Biomedical subjects

R Song

Publications and source records attributed to R Song.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Suture distraction osteogenesis for closure of cleft palate in the dog: long-term effect and its influence on facial growth].

OBJECTIVE: The purpose of the study was to evaluate the long-term effect and its influence on facial growth of suture distraction osteogenesis for closure of cleft palate. METHOD: 14 Beagle dogs were used in the study. Six of them were in the experimental group, eight served as the control. Direct measurements were taken on dry skulls of the dogs and the data were analysed statistically. RESULTS: The results showed that bony healing at the midline between the two horizontal portions of the palatine bones appeared in all the experimental dogs. There were no significant differences in the variables of facial length and height between the two groups. But the facial width and the distance between the two vertical portions of the palatine bones were significantly less in the experimental dogs than the control. CONCLUSIONS: It is suggested that bony repair of the cleft could be accomplished permanently with the technique of sutural distraction. This technique had no influence on facial length and height growth, but could led to underdevelopment of the width of the face and the respiratory tract of the palatal portion.

Animals↗

PubMed2000

[A serial histological study on suture expansion osteogenesis for cleft palate closure].

OBJECTIVE: The purpose of this study was to know the process of tissue response and regeneration in the palato-maxillary suture under tensile forces. METHODS: Sutural tissue changes after 3, 7, 14, 28, 56 days of suture expansion were examined histologically and fluorescently. RESULTS: It was found that a cyst-like zone appeared in the conjuncture of bony front and sutural connective tissue at the early stage of sutural expansion. Then a great amount of osteoblasts and fibroblasts proliferated. New bone deposited along the septum and the front of the cyst until the new bone front formed and the suture restored its original morphology. CONCLUSIONS: The findings suggested that sutural expansion be a process of bone tissue regeneration and fibrous tissue repair.

Animals↗

PubMed2000

[Applied anatomy of arterial supply for the soft palate].

OBJECTIVE: The correct design of a myomucosal or mucosal flap of the soft palate in the surgical procedure for cleft palate and velopharyngeal incompetence should be made with a thorough knowledge of the arterial supply for the soft palate, which is an important premise for functional rehabilitation of the soft palate postoperatively. METHODS: Anatomical dissection was undertaken in 14 cadavers (10 normal adults, 2 normal newborns and 2 newborns with cleft lip & palate). The arteriography and histological studies have been used in 10 newborn and 6 aborted fetuses. RESULTS: The results showed that the arterial supply of the soft palate is multi-original and the principal artery is the ascending palatal artery. Its anterior and posterior branches are myomucosal perforators. The other vessels to supply the soft palate are direct mucosal branches, which include the lesser palatine artery, the palatal branch of the ascending pharyngeal artery and the tonsillar artery. All above arteries anastomose under the mucosal, muscular and fascial layers in the soft palate. In cleft cases, all arteries in the soft palate are displaced anterior-laterally because of the deformities of the palatal muscles and bone structure. CONCLUSIONS: This study supports the facts that the major blood supply of the soft palate comes from ascending palatine artery and the generous arterial anastomosis of the velum allows it to tolerate the proper dissection during palatoplasty. We believe that decreasing the damage of the intrapalatal vascular supply by carefully dissection around the hamulus is very important to prevent wound break down, muscular fibrosis, flap failure, and also is the basis of design for surgical procedure and postoperative functional recovery in cleft palate patients.

Adult↗

PubMed2000

[Preventive and therapeutic effect of Chinese herbs naofeikang on experimental emphysema and pulmonary artery hypertension in hamsters].

OBJECTIVE: To observe preventive and therapeutic effect of Chinese herbs Naofeikang on hypoxic pulmonary artery hypertension of elastase-induced emphysema hamsters and investigate its mechanism. METHODS: Hamsters for 30 days after intratracheally-instilled elastase, were kept in hypoxia environment under normal atmospheric pressure for 15 days, 50 hamsters were divided into prevention group (Prv), treatment group (T), emphysema + hypoxia (EH), and control group(N). Mean pulmonary artery pressure (MPAP) was measured before hamsters were killed. And then right ventricle hypertrophy index (RVHI) was measured, as well as circulating endothelial cells (CEC) and cells recoveries from bronchoalveolar lavage fluid (BALF) were counted. Meanwhile, pulmonary tissue changes were studied under light microscope with morphometric analysis. RESULTS: Compared with EH group, MPAP, CEC, and cells recoveries of BALF of Prv and T groups were significantly decreased (P < 0.05 or P < 0.01); Mean linear intercept and percentage of arterial media area of Prv and T groups had totally a significant difference (P < 0.01) in comparison with EH group. CONCLUSIONS: Chinese herbs Naofeikang could lower pulmonary hypertension, preserve vessel endothelial cells and lessen the inflammatory reaction in pulmonary tissue. Thereby, it could hinder the further development of emphysema and inhibit the remodeling of pulmonary small artery.

Animals↗

PubMed1999

Thermolabile H-2Kb molecules expressed by transporter associated with antigen processing-deficient RMA-S cells are occupied by low-affinity peptides.

RMA-S cells do not express functional TAP, yet they express MHC class I molecules at the cell surface, especially at reduced temperatures (26 degrees C). It is generally assumed that such class I molecules are "empty," devoid of any associated peptide. A radiochemical approach was used to label class I-associated peptides and to determine the extent to which Kb molecules in RMA-S cells are associated with peptides. These studies revealed that at 26 degrees C Kb molecules in RMA-S cells are occupied with self-peptides. Such peptides stably associate with Kb at 26 degrees C but easily dissociate from them at 37 degrees C, suggesting low-affinity interactions between Kb and the associated peptides. At 26 degrees C, at least some of these Kb molecules are stably expressed in a peptide-receptive state on the cell surface, whereas at 37 degrees C they are short lived and are only transiently capable of binding and presenting exogenously supplied OVA 257-264 peptide for presentation to CD8+ Kb-restricted T lymphocytes. Thus contrary to current models of class I assembly in TAP-deficient RMA-S cells, the presumably "empty" molecules are in fact associated with peptides at 26 degrees C. Together, our data support the existence of an alternative mechanism of peptide binding and display by MHC class I molecules in TAP-deficient cells that could explain their ability to present Ag.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Phagosomes are fully competent antigen-processing organelles that mediate the formation of peptide:class II MHC complexes.

During the processing of particulate Ags, it is unclear whether peptide:class II MHC (MHC-II) complexes are formed within phagosomes or within endocytic compartments that receive Ag fragments from phagosomes. Murine macrophages were pulsed with latex beads conjugated with OVA. Flow or Western blot analysis of isolated phagosomes showed extensive acquisition of MHC-II, H-2M, and invariant chain within 30 min, with concurrent degradation of OVA. T hybridoma responses to isolated subcellular fractions demonstrated OVA (323-339):I-Ad complexes in phagosomes and plasma membrane but not within dense late endocytic compartments. Furthermore, when two physically separable sets of phagosomes were present within the same cells, OVA(323-339):I-Ad complexes were demonstrated in latex-OVA phagosomes but not in phagosomes containing latex beads conjugated with another protein. This implies that these complexes were formed specifically within phagosomes and were not formed elsewhere and subsequently transported to phagosomes. In addition, peptide:MHC-II complexes were shown to traffic from phagosomes to the cell surface. In conclusion, phagosomes are fully competent to process Ags and generate peptide:MHC-II complexes that are transported to the cell surface and presented to T cells.

Animals↗

PubMed1999

Frequency dependence of EPR signal-to-noise.

Direct measurements of electron spin-echo signal and noise in well-characterized X-band and S-band spectrometers agree with predictions of frequency dependence based on first principles. For the particular spectrometers compared, the echo at 9.52 GHz was 9.5 times larger than the echo at 2.68 GHz, after scaling for differences in spectrometer gain. The calculated ratio was 7.6. This result contrasts with prior predictions that the frequency dependence would be much greater.

Electron Spin Resonance Spectroscopy↗

PubMed1999

Absolute EPR spin echo and noise intensities.

EPR signal and noise, calculated from first principles, are compared with measured values of signal and noise on an S-band (ca. 2.7 GHz) EPR spectrometer for which all relevant gains and losses have been measured. Agreement is within the uncertainty of the calculations and the measurements. The calculational model that provided the good agreement is used to suggest approaches to optimizing spectrometer design.

Electron Spin Resonance Spectroscopy↗

PubMed1999

Non-kramers ENDOR and ESEEM of the S = 2 ferrous ion of [Fe(II)EDTA](2-).

We report here the first non-Kramers (NK) ESEEM and ENDOR study of a mononuclear NK center, presenting extensive parallel-mode ESEEM and ENDOR measurements on the S(t) = 2 ferrous center of [Fe(II)ethylenediamine-N,N,N',N'-tetraacetato](2-); [Fe(II)EDTA)](2-). The results disclose an anomalous equivalence of the experimental patterns produced by the two techniques. A simple theoretical treatment of the frequency-domain patterns expected for NK-ESEEM and NK-ENDOR rationalizes this correspondence and further suggests that the very observation of NK-ENDOR is the result of an unprecedentedly large hyperfine enhancement effect. The mixed nitrogen-carboxylato oxygen coordination of [Fe(II)EDTA](2-) models that of the protein-bound diiron centers, although with a higher coordination number. Analysis of the NK-ESEEM measurements yields the quadrupole parameters for the (14)N ligands of [Fe(II)EDTA](2-), K = 1.16(1) MHz, 0 </= eta </= 0.05, and the analysis indicates that the electronic zero-field splitting tetragonal axis lies along the N-N direction.

Chemical Phenomena↗

PubMed1999

Carnosine protects against excitotoxic cell death independently of effects on reactive oxygen species.

The role of carnosine, N-acetylcarnosine and homocarnosine as scavengers of reactive oxygen species and protectors against neuronal cell death secondary to excitotoxic concentrations of kainate and N-methyl-D-aspartate was studied using acutely dissociated cerebellar granule cell neurons and flow cytometry. We find that carnosine, N-acetylcarnosine and homocarnosine at physiological concentrations are all potent in suppressing fluorescence of 2',7'-dichlorofluorescein, which reacts with intracellularly generated reactive oxygen species. However, only carnosine in the same concentration range was effective in preventing apoptotic neuronal cell death, studied using a combination of the DNA binding dye, propidium iodide, and a fluorescent derivative of the phosphatidylserine-binding dye, Annexin-V. Our results indicate that carnosine and related compounds are effective scavengers of reactive oxygen species generated by activation of ionotropic glutamate receptors, but that this action does not prevent excitotoxic cell death. Some other process which is sensitive to carnosine but not the related compounds is a critical factor in cell death. These observations indicate that at least in this system reactive oxygen species generation is not a major contributor to excitotoxic neuronal cell death.

Animals↗

PubMed1999

Ultrasonic extraction and portable anodic stripping voltammetric measurement of lead in paint, dust wipes, soil, and air: an interlaboratory evaluation.

Recent studies have demonstrated the utility of ultrasonic extraction (UE), followed by portable anodic stripping voltammetry (ASV), for the on-site determination of lead in environmental and industrial hygiene samples. The aim of this work was to conduct an interlaboratory evaluation of the UE-ASV procedure, with a goal of establishing estimates of method performance based on results from collaborative interlaboratory analysis. In this investigation, performance evaluation materials (PEMs) with characterized lead concentrations were used for interlaboratory testing of the UE-ASV procedure. The UE-ASV protocol examined has been promulgated in the form of two separate national voluntary consensus standards (one for UE and another for electroanalysis, which includes ASV). The PEMs consisted of characterized and homogenized paints, soils, and dusts (the last of which were spiked onto wipes meeting national voluntary consensus standard specifications), and air filter samples (mixed cellulose ester membrane) generated using characterized paints within an aerosol chamber. The lead concentrations within the PEMs were chosen so as to bracket pertinent action levels for lead in the various sample matrices. The interlaboratory evaluation was conducted so as to comply with an applicable national voluntary consensus standard that can be used to estimate the interlaboratory precision of a given analytical test method. Based on the analytical results reported by the participating laboratories, relative standard deviations (RSDs) for repeatability and reproducibility were computed for three different lead contents of the four PEMs. RSDs for repeatability were 0.019-0.100 for paints; 0.030-0.151 for soils; 0.085-0.134 for dust wipes; and 0.095-0.137 for air filters. RSDs for reproducibility were 0.127-0.213 for paints; 0.062-0.162 for soils; 0.085-0.134 for dust wipes; and 0.114-0.220 for air filters. With the exception of one of the air filter samples and one of the paint samples, the precision estimates were within the +/- 20% precision requirement specified in the US Environmental Protection Agency National Lead Laboratory Accreditation Program (NLLAP). The results of this investigation illustrate that the UE-ASV procedure is an effective method for the quantitative measurement of lead in the matrices evaluated in this study.

Air Pollution, Indoor↗

PubMed1999

Peptide-receptive class I major histocompatibility complex molecules on TAP-deficient and wild-type cells and their roles in the processing of exogenous antigens.

These studies addressed the nature and origin of peptide-receptive class I major histocompatibility complex (MHC-I) molecules used to present exogenous antigens. Peptide-receptive Kb molecules in transporter for antigen presentation (TAP)1-/- and TAP1+/+ macrophages were quantitated by exposing cells to exogenous ovalbumin (OVA)(257-264) peptide and then measuring OVA(257-264):Kb complexes with a T hybridoma assay or flow cytometry (using a complex-specific antibody). Relative to TAP1+/+ cells, TAP1-/- cells had decreased levels of pre-existing cell-surface peptide-receptive MHC-I molecules at 37 degrees. With continued exposure of viable cells to peptide, however, TAP1-/- and TAP1+/+ cells formed similar levels of OVA(257-264):Kb complexes, suggesting that nascent labile MHC-I molecules were captured and stabilized by exogenous peptide. Brefeldin A inhibited generation of OVA(257-264):Kb complexes on TAP1-/- (but not TAP1+/+) cells at 37 degrees, confirming the importance of a flux of unstable nascent MHC-I molecules in TAP1-/- cells at 37 degrees. In contrast, at 26 degrees both TAP1-/- and TAP1+/+ cells expressed brefeldin A-resistant, peptide-receptive MHC-I molecules at similar levels. Alternate MHC-I processing of exogenous particulate antigen correlated with ability to present exogenous peptide. Thus, processing was brefeldin A-sensitive with TAP1-/- macrophages at 37 degrees, but brefeldin A-resistant with TAP1+/+ cells at 37 degrees, as well as with TAP1+/+ or TAP1-/- cells at 26 degrees. We conclude that alternate MHC-I antigen processing normally utilizes pre-existing MHC-I molecules, but TAP1-/- cells at 37 degrees mainly use nascent MHC-I molecules, because of a lack of pre-existing, stable, peptide-receptive MHC-I molecules. The results support a vacuolar processing mechanism with binding of peptides to MHC-I molecules in post-Golgi compartments or on the cell surface.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Evaluation of novel human immunodeficiency virus type 1 Gag DNA vaccines for protein expression in mammalian cells and induction of immune responses.

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) are an important parameter of host defenses that limit viral replication after infection. Induction of effective CTL against conserved viral proteins such as Gag may be essential to the development of a safe and effective HIV type 1 (HIV-1) vaccine. DNA vaccination represents a novel strategy for inducing potent CD8(+) CTL responses in vivo. However, expression of HIV-1 structural proteins by DNA vectors has been hampered by a stringent requirement for coexpression with other viral components, such as Rev and RRE. Furthermore, even with Rev and RRE present, the level of expression of HIV-1 Gag, Pol, or Env is very low in murine cells. These problems have limited our ability to address the key issue of how to generate effective CTL responses to Gag in a mouse model. To overcome this problem, we compared several novel DNA expression vectors for HIV-1 Gag protein expression in primate and mouse cells and for generating immune responses in mice after DNA vaccination. A DNA vector containing wild type HIV-1 gag coding sequences did not induce detectable Gag expression in any of the cells tested. Attempts to increase nuclear export of Gag expression RNA by adding the constitutive transport element yielded only a moderate increase in Gag expression in monkey-derived COS cells and an even lower increase in Gag expression in HeLa cells or several mouse cell lines. In contrast, silent-site mutations in the HIV-1 gag coding sequences significantly increased Gag expression levels in all cells tested. Furthermore, this construct induced both Gag-specific antibody and CTL responses in mice after DNA vaccination. Using this construct, we achieved stable expression of HIV-1 Gag in the mouse cell line p815, which can now be used as a target cell for measuring HIV-1 Gag-specific CTL responses in immunized mice. The DNA vectors described in this study should make it possible to systematically evaluate the approaches for maximizing the induction of CTL responses against HIV-1 Gag in mouse and other animal systems.

AIDS Vaccines↗

PubMed1999

Antipeptide antibodies reveal interrelationships of MBP 200 and MBP 235: unique apoB-specific receptors for triglyceride-rich lipoproteins on human monocyte-macrophages.

Two human monocyte-macrophage (HMM) membrane binding proteins, (MBP) 200 and 235, are receptor candidates that bind to the apolipoprotein (apo)B-48 domain in triglyceride-rich lipoproteins for uptake independent of apoE. Microsequence analysis of the purified reduced MBP 200R characterized tryptic peptides of MBP 200R. A synthetic peptide mimicking a unique, unambiguous 10-residue sequence (AEGLMVTGGR) induced antipeptide antibodies that specifically recognized MBP 200, 235 and 200R, in 1- and 2-dimensional analyses, indicating 1) the ligand binding protein was sequenced and 2) MBP 200 and 235 yielded MBP 200R upon reduction. These antibodies identified the MBPs in human blood-borne, THP-1, U937 MMs, and endothelial cells (EC) but not in human fibroblasts or Chinese hamster ovary (CHO) cells. Fluorescence activated cell sorting (FACS) analysis located the MBPs on the MM surface as necessary for receptor function. The 10-residue, unambiguous MBP 200-derived sequence is unique, with no matches in extant protein databases. Antipeptide antibodies bind to the MBPs in reticuloendothelial cells that have this receptor activity, but not to proteins in cells that lack this receptor activity. These studies provide the first direct protein sequence and immunochemical data that a new, unique apoB receptor for triglyceride-rich lipoproteins exists in human monocytes, macrophages, and endothelial cells.

Amino Acid Sequence↗

PubMed1999

An experimental study of electro-acupuncture on auditory impairment caused by kanamycin in guinea pigs.

Frequency following response (FFR) and auditory brain stem evoked potential response (ABR) were used to determine the auditory acuity in evaluating the effect of electro-acupuncture treatment of kanamycin-induced auditory impairment in guinea pigs. The succinate dehydrogenase (SDH) activity and morphological changes of the inner ear receptors were examined under the light and scanning electron microscope in cochlear spread preparations. The results showed that 1) electro-acupuncture was effective but no significant differences were found among the stimulating wave forms; 2) Tinggong (SI 19), Yifeng (SJ 17), Shenshu (UB 23), Sanyinjiao (Sp 6), Zhubin (K 9) and Waiguan (SJ 5) are all effective acupoints, especially the combination of Tinggong (SI 19), Sanyinjiao (Sp 6) and Zhubin (K 9) acupoints; 3) improvement in the cochlear function and excitability of the cortical and lower auditory center and increase of the mitochondrial SDH activity and energy supply in hair cells might contribute to the mechanism of the treatment.

Animals↗

PubMed1999

[Cleft lip repair using a lateral columellar flap].

OBJECTIVE: Since the important cosmetic structures of a good looking lip, viz. the philtrum column, philtrum dimple and Cupid's bow of a cleft lip repaired with the commonly used methods, are still defective in various degrees, a new method is designed. METHODS: On the medial side of the cleft, the short philtrum is lengthened and the upwardly displaced Cupid's bow maintained in a lowered position by a rectangular flap transplanted from the lateral surface of the columella. No lip flap has been formed on the lateral side of the cleft. RESULTS: In a period of three years (1996-1998), 23 cases of unilateral cleft lip, 9 cases of bilateral cleft lip and 14 cases of secondary deformities of cleft lip have been repaired with this new method. All of the repaired lips have normal looking philtrum column (limited by an uninterrupted straight-line scar), philtrum dimple and Cupid's bow. CONCLUSION: The lateral columellar flap method is a more rational surgical procedure for cleft lip repair in that it repairs tissue defect by transplanting tissue from the unexposed area. The appearance of the repaired lip is better than that of the commonly used methods.

Cleft Lip↗

PubMed1999

[Tissue response in circum-maxillary sutures after transverse palated suture expansion].

OBJECTIVE: This study was carried out to investigate the histological reactions of midfacial sutures induced by transverse palatal suture expansion. METHODS: Nine mongrel dogs of 8-week old were used in the study. Six of them were used as experimental group as described in a previous paper. The additional three served as controls. In the experimental dogs, a NiTi-shape memory alloy (NiTi-SMA) arch wire was used to expand the transverse palatal suture. Tetracycline was injected intramuscularly (50 mg/kg) three days before operation and at the time of sacrifice. Tissue reactions of premaxillo-maxillary suture, transverse palatal suture, zygomatico-maxillary suture, zygomatico-temporal suture and fronto-maxillary suture were observed in undecalcified tetracycline labeled sections and decalcified histological sections. RESULTS: The sutures in normal young dogs showed active bone formation. With the increase of age, the cellular components of the suture decreased. A great amount of new bone apposition was found in the bony front of expanded transverse palatal suture of the experimental dogs. Degenerative changes were found in premaxillo-maxillary suture at the expanded side while the contralateral showed active osteogenesis. Other sutures manifested both bone apposition and deposition due to the irregular interdigitations. CONCLUSION: After expansion, a great amount of new bone formed in the transverse palatal suture and thus the hard palate was lengthened. All the circum-maxillary sutures reacted in different patterns.

Animals↗

PubMed1999

[Suture expansion osteogenesis for closing the posterior hard palate: an experimental study in dogs].

OBJECTIVE: This study investigated the possibility of a new approach, e.g. suture expansion osteogenesis for closing the posterior hard palate. By this technique we might hope to replace missing tissue in the clefts by tissue regeneration and achieve bony repair in the posterior hard palate and circumvent the problems of speech and facial growth seen in traditional cleft surgery. METHODS: Nine 8-month mongrel dogs were divided into three groups: the control(n = 1), sham control(n = 2) and the experimental group(n = 6). In six experimental dogs, an 8 mm wide cleft was made surgically. Suture expansion devices made of NiTi-shape memory alloy with force levels of 200 g, 360 g and 480 g were secured in the palatine bones to expand the lateral sutures of the palatine bones. Clinical and histological examinations were performed to observe the changes. RESULTS: The clefts in the experimental group were closed completely sooner or later within a period from 5 to 14 days. While the clefts in the sham group became a little larger than their original size. There was significant new bone formation at the edge of the expanded suture. CONCLUSION: The clefts in young dogs could be closed by the technique of suture expansion. The NiTi-SMA expander used in the study was consistently effective and all the force levels could induce a great amount of new bone formation with the trabeculae being thinner and longer by heavy forces.

Animals↗