Biomedical subjects

R Song

Publications and source records attributed to R Song.

At least 55 records · Page 3Linked to original sources

PubMed1999

[Hard palate lengthening by palatal suture expansion: an experimental study in dogs].

OBJECTIVE: Scar contraction and lack of bony support for soft palate in traditional surgery of cleft palate are main causes of a shortening soft palate and its developmental deficiency. The wound and scar also lead to aberration of facial growth. In order to resolve these problems, lengthening of hard palate by transverse palatal suture expansion was studied. METHODS: Six mongrel dogs of 8-week age were used in the study. Amalgam markers were implanted in the hard palate of the animal. A NiTi-shaped memory alloy (NiTi-SMA) arch wire with a force level of 600 g was used to expand the palato-maxillary suture with a retention period of 8 weeks. The dogs were killed at the age of 36 weeks. Serial X-ray and cephalometry were used to investigate the changes. RESULTS: The suture expansion was generally completed in 4 weeks. The distance of separation of the palatine bone and maxilla was 1.0 to 1.5 cm. Premaxilla became protrusive significantly at the beginning of the suture expansion, then restored gradually to its original position. The length of hard palate increased 4.6 to 5.9 mm by dry skull measurement. CONCLUSION: Hard palate could be permanently lengthened anterior-posteriorly by transverse palatal suture expansion.

Animals↗

PubMed1999

[The morphometric analysis of lung on protective effect of Chinese herbs 814 on elastase-induced emphysema in hamsters].

OBJECTIVE: To determine the protective effect of Chinese herbal medicine 814 on elastase-induced emphysema in hamsters. METHODS: Animals were injected intratrachealy with elastase for emphysematous models, prophylactic-therapeutic groups were administrate with 814 through esophagus two weeks before the instillation of elastase untill animals were killed at three different time at first, second, and third month. Pulmonary artery pressure, blood gas analysis, heart index and the ratio of dried weight to wet weight of lungs (WW/DW) were examined. The lung paraffin sections were measured mean linear intercept (MLI), mean alveolar number (MAN), ratio of parenchyma area to total area (PA/TA) by the microscope-computer morphometric analysis system. RESULTS: WW/DW in the prophylactic-therapeutic groups was recovered at the same level with the controls, whereas the emphysematous were significantly increased (P < 0.05); and compared with the emphysematous groups, the prophylactictherapeutic groups significantly decreased in MLI, increased in MAN and PA/TA (P < 0.001 or P < 0.05). CONCLUSIONS: Administration of 814 could partly inhibit the development of emphysema induced by elestase in hamsters.

Animals↗

PubMed1998

Expression of multidrug resistance protein/GS-X pump and gamma-glutamylcysteine synthetase genes is regulated by oxidative stress.

Expression of the MRP1 gene encoding the GS-X pump and of the gamma-GCSh gene encoding the heavy (catalytic) subunit of the gamma-glutamylcysteine synthetase is frequently elevated in many drug-resistant cell lines and can be co-induced by many cytotoxic agents. However, mechanisms that regulate the expression of these genes remain to be elucidated. We report here that like gamma-GCSh, the expression of MRP1 can be induced in cultured cells treated with pro-oxidants such as tert-butylhydroquinone, 2,3-dimethoxy-1, 4-naphthoquinone, and menadione. Intracellular reactive oxygen intermediate (ROI) levels were increased in hepatoma cells treated with tert-butylhydroquinone for 2 h as measured by flow cytometry using an ROI-specific probe, dihydrorhodamine 123. Elevated GSH levels in stably gamma-GCSh-transfected cell lines down-regulated endogenous MRP1 and gamma-GCSh expression. ROI levels in these transfected cells were lower than those in the untransfected control. In the cell lines in which depleting cellular GSH pools did not affect the expression of the MRP1 and gamma-GCSh genes, only minor increased intracellular levels of ROIs were observed. These results suggest that intracellular ROI levels play an important role in the regulation of MRP1 and gamma-GCSh expression. Our data also suggest that elevated intracellular GSH levels not only facilitate substrate transport by the MRP1/GS-X pump as previously demonstrated, but also suppress MRP1 and gamma-GCSh expression.

Biological Transport↗

PubMed1998

A new principle for unilateral complete cleft lip repair, the lateral columellar flap method.

This article presents a different method for unilateral complete cleft lip repair. The tissue deficiency of the medial lip segment is filled with a flap from the lateral surface of the columella, which is in continuity with the lip segment. The lateral columellar flap and the medial lip segment are lowered in one piece vertically downward to such a position that the height of the arch of the Cupid's bow is equal on both sides. No lateral advancement is done. The suture line of the medial and lateral lip segments is an uninterrupted straight line, which imitates the natural line of the philtral column. The repaired lip has more fullness than the lips repaired with the conventional methods. The procedure is described in detail.

Cleft Lip↗

PubMed1998

Apolipoprotein B-48 or its apolipoprotein B-100 equivalent mediates the binding of triglyceride-rich lipoproteins to their unique human monocyte-macrophage receptor.

Studies in animals and humans have demonstrated uptake of plasma chylomicrons (triglyceride-rich lipoprotein [TGRLP] of Sf>400) by accessible macrophages in vivo. One potential mechanism is via a unique receptor pathway we previously identified in human blood and THP-1 monocytes and macrophages for the lipoprotein lipase (LpL)- and apolipoprotein (apo) E-independent, high-affinity, specific binding of plasma chylomicrons and hypertriglyceridemic VLDL (HTG-VLDL) to cell-surface membrane-binding proteins (MBP 200, 235; apparent Mr 200, 235 kD on SDS-PAGE) that leads to lipid accumulation in vitro. Competitive binding studies reported here demonstrate that anti-apoB antibodies specifically block the high-affinity binding of TGRLP to this receptor on THP-1 cells and on ligand blots. LpL, which binds to an N-terminal domain of apoB, also inhibits TGRLP binding both to this site on THP-1s and to MBP 200, 235 by binding to apoB. Chylomicrons of Sf>1100 that contain apoB-48, but not apoB-100, bind specifically to MBP 200, 235, and this binding is blocked by anti-apoB IgG. In contrast, lactoferrin and heparin do not inhibit TGRLP binding. We conclude that the receptor-binding domain is within apoB-48 (or an equivalent in apoB-100) near the LpL-binding domain, but not a heparin-binding domain. Uptake of TGRLP by this mechanism could provide essential nutrients or, in HTG, cause excess lipid accumulation and foam cell formation.

Antibodies↗

PubMed1998

[A method of unilateral operation for early cleft palate repair].

OBJECTIVE: This paper presents a new method for cleft palate repair. METHOD: Six changes have been made to the conventional procedures. After all of these six changes have been carried out on one side of the palate, the operated side becomes completely relaxed. It can be moved both posteriorly and medially to lengthen the side of the palate and to contact with the cleft margin of the non-operated side without tension. Obviously, there is no need to perform the same surgical maneuvers on the other side again. The cleft is then closed by layers. RESULT: Totally 151 cases of unilateral and bilateral cleft palate have been repaired with this method. The age of these patients ranged from 4 months to 5 years. Postoperatively, there was neither one death nor one dehiscence. All of the baby patients who received treatment before they began to speak had good quality of speech or near normal speech function. CONCLUSION: In the unilateral operation, the surgical trauma, blood loss and time required for the operation are all less than that of conventional procedures which operate on both sides. It is a safer method for early cleft palate repair.

Age Factors↗

PubMed1998

[Effects of selenium polysaccharide and sodium selenite on blood selenium concentration and liver cytochrome P450 monooxygenase system in rat].

The effects of selenium polysaccharide and sodium selenite administered by single or repetitive intraperitoneal injection (i.p.) on blood selenium concentration, the activities of liver cytochrome P450, b5 as well as NAD(P)H cytochrome C reductase, glutathione S-transferase and glutathione were studied in rats. The biological effects of selenium polysaccharide and sodium selenite were also compared. The results indicated that the blood selenium concentration was increased rapidly and reached the peak in 2 hours followed by gradual decline after selenium polysaccharide and sodium selenite were i.p. injected at a dose of Se 0.6 mg/kg. The absorption and eliminating rates of Se from sodium selenite were faster than that from selenium polysaccharide. Administration of selenium polysaccharide and sodium selenite at a dose of 0.2 mg/kg by i.p. increased the blood selenium concentration to 2.6 and 2.1 times of those of control group, respectively, and the blood selenium concentration of selenium polysaccharide group was significantly higher than that of sodium selenite group (P < 0.05). The activities of liver cytochrome P450, b5 and GST were inhibited by selenium polysaccharide and sodium selenium in vivo and in vitro experiments. Those proteins were decreased to 57%, 70% and 62% of the control, respectively, by selenium polysaccharide which has particularly stronger effects on cytochrome P-450 monooxygenase system (P < 0.05). The two selenium compounds did not appear to affect the activity of NAD(P)H cytochrome C reductase. Both of the selenium polysaccharide and sodium selenite could enhance the activity of glutathion peroxidase significantly (P < 0.05).

Animals↗

PubMed1998

[Effect of herbs 814 on tumor necrosis factor a production from alveolar macrophages in vitro].

OBJECTIVE: To study the influence of herbs 814 on the secretion of tumor necrosis factor alpha (TNF-alpha) from hamster alveolar macrophages (AMs) in vitro and elucidate mechanism of herbs 814's prevention of emphysema. METHODS: AMs of hamster were collected by bronchial alveolar lavage (BAL). The lung lavage cells were adjusted to 5 x 10(5)/ml and seeded in each well of a 24-well tissue culture plates. The herbs 814 was added into these wells before or after lipopolysaccharide (LPS) stimulation and then cultured supernatants were collected. TNF-alpha production in the supernatants was tested by ELISA, TNF-alpha cytotoxicity was assayed using L929 cells which were susceptible to TNF-alpha and a monoclonal antibody (MAb) that neutralizes rhTNF-alpha was utilized to identify the cytotoxicity of cultured TNF-alpha. RESULTS: ELISA showed that TNF-alpha production in the supernatants with 814 added was lower than those either in LPS-stimulated or non LPS-stimulated supernatants and there was a significant decrease in the supernatants of higher concentration (1:5) of herbs 814. Cytotoxicity test showed that TNF-alpha cytotoxic activity in the supernatants into which herbs 814 was added was lower than one in the LPS-stimulated supernatants and there was a significant decrease in the supernatants of higher concentration (1:5) of herbs 814. Meanwhile, MAb significantly reduced cytotoxicity of LPS-stimulated culture supernatants. CONCLUSIONS: Herbs 814 could inhibit the secretion of TNF-alpha and prevent the lung damage mediated by TNF-alpha.

Animals↗

PubMed1997

Nurses' job satisfaction, absenteeism, and turnover after implementing a special care unit practice model.

The purpose of the study was to compare job satisfaction, absenteeism, and turnover between nurses working in a nurse-managed special care unit (SCU) and those working in traditional intensive care units (ICU). A case management practice model with a shared governance management model and minimal technology was implemented in the SCU while contrasting features of a primary nursing practice model with a bureaucratic management model and high technology already in place in the traditional ICU. Individual nurses' perceptions of and their preferences for the SCU practice model also were examined related to job satisfaction. Using analysis of covariance, greater satisfaction with a lower absenteeism rate was found in nurses working in the SCU. Nurses' perceptions and preferences for the SCU practice model were closely related to their job satisfaction and growth satisfaction. The findings suggest that individual perception and preference should be taken into account before implementing autonomy, authority, and responsibility at the organizational level to lead to the desired nurse outcomes in a given working environment.

Absenteeism↗

PubMed1997

Interleukin-12 promotes enhanced resistance to Listeria monocytogenes infection of lead-exposed mice.

The heavy metal lead (Pb) has been shown to downregulate various parameters of cell-mediated immune (CMI) responses. This inhibition of CMI responses by Pb is exemplified by a higher mortality rate upon infections with sublethal doses of a variety of pathogens. Unlike Pb, which lowers host resistance, interleukin-12 (IL-12) exerts a substantial stimulatory influence on the host response to intracellular bacteria such as Listeria monocytogenes. To explore the influence of IL-12 in mice rendered susceptible to Listerial infection by oral exposure to Pb, we determined bacterial burdens and production of interferon gamma (IFN-gamma). As expected, Pb-exposed mice had increased morbidity due to higher Listerial titers as compared to control mice. However, administration of exogenous IL-12 reversed the Pb-induced inhibition of host defense and boosted the resistance of the non-Pb-treated mice. The enhanced CMI responses observed in both IL-12-treated groups were accompanied with elevations of IFN-gamma in the sera and spleens. Significant reduction in the number of viable Listeria in Pb-exposed mice upon IL-12 administration suggests that the processes downstream of IL-12 production were intact in the Pb-exposed mice and that the inhibition by Pb was due to the lack of functional IL-12. Alternatively, the exogenous IL-12 may have overcome a downstream effect by enhancing an secondary pathway. Support for the former hypothesis is based on the observation that Pb induced elevated levels of p40 splenic messenger RNA since increased p40 expression would result from lack of IL-12 formation. Contrary to the IFN-gamma levels, significantly higher levels of IL-6 and corticosterone were observed in the sera and spleens of Pb-exposed mice upon infection, suggesting heightened stress in the absence of IL-12. Overall, the results suggest that an environmental pollutant such as Pb can enhance the stress response, which naturally occurs during an infection, and can further compromise health by lowering host resistance by altering cytokine levels.

Animals↗

PubMed1997

Interlaboratory and intralaboratory variabilities in the Environmental Lead Proficiency Analytical Testing (ELPAT) Program.

The Environmental Lead Proficiency Analytical Testing (ELPAT) Program evaluates over 400 laboratories that perform lead measurements in paints, soils, and dusts. A previous National Institute for Occupational Safety and Health study, based on the ELPAT data over a 3-year period (1992-1995), found no large biases among common hotplate and microwave digestion techniques, but did detect small consistent bias between two common instrumental methods. This study expands on the earlier study by examining the total sample variability and its variation components (interlaboratory and intralaboratory). A correlation model was used to separate the variation components by estimating a variation ratio. The correlation model leads to a more general approach than a sample pairing technique developed by Youden. This study found no significant evidence that the relative contribution of intralaboratory and interlaboratory variability to total variability changes with lead loading levels. There were no significant differences in the relative contribution of variation components among three most commonly used analytical methods (combinations of sample preparation techniques and instrumental methods). The interlaboratory relative standard deviation is about 1.7 times the intralaboratory relative standard deviation. Both variation components are important parts of total variation although the laboratory-to-laboratory (including analyst-to-analyst) difference is greater than the within laboratory (including sample-to-sample) variation.

Chemistry Techniques, Analytical↗

PubMed1997

Study of boron neutron capture therapy used neutron source with protons bombarding a thick 9Be target.

Neutron sources created by 4-, 3.5-, and 3-MeV protons striking a thick beryllium target were studied via the time-of-flight technique. Protons were accelerated by the Peking University 4.5 MV electrostatic accelerator. Two disk-shaped 9Be targets with thickness 1.5 and 3 mm were used in the measurements. The time-of-flight spectra were observed at zero degrees with respect to the incident proton beam. The analysis to these time-of-flight spectra is given. The time-of-flight spectra were converted to the energy spectra and compared to a neutron spectrum of 7Li(p, n)7 Be reaction with incident energy 2.5 MeV, which was also measured in this work. Restricted by the spectrometer itself, the threshold of the measurements is 400 keV. The results show that by using several MeV protons bombarding a thick beryllium target, reactions other than 9Be(p, n)9B produce significant contributions to the neutron yield with energy less than 1 MeV.

Beryllium↗

PubMed1997

[Dynamic study on the mutagenic activity of organic concentration of water from one branch port of Huangpu River].

From 1991 to 1994, we studied the mutagenicity of drinking water in Shanghai by seasons by Ames test. The results indicated that the mean value of mutagenic activity of organic concentration on TA98 is 162 revertants per liter. Studies on the four branch ports of Huangpu river showed that they contributed 74% of the total mutagenicity, which accounted for the predominant fraction of the mutagenic activity of Shanghai drinking water. The mutagenicity of Hongkou branch was the highest, accounting for 1/3 of the total mutagenic activity of the 4 branches. Studies showed that the mutagenic activity of organic concentration of Hongkou branch water was declining year by year, and factors affecting the mutagenic activity were analysed.

China↗

PubMed1997

[Miniplate osteosynthesis for multiple mandibular fractures].

This retrospective study involved 34 patients with multiple mandibular fractures. Monocortical miniplates were used for fixation of fractures followed by a short term intermaxillary fixation. All the patients were evaluated radiographically and clinically. The results indicated that all fractures healed uneventfully. No malocclusion, delayed union, injury of the nerves or teeth due to the procedure were found. We concluded that monocortical miniplate osteosynthesis is effective and reliable for multiple mandibular fractures, and a short term intermaxillary fixation is helpful for the healing of fracture.

Adolescent↗

PubMed1996

Roles of proteasomes, transporter for antigen presentation (TAP), and beta 2-microglobulin in the processing of bacterial or particulate antigens via an alternate class I MHC processing pathway.

Latex-OVA and bacteria expressing an OVA fusion protein were processed by macrophages via an alternate class I MHC (MHC-I) processing pathway to present OVA(257-264):Kb. This pathway was resistant to dipeptide aldehyde proteasome inhibitors and brefeldin A, unlike the cytosolic MHC-I pathway. TAP1-/- macrophages exhibited decreases in cell surface peptide-receptive MHC-I and binding of extracellular peptide during transient incubations. This may explain an apparent influence of TAP on alternate MHC-I processing. Alternate MHC-I processing by TAP1-/- cells was enhanced by preincubation at 26 degrees C or with beta 2-microglobulin to increase peptide-receptive MHC-I. Thus, peptides may bind to MHC-I within post-Golgi vacuolar organelles accessible to exogenous beta 2-microglobulin or on the cell surface (following peptide regurgitation).

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1996

Surface thiols of human lymphocytes and their changes after in vitro and in vivo activation.

Cellular thiols have long been known to play a role in cell activation and proliferation; however, the differential expression of surface thiols on the lymphoid subsets had not been described. Neither was it known whether alteration of surface thiols occurs after exposure to mitogens or infectious agents. Herein, an impermeant thiol-specific fluorescent probe was employed for flow cytometric analysis of surface thiols. Quantification of surface thiols on resting lymphocytes revealed that some subsets expressed different concentrations of surface thiols (CD19+ > CD8+ > CD4+). Furthermore, surface thiols increased on all subsets by 8 h after mitogenic activation. This increase was blocked by cycloheximide or monensin but not by actinomycin D or inhibition of glutathione synthesis by buthionine sulfoximine. In addition, bacitracin, an inhibitor of protein disulfide isomerase, inhibited the increase in surface thiols and DNA synthesis. Lymphocytes from HIV-infected individuals displayed increased surface thiols on CD19+ and CD4+ cells but not CD8+ cells. Although cellular thiols in general have been believed to play a role in protection against oxidants, signaling associated with cell growth, and apoptosis, there is now evidence that changes in exofacial thiols appear to be involved in some of these critical cell reactivities. Thus, quantitative and possibly qualitative differences in surface thiols correlate with membrane differences between lymphoid subsets and with their differential sensitivities to oxidative stress, which suggests that the mechanisms by which surface thiols are maintained and modified after activation are important cellular functions that need to be further evaluated.

Antigens, CD19↗

PubMed1996

Summary of the NIOSH guidelines for air sampling and analytical method development and evaluation.

Suggested guidelines for the development and evaluation of sampling and analytical methods for industrial hygiene monitoring have recently been published in a NIOSH technical report. These guidelines are based in part on various published approaches for method development and evaluation and serve as an attempt at a more unified experimental approach. This paper presents some salient features of this unified approach for method development and evaluation. The basic goal of the approach is to determine if the method under study meets the criterion to produce a result that fell within 25% of the true value 95 times out of 100 on average, although other factors of method performance are evaluated. The experiments proposed for the evaluation of method performance include determination of analytical recovery from the sampler, sampler capacity, storage stability of samples and effect of environmental factors. Evaluation criteria for the experimental data and procedures for the calculation of method bias, precision and accuracy are also included.

Air Pollutants, Occupational↗

PubMed1996

Laboratory and analytical method performance of lead measurements in paint chips, soils, and dusts.

The National Lead Laboratory Accreditation Program (NLLAP) recognizes laboratories capable of analyzing lead in paints, soils, and dusts. NLLAP requires successful participation in the Environmental Lead Proficiency Analytical Testing (ELPAT) program. For paint chip analyses, laboratory-to-laboratory variability is about 10% relative standard deviation (RSD) for lead levels near 0.5%, the HUD definition of lead-based paint. For soil analyses, RSDs are about 9 to 10% near relevant federal soil standards and 16% near the lowest state bare soil standard that currently exists. For dust wipe analyses, RSDs range from 10 to 16% for lead levels near relevant HUD standards. Of participating laboratories, 92 to 93% consistently meet ELPAT performance limits. A variety of analytical methods gives similar results. No conclusive significant differences were found among most frequently used hotplate and microwave sample preparation techniques. In addition, several participating laboratories have successfully used ultrasonic extraction methods, a method suitable for use at abatement sites. The three most frequently used instrumental techniques, flame atomic absorption (FAA), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and graphite furnace atomic absorption show no statistically significant differences in ability to meet ELPAT performance limits. However, small statistically significant biases between these methods sometimes occur. The magnitude of biases is less than 5% of the corresponding laboratory mean near relevant federal standards except for lead levels near the lowest HUD lead wipe standard, where biases can be as high as 8%. Other instrumental methods that have been used successfully include ICP-mass spectroscopy, direct current plasma-atomic emission spectroscopy, dithizone spectrophotometry, and anodic stripping voltametry.

Accreditation↗