[A prospective study on the safety and efficacy of excimer laser coronary angioplasty for the treatment of degenerated great saphenous vein graft]

Objective: To explore the safety and efficacy of excimer laser coronary angioplasty (ELCA) for the treatment of degenerated great saphenous vein graft (SVG). Methods: This is a single-center, prospective, single-arm study. Patients, who were admitted to the Geriatric Cardiovascular Center of Beijing Anzhen Hospital from January 2022 to June 2022, were consecutively enrolled. Inclusion criteria were recurrent chest pain after coronary artery bypass surgery (CABG), and coronary angiography confirmed that the SVG stenosis was more than 70% but not completely occluded, and interventional treatment for SVG lesions was planned. Before balloon dilation and stent placement, ELCA was used to pretreat the lesions. Optical coherence tomography (OCT) examination was performed and postoperative index of microcirculation resistance (IMR) were assessed after stent implantation. The technique success rate and operation success rate were calculated. The technique success was defined as the successful passage of the ELCA system through the lesion. Operation success was defined as the successful placement of a stent at the lesion. The primary evaluation index of the study was IMR immediately after PCI. Secondary evaluation indexes included thrombolysis in myocardial infarction (TIMI) flow grade, corrected TIMI frame count (cTFC), minimal stent area and stent expansion measured by OCT after PCI, and procedural complications (Ⅳa myocardial infarction, no reflow, perforation). Results: A total of 19 patients aged (66.0±5.6) years were enrolled, including 18 males (94.7%). The age of SVG was 8 (6, 11) years. The length of the lesions was greater than 20 mm, and they were all SVG body lesions. The median stenosis degree was 95% (80%, 99%), and the length of the implanted stent was (41.7±16.3)mm. The operation time was 119 (101, 166) minutes, and the cumulative dose was 2 089 (1 378, 3 011)mGy. The diameter of the laser catheter was 1.4 mm, the maximum energy was 60 mJ, and the maximum frequency was 40 Hz. The technique success and the operation success rate were both 100% (19/19). The IMR after stent implantation was 29.22±5.95. The TIMI flow grade of patients after ELCA and stent implantation was significantly improved (all P>0.05), and the TIMI flow grade of all patients after stent implantation was Grade Ⅲ. The cTFC decreased significantly after ELCA (33.2±7.8) and after stent placement (22.8±7.1) than preoperative level (49.7±13.0) (both P<0.001). The minimum stent area was (5.53±1.36)mm², and the stent expansion rate was (90.0±4.3)%. Perforation, no reflow, type Ⅳa myocardial infarction and other complications were not observed. However, postoperative high-sensitivity troponin level was significantly increased ((67.937±33.839)ng/L vs. (5.316±3.105)ng/L, P<0.001). Conclusion: ELCA is safe and effective in the treatment of SVG lesions and could improve microcirculation and ensure full expansion of stent.

[Improvement of China's legal system for public health emergency management from the perspective of lifecycle management]

A crucial lesson gained through the pandemic preparedness and response to COVID-19 is that all measures for epidemic control must be law-based. The legal system is related not only to public health emergency management per se but also to all aspects of the institutional supporting system throughout the lifecycle. Based on the lifecycle emergency management model, this article analyses the problems of the current legal system and the potential solutions. It is suggested that the lifecycle emergency management model shall be followed to establish a more comprehensive public health legal system and to gather the intelligence and consensus of experts with different expertise, including epidemiologists, sociologists, economists, jurist and others, which will collaboratively promote the science-based legislation in the field of epidemic preparedness and response for the establishment of a comprehensive legal system for public health emergency management and with Chinese characteristics.

[Relationship between opacity of cytomegalovirus retinitis lesion borders and aqueous viral load among patients after allogeneic hematopoietic stem cell transplantation]

Objective: To evaluate the relationship between lesion features of cytomegalovirus (CMV) retinitis, including lesion size and degree of opacity of lesion borders, and aqueous CMV-DNA load in patients after allogeneic hematopoietic stem cell transplantation. Methods: It was a retrospective case series study. Data of patients diagnosed as CMV retinitis after allogeneic hematopoietic stem cell transplantation at the Department of Ophthalmology, Peking University Third Hospital from January 2018 to October 2020 were reviewed. Lesion size was detected by ultra-wide-field fundus image and measured by ImageJ, an image processing and analysis software. Opacity of lesion borders was evaluated by a masked reader. The CMV retinitis lesions were divided into 3 types according to the opacity degree of the border of the lesions: suspected active lesion mildly to moderately opacified lesion and severely opacified lesion. All eyes were diagnosed as active cytomegalovirus retinitis. CMV-DNA in aqueous humor was detected at the first visit and at the end of the induction period of antiviral drugs. CMV-DNA load was quantitatively detected by polymerase chain reaction after 100 μl of aqueous humor was extracted, and were converted to common logarithmic representations. Pearson correlation analysis was used to analyze the correlation between lesion area, opacity degree of lesion border and aqueous humor CMV-DNA load. Results: A total of 71 eyes from 46 patients were included and 26 was male and 20 was female. The age of the patients was 27(13, 33)years. The active lesion size of CMV retinitis was 40(12, 65) disc areas. Eight eyes (11.3%) had a suspected active lesion, 51 eyes (71.8%) had a mildly to moderately opacified lesion border, and 12 eyes (16.9%) had a severely opacified border. At the first visit, 67 eyes (94.4%) were CMV-positive, and the CMV-DNA load was 2.04×10⁴ (6.24× 10², 1.48 ×10⁵) copies/ml. After 2 weeks of induction therapy, the viral load was 2.47×10² (1.08× 10, 6.87 ×10³) copies/ml. The correlation analysis showed that the CMV-DNA load in aqueous humor was significantly correlated with the lesion border opacity both at presentation and 2 weeks after intravitreal antiviral treatment (r=0.765, P<0.001; r=0.761, P<0.001), but was not related with the size of active fundus lesions (r=0.209, P=0.095; r=0.220, P=0.078). Conclusion: Degrees of lesion border opacity can reflect levels of aqueous viral load of CMV retinitis in patients after allogeneic hematopoietic stem cell transplantation and can become a useful measurement for investigation of CMV retinitis activity.

Helical micro-swimmer: hierarchical tail design and propulsive motility

Helical micro-swimmers have markedly extended the reach of human beings in numerous fields, ranging from in vitro tasks in lab-on-a-chip to in vivo applications for minimally invasive medicine. The previous studies on the propulsive motility optimization of the micro-swimmers mainly focused on the distinct actuation principles (e.g., chemically powered, magnetic- or ultrasound energy-driven) and paid little attention to the structural design of these swimming machines themselves. The improvements of the structures can assist the externally powered motors in providing propulsion in a tiny scale and satisfy the agile locomotion demands. This paper presents the design, mechanics modeling and available experiments of a novel type of hierarchical helical swimming robot that significantly enhances the motility of the helix-based swimmers. Validated by the resistive force theory, our numerical model can well analyze the mechanical properties with a variety of geometric parameters. The motion performance of the hierarchical and conventional helical structures in low Reynolds regimes is presented, highlighting the advantages of hierarchical swimmers over the existing typical swimmers. In addition, the stability and resilience of the hierarchical swimmers can be maintained at a decent level. Moreover, the variable forward velocity resulting from the combined hierarchical structures is investigated here, which can thereby serve as a reliable design strategy. The proposed hierarchical helical design enables enticing opportunities for various device systems of medical robots and bio-integrated electronics.

The effect of cytoplasmic dynein on the development and functional maintenance of retinal photoreceptor cells

Cytoplasmic dynein is a multi-subunit complex that includes cytoplasmic dynein-1 (dynein1) and cytoplasmic dynein-2 (dynein2). It participates in various basic cellular processes, including nuclear migration, mitotic spindle organization, chromosome separation during mitosis, and the location and function of numerous intracellular organelles. Retinal photoreceptor cells are terminally differentiated neurons that cannot regenerate and cannot be replaced once lost. It is thus crucial to study their development to facilitate the generation and improvement of photoreceptor disease treatments. The outer segment (OS) of photoreceptor cells is a specific sensory cilium. An increasing number of studies have shown that cytoplasmic dynein plays an essential role in the development of retinal photoreceptor cells. To date, people have done a lot of studies on the various functions of dynein in cells and have a very detailed understanding. However, the role of dynein in retinal photoreceptor cells has not been summarized in detail. This article summarizes the currently available knowledge relating to the effects and mechanisms of cytoplasmic dynein on the development and functional maintenance of retinal photoreceptor cells.

N95 respirator decontamination: a study in reusability

The coronavirus disease 2019 (COVID-19) pandemic had caused a severe depletion of the worldwide supply of N95 respirators. The development of methods to effectively decontaminate N95 respirators while maintaining their integrity is crucial for respirator regeneration and reuse. In this study, we systematically evaluated five respirator decontamination methods using vaporized hydrogen peroxide (VHP) or ultraviolet (254 nm wavelength, UVC) radiation. Through testing the bioburden, filtration, fluid resistance, and fit (shape) of the decontaminated respirators, we found that the decontamination methods using BioQuell VHP, custom VHP container, Steris VHP, and Sterrad VHP effectively inactivated Cardiovirus (3-log10 reduction) and bacteria (6-log10 reduction) without compromising the respirator integrity after 2-15 cycles. Hope UVC system was capable of inactivating Cardiovirus (3-log10 reduction) but exhibited relatively poorer bactericidal activity. These methods are capable of decontaminating 10-1000 respirators per batch with varied decontamination times (10-200 min). Our findings show that N95 respirators treated by the previously mentioned decontamination methods are safe and effective for reuse by industry, laboratories, and hospitals.

[Clinical characteristics of epidermal growth factor receptor-mutated advanced adenocarcinoma transformed into small-cell lung cancer]

Objective: To explore the clinicopathological characteristics and genomic characteristics of four patients with epidermal growth factor receptor(EGFR)-mutated advanced adenocarcinoma transformed into small-cell lung cancer. Methods: Four cases of EGFR-mutated advanced adenocarcinoma of the lung transformed into small-cell lung cancer were studied by clinical data, pathological morphology, immunohistochemistry and gene detection. Result: EGFR-mutated adenocarcinoma of the lung was heterogeneous in clinical and genomic profiles, of ten characterized by RB1, TP53 and PIK3CA mutations. Its transformation into small-cell lung cancer was a particularly aggressive mechanism of drug resistance, but the machanisms were not clear NSE and other tumor indicators had low diagnostic value for transformation. Conclusions: EGFR-mutated adenocarcinoma of the lung transformed into small-cell lung cancer was one of the reasons for EGFR resistance with avery poor prognosis.

[Evaluation of intravascular therapy for cerebral ischemic tandem stenosis]

Objective: To investigate the efficacy and the safety of intravascular therapy for cerebrovascular ischemic tandem stenosis. Methods: Clinical data of 35 patients with symptomatic anterior circulation and posterior circulation tandem stenosis who received intravascular therapy for two sites of stenosis at the same time at Department of Neurosurgery of Peking University First Hospital from January 2013 to December 2018 were analyzed retrospectively. There were 27 males and 8 females,aged (65.6±9.4)years (range:47 to 81 years).There were 14 cases of anterior circulation tandem stenosis and 21 of posterior circulation tandem stenosis.The medical records were collected with emphasis on postoperative symptoms,imaging manifestations and modified Rankin scale(mRS) scores. Results: Sixty-eight stents were implants in to 35 patients,including 49 extracranial implants and 19 intracranial implants.The surgical success rate was 100%.The perioperative death rate was 0,and 1 patient(1/35,2.9%) had cerebral hemorrhage.All patients were followed up for 18 months.During 3 to 12 months after the intervention,1 case(1/35,2.9%) had stent restenosis,and 4 cases(4/35,11.4%) had persisted symptoms such as dizziness and weakness in limbs.All patients'mRS scores were ≤2. No new stroke occurred. During 12 to 18 months after the intervention,3 cases had in-stent restenosis,increasing the rate to 11.4% (4/35). The mRS scores of 32 patients(32/35,91.4%) were ≤2. Conclusion: Intravascular therapy for patients with symptomatic tandem stenosis is a feasible and safe procedure with good short-term outcomes.

Direction and symmetry transition of the vector order parameter in topological superconductors CuxBi2Se3

Topological superconductors have attracted wide-spreading interests for the bright application perspectives to quantum computing. Cu0.3Bi2Se3 is a rare bulk topological superconductor with an odd-parity wave function, but the details of the vector order parameter d and its pinning mechanism are still unclear. Here, we succeed in growing CuxBi2Se3 single crystals with unprecedented high doping levels. For samples with x  = 0.28, 0.36 and 0.37 with similar carrier density as evidenced by the Knight shift, the in-plane upper critical field Hc2 shows a two-fold symmetry. However, the angle at which the Hc2 becomes minimal is different by 90° among them, which indicates that the d-vector direction is different for each crystal likely due to a different local environment. The carrier density for x  = 0.46 and 0.54 increases substantially compared to x ≤ 0.37. Surprisingly, the in-plane Hc2 anisotropy disappears, indicating that the gap symmetry undergoes a transition from nematic to isotropic (possibly chiral) as carrier increases.

Proton Shell Evolution below ^{132}Sn: First Measurement of Low-Lying β-Emitting Isomers in ^{123,125}Ag

The β-delayed γ-ray spectroscopy of neutron-rich ^{123,125}Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2^{-} β-emitting isomers in ^{123,125}Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2^{+} and 1/2^{-} levels is extended in Ag isotopes up to N=78, providing a clear signal for the reduction of the Z=40 subshell gap in Ag towards N=82. Shell-model calculations with the state-of-the-art V_{MU} plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in ^{123,125}Ag. The tensor force is found to play a crucial role in the evolution of the size of the Z=40 subshell gap. The observed inversion of the single-particle levels around ^{123}Ag can be well interpreted in terms of the monopole shift of the π1g_{9/2} orbitals mainly caused by the increasing occupation of ν1h_{11/2} orbitals.

Behavioral Characteristics and Medicolegal Identification of Infanticide

Due to the concealment and incidence higher than reported statistics, infanticide should attract the attention of legal medical experts. The infanticide process has common behavioral characteristics. The perpetrators are most frequently biological mothers who are unmarried, with inferior education, and lack of routine pregnancy tests. Medicolegal identification of infanticide cases includes identification of live births and causes of death. Besides the classical lung floating test, there are other methods to identify live births such as pulmonary interstitial emphysema, CT imaging examination, immunohistochemical examination of umbilical cord vitality markers. Neonatal line measurement is the only way to identify live births in corpse with severe decomposition. The main causes of death in infanticide are mechanic asphyxia and fatal head trauma. Shaken baby syndrome, as a common abusive head trauma, is pathologically characterized by the triad of encephalopathy, subdural haemorrhage （SDH） and retinal haemorrhage （RH）. During the autopsy of suspected shaking baby syndrome, in addition to carefully examining cervical cord, the possibility of pathological temporal lobe hemorrhage should also be ruled out.

Electron Mass Enhancement near a Nematic Quantum Critical Point in NaFe_{1-x}Co_{x}As

A magnetic order can be completely suppressed at zero temperature (T), by doping carriers or applying pressure, at a quantum critical point, around which physical properties change drastically. However, the situation is unclear for an electronic nematic order that breaks rotation symmetry. Here, we report nuclear magnetic resonance studies on NaFe_{1-x}Co_{x}As where magnetic and nematic transitions are well separated. The nuclear magnetic resonance spectrum is sensitive to inhomogeneous magnetic fields in the vortex state, which is related to London penetration depth λ_{L} that measures the electron mass m^{*}. We discovered two peaks in the doping dependence of λ_{L}^{2}(T∼0), one at x_{M}=0.027 where the spin-lattice relaxation rate shows quantum critical behavior, and another at x_{c}=0.032 around which the nematic transition temperature extrapolates to zero and the electrical resistivity shows a T-linear variation. Our results indicate that a nematic quantum critical point lies beneath the superconducting dome at x_{c} where m^{*} is enhanced. The impact of the nematic fluctuations on superconductivity is discussed.

A rapid and high-quality method for total RNA isolation from Haematococcus pluvialis

Haematococcus pluvialis, as the most potential natural source of astaxanthin, which is a powerful antioxidant with high economic value, has attracted more and more scientific attention in recent years. An in-depth understanding of the mechanism for how H. pluvialis produces astaxanthin requires the intensive investigations on its genetic information. In particular, many reported studies were based on a variety of RNA analyses. However, it is difficult to extract RNA with high quality and quantity from H. pluvialis, because of the blockage from its thick cell wall and contamination by a large quantity of pigments, polysaccharides, and lipids. Therefore, we proposed an optimized Trizol-based RNA extraction method for H. pluvialis by investigating the effect of cell wall broken ways, algal strains, and cell growth status on total RNA isolation. Using this rapid, convenient, and cost-saving method, isolated H. pluvialis RNA had high quantity and quality (with an RNA integrity number of 7.0 and a concentration of 1604.1 ng/μL) equivalent to that isolated by commercial kit, enabling its applications into downstream RNA analyses.

[Evaluation between bypass surgery and endovascular therapy to peripheral arterial disease patients with critical limb ischemia]

Bypass surgery(BSX) and endovascular therapy(EVT) are the most important therapeutic method to critical limb ischemia.EVT has potential advantages in reducing surgical trauma and early postoperative complications, shortening hospital stay and so on. Concerning long-term results, BSX is better in reducing long-term mortality and improving long-term patency than EVT group. Therefore, control indications reasonably and select individualized methods, avoid the abuse of EVT are more meaningful for patients.

The interactive bending wrinkling behaviour of inflated beams

A model is proposed based on a Fourier series method to analyse the interactive bending wrinkling behaviour of inflated beams. The whole wrinkling evolution is tracked and divided into three stages by identifying the bifurcations of the equilibrium path. The critical wrinkling and failure moments of the inflated beam can then be predicted. The global-local interactive buckling pattern is elucidated by the proposed theoretical model and also verified by non-contact experimental tests. The effects of geometric parameters, internal pressure and boundary conditions on the buckling of inflated beams are investigated finally. The results reveal that the interactive buckling characteristics of an inflated beam under bending are more sensitive to the dimensions of the structure and boundary conditions. We find that for beams which are simply supported at both ends or clamped and simply supported, boundary conditions may prevent the wrinkling formation. The results provide significant support for our understanding of the bending wrinkling behaviour of inflated beams.

Orientation-dependent nanostructure arrays based on anisotropic silicon wet-etching for repeatable surface-enhanced Raman scattering

Repeatable fabrication of sensitive plasmonic substrates through a simple procedure has become a major challenge for SERS-based sensing and imaging. Herein, a new class of high-performance SERS substrates, including pyramid, ridged-hexagon, and quasi-triangle nanostructures, is successfully fabricated based on the nanosphere lithography technique and anisotropic wet etching. Using the wafer-scale Cr-hole array as the etching mask, cavity-templates of various configurations are fabricated by the orientation-dependent wet etching technique, from where the nanostructure arrays are finally peeled-off. The anisotropic wet etching on (100), (110), and (111) silicon wafers has been systematically studied at the nanoscale revealing the formation mechanism of these cavity-templates. The peeled-off nanostructure arrays provide high-density tips and/or gaps (about 2.5 × 10(7) mm(-2)) and thus facilitate the generation of "hot spots". The distribution of the electromagnetic field is visualized by the finite difference time domain calculation. And the calculation results are validated by SERS characterization. The SERS enhancement factors of these substrates are in the order of 10(6)-10(7), with the maximum enhancement factor of 1.32 × 10(7) yielded by the ridged-hexagon arrays. The proposed nanostructure arrays present excellent homogeneity and reproducibility (with the largest relative standard deviation of 16.43%) for the reason that the SERS-active substrates are peeled-off from an identical template. The cost-effective fabrication, high sensitivity, good homogeneity and well-performed reproducibility demonstrate that these orientation-dependent NSs are good candidates for SERS-based in vitro and in situ detection and biosensing.

Tunable organic hetero-patterns via molecule diffusion control

A simple, scalable method is reported to fabricate ordered hetero-structures of organic materials using template-directed growth. The 3D extension of the structures is firstly determined by pre-pattern size and deposition amount, and can further be in situ tuned by annealing at appropriate temperature.

A treatment for large defects of the tibia caused by infected nonunion: Ilizarov method with bone segment extension

OBJECTIVES

To investigate the efficacy of the Ilizarov technique with bone segment extension in tibial infected nonunion.

METHODS

From September 2003 to June 2011, we treated 30 patients (21 males, 9 females; age 19-49 years, mean 34.1 years) for tibial infected nonunion with bone defects. Eleven cases were compound fractures internally fixed with steel plates, nine were compound fractures internally fixed with IM Nails, eight were compound fractures externally fixed with external fixation devices, and two were closed fractures internally fixed with steel plates. All 30 patients underwent debridement followed by the Ilizarov technique using bone segment extension.

RESULTS

After follow-up of 12 months-6 years (mean 29 months), stable union of fracture was achieved in all 30 patients. The time from bone fracture to union was 6-24 months, mean 8.8 months; external fixation was in place for 8-14 months, mean 10 months. External fixation index was 41 days/cm. Complications were three cases of pin site infection, one skin allergy, two fractures malunion, one early mineralization and one wire breakage. There were no cases of deep infection, nonunion or stiffness of the knee joint. According to the Paley fracture healing score criteria, 30 cases had excellent outcomes and two were good.

CONCLUSIONS

The Ilizarov technique with bone segment extension is effective in treating tibial infected nonunion with large bone defects.

Detection of resistance phenotype and genotype of avian Escherichia coli in Hebei Province

We investigated the resistance of avian Escherichia coli to commonly used clinical antibiotics in Hebei Province. It is of significance to reveal the extent and mechanism of drug resistance, as well as to prevent and control colibacillosis. We investigated the resistance of 132 E. coli isolates to 5 kinds of antibiotics (including β-lactams, aminoglycosides, tetracyclines, sulfonamides, and chloramphenicol) using the Kirby-Bauer drug susceptibility test, and resistance genes were detected by PCR. The results showed that the E. coli had a higher resistance rate to ampicillin, cephalotin, gentamicin, streptomycin, tetracycline, doxycycline, sulfamethoxazole trimethoprim, sulfamonomethoxine, and florfenicol, but it had higher sensitive rate to cefepime, imipenem, spectinomycin, and minocycline. Of the resistance genes, the TEM, aac(3)-IIa, tetA, Sul1, Sul2, and forl had higher positive rates. Therefore, drug resistance of avian E. coli in Hebei Province is very serious. The resistance mechanisms may include structure changes of the target enzyme mediated by multiresistance genes, and resulting in reduced affinity and increased efflux of antibiotics.

Survey on tetracycline resistance and antibiotic-resistant genotype of avian Escherichia coli in North China

The experiment was performed to investigate the tetracycline resistance and antibiotic-resistant genotype of avian Escherichia coli in North China and to analyze the correlation of genotype and phenotype. The resistance of 164 E. coli isolates (from Beijing, Tianjin, inner Mongolia, Shanxi, and Hebei regions of China) to tetracycline, doxycycline, and minocycline was investigated by using a drug susceptibility test. The results show that the rate of resistance to tetracycline antibiotics was 89.63% (147/164). The higher resistance rate was 84.76% (139/164) to tetracycline and 70.12% (115/164) to doxycycline, and the lowest resistance rate was 4.88% (8/164) to minocycline. The distribution of tetracycline resistance (Tcr) genes (tetA, tetB, tetC, and tetM) in avian E. coli isolates was detected by PCR. Of the isolates, 82.32% (135/164) carried tetracycline resistance genes. The positive rates of tetA, tetB, and tetM were 57.93% (95/164), 38.41% (63/164), and 10.97% (18/164), respectively. No tetC was amplified in avian E. coli isolates. The total positive rate of resistance genes (82.32%) was almost equal to the total rate of resistance to tetracycline antibiotics (89.63%). Thus, the positive rate of genotype was basically in line with that of phenotype for tetracycline resistance. The tetracycline resistance genes are widely distributed in E. coli and their main resistance mechanism to tetracycline is the active efflux effect mediated by tetA and tetB.

Molecular epidemiological survey on aminoglycoside antibiotics-resistant genotype and phenotype of avian Escherichia coli in North China

Monitoring drug resistance in Escherichia coli is important for prevention and treatment of colibacillosis. To choose effective drugs to prevent and control avian colibacillosis in North China, we investigated resistance of 205 E. coli isolates (from Beijing, Tianjin, inner Mongolia, Shanxi, and Hebei regions) to commonly used clinical aminoglycoside antibiotics using a drug susceptibility test. The results show that the isolates had varying degrees of resistance to kanamycin, gentamicin, streptomycin, amikacin, neomycin, and spectinomycin. Particularly, the resistance rates of the former 3 antibiotics exceeded 40%. To explore the reasons for wide drug resistance, aminoglycosides modifying enzymes (AME) genes, which are important in generation of aminoglycoside resistance, were detected by PCR. Of the isolates, 60.98% carried AME genes and 38.05% carried commensal multidrug resistance genes. Therefore, resistance of avian E. coli to aminoglycoside antibiotics is very serious in North China, perhaps due to the existence of resistance genes.

Magnetic resonance imaging as a new method to diagnose protein losing enteropathy

The main cause of protein losing enteropathy (PLE) in children is intestinal lymphangiectasia. PLE is commonly diagnosed with radiotracer scintigraphy. We report the use of magnetic resonant imaging in diagnosis of a child with primary PLE. MRI clearly revealed abnormality in intestine and mesentery and dilated thoracic duct and mesenteric lymphatic as well as prominent subcutaneous lymphatics in the extremity. We conclude that MRI is a useful tool in diagnose of primary PLE.

Seroepidemiology and molecular epidemiology of the Chinese rotavirus

The Chinese rotavirus which causes epidemics of diarrhoea in adult humans was isolated in 1983. This virus, designated adult diarrhoea rotavirus (ADRV), resembles typical rotaviruses morphologically and has a genome made up of 11 discrete segments of double-stranded RNA. Because the Chinese rotavirus has a unique RNA pattern on polyacrylamide gel electrophoresis and is antigenically distinct from group A rotaviruses, it is tentatively included in group B. Infection with ADRV or ADRV-related viruses (as shown by serological study) is detected in human populations as widespread as mainland China, Hong Kong, Australia, the United States and Canada, and in some domestic animals. RNA co-electrophoresis has shown homology of isolates from 12 different outbreaks (with some minor variations at segments 10, 11, 3 and 5). cDNA probes and monoclonal antibodies have been prepared to improve the detection and further characterization of the virus.

[Relationship between hepatitis B virus genotypes and basic core promoter/precore mutations in patients with severe hepatitis.]

BACKGROUND

To investigate the relationship between hepatitis B virus genotypes and basic core promoter (BCP)/precore mutations in patients with severe hepatitis.

METHODS

HBV genotypes were determined by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 52 patients with severe hepatitis and 52 cases with chronic hepatitis B (CHB). Eight samples of genotypes B and C were randomly selected and their S gene was directly sequenced, and then their phylogenetic trees were analyzed. Fifteen samples of each of genotypes B and C were randomly selected and their BCP and precore genes were directly sequenced with PCR, and then the relationship between genotypes and BCP(T1762/A1764)/precore (A1896) mutations were analyzed.

RESULTS

Genotype B C and mixed genotypes (B and C) were detected in patients with severe hepatitis in Quanzhou area. Genotype B was the majority with a proportion 48.08% others had a proportion 30.77% and 17.31%, respectively. Genotype A, E and F were not detected. The percents of genotype C, mixed B and C in severe hepatitis were significantly higher than that in CHB. The double mutation in BCP (T1762/A1764) was significantly more frequent in severe hepatitis with genotype C than that in genotype B (P less than 0.05). However, there was no significant difference in the distribution of precore mutant with A1896 between genotype B and C patients (P greater than 0.05).

CONCLUSION

Genotype C may induce more severe liver inflammation than that genotype B may do. Mixed genotypes B and C infection may be an important determinant of inducing severe hepatitis. The double mutation in BCP (T1762/A1764) was more common in severe hepatitis with genotype C than that with genotype B.

Purification of two depressant insect neurotoxins and their gene cloning from the scorpion Buthus martensi Karsch

Insect-specific neurotoxins are important components of scorpion venoms. In this study, two toxins from the scorpion Buthus martensi Karsch (BmK) were purified. They shared high sequence homology with other depressant insect toxins and were designated BmK ITa and BmK ITb, respectively. They were able to suppress the action potential of cockroach isolated axon, which is due to a decrease in the peak sodium current. Furthermore, the effect of BmK ITb was lower than that of BmK ITa, and some of the electrophysiological characteristics of BmK ITb even resemble that of excitatory insect toxins. Their primary structures were determined by N-terminal partial sequence determination and cDNA cloning. The differences in their structures, especially the 31st residues, may result in the unique activity of BmK ITb.

Greater velocity and magnitude of airway narrowing in immature than in mature rabbit lung explants

Methacholine (MCh)-induced bronchoconstriction in vivo produces greater maximal increases in pulmonary and airway resistances in immature than in mature rabbits. Our recent findings of lower shear modulus and greater airway distensibility suggest a lower elastic load limiting airway smooth muscle (ASM) shortening in immature rabbit lungs. We hypothesized that a lower elastic load should result in greater velocity of airway narrowing. Lung explants were prepared from three immature and five mature rabbits. Dynamic narrowing of intraparenchymal airways after maximal MCh stimulation was assessed by video microscopy. Immature airways (n = 80) compared with mature airways (n = 110) demonstrated greater peak velocity of shortening (6.98 +/- 0.32 versus 4.22 +/- 0.18% of baseline perimeter/s) and greater maximal airway narrowing, expressed as percentage of baseline area (31.9 +/- 1.6 versus 42.2 +/- 1.8%). For both groups, a greater velocity of shortening resulted in greater airway narrowing. As available data do not support maturational differences in rabbit ASM, our results are consistent with a lower elastic load limiting ASM shortening in the immature rabbit.

A depressant insect toxin with a novel analgesic effect from scorpion Buthus martensii Karsch

A new peptide named BmK dITAP3 from scorpion Buthus martensii Karsch (BmK) has been identified to possess a dual bioactivity, a depressant neurotoxicity on insects and an analgesic effect on mice. The bioassays also showed that the peptide was definitely devoid of the neurotoxicity on mammals, which indicated that the analgesic effect of BmK dITAP3 could not be ascribed to the syndromic effects of a mammalian neurotoxicity. BmK dITAP3 exhibited 43.0% inhibition efficiency of the analgesic effect on mice at a dose of 5 mg/kg and the FPU value of 0.5 microg/body (approximately 30 mg) on the fly larvae. The pI value and the molecular mass determined by MALDI-TOF MS for dITAP3 were 6.5 and 6722.7, respectively. Its first 15 N-terminal residues were determined by Edman degradation, based on which the full amino acid sequence was deduced from the cDNA sequence encoding the peptide with 3'-RACE. Circular dichroism and sequence based prediction analyses showed dITAP3 may have a similar molecular scaffold as the most scorpion toxins but with features of the more beta structures and much less of alpha helix. The details of the purification, characterization and sequencing as well as the sequence comparison with other depressant insect toxins and the correlation between the analgesic effect and the insect toxicity will be reported and discussed, respectively.

Molecular characterization of an anti-epilepsy peptide from the scorpion Buthus martensi Karsch

For a long time Asian scorpion Buthus martensi Karsch (BmK) has been used in Chinese traditional medicine to cure many diseases of nervous system. Here we report the purification and characterization of a pharmacologically active neurotoxin from the scorpion BmK. This toxin had little toxicity in mice and insects but was found to have an anti-epilepsy effect in rats, and is thus named as BmK anti-epilepsy peptide (BmK AEP). Its amino-acid sequence was determined by lysylendopeptidase digestion, Edman degradation and mass spectrographic analysis. Based on the determined sequence, the gene coding for this peptide was also cloned and sequenced by the 3' and 5' RACE methods. It encodes a precursor of 85 amino-acid residues including a signal peptide of 21 residues, a mature peptide of 61 residues and three additional residues Gly-Lys-Lys at the C-terminus. The additional Gly sometimes followed by one or two basic residues is prerequisite for the amidation of its C-terminus. C-terminal amidation was also verified by the molecular-mass determination of BmK AEP. This anti-epilepsy peptide toxin shares homology with other depressant insect toxins. The remarkable difference between them was mainly focused at residues 6, 7 and 39; these residues might relate to the unique action of BmK AEP.

Bronchial responsiveness among inbred mouse strains. Role of airway smooth-muscle shortening velocity

To investigate the relationship between bronchial responsiveness and airway smooth-muscle (ASM) contractile properties, we studied inbred mice with known interstrain differences in airway responsiveness. Using oscillatory mechanics, we confirmed that A/J mice were hyperresponsive to methacholine (MCh) as compared with mice of the C3H/HeJ and C57BL/6J strains. Analysis of respiratory system resistance and elastance at different flow oscillation frequencies indicated that interstrain differences in responsiveness are present in both central and peripheral airways of these mice. We used video microscopy to measure the rate of contraction of explanted airways, and found that the airways of A/J mice contracted more rapidly than those of C3H/HeJ or C57BL/6J mice. In studies of a fourth strain (Balb/C) of mice, we found both bronchial hyperresponsiveness and increased ASM shortening velocity. The rank order of responsiveness among strains was the same as that for shortening velocity (A/J > Balb/C > C3H/HeJ > C57BL/6J). Furthermore, in each strain of mice, shortening velocity correlated with the achieved degree of airway narrowing and with a greater likelihood of airway closure in individual airways. In contrast, generation of isometric tension in trachealis, morphometric measurements of tracheal ASM, tracheal myosin content, and dose-response curves for MCh of explanted intraparenchymal bronchi failed to correspond to the in vivo phenotype of airway reactivity. These results indicate that bronchial responsiveness is related to ASM shortening velocity, and underscore the importance of smooth-muscle dynamics in understanding the mechanisms of bronchial responsiveness.

Molecular characterization of a new excitatory insect neurotoxin with an analgesic effect on mice from the scorpion Buthus martensi Karsch

Besides the neurotoxins active on mammals, a new excitatory insect selective toxin with a mice analgesic activity was found and purified from the venom of the scorpion Buthus martensi Karsch (BmK) (Ji, Y.H., Mansuelle, P., Terakawa, S., Kopeyan, C., Yanaihara, N., Hsu, K., Rochat, H., 1996. Toxicon 34, 987; Luo, M.J., Xiong, Y.M., Wang, M., Wang, D.C., Chi, C.W., 1997. Toxicon 35, 723.). This peptide (designated as BmK IT-AP) is composed of 72 amino acid residues. Its primary structure was determined by automated Edman degradation of the N-terminal part of the reduced and S-carboxamidemethylated protein and its lysylendopeptidase degraded fragments. Based on the determined sequence, the gene specific primers were designed and synthesized for 3' and 5' RACE (rapid amplification of cDNA ends). Their partial cDNA fragments obtained by 3' and 5' RACEwere cloned and sequenced and the full length cDNA sequence of BmK IT-AP was then completed by overlapping their two partial cDNA sequences. It encodes a precursor of 90 amino acid residues: a signal peptide of 18 residues and a mature peptide of 72 residues which are consistent with the determined protein sequence of BmK IT-AP. The genomic DNA of the peptide was also amplified by PCR from the scorpion genomic DNA and sequenced, which is a first report on the genomic structure of a scorpion toxin specific for insects. Its sequence revealed an intron of 590 bp inserted in the end part of the signal peptide. The peptide caused a fast excitatory contraction paralysis on house fly larvae. Furthermore, the peptide also showed an obvious analgesic effect on mice, as assayed by using a twisting test model. This effect of BmK IT-AP well characterized at molecular level is first reported among the known scorpion insect neurotoxins.

[Analysis of HLA-DRB1 allele in patients with chronic bronchitis]

OBJECTIVE

To study the difference in HLA-DRB1 allele frequencies between patients with simple chronic bronchitis and with coal worker's pneumoconiosis (CWP) complicated with chronic bronchitis.

METHODS

HLA-DRB1 allele frequencies were measured in 37 patients with simple chronic bronchitis and 33 with CWP complicated with chronic bronchitis of Han ethnicity in Shanxi Province using polymerase chain reaction with sequence specific primer, in comparison with those in normal population of the same province.

RESULTS

Allele frequency of HLA-DRB1 * 120X was 24.32% in those with simple chronic bronchitis, and that of HLA-DRB1 * 040X was 22.73% in those with CWP complicated with chronic bronchitis, significantly increased than that in normal people with both P < 0.01. There was no significant difference in other alleles between the three groups.

CONCLUSION

It suggests that in Han ethnicity of Shanxi Province HLA-DRB1 * 120X allele frequency is associated with simple chronic bronchitis and that of HLA-DRB1 * 040X is associated with CWP complicated with chronic bronchitis.

[Effect of glucocorticoid on [Ca2+]i induced by high-K+ in single PC12 cells and its characteristics]

The effect of glucocorticoid on the increase of cytosolic free calcium [Ca2+]i) induced by high-K+ was investigated in pheochomocytoma PC12 cells. The main result was as follows: (1) When the cells were preincubated at 37 degrees C for various time intervals in the presence of 10(-5) mol/L of corticosterone and stimulated with 55 mmol/L KCl, an inhibitory effect of corticosterone on delta [Ca2+]i was observed in a time-dependent manner with maximal effect at 5th min and no effect at 25th min. (2) When PC12 cells were preincubated with various concentration of corticosterone at 37 degrees C for 5 min, the inhibitory effect of corticosterone on delta [Ca2+]i induced by 55 mmol/L KCl was concentration-dependent. The effect was found to be maximal at 10(-5) mol/L of corticosterone and disappeared at 10(-9) mol/L of corticosterone. (3) Other steroids such as cortisol, dexamethasone, progesterone, testosterone, 17 beta-estradiol and aldosterone also inhibited the rise of [Ca2+]i evoked by 55 mmol/L KCl in PC12 cells to different extents, i.e., in the rank of P = F > Dex > T > Ald = E2. Cholesterol was ineffective at the concentration up to 10(-5) mol/L for inhibiting [Ca2+]i evoked by 55 mmol/L KCl. (4) Corticosterone could not inhibit the [Ca2+]i rise induced by changing the concentration of extracellular calcium from Ca(2+)-free to 3 mmol/L.

The role of magnetic resonance imaging in diagnosis of peripheral lymphatic disorders

Magnetic resonance imaging (MRI) was used in 13 patients with peripheral lymphedema and 2 patients with extensive cavernous lymphangioma of the limb for the purpose of evaluating its role in diagnosis of lymphatic disorders. In chronic lymphedema, MRI showed deformity of lymphatics at different tissue levels. In the subcutis, MRI characteristically displayed diffuse edema or a honeycombed pattern consistent with reticular lymphangiectasis and "lakes" with a marked increase in signal intensity with T2-weighted imaging. In lymphedema hyperplasia and chylous reflux, MRI depicted dilated retroperitoneal lymphatic collectors and lumbar trunks. In cavernous lymphangiomatosis, MRI demonstrated a prominent lattice-like pattern which had lower signal intensity on T1-weighted imaging and higher intensity on T2-weighted imaging. The findings of MRI are valuable not only for accurate assessment of lymphatic dysplasia syndromes but also provide a blueprint for treatment options.

Human nasal ciliary-beat frequency in normal and chronic sinusitis subjects

OBJECTIVE

Ciliary-beat frequency (CBF) is an important factor influencing mucociliary flow in the respiratory tract. A significant correlation exists between CBF and mucus transport time (MTT), which suggests that CBF is the main factor in nasal mucociliary clearance in healthy individuals. Mucociliary clearance is influenced by the temperature of the inspired air and decreases at temperatures below 33 degrees C. It is unknown whether CBF varies in different sites within the nasal chamber and exactly how CBF is altered in disease states such as chronic sinusitis (CS) and nasal polyposis (NP). Our study was conducted in an attempt to answer these questions.

METHOD

CBF was measured in nasal biopsies from eight normal control subjects: 6 CS and 8 NP patients. Biopsies from the regions of the maxillary, ethmoid, frontal, and sphenoid sinus ostia were also obtained. The material was analyzed using a computerized image-processing system.

RESULTS

Our data demonstrated a significant decrease in CBF at 22 degrees C compared to at 35 degrees C for all sinus biopsies (p < .05). We found no statistical difference between the CBF of biopsies from the regions of the various sinus ostia. A comparison between the patients with CS and normal controls again revealed no significant difference in CBF, a finding which contradicts previously published reports. Surprisingly, an increase in CBF was observed in NP patients compared to control and CS patients (p < .05).

CONCLUSIONS

We conclude that our technique is a viable model for studying sinonasal CBF in the human. Our data suggest that a mechanism other than decreased CBF may account for the decreased mucociliary clearance observed in chronic sinusitis.

[Intracellular Ca2+ distribution and its role in mouse oocytes maturation]

To determine the role of calcium and calmodulin in mouse oocyte maturation, we examined the distribution of intracellular calcium during mouse oocyte maturation by using Mira Cal Imaging System. The calcium was present homogeneously in oocytes with intact germinal vesicle (GV) and accumulated around the nuclear region after GV breakdown(GVBD). The high level of calcium disappeared 6 hours later after GVBD. In the presence of 50 mumol/L BAPTA/AM, we failed to observe this phenomena. All eggs treated with 20 mumol/L W7, an antagonist of calmodulin, 50 mumol/L BAPTA/AM, a calcium chelator, could not develop to metaphase II (MII), although GVBD was not affected. We also detected the activity of a cytoplasmic maturation-promoting factor (MPF). W7 and BAPTA/AM had no effects on the rise of MPF activity in the course of maturation. We suggest that compartment distribution of calcium around nuclear region plays an important role in mouse oocyte maturation.

Differential responses of pulmonary arteries and veins to histamine and 5-HT in lung explants of guinea-pigs

1. The mechanisms by which histamine and 5-HT differentially contract pulmonary arteries and veins are unclear. In lung explants from 26 guinea-pigs, we compared responses of pulmonary arteries and vein to histamine, 5-HT and KCI, and examined potential determinants for the differential responses. Lungs were filled with agarose, sectioned into approximately 1 mm thick slices, and vascular luminal areas measured by image analysis. 2. Histamine and 5-HT produced a concentration-dependent constriction in arteries and veins, greater in the latter. KCl constricted arteries and veins equally. 3. The histamine H1 antagonist chlorpheniramine (10(-4) M) abolished contractions to histamine; the H2 antagonist cimetidine enhanced maximal responses and sensitivity of arteries and veins to histamine, and diminished the differences between their maximal responses; the NO synthase inhibitor Nomega-nitro-L-arginine (L-NOARG) increased the maximal responses of arteries and veins, and the differences between their responses; indomethacin had no effect. 4. Contractions to 5-HT were abolished in arteries and markedly reduced in veins by the 5-HT2 antagonist ketanserin (10(-4) M); L-NOARG potentiated the maximal responses of arteries but not of veins; indomethacin increased the maximal responses of arteries but reduced them in veins. 5. By morphometry, arteries had a greater medial thickness and luminal diameter than veins. 6. The data suggest that in guinea-pigs, H2 receptors are responsible for the differential contractile responses of pulmonary arteries and veins to histamine, whereas endothelium-derived vasoactive substances are responsible for their differential contractile responses to 5-HT.

Mucociliary clearance in cystic fibrosis knockout mice infected with Pseudomonas aeruginosa

In this study, we examined whether mucociliary clearance differed between cystic fibrosis (CF) knockout mice and wildtype controls. Additionally, we investigated whether infection with Pseudomonas aeruginosa, a common pathogen in the CF lung, affected this important host defence mechanism. Ciliary beat frequency (fcb) and particle transport (PT) were recorded using an in vitro lung explant preparation. Measurements were made from uninfected cystic fibrosis transmembrane conductance regulator (CFTR) knockout (-/-) mice and littermate controls (+/+) and compared to measurements from infected animals. While there were no differences detectable in fcb between CFTR -/- mice and their +/+ controls either in the presence or absence of P. aeruginosa, PT rates were different between these groups; interestingly, PT rates appeared dependent on both CFTR and infection status, with uninfected CFTR +/+ animals demonstrating higher rates of PT than their -/- littermates, while CFTR +/+ P. aeruginosa-infected mice demonstrated lower PT than knockout mice. These data demonstrate differences in mucociliary clearance between cystic fibrosis transmembrane conductance regulator knockout mice and controls, and further that Pseudomonas aeruginosa infection affects mucociliary clearance in the peripheral airways of mice. Additionally, the observed differences in particle transport suggest that cystic fibrosis transmembrane conductance regulator knockout mice demonstrate different mucociliary responses to infection.

Heterogeneity of responsiveness of individual airways in cultured lung explants

Several lines of evidence suggest that the responsiveness of the airways is heterogeneous, although the magnitude of this heterogeneity has not been quantified. We have developed a videomicroscopic method that allows the measurements of the responsiveness of individual explanted airways to contractile agonists such as methacholine. Liquid agarose at 37 degrees C is injected into human lung segments to inflate them to a volume equivalent to total lung capacity. The agarose-filled lungs are then gelled by brief refrigeration and 0.5-mm-thick explants prepared by sectioning. The explants are cultured overnight under conventional conditions. Sections with airways cut in cross section are identified and placed on an inverted videomicroscope. Airway lumen area is then measured following administration of methacholine in increasing concentrations, permitting the construction of dose-response curves for each airway segment studied. This system thus lends itself to the study of the heterogeneity of airway responsiveness across the airway tree by permitting the study of distributions of airways. Using this approach, we have observed a very high degree of heterogeneity of responsiveness across the airways of human lungs. In this report, we review these findings and discuss the physiologic implications of heterogeneity.

In vitro bronchial responsiveness in two highly inbred rat strains

We investigated methacholine (MCh)-induced bronchoconstriction in explanted airways from Fischer and Lewis rats. Lung explants, 0.5- to 1.0-mm thick, were prepared from agarose-inflated lungs of anesthetized 8- to 12-wk-old male rats. After overnight culture, videomicroscopy was used to record baseline images of the individual airways. Dose-response curves to MCh were then constructed by repeated administration of MCh; airways were reimaged 10 min after each MCh administration. Airway internal luminal area (Ai) was measured at successive MCh concentrations from 10(-9) to 10(-1) M. In addition to the effective concentration leading to 50% of the achieved maximal response, we also determined the effective concentration leading to a 40% reduction in Ai. Both the effective concentration leading to 50% of the achieved maximal response and the concentration leading to a 40% reduction in Ai were significantly lower among Fischer rat airways (P < 0.05). Airway closure was more common among Fischer rat airways (17%) than among those of Lewis rats (7.5%). Responsiveness of Fischer rat airways was more heterogeneous than among Lewis airways; a larger number of Fischer rat airways exhibited high sensitivity to MCh. There was no relationship between responsiveness and baseline Ai in either strain. In a second experiment, we measured the rate of contraction of explanted airways from lungs inflated to 50, 75, and 100% of total lung capacity. The average rate of contraction in the first 15 s was higher in Fischer rat airways at each inflation volume. These data indicate that the hyperresponsiveness of the Fischer rat reflects the responsiveness of individual airways throughout the airway tree and are consistent with the notion that in this model hyperresponsiveness is an intrinsic property of airway smooth muscle.

Effect of nedocromil sodium on allergen-induced airway responses and changes in the quantity of airway smooth muscle in rats

BACKGROUND

Allergen exposures induce growth of airway smooth muscle in the Brown Norway rat.

OBJECTIVE

The purpose of the study was to examine the role of mediators associated with the early and late responses in the induction of airway smooth muscle growth.

METHODS

Nedocromil sodium was administered to block early and late responses in ovalbumin-sensitized and ovalbumin-challenged rats undergoing single or multiple challenges (5 times at 5-day intervals) with ovalbumin. Airway smooth muscle was quantitated by morphometry on lungs removed 2 days after the final challenge.

RESULTS

Nedocromil sodium administered before ovalbumin challenge blocked both the early and late responses. When administered 2 hours after ovalbumin challenge, it also blocked the late response. Rats undergoing challenge with aerosolized ovalbumin five times at 5-day intervals were also treated with nedocromil before (n = 10) or 2 hours after (n = 10) each ovalbumin inhalation, respectively. The quantity of airway smooth muscle standardized for size was greater after ovalbumin challenge (0.069 +/- 0.005) compared with saline controls (0.033 +/- 0.003, p < 0.005). Nedocromil significantly reduced the airway smooth muscle (0.036 +/- 0.003, p < 0.005) when administered before ovalbumin. However, the airway smooth muscle in rats that received nedocromil 2 hours after ovalbumin challenge (0.046 +/- 0.003), although lower than in ovalbumin-challenged rats (p < 0.01), was still significantly higher than in saline-treated rats (p < 0.05).

CONCLUSIONS

Allergen-induced early responses, late responses, and airway inflammation are antagonized by nedocromil. The mediators of both the early and late responses contribute to allergen-induced airway smooth muscle growth, a process that can be prevented by administration of nedocromil.

Mucociliary function in the mouse measured in explanted lung tissue

To develop a method for the study of mucociliary clearance in small-caliber airways, we investigated ciliary function in an in vitro lung tissue culture technique in mice. Lungs were excised from 45 anesthetized mice [weight 30.9 +/- 6.2 (SD) g] and inflated with 2% liquid agarose at 37 degrees C via the trachea. After cooling to 4 degrees C, the lungs were cut into 0.5- to 1.0-mm thick slices and cultured overnight. Ciliary beat frequency (CBF) was measured in airways cut in cross section using a computerized image processing system. In some experiments, charcoal particle transport (PT) in tangentially cut airways was also measured. Airway diameter ranged from 0.3 to 0.8 mm. In this preparation CBF was stable over a 3-h period and unaffected by minor pH changes. Both CBF and PT exhibited a linear dependency on temperature. CBF and PT were significantly correlated with each other. CBF at 37 degrees C (18.7 +/- 2.93 Hz) was almost twofold higher than values at 22 degrees C (9.74 +/- 3.11 Hz). Isoproterenol increased CBF in a dose-dependent fashion (50% effective concentration of 10(-6.75) M); the effect of isoproterenol could be blocked by propranolol. Administration of forskolin (10 microM) also increased both CBF and PT significantly. These findings demonstrate the feasibility of measuring the major aspects of mucociliary clearance in this system. This approach holds promise as a technique suitable to the investigation of both the small airways of humans and other large animals as well as of airways in murine genetic models of respiratory disease.

Computer-aided molecular modeling, synthesis, and biological evaluation of 8-(benzyloxy)-2-phenylpyrazolo[4,3-c]quinoline as a novel benzodiazepine receptor agonist ligand

Using computer-aided conformational analysis, based on molecular dynamics simulation, cluster analysis, and Monte Carlo techniques, we have designed and synthesized compounds in which a benzyloxy substituent has been incorporated into a series of pyrazoloquinoline benzodiazepine receptor (BZR) ligands. Earlier studies had shown that the benzyloxy group could act as part of the agonist pharmacophoric determinant in the beta-carboline ring system. Furthermore, the agonist beta-carboline had been correlated with a binding site orientation and volume fit for an agonist 6-phenylimidazobenzodiazepine carboxylate. The present study was undertaken to determine whether the benzyloxy substituent could be used as an agonist pharmacophoric descriptor for the phenylpyrazolo[4,3-c]quinolin-3-one BZR ligands. The results of a determination of GABA shift ratios for the synthetic ligands indicate that 8-(benzyloxy)-2-phenylpyrazolo[4,3-c]quinolin-3-one can be predicted to be an agonist at the BZR.

In vitro allergic bronchoconstriction in the brown Norway rat

The ovalbumin (OA)-sensitized Brown Norway rat (BN) demonstrates early-response (ER) and late-response (LR) allergic bronchoconstriction. To determine whether these responses could be replicated in vitro, we studied lung explants from 8-wk-old male BN rats (wt: 239 +/- 28 g), of which 19 were sensitized to OA (test) and 16 served as controls. Two weeks after sensitization, the animals' lungs were removed, filled with a 1% (wt/vol) agarose-containing solution at 37 degrees C, and cooled to 4 degrees C. Transverse slices (0.5 to 1.0 mm thick) were cut and cultured overnight. Airways were visualized with an inverted microscope and baseline images were obtained with a video camera. To study the ER, 40 airways from 15 test rats and 29 airways from 10 control rats were challenged with 2 micrograms OA and imaged each minute for 10 min. To study the LR, 40 airways from 12 test rats and 44 airways from 12 control rats were challenged with 2 micrograms OA and imaged each hour for 8 h. The maximal response (MR) for each airway was defined as the percent of airway closure. The ER and LR were both defined as an MR > or = mean + 2 SD of the controls. An ER occurred in 38 of 40 test and 2 of 29 control airways (mean MR: 42 +/- 24% versus 4 +/- 3%, p < 0.001), and was completely blocked by methysergide pretreatment in 13 airways.(ABSTRACT TRUNCATED AT 250 WORDS)

[Detection of DNA adducts and their persistence in leucocytes of benzene-exposed mice]

DNA adducts in peripheral leucocytes of mice injected intraperitoneally with benzene were assayed by 32P-postlabelling technique. Results showed two kinds, at least, of DNA adducts could be formed in the mice, and they could still be detected 3 weeks after exposure. It laid a preliminary basis for further studies on the DNA adducts as biological markers for monitoring occupational exposure to benzene.

Role of leukotriene D4 in allergen-induced increases in airway smooth muscle in the rat

The purpose of the study was to investigate whether allergen-induced hyperresponsiveness to methacholine and an increase in airway smooth muscle (ASM) in Brown Norway (BN) rats could be mediated by LTD4, an important mediator of allergic airway responses. Male BN rats, 8 to 12 wk of age, were sensitized with ovalbumin (OA). Rats were exposed 2 wk later to aerosols of saline (n = 6), OA (n = 8), or OA after pretreatment with the LTD4 antagonist MK-571 (2 mg/kg intraperitoneally, n = 9), on six occasions at 5-day intervals. Airway responsiveness to methacholine (the concentration required to double pulmonary resistance, EC200 RL) was measured immediately before the first aerosol exposure and 2 days after the last exposure. ASM was quantitated by morphometry, and areas were standardized for size using the epithelial basement membrane length (BM). Following OA challenges EC200 RL decreased from 6.5 to 3.1 mg/ml (p < 0.05) but did not change significantly after saline or OA exposures in MK-571-pretreated animals. ASM/BM2 in the large airways was significantly greater, 3.41 +/- 0.19 x 10(-3), after OA compared with 2.35 +/- 0.22 x 10(-3) for saline exposures (p < 0.01). The ASM/BM2 after OA exposures but with MK-571 pretreatment (2.75 +/- 0.25 x 10(-3)) was intermediate in value. The results indicate that both the increase in airway responsiveness and the increase in ASM following repeated antigen exposures appear to be mediated predominantly by LTD4.

Synthesis of (3'-5'),(2'-5')-linked di- and tri-adenylyl methylphosphonate analogs

Stereoselectivity was found during the coupling reaction, to form 2',5'- and 3',5'-linked di- and triadenylyl methylphosphonate. The configuration of phosphorus was determined by 1HNMR NOE.