[Feasibility analysis of CT angiography derived computational fluid dynamics in evaluating intracranial artery stenosis].

A retrospective study was performed on 8 patients, including 7 males and 1 female, aged 47 to 77 (59±3) years, with intracranial artery stenosis in General Hospital of Eastern Theater Command from November 2018 to May 2019, who underwent CT angiography (CTA), digital subtraction angiography (DSA) and invasive fractional flow reserve (FFR) assessment. Three-dimensional (3D) prototyping models of intracranial artery based on image data of CTA was constructed and the hemodynamic parameters were obtained using computational fluid dynamics methods. The results showed that CT-FFR value was 0.59±0.18, and invasive FFR value was 0.60±0.22, from which we propased that noninvasive hemodynamic analyses can be used to evaluate the physiological significance of intracranial arterial stenosis.

Clinical and radiological characteristics of COVID-19: a multicentre, retrospective, observational study.

BACKGROUND: Multicentre cohort investigations of patients with coronavirus disease 2019 (COVID-19) have been limited. We investigated the clinical and chest computed tomography characteristics of patients with COVID-19 at the peak of the epidemic from multiple centres in China. METHODS: We retrospectively analysed the epidemiologic, clinical, laboratory, and radiological characteristics of 189 patients with confirmed COVID-19 who were admitted to seven hospitals in four Chinese provinces from 18 January 2020 to 3 February 2020. RESULTS: The mean patient age was 44 years and 52.9% were men; 186/189 had ≥1 co-existing medical condition. Fever, cough, fatigue, myalgia, diarrhoea, and headache were common symptoms at onset; hypertension was the most common co-morbidity. Common clinical signs included dyspnoea, hypoxia, leukopenia, lymphocytopenia, and neutropenia; most lesions exhibited subpleural distribution. The most common radiological manifestation was mixed ground-glass opacity with consolidation (mGGO-C); most patients had grid-like shadows and some showed paving stones. Patients with hypertension, dyspnoea, or hypoxia exhibited more severe lobe involvement and diffusely distributed lesions. Patients in severely affected areas exhibited higher body temperature; more fatigue and dyspnoea; and more manifestations of multiple lesions, lobe involvement, and mGGO-C. During the Wuhan lockdown period, cough, nausea, and dyspnoea were alleviated in patients with newly confirmed COVID-19; lobe involvement was also improved. CONCLUSIONS: Among patients with COVID-19 hospitalised at the peak of the epidemic in China, fever, cough, and dyspnoea were the main symptoms at initial diagnosis, accompanied by lymphocytopenia and hypoxaemia. Patients with severe disease showed more severe lobe involvement and diffuse pulmonary lesion distribution.

[Association of coronary perivascular fat attenuation index, the parameters of plaque and fractional flow reserve].

Objective: To explore the association of coronary perivascular fat attenuation index (FAI), the parameters of plaque and fractional flow reserve (FFR). Methods: A total of 113 patients (with 141 plaques) (78 males and 35 females, age from 40 to 83 years) with stable coronary artery disease were retrospectively collected from Jingling Hospital and Shanghai Sixth People's Hospital. All the patients underwent coronary CT angiography and invasive FFR examinations. The quantitative and qualitative parameters of plaque and vessel (such as the length and volume of plaque, the characteristics of plaque and high-risk plaque) and the FAI around the plaque were measured. The patients were divided into positive FAI group (n=46) and negative FAI group (n=66) according to the standard of whether the threshold of FAI≥ -70 HU. The quantitative indexes, including age, the length and volume of plaque, minimal lumen area (MLA) and FAI, as well as the qualitative indexed, including the characteristics of plaque, the number and characteristic of high-risk plaque and the number of patients and plaque with positive FFR were compared between the two groups. Further, logistic regression analysis was performed to analyze the correlation among myocardial ischemia, age, the length of plaque, minimal lumen area (MLA), FAI and so on. ROC curve was used for evaluating the performance of each parameter. Results: Compared to the negative FAI group, positive FAI group had lower MLA (2.00±1.33 mm2 vs 4.13±2.41 mm2, P<0.001). The proportion of patients and vessels with FFR<0.75 in positive FAI group were significantly higher than that in negative FAI group (21.3% vs 4.5%, P=0.006; 23.2% vs 8.2%, P=0.016). The FAI between high-risk plaque and non-high-risk plaque had no significant difference (21.2% vs 16.1%, P=0.451). FAI predicted myocardial ischemia (AUC=0.666, P=0.021) and significantly improved the prediction efficiency of complex model(0.915 vs 0.951,P=0.033). Conclusion: Lower MLA and higher incidence of myocardial ischemia were associated with patients with higher FAI. In addition, FAI has a certain prediction efficiency and can provide incremental value for the determination of myocardial ischemia.

[Application of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients].

Objective: To investigate the diagnostic efficacy and potential application value of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients. Methods: A total of 403 patients, including 254 males and 149 females aged from 16 to 100 (50±19) years, who received emergency treatment for trauma and chest CT examination in the Eastern Theater General Hospital from September 2019 to November 2019 were retrospectively analyzed. Dr. Wise Lung Analyzer's chest CT auxiliary diagnosis system was applied to detect 5 types of injuries, including pneumothorax, pleural effusion/hemothorax, pulmonary contusion (shown as consolidation and ground glass opacity), rib fractures, and other fractures (including thoracic vertebrae, sternum, scapula and clavicle, etc.) and 6 other abnormalities (bullae, emphysema, pulmonary nodules, stripe, reticulation, pleural thickening). The diagnostic reference standards were labeled by two radiologists independently. The sensitivity and specificity of the auxiliary diagnosis system were evaluated. The imaging diagnostic reports were compared with the results of the auxiliary diagnosis system, and the diagnostic consistency between the two was calculated by using the Kappa test. Results: According to the reference standards, among the 403 patients, 29 were pneumothorax, 75 were pleural effusion/hemothorax, 131 were pulmonary contusion, 124 were rib fractures, and 63 were other fractures. The sensitivity and specificity of the auxiliary diagnosis system for detection of pneumothorax, pleural effusion/hemothorax, rib fractures, and other fractures were 96.6%, 97.6%, 80.0%, 99.7%, 99.2%, 83.9%, 84.1%, and 99.7%, respectively. The sensitivity of detecting lung contusion was 97.7%. There was a high consistency between the auxiliary diagnosis system and imaging diagnosis in the diagnosis of injuries, in which the kappa values of pneumothorax, pleural effusion, rib fracture and other fractures were 0.783, 0.821, 0.706 and 0.813, respectively (all P<0.001). Two cases of pneumothorax, three cases of pleural effusion/hemothorax, nine cases of rib fractures, and six cases of other fractures missed by imaging diagnosis were all detected by the auxiliary diagnosis system. The detection sensitivity of the auxiliary diagnosis system was higher for emphysema, pulmonary nodules and stripe (all>85%), but lower for bullae, reticulation and pleural thickening. Conclusions: The deep learning-based chest CT auxiliary diagnosis system could effectively assist chest CT to detect injuries in emergency trauma patients, which was expected to optimize the clinical workflow.

Suppression of p38/HBP1 pathway alleviates hyperosmotic stress-induced senescent progression of chondrocyte senescence.

This study aims to explore the effect of p38 mitogen-activated protein kinase and its downstream target HMG-box transcription factor 1 (HBP1) in the chondrocyte (CH) senescence caused by hyperosmotic stress. Human cartilage tissue with or without osteoarthritis (OA) were collected to detect the differential expression of p38 and HBP1 by Western blot. CHs were isolated from cartilage without OA and used the hyperosmotic medium to accelerate CH senescence in vitro. A p38 inhibitor and siRNA were used to mediate the expression of p38 and HBP1. The viability of CHs was determined by cell counting kit 8 (CCK8) assay. CH-related mRNA expression was analyzed by quantitative real-time polymerase chain reaction (RT-PCR). Immunofluorescence was also used to detect collagen II and beta-galactosidase expression. Senescent cells were increased in both OA cartilage and hyperosmotic stress treatment with a marked upregulation of p38 and HBP1. Suppression of p38 activation reversed the hyperosmotic stress-induced CH senescence and led to an inhibition of HBP1, p16, Runx-2, MMP-13, collagen X expression, and an upregulation of collagen II and SOX-9 expression. Moreover, the silencing of HBP1 also played a protective effect on CH senescence. The suppression of the p38/HBP1 pathway alleviates the hyperosmotic stress-induced senescent progression of CHs.

[Radiation dose and image quality of noncontrast chest CT in domestic and imported main stream manufacturers].

Objective: To compare the radiation dose and image quality of noncontrast chest CT and detection of ground-glass opacity pulmonary nodules (GGN) in domestic 128-slice spiral CT with the other CT scanners from three main stream manufacturers. Methods: From May 8, 2018 to October 31, 2018, noncontrast chest CT images from Neusoft 128-slice CT (75 males, 25 females, (42±16) years), dual-source 64-slice CT (53 males, 47 females, (50±16) years) and dual-source 128-slice CT scanners(69 males, 31 females, (62±17) years), Toshiba 128-slice CT (51 males, 49 females, (58±13) years) and GE 128-slice CT scanner (55 males, 45 females, (60±10) years) were collected in Eastern Theater Command and Tianjin People's Hospital. Radiation dose and image quality were evaluated.GGN detected both in Neusoft CT and dual-source CT scanners were used to analyze the displaying ability of lesions. Results: The noise in lung window of Neusoft CT ((37.8±4.9) HU) was higher than that of other mainstream CT scanners, and the noise in mediastinal window ((8.4±1.9) HU) was lower than that of GE 128-slice CT ((9.8±3.2) HU), but higher than that of dual-source CT and Toshiba 128-slice CT ((6.9±3.5)HU) (P<0.05). The absolute value of lung SNR in Neusoft CT was lower than that of other mainstream CT scanners, and the SNR in aorta (4.6±1.3) was lower than those of dual-source CT and Toshiba 128-slice CT(6.8±2.2) (P<0.05), but was not statistically significant compared with GE 128-slice CT (5.0±1.7). The mean CT value of upper lung ((-863±31) HU) at Neusoft CT was higher than 128-row dual-source CT ((-869±35) HU), and the mean CT value of aorta ((37±7) HU) was lower than that of Toshiba 128-slice CT((42±7) HU) and GE 128-slice CT ((45±9) HU) (P<0.05), while the mean CT values of the remaining lung and aorta were not statistically significant (P>0.05). The two readers had good to excellent consistency for image quality in five scanners (the highest kappa value=0.984). The delineation ability of Neusoft CT for GGN boundary was lower than that of dual-source CT (P<0.05), but had similar abilities to display the solid components, lobulation, burring, vacuoles, vascular bundle sign and pleural depression sign of GGN (all P>0.05). Radiation dose of Neusoft CT was lower than Toshiba 128-slice CT, but higher than dual-source 64-sliceCT and GE 128-slice CT scanners (P<0.05). Conclusions: With lower radiation dose than Toshiba 128-slice CT, Neusoft CT chest examination can meet the requirements of clinical diagnosis, but higher radiation dose and the lower image quality than dual-source CT and GE 128-slice CT shown in this study indicate further improvement is needed in terms of software and hardware.

Effect of tea catechins on regulation of cell proliferation and antioxidant enzyme expression in H2 O2 -induced primary hepatocytes of goat in vitro.

Tea catechins (TC) are polyphenols that have potent antioxidant activity. The objectives of this study were to determine the effects of TC on antioxidant status of hepatocytes challenged with H2 O2 . Primary hepatocytes of goat were exposed to 1 mm H2 O2 without or with 5, 50 and 500 µg/ml TC. The cells were harvested at 48 h post-treatment to determine effects of TC on proliferation, apoptotic features and membrane integrity of cells, and expression of genes and activities of antioxidant enzymes. H2 O2 exposure caused damage to cells (p < 0.001). A lower concentration of TC (5 µg/ml) displayed a protective effect by inhibiting exorbitant cell proliferation and DNA degradation. Both H2 O2 exposure and TC pre-incubation affected expression of antioxidant enzymes at mRNA and protein levels (p < 0.001). The activities of catalase (CAT) (p = 0.027), CuZn-superoxide dismutase (CuZn-SOD) (p < 0.001) and glutathione peroxidase (GPx) (p < 0.001) increased with TC pre-incubation followed by H2 O2 challenge. Changes of CuZn-SOD activity induced by H2 O2 and TC basically paralleled the changes in the corresponding mRNA and protein levels, but the correlation in CAT and GPx expression displayed slightly different patterns at different concentrations of TC. These findings infer that oxidative stress can induce deleterious cellular responses and this unfavourable condition may be alleviated by treatment with TC.

Machine Learning-Based Prediction of Small Intracranial Aneurysm Rupture Status Using CTA-Derived Hemodynamics: A Multicenter Study.

BACKGROUND AND PURPOSE: Small intracranial aneurysms are being increasingly detected while the rupture risk is not well-understood. We aimed to develop rupture-risk models of small aneurysms by combining clinical, morphologic, and hemodynamic information based on machine learning techniques and to test the models in external validation datasets. MATERIALS AND METHODS: From January 2010 to December 2016, five hundred four consecutive patients with only small aneurysms (<5 mm) detected by CTA and invasive cerebral angiography (or surgery) were retrospectively enrolled and randomly split into training (81%) and internal validation (19%) sets to derive and validate the proposed machine learning models (support vector machine, random forest, logistic regression, and multilayer perceptron). Hemodynamic parameters were obtained using computational fluid dynamics simulation. External validation was performed in other hospitals to test the models. RESULTS: The support vector machine performed the best with areas under the curve of 0.88 (95% CI, 0.85-0.92) and 0.91 (95% CI, 0.74-0.98) in the training and internal validation datasets, respectively. Feature ranks suggested hemodynamic parameters, including stable flow pattern, concentrated inflow streams, and a small (<50%) flow-impingement zone, and the oscillatory shear index coefficient of variation, were the best predictors of aneurysm rupture. The support vector machine showed an area under the curve of 0.82 (95% CI, 0.69-0.94) in the external validation dataset, and no significant difference was found for the areas under the curve between internal and external validation datasets (P = .21). CONCLUSIONS: This study revealed that machine learning had a good performance in predicting the rupture status of small aneurysms in both internal and external datasets. Aneurysm hemodynamic parameters were regarded as the most important predictors.

The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats.

The effect of dietary methionine (Met) levels on endogenous N and amino acids (AA) flows at different part of the digestive tract of growing goats was determined using a (15)N isotope dilution technique. Three goats (25 ± 2.5 kg) were fitted with the ruminal, duodenal and ileal cannulae and allocated to three dietary treatments in a 3 × 3 Latin square design. The dietary treatments consisted of a total mixed ration containing three levels of Met (0.15%, 0.25% and 0.35%) respectively. It was found that at 0.15% Met level, the lowest flow in endogenous N and total AA at the duodenum and ileum occurred. The endogenous N secretion contributed to 26% and 23% of the duodenal and ileal total N flows, respectively, and the proportions were not affected by the dietary Met levels. The duodenal and ileal flows of endogenous total AA were 11.1, 11.8, 11.3 g/d and 2.9, 3.9, 4.1 g/d respectively. The average real digestibility of N was 65%, 87% and 95% in the forestomach, intestine and whole digestive tract respectively.

Effects of variety, sowing season and maturity stage on ruminal phosphorus release from whole maize stover and its morphological fractions.

An in situ degradation technique was used to investigate the effects of variety, season and maturity stage on ruminal Phosphorus (P) release from whole maize stover and morphological fractions from five varieties of maize (conventional maize, CM; sweet maize, SM; waxy maize, WM; high oil maize, HOM; and fodder maize, FM). Maize plants were harvested in 2005, 17 and 31 days after tasselling and manually separated into leaf blade, leaf sheath, stem and husk. Results showed that the values of rapidly released P fractions (a), slowly released P fractions (b), rate constant of P release for fraction b (c) and effective disappearance (ED) of P were significantly influenced by variety, sowing season and maturity stage (p < 0.05). The ED of P in whole maize stover among the varieties decreased in the following order: FM (89.8%) > HOM (87.9%) > CM (87.0%) > SM (86.9%) > WM (83.9%). Advanced maturity stage increased (p < 0.001) the a and ED values of P in the leaf blade and leaf sheath, but decreased (p < 0.001) these parameters in the husk. The a fraction and ED of P were higher (p < 0.001) for maize sown in spring than those sown in summer. Significant (p < 0.05) interactions among variety, sowing season and maturity stage were noted in the a and ED values of P. Effective disappearance of morphological fraction varied significantly (p < 0.001) and followed the order: stem (90.3%) > leaf sheath (88.2%) > leaf blade (85.2%) > husk (84.9%). In conclusion, most of P in maize stover could be released in the rumen. The potential pollution resulting from P excretion in faeces may be alleviated, when maize stover is largely used as the main forage source of ruminants.

Postnatal differential expression of chemoreceptors of free fatty acids along the gastrointestinal tract of supplemental feeding v. grazing kid goats.

The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as 'gut nutrient chemosensing'. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.

The anti-proliferative effects of recombinant human lysozyme on human gastric cancer cells.

We investigated the anti-proliferative effects of recombinant human lysozyme (rHlys) on gastric cancer cell lines and normal human lung fibroblasts. Using conventional molecular cloning techniques we purified rHlys, which we incubated with cultured cells and measured the effects on cell proliferation and viability. At concentrations of 100 and 1000 microg/l, rHlys significantly inhibited the growth of human gastric cancer cell lines. In contrast, 10 and 50 microg/l of rHlys stimulated gastric cancer cell growth. None of the concentrations of rHlys affected cell viability. Only the highest concentration of rHlys (1000 microg/l) inhibited human lung fibroblast growth. Our results suggest that 100 microg/l is the optimum growth inhibiting concentration, which inhibited cancer cell growth but not normal cell growth. Our in vitro findings suggest that genetically engineered rHlys might inhibit human gastric cancer cell proliferation in vivo, so it might warrant further investigation as a potential novel anti-cancer agent.

Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms. MATERIALS AND METHODS: Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared. RESULTS: Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B. CONCLUSIONS: In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.

Postnatal bacterial succession and functional establishment of hindgut in supplemental feeding and grazing goats.

The objectives of this study were 1) to investigate the age-related changes in functional achievement (establishment of fermentation capacity and enzyme activities) and bacterial succession (selected functional bacterial species) in the cecum and colon and 2) to assess the effect of feeding system (supplemental vs. grazing, Sup vs. G) on hindgut development in small ruminants. A total of 44 Liuyang black goat kids were randomly slaughtered at 0, 7, and 14 d of age (nonrumination period), 28 and 42 d of age (transition period), and 56 and 70 d of age (rumination period). Intestinal contents were sampled to determine VFA, activities of amylase, carboxymethylcellulase (CMCase), and xylanase, as well as abundances of total bacteria and selected functional bacterial species (genus Prevotella, cellulolytic and amylolytic bacteria) with quantitative PCR targeting the 16S rRNA subunit genes. Total VFA concentration (P < 0.01) and enzyme activities (P < 0.05) in hindgut contents were greater and total bacterial 16S rRNA gene copy numbers (P = 0.003) in the cecum were lower for Sup vs. G. Furthermore, irrespective of feeding system, hindgut total VFA concentrations and total bacterial 16S rRNA gene copy numbers increased with age (P < 0.01), with the greatest increase rate observed from 14 to 28 d. Amylase fluctuated with age, whereas CMCase and xylanase activities in Sup kids increased (P < 0.05) as age increased. The proportions of 16S rRNA copy numbers associated with the genus Prevotella and P. ruminicola increased (P < 0.05) with age, but those of cellulolytic bacteria and Ruminobacter amylophilus were detected only after 28 d of birth. The bacterial succession, fermentation capacity, and starch-degrading capacity in the hindgut of both groups were achieved at 1 mo, whereas fiber-degrading capacity in Sup kids was established at 2 mo of age; and supplemental feeding surpassed the grazing system in shaping hindgut development.

Effect of protein or energy restriction during late gestation on hormonal and metabolic status in pregnant goats and postnatal male offspring.

The objective of this study was to investigate the effects of maternal protein or energy restriction on hormonal and metabolic status of pregnant goats during late gestation and their postnatal male kids. Forty-five pregnant goats were fed a control (CON), 40% protein-restricted (PR) or 40% energy-restricted (ER) diet from 90 days of gestation until parturition. Plasma of mothers (90, 125 and 145 days of gestation) and kids (6 weeks of age) were sampled to determine metabolites and hormones. Glucose concentration for pregnant goats subjected to PR or ER was less (P < 0.001) than that of CON goats at 125 and 145 days of gestation. However, plasma nonesterified fatty acids concentration was greater (P < 0.01) at 125 and 145 days for PR and ER than CON. Protein restriction increased (P < 0.01) maternal cortisol concentration by 145 days of gestation, and ER decreased (P < 0.01) maternal insulin concentration at 125 days of gestation. Moreover, maternal amino acid (AA) concentrations were affected by nutritional restriction, with greater (P < 0.05) total AA (TAA) and nonessential AA (NEAA) for PR goats but less (P < 0.05) TAA and NEAA for ER goats at 125 days of gestation. After 6 weeks of nutritional recovery, plasma concentrations of most metabolic and hormonal parameters in restricted kids were similar to CON kids, except for reduced (P < 0.05) insulin concentration in ER, and reduced (P < 0.05) Asp concentration in PR and ER kids. These results provide information on potential metabolic mechanisms responsible for fetal programming.

Noise-enhanced synchronization of homoclinic chaos in a CO2 laser.

Many chaotic oscillators have rather coherent phase dynamics but strong fluctuation in the amplitudes. Conversely, homoclinic chaos is characterized by quite regular spikes but strong fluctuation in their time intervals. We study the effects of noise on the synchronization of homoclinic chaos to a weak periodic signal and demonstrate numerically and experimentally in a CO2 laser system that noise enhances synchronization of homoclinic chaos. The system exhibits both conventional resonance versus driving frequency and stochastic resonance with respect to noise intensity.

Constructive effects of noise in homoclinic chaotic systems.

Many chaotic oscillators have coherent phase dynamics but strong fluctuations in the amplitudes. At variance with such a behavior, homoclinic chaos is characterized by quite regular spikes but strong fluctuation in their time intervals due to the chaotic recurrence to a saddle point. We study influences of noise on homoclinic chaos. We demonstrate both numerically and experimentally on a CO2 laser various constructive effects of noise, including coherence resonance, noise-induced synchronization in uncoupled systems and noise-enhanced phase synchronization, deterministic resonance with respect to signal frequency, and stochastic resonance versus noise intensity in response to weak signals. The peculiar sensitivity of the system along the weak unstable manifold of the saddle point underlines the unified mechanism of these nontrivial and constructive noise-induced phenomena.

[Intracytoplasmic desmosome in squamous cancer cells of the lung in man].

Ultrastructure of intracytoplasmic (cytoplasmic) desmosomes in the squamous cancer cells of the human lung was studied by electron microscopy. In 17 cases of non-keratosic squamous cell carcinoma of the lung, intracytoplasmic (cytoplasmic) desmosomes were found in 4. In contrast to what previous investigators had proposed that the intracytoplasmic desmosomes are formed by cell fusion with the membrane being deep in the cell and cell digestion under the diffusion of hydrolytic enzymes, our result indicates that the intracytoplasmic desmosomes might be a structure formed by cell intima system itself during cell division. The structure suggests that the desmosomes originate from the cell intima system.

[A monoclonal antibody directed against an enediyne antitumor antibiotic and its preliminary application].

C1027, composed of an enediyne chromophore and an apoprotein of 110 amino acid residues, is a new highly potent macromolecular antitumor antibiotic. In order to prepare monoclonal antibodies (McAb) against C1027 by hybridoma technique, natural C1027 was inactivated by ultraviolet and coupled with human serum albumin, then immunized BALB/c mice. After cell fusion and screening by ELISA, a hybridoma secreting anti-C1027 McAb designated as F9 was obtained. McAb F9 specifically reacted with C1027 as determined by immunoblot assay. No obvious difference was observed between the reactivity of McAb F9 to natural C1027 and that of McAb F9 to ultraviolet inactivated C1027. This result indicates that the ultraviolet-sensitive chromophore of C1027 may not participate in the epitope for McAb F9. The isotype of F9 is IgG1 and its affinity constant was found to be (2.2 +/- 0.47) x 10(7) L.mol-1 according to Beatty's method. By clonogenic assay, McAb F9 neither affected the cytotoxicity of C1027 to KB cells nor blocked the activity of the chromophore. McAb F9 also specifically reacted with the recombinant truncated C1027 apoprotein in which 16 amino acid residues at the C terminus were deleted. This study suggests that F9 is a valuable McAb for the research of C1027 apoprotein engineering, C1027 related immunoconjugates and screening of new macromolecular antitumor substances with homology to the protein part of C1027.

Effects of maternal protein or energy restriction during late gestation on immune status and responses to lipopolysaccharide challenge in postnatal young goats.

Knowledge of maternal malnutrition of ruminants and effects on development of the immune system of their offspring is lacking. A study was conducted to investigate the effects of maternal protein or energy restriction during late gestation on immune status of their offspring at different ages. Sixty-three pregnant goats (local breed, Liuyang black goat, 22.2 ± 1.5 kg at d 90 of gestation) were fed control (CON, ME = 9.34 MJ/kg and CP = 12.5%, DM basis), 40% protein restricted (PR), or 40% energy restricted (ER) diets from d 91 of gestation to parturition, after which all animals received an adequate diet for nutritional recovery. Plasma concentrations of complement components (C3, C4), C-reactive protein (CRP) and immunoglobulins (IgG and IgM), jejunum cytokines (IL-2, IL-6, and IL-10) expression levels and morphology in the offspring were measured. Additionally, plasma concentration of complement and IL-6, and cytokines expression levels in gastrointestinal tract obtained at 6 wk from young goats were assessed under saline or lipopolysaccharide (LPS) challenging conditions. Maternal PR or ER decreased (P < 0.05) plasma C3, C4, IgG, and IgM concentrations, and IL-2 and IL-6 mRNA expression in the jejunum from neonatal kids, but did not alter (P > 0.05) plasma CRP concentration. The IL-10 mRNA expression of jejunum from PR kids was also less (P < 0.01) than that from CON kids. Moreover, jejunum villous height (P < 0.10 in PR, P < 0.05 in ER) and crypt depth (P < 0.05 both in PR and ER) were reduced in neonatal kids from malnourished mothers. At 6 wk of age, there were no differences (P > 0.05) in any plasma or tissue immune parameters among the 3 treatments. However, when given a LPS challenge, ER and PR kids had greater (P = 0.02) IL-6 concentration compared with CON kids. Our results suggest that both PR and ER during late gestation induced short-term as well as long-lasting alterations on immune responses in their offspring, which may make the animals more susceptible to a bacterial pathogen challenge. The present findings expand the existing knowledge in immunological mechanisms responsible for the development of disease in later life.