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Biomedical subjects

M Ye

Publications and source records attributed to M Ye.

At least 55 records · Page 3Linked to original sources
PubMed1999

Recovery of laryngeal sensation after superior laryngeal nerve anastomosis.

OBJECTIVES/HYPOTHESIS: Reliable motor reinnervation has been show in multiple laryngeal transplant studies; however, sensory reinnervation of the larynx after nerve anastomosis has yet to be demonstrated. The role of sensory nerve anastomosis in the transplanted larynx in unknown, but is thought to be necessary to provide airway protection. A canine model was developed to examine the possibility of reformation of sensory pathways in the larynx after nerve section and anastomosis. STUDY DESIGN: Randomized controlled experiment. METHODS: Ten canines were randomly assigned to two groups. Hydrochloric acid-induced laryngospasm was demonstrated in every dog. All dogs then had their necks explored, and the internal branch of the superior laryngeal nerve was identified and transected bilaterally. Following nerve section all dogs were retested for an acid-induced laryngospasm reflex. The control group had their wounds closed and were then awakened from anesthesia. The study group underwent microscopic anastomosis of their sensory nerves. Following a 6-month period the two groups of dogs were compared for the presence of the laryngospasm reflex. RESULTS: No dog in the control group had a response to the acid. All dogs in the study group had some response to the acid, although none of them had return of true laryngospasm. CONCLUSION: We concluded that sensory reinnervation does occur after nerve anastomosis, but the recovery of sensation may be incomplete or altered.

Anastomosis, Surgical↗
PubMed1999

Varicella-zoster virus Fc receptor component gI is phosphorylated on its endodomain by a cyclin-dependent kinase.

Varicella-zoster virus (VZV) glycoprotein gI is a type 1 transmembrane glycoprotein which is one component of the heterodimeric gE:gI Fc receptor complex. Like VZV gE, VZV gI was phosphorylated in both VZV-infected cells and gI-transfected cells. Preliminary studies demonstrated that a serine 343-proline 344 sequence located within the gI cytoplasmic tail was the most likely phosphorylation site. To determine which protein kinase catalyzed the gI phosphorylation event, we constructed a fusion protein, consisting of glutathione-S-transferase (GST) and the gI cytoplasmic tail, called GST-gI-wt. When this fusion protein was used as a substrate for gI phosphorylation in vitro, the results demonstrated that GST-gI-wt fusion protein was phosphorylated by a representative cyclin-dependent kinase (CDK) called P-TEFb, a homologue of CDK1 (cdc2). When serine 343 within the serine-proline phosphorylation site was replaced with an alanine residue, the level of phosphorylation of the gI fusion protein was greatly reduced. Subsequent experiments with individually immunoprecipitated mammalian CDKs revealed that the VZV gI fusion protein was phosphorylated best by CDK1, to a lesser degree by CDK2, and not at all by CDK6. Transient-transfection assays carried out in the presence of the specific CDK inhibitor roscovitine strongly supported the prior results by demonstrating a marked decrease in gI phosphorylation while gI protein expression was unaffected. Finally, the possibility that VZV gI contained a CDK phosphorylation site in its endodomain was of further interest because its partner, gE, contains a casein kinase II phosphorylation site in its endodomain; prior studies have established that CDK1 can phosphorylate casein kinase II.

Amino Acid Sequence↗
PubMed1999

Comparison of nerve banking techniques in delayed laryngeal reinnervation.

Successful laryngeal transplantation will require adequate reinnervation of the larynx to allow phonation, coordinated swallowing, and respiration. A delay between laryngectomy and transplantation would be necessary in oncology patients because of the need for immunosuppression. In these patients, reinnervation of the donor organ would require "banking" and recovery of dormant recipient recurrent laryngeal nerves (RLNs). This pilot study was undertaken to compare the effectiveness of RLN storage using 1 of 2 techniques: 1) inserting the nerve into a muscle pocket or 2) anastomosing the proximal RLN stump to the ansa cervicalis. Six months following nerve transection and "banking," the proximal anterior branch of the RLN was reanastomosed to the distal anterior segment and the posterior branch was anastomosed directly to the posterior cricoarytenoid muscle. Tensionometry, image analysis, and electromyographic data were collected 1 year later. Results show reinnervation of adductors and abductors with both techniques. Banking of the RLN branches during total laryngectomy is effective and should permit delayed physiological reinnervation following laryngeal transplantation.

Anastomosis, Surgical↗
PubMed1999

Apodization by the Stiles-Crawford effect moderates the visual impact of retinal image defocus.

Previous optical modeling of the human eye with large pupils has predicted a larger impact of defocus on the human contrast sensitivity function and modulation transfer function than is observed experimentally. Theory predicts that aberrations and the Stiles-Crawford effect (SCE) should both lead to increased depth of focus, resulting in higher contrast sensitivities and veridical (not phase-reversed) perception over a larger range of spatial frequencies in defocused retinal images. Using a wave optics model, we examine these predictions quantitatively and compare them with psychophysical experiments that measure the effect of defocus on contrast sensitivity and perceived phase reversals. We find that SCE apodization has its biggest effect on defocused image quality when defocus and spherical aberration have the same sign. A model including typical amounts of spherical aberration and pupil apodization provides a dramatically improved prediction of the effects of defocus on contrast sensitivity with large pupils. The SCE can significantly improve defocused image quality and defocused vision, particularly for tasks that require veridical phase perception.

Contrast Sensitivity↗
PubMed1999

[The complications of excimer laser in-situ keratomileusis for myopia].

OBJECTIVE: To analyze the complications of excimer laser in-situ keratomileusis (LASIK) for myopia, investigate the causes and discuss the prevention of these complications. METHODS: The SCMD microkeratome and Schwind Keratom F excimer laser were used to correct myopia on 1,265 eyes in 662 cases. The eyes were divided into 3 groups: A: -10.00 D, 252 eyes. All of them were followed up for a period of 12 months. RESULTS: Intraoperative corneal disk completely detached: 6 eyes (0.5%); corneal disk incomplete sectioned: 3 eyes (0.2%); corneal epithelial disk: 2 eyes (0.2%); corneal interface minute foreign metal bodies: 11 eyes (0.9%); postoperative steroid intraocular hypertension: 21 eyes (1.7%); macular hemorrhage: 2 eyes (0.2%). At postoperative 3 months, there was refractive regression > 1.00 D in 0.0%, 3.1% and 7.9% respectively in the 3 groups; the increase in astigmatism > 1.00 D, 0.4%, 2.8% and 4.4% respectively. CONCLUSION: LASIK is a safe effective method for correcting myopia. Yet attention should be paid on the complications during and after operation. With the improvement in operative technique and better designed procedure, these complications can be decreased and the preoperative correctness in estimation of the postoperative results and the postoperative accuracy in the correction of myopia can be elevated.

Adolescent↗
PubMed1999

Method development of adsorbed stationary phase open tubular capillary electrochromatography.

The adsorption effect of capillary wall, which was usually considered as a troublesome factor, has been used as driving force for preparing stationary phase for open tubular capillary electrochromatography (OTCEC). A number of compounds have been applied as stationary phase materials, which include cationic surfactants such as cetyltrimethylammonium bromide (CTAB), basic proteins such as lysozyme and cytochrome C, basic peptides such as Lys-Tyr and Lys-Ser-Tyr, and basic amino acid L-lysine. The adsorbed CTAB phase is used for separation of neutral compounds while other adsorbed stationary phases are used for chiral separation. The run-to-run reproducibility of retention time is rather good with RSD values less than 2.3%. The separation efficiency is excellent with the highest theoretical plate number of up to 590,000/m and the average plate number of more than 250,000/m. Being stored at 2-8 degrees C in refrigerator, the adsorbed stationary phase can last at least one month.

Adsorption↗
PubMed1999

[Preparation and evaluation of open tubular capillary electrochromatographic columns by sol-gel method].

Open-tubular capillary electrochromatographic columns were prepared by sol-gel method. The influence of pH of gel solution on the column performance was investigated with a series of gel solution prepared by hydrochloric acid at different pH value. The results show that the pH of gel solution influences the capacity factors (k') of solutes in a complex way. The general trend is that the values of k' increase as the pH value increases except that at pH of 2.0. The gel solution of pH 2.8 was selected to prepare the column, at which the greatest capacity factors can be obtained within an acceptable reaction rate. The influence of reaction time of gel solution in column was also investigated. Out of expectation, the k' value didn't increase with increase in reaction time. The reason may be that the pore of silica gel is so small that the sample molecule can't migrate into it. The surface area is only offered by outer surface of silica gel, so the phase ratio of column prepared by this method is still not large enough. It was found that the joule heat effect can be neglected since the capillaries used were very small in inner diameter. The electroosmotic flow plays an important role in the separation as it determines the separation time. In order to accelerate the separation, high pH condition is necessary. Therefore, the stability of column under high pH is very important. The column shows a good stability under pH 9 of the mobile phase. The relative standard deviations (RSD) of capacity factor of four solutes were less than 3.7% for 100 times of operations. The separation efficiency was evaluated and the average theoretical plate numbers under optimal conditions for thiourea, phenetole, naphthalene, biphenyl, and 2,6-dimethyl naphthalene were 4.66 x 10(5), 5.24 x 10(5), 5.02 x 10(5), 4.77 x 10(5), and 3.58 x 10(5)/m, respectively. The column shows good repeatability. The RSD values for k' are less than 1% and the RSD values for efficiency are less than 8% (n = 5). In addition, fast separation was obtained with shorter column and higher voltage used, where four aromatic compounds were baseline separated in 101 s.

English Abstract↗
PubMed1999

[Effects of temperature on the migration time window of micellar electrokinetic capillary chromatography].

The effects of capillary temperature, the nature and concentration of buffer on the migration time window of micellar electrokinetic capillary chromatography are investigated through three parameters including electroosmotic mobility (micro eo), the electrophoretic mobility micelle (micro ep,mc) and mobility ratio (Rm,mc). (micro eo) and (micro ep,mc) increase linearly as capillary temperature increases. Change in the viscosity of the running buffer is the main factor in the temperature effect. It is proved theoretically that the local viscosity at the capillary wall is different from the bulk viscosity. The increasing rate of micro eo with temperature is different from that of micro ep,mc. The migration time window can be expanded by lowering capillary temperature. Although the expanding is limited, this method can be very easily achieved on a commercial apparatus. A uniform formula has been derived to describe the relationships between micro eo, micro ep,mc and the concentration of buffer. For Tris and borate buffer, both micro eo and micro ep,mc decrease with increasing buffer concentration, but the decreasing rate is limited. Thus the effect on the migration time window is not significant. For phosphate buffer, the effects on micro eo and micro ep,mc are different in different concentration ranges. micro eo decreases rapidly in low concentration range but decreases slowly in high concentration range with increasing buffer concentration. micro ep,mc decreases in low concentration range but increases in high concentration range with increasing buffer concentration. The migration time window can be significantly expanded by increasing the concentration of phosphate buffer.

English Abstract↗
PubMed1999

[Rhinitis and maxillary sinuitis caseosa].

OBJECTIVE: To investigate the effect of surgical procedures on patients with rhinitis caseosa and maxillary sinusitis caseosa. METHOD: The clinical analysis for 21 cases (24 sides) were reported in this paper, there were 6 rhinitis caseosa, 13 maxillary sinusitis caseosa, 5 rhinitis and sinusitis caseosa, all patients had caseation material in the nasal cavity or sinus cavity. All patients were treated successfully by surgery, transmaxillary sinus microsurgery and the middle meatal antrostomy were performed for 12 cases. RESULT: 21 cases who were followed-up 3-5 years after surgery were disappearance for symptoms, and did not recurring. CONCLUSION: The key of surgery is to allow free drainage for sinus ostium.

Adult↗
PubMed1999

[Experimental study on pharmacological action of fukean tablet on gastrointestinal tract].

The pharmacological effects of FuKean Tablet(FKT) on gastrointestinal tract were studied. The results showed FKT cured the diarrhea induced by rhubarb or senna, prominently reduced the quantity of feces and delayed the time of excreting charcoal powder in the diarrhea induced by rhubarb or senna model NIH mice; FKT inhibited intestinal propelling-movement in diarrhea induced by senna mmodel NIH mice. FKT inhibited the automatic contraction and Ach induced spasmodic contraction of isolated rabbit intestine(decreased the frequency and intensity of contraction). The above results revealed that the pharmacological base of curing the urgent disease in gastrointestinal tract may be curing the diarrhea, inhibiting intestinal propelling-movement and inhibiting the contraction of intestine.

Animals↗
PubMed1998

Transfection of TAP 1 gene restores HLA class I expression in human small-cell lung carcinoma.

HLA class I antigens of the human major histocompatibility complex (MHC) play an important role in immune response. Consistent with their role in immune surveillance, these antigens are expressed on most cell types. However, a marked deficiency or lack of expression of these antigens has been observed in a variety of human neoplasms. We have shown that a number of class I-deficient human tumor cell lines, including small-cell lung carcinoma, lacked products of MHC-encoded TAP1 and LMP2 genes. Since a direct evidence for the role of these genes in class I expression in tumor cells is not available, in the present study we transfected class I-deficient human small-cell lung carcinoma cells with cDNAs corresponding to TAP1 gene and to LMP2 gene. Following transfection, tumor cells expressed products of the respective transfected gene. Cell-surface expression of class I molecules was, however, observed in cells transfected with TAP1, but not in tumor cells transfected with LMP2 gene. Our results provide conclusive evidence for a role of TAP1 gene in class I expression and suggest that transfection of TAP genes may be useful to upregulate class I expression in tumor cells. This strategy for restoration of class I expression by transfection of TAP genes is relevant for tumor rejection and/or abrogation of metastases formation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Isolation and identification of peptide degradation products of heat stressed pramlintide injection drug product.

PURPOSE: This report summarizes the identification of nine deamidation and four hydrolysis products from a sample of pramlintide injection final drug product that was subjected to stress at 40 degrees C for 45 days. METHODS: The pramlintide degradation products were isolated by strong cation exchange HPLC followed by reversed-phase HPLC. Subsequent to isolation, the molecular weight of each component was determined by liquid chromatography-mass spectrometry (LC/MS). Further characterization was accomplished by amino acid sequence analysis and/ or enzymatic (thermolysin) digestion followed by LC/MS and sequence analysis. RESULTS: The isolated products were identified as [iso-Asp21]-pramlintide, [iso-Asp3]-pramlintide, and [iso-Asp22]-pramlintide, the deamidation products of pramlintide with rearrangement at Asn21, Asn3, and Asn22, respectively. Also found were [Asp/iso-Asp14]-pramlintide, and [Asp/iso-Asp35]-pramlintide, the deamidation products at Asn14, and Asn35, and [Asp21]-pramlintide together with [Asp22]-pramlintide. For the deamidations at the 14th and 35th residues, it could not be determined whether the substance corresponded to the Asp or the iso-Asp product. The [Asp21] and [Asp22] products could not be separated from each other chromatographically but were both identified in a single fraction. Two minor degradation products were also identified as deamidated species. However, the sites of deamidation remain unknown. Also identified were [1-18]-pramlintide, [1-19]-pramlintide, [19-37]-pramlintide, and [20-37]-pramlintide, the products of hydrolytic peptide backbone cleavage at amino acids His18/Ser19 and Ser19/Ser20, respectively. One other product was isolated and tentatively identified as a cyclic imide intermediate preceeding deamidation. CONCLUSIONS: The primary mode of thermally induced degradation for this peptide is deamidation. A second degradation mechanism is peptide backbone hydrolysis.

Amino Acid Sequence↗
PubMed1998

Objective measures of laryngeal function after reinnervation of the anterior and posterior recurrent laryngeal nerve branches.

Previous research indicates that separate reinnervation of the anterior and posterior branches of the recurrent laryngeal nerve (RLN) can provide purposeful motion of the larynx, even after transplantation. This canine study was undertaken to better determine the results of RLN reinnervation after nerve transection distal to its bifurcation. This approximates ideal conditions for transplantation, because potential rejection and nerve branch mismatch are eliminated. Eight months after nerve repair, video, electromyographic, mechanical, and histologic data were collected on four canines. Results show return of appropriate motion without synkinesis, including purposeful abduction on endotracheal tube occlusion. Abductory function was weaker on the reinnervated side, but adduction was equal or stronger on the reinnervated vocal cord. These results indicate that this method of RLN reinnervation produces consistent, strong physiologic motion in the denervated larynx.

Animals↗
PubMed1998

DQCAR microsatellite polymorphism and susceptibility to rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease associated with HLA-DR genes that share a five amino acid sequence motif, QKRAA or QRRAA, from position 70 to 74 in the third hypervariable region of the DRbeta1 molecule. Since the associations between DRB1 genes and susceptibility to RA are incomplete, in this study we examined the CA repeat polymorphic marker DQCAR, located between DQA1 and DQB1 genes, alleles in 98 adult patients with seropositive RA and 100 normal healthy controls. The prevalence of the DQCAR 117 allele was significantly higher in RA patients as compared to normal controls. On the other hand, the frequency of DQCAR 99 was lower in patients than in normal subjects. Analysis of the data suggested that DRB1 genes sharing the QKRAA/QRRAA epitope have the primary association with disease susceptibility and DQCAR alleles do not provide an additional risk for the development of RA.

Adult↗
PubMed1998

D6S273 microsatellite polymorphism and susceptibility to rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic articular inflammatory disease associated with HLA-DR genes that share a five amino acid sequence motif, QKRAA or QRRAA, from position 70 to 74 in the third hypervariable region of the DRB1 molecule. Since these associations between DRB1 genes and susceptibility to RA are incomplete, we examined the role of a CA repeat polymorphic microsatellite marker, D6S273, located between HSP70 and Bat2 genes in the class III region of MHC, in susceptibility to RA. Ninety-seven adult patients with seropositive RA and 100 normal healthy subjects were studied. Two D6S273 alleles (132 and 138) showed significant differences in their prevalence in RA patients as compared to normal controls; allele 132 was significantly higher in total patients and in DRB1 QKRAA/QRRAA epitope-positive patients, and allele 138 was significantly higher in QKRAA/QRRAA-negative patients. Analysis of data suggested that the association of D6S273 132 allele with RA was secondary to that of DRB1 genes. On the other hand, D6S273 138 allele showed primary association with RA susceptibility in QKRAA/QRRAA epitope-negative patients. The D6S273 138 allele thus provides an additional risk in RA susceptibility. The results in the present study therefore suggest that two regions in MHC, DRB1 and D6S273, contribute to susceptibility to RA.

Adult↗
PubMed1998

Functional differences between the two bellies of the cricothyroid muscle.

The contraction of the cricothyroid (CT) muscle, which results in a decrease in the distance between the thyroid and cricoid cartilages, is considered to be the main factor in lengthening the vocal folds. This is achieved by rotation of the CT joint. The CT muscle is composed of two distinct bellies, the pars recta and the pars obliqua. The function of each subunit is not clearly understood, although it is believed that they act differently because their fibers run in different directions. To clarify the function of the two bellies in phonation, the fundamental frequency (F0), vocal intensity, subglottic pressure, vocal fold length, and CT distance were measured using an in vivo canine laryngeal model. On the basis of these measurements, we demonstrated that the two bellies are varied in their effect on raising the pitch, rotation, and forward translation of the CT joint. The stimulation of the pars recta nerve resulted in a greater increase in the F0 value compared with that of pars obliqua. The combined activity of the pars recta and pars obliqua is important in adjustment of the vocal fold length. The CT approximations directed parallel to the pars recta and pars obliqua simultaneously were more effective in elevation of the pitch than the approximation placed parallel to the pars recta only. This finding may be clinically significant with regard to CT approximation thyroplasty in human trails.

Analysis of Variance↗
PubMed1998

HLA-DM polymorphisms in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the contribution of HLA-DMA and DMB genes, which play a crucial role in the HLA class II restricted antigen presentation pathway, in susceptibility to rheumatoid arthritis (RA). METHODS: The distribution of DMA and DMB alleles was examined in patients with RA and in healthy subjects by oligotyping of PCR amplified genomic DNA with sequence specific oligonucleotide probes. RESULTS: There were no significant differences in the prevalence of DMA and DMB alleles in patients with RA as compared to healthy controls. In addition, no significant differences in frequencies of DMA and DMB alleles were observed in RA susceptibility epitope positive RA patients and controls. CONCLUSION: DMA and DMB genes do not appear to play a role in susceptibility to RA.

Alleles↗