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Biomedical subjects

X Guo

Publications and source records attributed to X Guo.

At least 199 records · Page 11Linked to original sources
PubMed2000

[Long-term follow-up result of partial laryngectomy].

OBJECTIVE: To study the long-term follow-up result of partial laryngectomy and reservation of laryngeal function. METHODS: Three hundred and seventy-nine patients who underwent partial laryngectomy from 1986 to 1995 were summarized (male 290 cases, female 89 cases). Among them, 184 cases were supraglottic carcinomas (T1 8 cases, T2 115, T3 48, T4 13, according to UICC in 1992), 192 cases were glottic carcinomas (T1 115, T2 63, T3 13, T4 1), 3 cases were transglottic carcinomas (T2 1, T3 2). In common 8 kinds of operations were performed: 26 cases underwent cordectomy, 138 vertical laryngectomy, 7 frontolateral laryngectomy, 12 horizontal glottic laryngectomy (middle part of the larynx), 58 supraglottic laryngectomy, 95 horizontovertical (3/4) laryngectomy, 24 subtotal laryngectomy with cricoglossoepiglottic anastomosis, 19 near-total laryngectomy with cricoglossal anastomosis (with reservation of unilateral arytenoid cartilage). 193 cases underwent concurrent neck dissection(121 unilateral, 72 bilateral). RESULTS: All cases restored their phonation and overcame aspiration with removing nasal feeding from 7 to 23 days after operations. 362 cases were decannulated from 9 days to 3 months after operations. Another 8 cases were decannulated after a secondary plastic operation. Decannulation rate was 97.6%. The three, five and ten year survival rates were 86.8% (329/379), 81.3% (266/327) and 69.4% (120/173) respectively. CONCLUSION: Partial laryngectomy is a kind of radical operation with reservation of laryngeal function. Mastering indications strictly, correct operation choices, excellent surgical skills and perfect repairing technique are bases of improving life qualities and curative effect.

Adult↗
PubMed2000

[Study of mechanisms of lightening aspiration and increasing decannulation rate in anastomosis of cricoid cartilage and base of tongue (epiglottis)].

OBJECTIVE: To study laryngopharyngeal anastomosis and fixing methods of super-cricoid laryngectomy with reconstruction of functions in lightening aspiration and increasing decannulation rate. METHODS: Recovering conditions of laryngeal functions in 66 patients who underwent supracricoid laryngectomy and anastomosis of cricoid cartilage and base of tongue (epiglottis) in recent eight years were summarized. Some relevant caliber distances in 21 residual larynges were measured. RESULTS: All cases restored their phonation. In 36 cases that underwent anastomosis of cricoid cartilage and base of tongue, 15 cases without aspiration, 18 with mild aspiration, 3 moderates. Decannulation rate is 94.4%. In 30 cases who underwent anastomosis of cricoid cartilage and base of tongue, 10 with mild aspiration, 17 moderate, 3 serious. All cases overcame aspiration within 3 weeks. 7 cases were cannulated. 3, 5, 10 year survival rates were 80.3%, 74.4%, and 3/7. The longitudinal and transverse calibers of epiglottis were 1.5-2.0 times longer than that of the entrance of cricoid cartilage. After anastomosis of cricoid cartilage and base of tongue (epiglottis), the epiglottis can exactly cover the entrance of cricoid cartilage to prevent aspiration fully and increase decannulation rate. Previously the cricoid cartilage was anatomized and fixed under the hyoid bone. Because some spaces exist between cricoid cartilage, base of tongue and epiglottis, aspiration is likely to occur. That hyoid bone covers the entrance of cricoid cartilage will bring constriction of the new laryngeal orifice and make decannulation difficult. Hyoidectomy and anastomosis of cricoid cartilage and base of tongue (epiglottis) overcame the two shortcomings and had good effects. CONCLUSION: Cricoid-hyoid-anastomosis was the main reason of severe aspiration and low decannulation rate. The ideal methods to lighten aspiration and increase decannulation rate are hyoidectomy and anastomosis of cricoid cartilage and base of tongue (epiglottis).

Adult↗
PubMed2000

[The gaseous phase enrichment techniques in hydride generation (review)].

The gaseous phase of hydride enrichment techniques have been systematically described in this paper. These enrichment techniques including liquid nitrogen trap, balloon collection, in situ pre-concentration in pre-heated graphite furnace, trapped in absorbing solutions, and in some absorbing solid substances. The principle and the application of these techniques have been discussed detail too. The near future trends of the techniques have reviewed also.

Arsenic↗
PubMed1999

Correlation between curve severity, somatosensory evoked potentials, and magnetic resonance imaging in adolescent idiopathic scoliosis.

STUDY DESIGN: A prospective study in patients with adolescent idiopathic scoliosis of different clinical severity using whole-spine magnetic resonance imaging and somatosensory evoked potentials. OBJECTIVES: To correlate the presence of magnetic resonance imaging structural abnormalities with somatosensory evoked potential-detected functional disorders in the hind brain and spinal cord and the Cobb's angle in patients with adolescent idiopathic scoliosis and to compare the result with those in healthy matched control subjects. SUMMARY OF BACKGROUND DATA: Many different types of neurologic dysfunction have been reported in scoliosis. With the advent of magnetic resonance imaging, there are increased reports on the association of idiopathic scoliosis and syringomyelia, Chiari I malformation, or tonsillar ectopia. The actual link between structural and functional disorder in idiopathic scoliosis is, however, unclear. METHODS: Posterior tibial nerve evoked potentials and whole-spine magnetic resonance imaging were performed in 36 healthy control subjects, 135 patients with adolescent idiopathic scoliosis with Cobb's angle less than 45 degrees, and 29 patients with Cobb's angle more than 45 degrees. RESULTS: Tonsillar ectopia or syringomyelia, detected by magnetic resonance imaging, or functional disturbance in the somatosensory pathway, detected by somatosensory evoked potentials, was found to be significantly more frequent in the group of patients with severe scoliosis curvature, with an incidence of 31% and 27.6%, respectively. Incidence of tonsillar ectopia was 33.3% in patients with abnormal somatosensory evoked potentials in contrast to the much lower incidence of 2.9% in patients with normal somatosensory evoked potentials. There was a significant structural and functional link. The incidence of syringomyelia in patients with and without tonsillar ectopia was 33.3% and 0.7%, respectively. CONCLUSIONS: In patients with adolescent idiopathic scoliosis with severe curve, the significant association with tonsillar ectopia and abnormal somatosensory function points to a neural origin. Disorders in the somatosensory function may be one of the mechanisms linking tonsillar ectopia to scoliosis. Somatosensory evoked potentials and magnetic resonance imaging may have important diagnostic and predictive value and may help in the management of adolescent idiopathic scoliosis.

Adolescent↗
PubMed1999

Sequencing of argentinated peptides by means of electrospray tandem mass spectrometry.

A strategy for semiautomatic sequencing of argentinated (silver-containing) oligopeptides has been developed. Sequencing is based on a search algorithm that identifies a triplet peak relationship in a product ion spectrum of the [M + Ag]+ ion of an oligopeptide. The ions that constitute a triplet are [bn + OH + Ag]+, [bn - H + Ag]+, and [a(n) - H + Ag]+, which are separated by 18 and 28 m/z units, respectively. The difference in the m/z values of adjacent triplets identifies the residue that is "cleaved". Observation of the [yn + H + Ag]+ ion containing the cleaved residue confirms the assignment. Sequencing of argentinated tryptic peptides may prove useful for automated proteome analysis via the sequence tag method.

Amino Acid Sequence↗
PubMed1999

Persistent osteopenia in adolescent idiopathic scoliosis. A longitudinal follow up study.

STUDY DESIGN: A follow-up study assessing the bone mineral dynamics in adolescent patients with idiopathic scoliosis and associated osteopenia. OBJECTIVES: To investigate whether osteopenia in patients with adolescent idiopathic scoliosis is a transient phenomenon or a persistent problem. SUMMARY OF BACKGROUND DATA: Investigators have suggested a significant correlation of osteopenia with adolescent idiopathic scoliosis. Because one half of the skeletal mass is acquired during the adolescent years, it is of importance to know whether the osteopenia is transient or persistent. METHODS: Using dual-energy x-ray absorptiometry, bone mineral density of bilateral proximal femurs was studied longitudinally in 70 healthy control subjects and 14 patients with adolescent idiopathic scoliosis with significant osteopenia more than 2 standard deviations below the mean normal value. RESULTS: The 14 girls with osteopenic adolescent idiopathic scoliosis who were followed up longitudinally for up to 3 years showed persistent and significantly lower bone mineral density when compared with normal age-, sex- and maturity-matched control subjects. CONCLUSIONS: Patients with adolescent idiopathic scoliosis are at increased risk of osteoporosis than are healthy adolescents. The lower rate of increase of bone mineral density in patients with adolescent idiopathic scoliosis who have low bone mineral density could predict a significantly lower peak bone mass in adulthood, with all the associated problems of osteoporosis. Further investigation is needed to define whether osteopenia-associated scoliosis has the same cause, pathogenetic mechanism, and risk of progression when compared with adolescent scoliosis without osteopenia.

Absorptiometry, Photon↗
PubMed1999

[Loss of heterozygosity and microsatellite instability in laryngeal carcinoma near p16 gene]

OBJECTIVE: To search for the minimal overlap region of tumor suppressor gene in laryngeal carcinoma and discuss the correlation of p16 gene with laryngeal carcinogenesis. METHODS: Five microsatellite polymorphism markers near p16 gene were selected to detect loss of heterozygosity (LOH) and microsatellite instability (MI) in 60 cases of laryngeal squamous cell carcinoma. RESULTS: The frequencies of LOH in 5 markers were less than 23.1%, while the frequencies of MI in 2 markers were higher, with the highest frequency (46.1%) in D9S1752. CONCLUSION: The results suggest that the deletion of p16 gene does not play an important role in the laryngeal carcinogenesis and there may exist a gene around D9S1752 participating in the development of laryngeal carcinoma, which correlates with the mutation of repair gene.

Journal Article↗
PubMed1999

Leukemia inhibitory factor and ciliary neurotrophic factor cause dendritic retraction in cultured rat sympathetic neurons.

Dendritic retraction occurs in many regions of the developing brain and also after neural injury. However, the molecules that regulate this important regressive process remain largely unknown. Our data indicate that leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF) cause sympathetic neurons to retract their dendrites in vitro, ultimately leading to an approximately 80% reduction in the size of the arbor. The dendritic retraction induced by LIF exhibited substantial specificity because it was not accompanied by changes in cell number, in the rate of axonal growth, or in the expression of axonal cytoskeletal elements. An antibody to gp130 blocked the effects of LIF and CNTF, and both cytokines induced phosphorylation and nuclear translocation of stat3. Moreover, addition of soluble interleukin-6 (IL-6) receptor to the medium endowed IL-6 with the ability to cause dendritic regression. These data indicate that ligands activating the gp130 pathway have the ability to profoundly alter neuronal cell shape and polarity by selectively causing the retraction of dendrites.

Animals↗
PubMed1999

Traumatic instabilities of the cervical spine caused by high-speed axial compression in a human model. An in vitro biomechanical study.

STUDY DESIGN: Traumatic injury of the cervical spine was produced on human cadavers and evaluated with instability tests and radiographs. OBJECTIVE: To relate traumatic injuries of the cervical spine to instability and patterns of traumatic injury to different levels of impact energy. SUMMARY OF BACKGROUND DATA: Data from young human cadavers are rare in traumatic models of the cervical spine, and instabilities caused by axial compression with different impacts remain unknown. METHODS: Fourteen cervical spine specimens (C2-C4) obtained from fresh human cadavers were divided evenly into two groups and subjected to axial compressive impact with 30 J and 50 J impact energy, respectively. Pure moments in flexion-extension, left/right lateral bending, and left/right axial rotation were applied to each specimen before and after trauma. The maximum moment was 2.0 Nm in each case. Ranges of motion and neutral zones were measured using stereophotogrammetry. RESULTS: Ranges of motion and neutral zones for both groups increased after trauma. No bony injury was observed on the radiographs after trauma with 30 J, but motions increased significantly in flexion, extension, and axial rotation. All specimens showed bony injuries after trauma with 50 J, whereas motions continued to increase significantly in all directions. The relative neutral zone values were larger than the corresponding range of motion values, except in flexion-extension after trauma with 50 J. CONCLUSIONS: The injury patterns of the cervical spine were associated with impact energy, and a high level of impact energy could produce either three-column injury or anterior middle-column injury. Instabilities of the cervical spine caused by compressive trauma increased with the level of impact energy. The neutral zone was more sensitive than the range of motion in representing spinal instability, whereas instability testing was more sensitive than radiographs in evaluating traumatic injury of cervical spine.

Adult↗
PubMed1999

Analysis of metallothioneins by means of capillary electrophoresis coupled to electrospray mass spectrometry with sheathless interfacing.

Capillary electrophoresis (CE) coupled to electrospray mass spectrometry via sheathless interfacing has been applied to the analysis of mammalian metallothionein (MT) extracts. In a rabbit-liver extract, four (MT-2C, MT-2A, MT-2D and MT-2E) out of six known MT sub-isoforms were unambiguously identified under three CE-resolved peaks. A fourth peak was found to contain MT-1A and/or MT-2B, whose molecular masses differ by only 1 Da. Traces of non-N-acetylated MT-2D and MT-2E were observed in a fifth, minor peak. In a rat-liver extract, both MT-1 and MT-2 were resolved and identified. Non-N-acetylated MT-2 was also identified in a resolved, minor peak. Minimum detectable amounts of MTs have been estimated to be approximately 0.6 fmol per sub-isoform.

Animals↗
PubMed1999

The experimental study on mixed culture of osteoblasts and tricalcium phosphate ceramics in vitro.

To study the effects of tricalcium phosphate (TCP) ceramics on osteoblasts, the rat osteoblasts were cultured with the TCP ceramics in vitro. Scanning electron microscopy and the colorimetric methyl-thiazol-tetrazolium assay showed that the osteoblasts could adhere well to the surface of the ceramics and the culture dish, and the proliferation of the cells was not inhibited. The results demonstrated that TCP ceramics possessed an excellent cytocompatibility with the osteoblasts, and had some promoting effects on proliferation of osteoblasts.

Animals↗
PubMed1999

MRI evaluation of multifidus muscles in adolescent idiopathic scoliosis.

BACKGROUND: The role of the multifidus muscles in the initiation and progression of curve in adolescent idiopathic scoliosis is not fully understood and controversy exists as to the side of the abnormality. OBJECTIVE: To evaluate on MRI the multifidus muscles at the apex of the major curve in adolescent idiopathic scoliosis to ascertain if the multifidus muscles on the convex or concave side are abnormal and the relationship to curve severity. MATERIALS AND METHODS: Forty-six patients with adolescent idiopathic scoliosis, separated into two groups, were studied using a 1.5-T MR scanner with the synergy spine coil, employing a modified STIR (short tau inversion recovery) axial sequence obtained at the apex of the major scoliotic curve. RESULTS: No hyperintense signal change was demonstrated in the convex side multifidus muscles in any patient. In group I, 16 of 18 patients with severe or rapidly progressive curve showed increase in signal intensity in the multifidus muscle on the concave side of the apex of the curve. In group II, of the 15 patients with mild curve (Cobb angle 10-30 degrees), 4 had increased signal intensity in the multifidus muscle on the concave side; of the 13 with more severe curve (Cobb angle greater than 30 degrees), 10 had increase in multifidus signal intensity on the concave side. CONCLUSIONS: The concave-side multifidus muscle at the apex of a scoliotic curve was morphologically abnormal. A significant association between abnormal signal change and curve severity was also established.

Adolescent↗
PubMed1999

Involvement of neutrophils and free radicals in the potentiating effects of passive cigarette smoking on inflammatory bowel disease in rats.

BACKGROUND & AIMS: Cigarette smoking is associated with inflammatory bowel diseases (IBDs), particularly Crohn's disease, in humans. The aim of this study was to examine whether passive cigarette smoking aggravates experimental IBD in rats and to clarify the underlying mechanisms. METHODS: Rats were exposed to cigarette smoke (CS) for 1 hour once daily for 4 days before induction of IBD by 2,4, 6-trinitrobenzene sulfonic acid (TNBS)-ethanol enema and were then killed at 2, 6, or 24 hours later. RESULTS: Preexposure to CS significantly potentiated colonic damage induced by TNBS. TNBS-ethanol enema caused a pronounced increase in colonic myeloperoxidase activity, leukotriene B(4) level, and also inducible nitric oxide synthase activity, its protein, and messenger RNA expression. These parameters were all significantly increased further by exposure to CS. In contrast, increased colonic superoxide dismutase activity after TNBS-ethanol enema was attenuated by CS exposure. The potentiating effects of CS exposure on TNBS-induced IBD were significantly alleviated after pretreatment with cyclosporin A (an immunosuppressant), N (G)-nitro-L-arginine methylester (a nitric oxide synthase inhibitor), and dimethyl sulfoxide (a hydroxyl radical scavenger). CONCLUSIONS: The results show that promotion of neutrophil infiltration and free radical production contributed significantly to the potentiating effect of passive cigarette smoking on experimental IBD.

Animals↗
PubMed1999

Screening for yeasts incorporating the exogenous eicosapentaenoic and docosahexaenoic acids from crude fish oil.

The screening for yeasts incorporating exogenous eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into their cellular lipids was conducted. Two percent of oil from fish scraps was added to a yeast isolation medium as a sole carbon source. From 143 soil samples, we isolated 23 yeast strains, nine of them were found to be capable of quickly assimilating the scrap fish oil. These nine strains, in addition to four previously isolated triglyceride-assimilating and lipase-producing strains, Yarrowia lipolytica and three Geotrichum species (FO274A, FO347-2 and FO401B), were cultured in a growth medium at 30 degrees C. Strains FO726A, FO765A and FO347-2 were selected on the basis of dry cell weight production and ability to store EPA and DHA in their cells, and their performance was further compared by varying cultivation temperature and time. From 1 g of the scrap fish oil, FO726A yielded 620 mg of dry cells, containing 47.1% lipid, 38.1% triglyceride, 3.3% EPA, and 4.9% DHA, when cultured at 25 degrees C for 36 h. Strain FO726A apparently has the highest ability to incorporate EPA and DHA into its cellular lipids. Results from further experiments showed that the incorporated EPA and DHA mainly existed in the form of triglyceride in the FO726A cell. These results suggest that FO726A is suitable for the production of cell mass rich in EPA and DHA for feed.

Journal Article↗
PubMed1999

Molecular basis of the polydispersity of mucins: implications for the generation of saccharide diversity.

Secreted epithelial mucins are large macromolecules which exhibit extreme polydispersity, the molecular basis of which is not fully understood. We have obtained partial sequences of two genes (BSM1 and BSM2) coding for two distinct molecules. This is the first time that such closely-related genes have been identified for any mucin from an animal. We propose that a combination of multiple homologous genes, alternative splicing, differential glycosylation, and additional post-translational processing all contribute to the extreme polydispersity of mucins. The multiple domain structure and non-identical tandem repeats are also very important for the generation of the saccharide diversities of mucins.

Amino Acids↗
PubMed1999

Potentiating effect of passive cigarette smoking on gastrointestinal damage induced by indomethacin in rats.

Cigarette smoking and nonsteroidal antiinflammatory drugs (NSAIDs) have been associated with gastroduodenal ulcers. The present study aimed to clarify the ulcerogenic mechanisms of passive cigarette smoking on gastrointestinal damage induced by indomethacin in fasted or in fasted and refed rats. Rats were exposed to cigarette smoke (0%, 1%, 2%, or 4%, v/v) before and/or after indomethacin administration. Cigarette smoke dose-dependently potentiated indomethacin-induced gastric mucosal lesions in the fasted animals and further lowered gastric blood flow. The gastric myeloperoxidase activity (a marker enzyme for neutrophils) was also potentiated. In addition, passive cigarette smoking increased the mortality and aggravated duodenal ulceration and also the reduction of duodenal blood flow in the fasted and refed rats after indomethacin treatment. The results indicated that the potentiating effect of passive cigarette smoking on indomethacin-induced gastroduodenal lesions is probably due to the depression of blood flow in the gastroduodenal mucosa and to the aggravation of neutrophil infiltration in the gastric mucosa.

Animals↗
PubMed1999

Synphilin-1 associates with alpha-synuclein and promotes the formation of cytosolic inclusions.

Parkinson disease (PD) is a neurodegenerative disease characterized by tremor, bradykinesia, rigidity and postural instability. Post-mortem examination shows loss of neurons and Lewy bodies, which are cytoplasmic eosinophilic inclusions, in the substantia nigra and other brain regions. A few families have PD caused by mutations (A53T or A30P) in the gene SNCA (encoding alpha-synuclein). Alpha-synuclein is present in Lewy bodies of patients with sporadic PD, suggesting that alpha-synuclein may be involved in the pathogenesis of PD. It is unknown how alpha-synuclein contributes to the cellular and biochemical mechanisms of PD, and its normal functions and biochemical properties are poorly understood. To determine the protein-interaction partners of alpha-synuclein, we performed a yeast two-hybrid screen. We identified a novel interacting protein, which we term synphilin-1 (encoded by the gene SNCAIP). We found that alpha-synuclein interacts in vivo with synphilin-1 in neurons. Co-transfection of both proteins (but not control proteins) in HEK 293 cells yields cytoplasmic eosinophilic inclusions.

Amino Acid Sequence↗