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Biomedical subjects

S B Liu

Publications and source records attributed to S B Liu.

At least 19 recordsLinked to original sources

Modulational instability of short-wavelength ion waves in strongly coupled dusty plasmas.

Modulational instability of electrostatic short-wavelength ion waves in plasmas containing strongly coupled dusts with variable charge is considered. The evolution equations for the ion waves modulated by slow dust motion are obtained. The instability behavior differs considerably from that of plasmas with weakly coupled dust grains and depends strongly on the Coulomb coupling parameter as well as the dust-charge relaxation rate.

Journal Article↗

Three-dimensional optical trajectory tracing and energy deposition of a laser beam in a laser-driven fusion.

A convenient method of three-dimensional ray tracing is suggested in the geometrical optical approximation, in which the laser ray propagation is completely based on the concept of optical trajectory tracing rather than depending upon the effective force and propagation time. This tracing has two obvious advantages that the direct application of Snell's law can be avoided when a ray crosses a different density zone and that to any desired accuracy it takes much less computation time than existing tracing. For Gaussian light beam propagation, in a spherically symmetric plasma atmosphere, the results emphasize that the deposition uniformity is strongly dependent not only on the wavelength of the laser but also on the temperature of the plasma.

Journal Article↗

[Application of molecular markers-assisted selection of wx genes in breeding the waxy wheat].

Chinese Spring and its null-tetrasomic lines were used to identify the specific bands of STS-marker and microsatellites (SSR) marker of wx genes. Twelve varieties and five waxy wheat lines were screened with these two markers, and the results are in agreement with those from Wx subunits SDS-PAGE. A F2 segregating population from cross Jiangsu Baihuomai x Kanto 107 was also detected by molecular markers, not only eight wx genotypes were developed while three genotypes did not exist in the nature, but also the first batch of waxy wheat lines were bred. The Jiangsu Bainuomai improvement population was screened, and six 7D momosomic plants with wx-D1b were obtained, which could provide materials for waxy wheat breeding. Application molecular markers of wx genes will improve the selection procedure for the waxy wheat and good noodle-quality wheat.

Breeding↗

[The detection and analysis of human papillomavirus in infantile respiratory tract papillomas by PCR/RFLP study].

OBJECTIVE: To study the relationship between human papillomavirus (HPV) and pathological characteristics of the patients with infantile respiratory tract papillomas (IRP). METHOD: Thirteen cases of infantile respiratory tract papillomas tissue were analysed for Papillomavirus by the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). RESULT: The amplified products of the HPV-L1 region by PCR by using the consensus primers showed that the presence of HPV was 100 percent. Eight cases(61.5 percent) were positive for HPV6 only. Four cases (30.8 percent) were positive for HPV11 only. One case (7.7 percent) showed the presence of HPV18. None were positive for HPV16, 31, 33, 52, 58. CONCLUSION: Infantile respiratory tract papillomas are associated with HPV6, 11, 18 infection, but the subtypes of HPV are not associated with clinical pathological characteristics.

Child, Preschool↗

Dynamic nuclear polarization in pulsed ENDOR experiments.

Properly prepared pulse sequences of microwave and radio frequency have been employed to investigate the effect of polarization transfer from the polarized photo excited triplet state of pentacene in p-terphenyl crystals to the surrounding protons in pulsed ENDOR experiments. The ENDOR signal, measured as the change of electron spin echo (ESE) amplitude, is affected by the mode of RF pulses. When B0 parallelx (the long molecular axis), the ESE amplitude of the high-field transition of the triplet state changes from the maximum positive to zero with a pi RF pulse, and to the maximum negative with a 2pi pulse, while that of the low-field transition changes from nearly zero to the maximum negative as the RF pulse width increases. The effect is attributed to the strong electron spin polarization produced in the creation of the photoexcited triplet state and the subsequent efficient electron- nuclear polarization transfer process.

Magnetic Resonance Spectroscopy↗

Acceleration and double-peak spectrum of hot electrons in relativistic laser plasmas.

A spectrum equation of hot electrons in relativistic laser plasmas is derived in which two hot-electron population peaks appear as the laser strength parameter reaches a threshold. These calculations can explain the generation of very hot electrons with several tens of MeV energy and two hot-electron population peaks observed in the recent experiments.

Journal Article↗

Randomized, controlled trial of high-dose intravenous pyridoxine in the treatment of recurrent seizures in children.

To determine the efficacy of pyridoxine in treating seizures, 90 infants and children with recurrent convulsions primarily due to acute infectious diseases were enrolled in the present study. Forty patients were treated with high-dose pyridoxine (30 or 50 mg/kg/day) by intravenous infusion, and 50 subjects served as controls. Antiepileptic drugs and other therapies were similar in the two groups except for pyridoxine. Clinical efficacy criteria were based on the frequency of convulsions per day and on the duration of individual seizures after therapy was initiated. The results indicated that total response rates in the pyridoxine group and control group were 92.5% and 64%, respectively (chi-square = 14.68, P < .001). After initiation of therapy, seizures resolved after 2.4 +/- 1.4 days in the pyridoxine group and after 3.7 +/- 2.0 days in the control group (t = 3.67, P < .001). No adverse effects of pyridoxine were apparent during the observation period. We conclude that pyridoxine is an effective, safe, well-tolerated, and relatively inexpensive adjunct to routine antiepileptic drugs for treatment of recurrent seizures in children.

Anticonvulsants↗

Absence of androgen-mediated transcriptional effects in osteoblastic cells despite presence of androgen receptors.

Androgen excess and deficiency affect skeletal maturation and bone cell function. Understanding the molecular basis for these androgen effects could improve therapy/prevention of short stature and osteoporosis. Androgens act through binding to androgen receptors (ARs), which modulate gene transcription via interactions with DNA response elements on target genes. Because osteoblasts contain ARs at levels just below certain androgen-sensitive tissues, we sought to define the function of AR in a number of commonly used osteoblastic cell lines. Presence and quantification of AR protein and mRNA were evaluated by ligand binding assay, western blotting, and RNAse protection assay. AR-containing osteoblastic cell lines were exposed to nonaromatizable androgens and effects on gene expression were assessed. We found no evidence for direct effects of androgen on endogenous genes nor was androgen involved in modulation of parathyroid hormone effects on early gene activation. Androgen-sensitive reporter gene constructs were stimulated by androgen only when AR cDNA expression vectors were introduced into cells by cotransfection. We conclude that, in commonly used osteoblastic cell lines, the presence of AR at the levels described here does not guarantee androgen transcriptional activity. The effects of androgen on bone in vivo may involve direct stimulation of osteoblastic cells in a different setting or stage of differentiation. Alternatively, androgen may act on bone cells other than osteoblasts, or through metabolic conversion to estrogens.

Androgens↗

Risk factors for peptic ulcer in Shanghai.

OBJECTIVES: To investigate the combined effects of Helicobacter pylori infection and traditional risk factors for peptic ulcer. METHODS: A case-control study was conducted in chemical factories in Shanghai, China. The cases were 500 people with peptic ulcer randomly selected from all staff who met the selection criteria. The controls were 500 employees randomly selected from the same factories as the cases. RESULTS: The infection rate for H. pylori was 81% among the cases and 70% among the controls and 85% of all ulcers were duodenal. Current cigarette smoking was common among male cases (80%) and male controls (64%). Univariate analysis suggested that male gender, age, lower socioeconomic status, cigarette smoking, family history of peptic ulcer and infection with H. pylori were all associated with increased risk of peptic ulcer. Separate analyses were performed by sex and occupational group to avoid confounding by cigarette smoking and age. Multivariate analyses showed that for all women and for male staff members, only family history was significantly predictive of peptic ulcer or duodenal ulcer. Among male workers or drivers, however, all the major risk factors were statistically significantly associated with increased risk. CONCLUSIONS: In a population where the rate of infection with H. pylori is high, the traditional risk factors for peptic ulcer or duodenal ulcer (i.e. family history, male gender, increasing age, lower socioeconomic status and cigarette smoking) are still significant predictors of increased risk of ulcer. If men with ulcers (or with a family history of peptic ulcer) gave up cigarette smoking, morbidity could be reduced in this population.

Adult↗

Simple non-radioactive methods of analysis of polymorphic markers flanking human apolipoprotein C-III gene.

We describe two rapid non-radioactive methods for the analysis of polymorphic markers in the flanking region of the human apolipoprotein CIII gene. The polymorphic markers comprise previously described variable sites located upstream from the coding region of the gene (C-641-->A, G-630-->A, T-625-->deletion, C-482-->T, and T-455-->C) and a polymorphic SstI/SacI site in the apoC-III 3' untranslated region. The first method is allele-specific amplification (ASA) with primers complementary to the normal ("wild-type") allele or to the variable ("mutant") allele at their 3' ends. The other is allele-specific oligonucleotide hybridization (ASO hybridization) with pairs of probes labeled by digoxigenin. Comparison with sequencing data showed that both methods are reliable for polymorphism analysis.

Apolipoprotein C-III↗

Immunological status of patients with obstructive jaundice and immunostimulatory effect of arginine.

Sepsis is a major factor in the high mortality and morbidity following diagnostic and therapeutic procedures in patients with obstructive jaundice. The reasons for this increased susceptibility to infection are not fully understood. We therefore observed prospectively changes in immunological status of patients with obstructive jaundice in the perioperative period and studied immunological effects of perioperative arginine therapy. The results showed that there was a significant reduction in interleukin 2 (IL-2) production, interleukin 2 receptor (IL-2R) expression and lymphocyte response to phytohemagglutinin (PHA) mitogen in patients with obstructive jaundice compared with normal controls. After operation, the immune suppression in patients with obstructive jaundice was more significant. Arginine is a known T lymphocyte stimulator. Perioperative supplement with arginine significantly enhanced the immune function of patients with obstructive jaundice, the mechanism being related to increased IL-2 production and IL-2R expression.

Adjuvants, Immunologic↗

Effects of surgical trauma on interleukin 2 production and interleukin 2 receptor expression.

To elucidate the mechanism of immunologic abnormalities induced by surgical trauma, we measured interleukin 2 (IL-2) production and IL-2 receptor expression in peripheral blood mononuclear cells from 16 patients with cholelithiasis. Compared with preoperative levels, IL-2 production and IL-2 receptor expression were significantly reduced on postoperative day 4, and the reduction was consistent with the suppression of lymphocyte proliferative response to phytohemagglutinin.

Adult↗

Interleukin 2 production and its relationship with T lymphocyte subsets in patients with obstructive jaundice.

Sepsis remains a major risk in the high mortality and morbidity after surgery for obstructive jaundice. The reasons for the increased susceptibility to infection are unknown. This study examined interleukin 2 (IL-2) production and the lymphocyte response to PHA mitogen in 31 patients with obstructive jaundice. Among them, 18 patients were simultaneously investigated by enumeration of T lymphocyte subsets in peripheral blood with APAAP technique. The results showed that the patients had significantly decreased IL-2 production and lymphocyte response to PHA mitogen. The percentage of Leu 3a (helper/inducer T cell) in the patients was significantly lower than that in normal controls. Leu 3a/Leu 2a (suppressor/cytotoxic T cell) ratio was significantly lower in these patients. The reduction of IL-2 production correlated significantly with the suppression of lymphocyte proliferation but not with the percentage of Leu 3a cells. From these results, it may be suggested that the reduction of IL-2 production in the patients with obstructive jaundice is an important reason for the suppression of T lymphocyte proliferative response, not merely a reflection of the decrease of helper T cells.

Adult↗

[A study about the ability of interleukin-2 production, interleukin-2 receptor expression by lymphocytes from patients with lung cancer].

The ability of Interleukin-2 (IL2) production, IL2 receptors expression and proliferative response by lymphocytes from 48 patients with primary lung cancer and 50 normal controls were studied. The results indicated that after lymphocytes were stimulated with PHA for 48 hours, the IL2 activity produced by lymphocytes from lung cancer patients was significantly reduced, the mean IL2 activity was only about 30% of that of normal controls, with lung cancer progression, the lymphocytes IL2 production tended to be more depressed. The lymphocytes IL2 receptors expression and proliferative response in cancer patients were also significantly decreased. Our study suggested that impaired IL2 production and IL2 receptors expression by lymphocytes from lung cancer patients may depress the IL2 dependent anti-tumor reaction in vivo.

Adenocarcinoma↗

Altered lymphocyte subsets and natural killer cells of patients with obstructive jaundice in perioperative period.

Sepsis is a common and occasionally lethal complication of obstructive jaundice. The reasons for the increased susceptibility to infection are not fully understood. This study was conducted to examine lymphocyte subsets and natural killer cells of patients with obstructive jaundice in perioperative period. In these patients, when compared with normal controls, there was a significant reduction in the percentage of Leu 4 (pan T lymphocytes), Leu 3a (T helper cells) and Leu 7 (natural killer cells) before operation, and the immune suppression induced by surgical operation was more marked and persistent.

Adult↗

Effect of experimental acute hypertension of the biliary tract on hemodynamics and activity of the major splanchnic nerve in rabbits.

An experimental study of the effect of acute biliary hypertension on hemodynamics and activity of the major splanchnic nerve was conducted in Japanese big ear white rabbits. A catheter with an inflatable rubber bag fixed to its anterior end was inserted into the extrahepatic biliary duct via the duodenum, and a biliary high pressure of 20 kFa (150 mmHg) was created and maintained for 2 h by inflating the bag with water. The right major splanchnic nerve was isolated and the impulse frequencies of the nerve were recorded during the study. Arterial blood pressure was also dynamically monitored. A significant fall of the arterial blood pressure (P less than 0.01) and an increase in impulse frequency of the nerve (P less than 0.01) were found in this "simple type" acute biliary high pressure without infection. Biliary decompression immediately eliminated these abnormalities (P less than 0.01). The drop in blood pressure was much less prominent if the right splanchnic nerve was blocked prior to biliary high pressure.

Animals↗

Gravitational forces on the chest wall.

The gravitational work of breathing was determined by measuring the vertical motion of body mass. The subject, seated or lying supine on a force platform, performed breathing maneuvers in which rib cage volume (Vrc) and abdominal volume (Vab) were changed in varying proportions. The increment in the vertical force exerted on the platform and Vrc and Vab were measured over the course of each maneuver. The force signal was integrated twice with respect to time to obtain the change in the product of mass and height of the subject. This was multiplied by the gravitational acceleration to obtain the change in the gravitational potential (Ug). Simultaneous values of Ug, Vrc, and Vab were taken from the data, and the values of the coefficients for which the following equation best fit these values were determined: Ug = a1 Vrc + a2 Vab + (1/2)a11 Vrc2 + a12 Vrc Vab + (1/2)a22 Vab2. The coefficients a1 and a2 can be interpreted as the values of the expiratory gravitational forces on the rib cage and abdomen, respectively. In the seated posture, the force on the rib cage is expiratory and the force on the abdomen is inspiratory; the magnitudes of both are approximately 8 cmH2O. In the supine posture, both are expiratory forces of approximately 9 cmH2O. The coefficients of the quadratic terms in Ug are all positive, and the gravitational work per unit volume of chest wall expansion increases with increasing volume in both postures. The coefficients of the quadratic terms can be interpreted as gravitational contributions to the elastances of the compartments.

Acceleration↗