at 20 +/- 3 degrees C for the same period) were recorded and compared. The results showed that: (1) The percentage of cold-sensitive neurons in CR were higher than that in WR, the critical temperature and the lowest temperature of the spontaneous firing activity of cold-sensitive neurons in CR were also lower than that in WR. (2) Thermosensitivity and critical temperature of the warm-sensitive neurons in CR were remarkably decreased, and spontaneous firing rate under 37 degrees C was increased. (3) Spontaneous firing rate (37 degrees C) of temperature insensitive neurons in CR were conspicuously increased and the lowest temperature extended downward. These profound changes in response to long-term cold exposure suggested that plasticity of preoptic neurons was involved in the thermoregulation in cold adaptation.

Induction of acute phase gene expression by brain irradiation

PURPOSE

To investigate the in vivo acute phase molecular response of the brain to ionizing radiation.

METHODS AND MATERIALS

C3Hf/Sed/Kam mice were given midbrain or whole-body irradiation. Cerebral expression of interleukins (IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6), interferon (IFN-gamma), tumor necrosis factors (TNF-alpha and TNF-beta), intercellular adhesion molecule-1 (ICAM-1), inducible nitric oxide synthetase (iNOS), von Willebrand factor (vWF), alpha 1-antichymotrypsin (EB22/5.3), and glial fibrillary acidic protein (GFAP) was measured at various times after various radiation doses by ribonuclease (RNase) protection assay. The effects of dexamethasone or pentoxifylline treatment of mice on radiation-induced gene expression were also examined.

RESULTS

Levels of TNF-alpha, IL-1 beta, ICAM-1, EB22/5.3 and to a lesser extent IL-1 alpha and GFAP, messenger RNA were increased in the brain after irradiation, whether the dose was delivered to the whole body or only to the midbrain. Responses were radiation dose dependent, but were not found below 7 Gy; the exception being ICAM-1, which was increased by doses as low as 2 Gy. Most responses were rapid, peaking within 4-8 h, but antichymotrypsin and GFAP responses were delayed and still elevated at 24 h, by which time the others had subsided. Pretreatment of mice with dexamethasone or pentoxifylline suppressed radiation-induced gene expression, either partially or completely. Dexamethasone was more inhibitory than pentoxifylline at the doses chosen.

CONCLUSIONS

The initial response of the brain to irradiation involves expression of inflammatory gene products, which are probably responsible for clinically observed early symptoms of brain radiotherapy. This mechanism explains the beneficial effects of the clinical use of steroids in such circumstances.

Lack of differential radiosensitization of hypoxic cells in a mouse tumor at low radiation doses per fraction by cisplatin

Korbelik and Skov (Radiat. Res. 119, 145-156, 1989) have reported that cis-diamminedichloroplatinum (II) (cisplatin) shows substantial preferential radiosensitization of hypoxic cells in vitro at low radiation doses (1-4 Gy), and that the interaction seen with low doses of radiation is greatly diminished at high radiation doses. If such an interaction occurred with fractionated irradiation in vivo, it would be extremely important to radiation therapy, since the sensitizer enhancement ratios achievable in the low-dose region are higher than those achievable with current hypoxic cell radiosensitizers. We have tested this possibility in an experimental mouse tumor using fractionated irradiation under conditions in which the response of the tumor was determined by either its aerobic or its hypoxic cells. RIF-1 tumors were irradiated with 10 fractions of 1-4 Gy every 12 h with cisplatin given either as 12 mg/kg once before the first radiation dose or as 1.2 mg/kg at various times prior to each radiation dose. The tumors were irradiated with or without a clamp applied 2-3 min before each radiation dose. The effectiveness of the treatments was assayed by regrowth delay. Cisplatin caused a similar regrowth delay when used alone in both clamped and nonclamped tumors and produced a similar additive or supra-additive interaction when used with the 10 fractionated radiation schedule whether the tumors were hypoxic or aerobic. Our data suggest that cisplatin does not show any preferential radiosensitization of hypoxic cells with low-dose multifraction irradiation in this tumor, although a clear schedule-dependent interaction between the drug and radiation was seen for both aerobic and hypoxic tumors.

Enhancement of the antitumor effect of flavone acetic acid by the bioreductive cytotoxic drug SR 4233 in a murine carcinoma

Flavone acetic acid (FAA, NSC 347512) is a new anticancer drug currently undergoing clinical investigation. Although the precise mechanism for its broad spectrum of activity against transplanted murine solid tumors is unknown, it has been reported that FAA reduces tumor blood flow and produces hemorrhagic necrosis. We have confirmed this finding with the murine transplanted carcinoma SCCVII: 200 mg/kg FAA reduced tumor blood flow to 20-30% of normal for 1-2 days as determined by rubidium 86 extraction. In an attempt to exploit the tumor hypoxia produced by FAA, we have combined it with the novel bioreductive drug SR 4233, a benzotriazine dioxide with high selective toxicity for hypoxic cells. Marked enhancement of the antitumor effect of FAA (200 mg/kg) was observed when it was combined with SR 4233 (0.1 and 0.2 mmol/kg). This was seen using tumor cell survival, regrowth delay, and histological endpoints, with the best results obtained when the two agents were injected simultaneously. These data suggest that targeting bioreductive cytotoxic agents to tumors by producing tumor hypoxia may be a valid way of increasing the tumor cell killing of these agents.

Establishment, characteristics, and utilization of a new in vivo-in vitro system

Radiotherapy and chemotherapy are two important methods for malignant tumor treatment. To research radiobiological response in therapy, we have established a better experimental method in contrast to the traditional ones such as TCD50, regrowth delay, cell survival curve, etc, all with their limitations. A new mouse tumor in vivo-in vitro system LA795 Vv-Vt has been developed for studies on radiobiology. Such a system could be used to study the in vivo response of a solid tumor by the in vitro cloning assay. For the purpose of increasing the PE in vitro, LA795 Vv-Vt tumor line was purified through culturing the cells as a clonogenic spheroid. The spheroids were then injected into the flank of mouse subcutaneously for tumor growth. The in vivo-in vitro system LA795 Vv-Vt is an excellent model dissecting and analyzing the various factors which affect tumor development and determine the response of tumor to specific agent and regimens.

[In vivo experiments, in vitro assays in experimental oncology: establishment of LA 795 Vv-Vt]

In vivo experiment, in vitro assays (in vivo-in vitro system) is a kind of experimental technique which is different from both in vitro cell line and tumor line. The new model can be grown and studied either as an animal tumor or a cell culture. The specimen could be assayed for cell survival in vitro. This model can be used to study the response of malignant cells to the treatment in a precision and depth that is impossible in tumors grown in vivo. LA 795 Vv-Vt is the first in vivo-in vitro system developed in China. It was established with lung adenocarcinoma of T-739 mouse. The tumor cells could grow freely both in vivo and in vitro with a plating efficiency of 20%. Characteristics of LA 795 Vv-Vt tumor and cell in culture were described and compared. In order to estimate the radiation response of different doses, cell survival curves of tumors irradiated under oxic and hypoxic conditions were drawn and compared. The oxygen enhance ratio was 2.98. The experiments indicate that in vivo-in vitro system has a good dependent relation in dose and effect and is worth extensive application.