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Biomedical subjects

Y Ding

Publications and source records attributed to Y Ding.

At least 289 records · Page 16Linked to original sources
PubMed1995

Effects of lead on systolic and diastolic cardiac functions.

In this paper, both systolic and diastolic cardiac functions were evaluated in 54 lead exposed and 24 non-exposed workers by Doppler echocardiography. With regard to systolic cardiac function, the results suggested that cardiac systolic function increased in exposed groups as a compensatory response for the effect of lead on myocardium. To study left ventricular diastolic function, 2.5 MHz pulsed Doppler analyses of transmitral flow velocity were performed from apical four-chamber view. The results showed that time-related parameters were comparable among all groups, but blood flow velocity through the mitral valve and Doppler area fractions changed significantly in lead-exposed groups as evidenced by increased value A, decreased value E and E/A ratio. The decrease of diastolic cardiac function was more significant in lead intoxication group. It was also observed in this study that the activity in serum of the MB isoenzyme of creatine phosphokinase (CPK-MB), one of the indices of myocardial damage, was significantly higher in exposed group than that in control (P < 0.05), and a positive correlation was found between CPK-MB activity and Pb-B. It denoted that the increasing of lead burden leads to more release of CPK-MB from the myocardial cells and suggested the existence of slight myocardial damage, which, conceivably, might cause harm to diastolic cardiac function.

Adult↗
PubMed1995

Diagnostic pars plana vitrectomy report of a 21-year retrospective study.

PURPOSE: To review the experience of diagnostic pars plana vitrectomies (PPV). METHODS: The authors reviewed 405 consecutive diagnostic PPV's performed between November 1973 and October 1994. RESULTS: Diagnostic vitrectomy was performed in 215 (53%) of 405 eyes for suspected endophthalmitis. Of those 215 cases, acute inflammation was confirmed in 62 (28.8%), 60 (27.9%) had microbial organisms present and 36 (16.7%) were culture-positive. Microbial organisms were observed microscopically in 31 (20%) of 156 patients suspected of postoperative endophthalmitis. Of those 31 cases, 23 (74%) were gram-positive, eleven (37%) of 30 eyes had organisms associated with glaucoma filtering procedures and 20 (16%) of 126 eyes had organisms with non-filtering procedures. The pooled percentage of eyes that developed postoperative endophthalmitis as a complication during the period July 1990 thru June 1994 is 5 (0.046%) out of a heterogeneous group of 10,898 cases operated on at the Wilmer Eye Institute for cataract, glaucoma, corneal transplant, pars plana vitrectomy and retinal detachment. Bacteria were identified microscopically in 6 (18%) of 34 post-traumatic cases. Microbial organisms were identified in 23 (92%) of 25 cases with an endogenous infection. Patients with endogenous infections had the most fungal infections, and the majority were in males. Neoplasms were diagnosed in 58 (14%) of the 405 cases. The most common neoplasm was ocular lymphoma 42 (72%), 69% of which were in females. Only 42 (48.3%) of 87 patients clinically suspected of having ocular lymphoma, actually had ocular lymphoma. Those negative for lymphoma were significantly older (67.4 +/- 10 years) compared to those with lymphoma (60.4 +/- 14 years) (P = 0.01). CONCLUSION: Diagnostic PPV has proved to be valuable in confirming and establishing various clinical diagnoses.

Acute Disease↗
PubMed1995

[Orthotopic heart transplantation: a case report].

In July 1994, we performed orthotopic heart transplantation for a patient with hypertrophic myocardiopathy, who had had open heart surgery enlarging the right ventricular outlet. The patient had an excellent postoperative result. He received triple-drug immunosuppressive therapy. Large dose of methyl-prednisolone was used successfully for his acute rejection reaction. At present, the patient is living well with good cardiac, hepatic and renal function. We described donor heart harvest, myocardial protection, operative procedure, immune monitoring, anti-rejection and anti-infectious therapy. We introduced the process of protecting donor heart on the way to hospital by retrograde perfusion with medium hypothermic oxygenated-blood combined with St. Thomas cardioplegia. Besides endomyocardial biopsy, other noninvasive examinations such as noninvasive cardiac output monitoring could be helpful to monitor acute rejection reaction.

Adult↗
PubMed1995

Effects of salvia miltiorrhiza bunge (SMB) on MC3T3-E1 cells.

In previous research, we found that the Salvia Miltiorrhiza Bunge (SMB), a traditional Chinese medicinal herb, accelerates orthodontic tooth movement. In the present study, to characterize the actions of SMB on bone remodeling, we investigated the effect of SMB on DNA synthesis and alkaline phosphatase activity of murine osteoblast like cell-clone, MC3T3-E1 cells in vitro. Treatment of the cells with SMB for 72 hours caused significant increase in ALPase activity. It was found that SMB increased ALPase activity in a dose-dependent manner, and up to maximum at the concentration of 5.0 mg/ml. At that concentration, ALPase activity was about 135% greater than that of control. SMB at 5.0 mg/ml significantly stimulated ALPase activity of the cells in multilayer on day 8 or calcification stage on day 16, but inhibited it in the sparse stage on day 2 or subconfluency stage on day 4. SMB had no effect on DNA synthesis in any stage of culture. ALPase activity significantly increased at 48 hours and was up to 300% greater than that of control activity at 96 hours. These findings suggest that SMB directly stimulates ALPase activity of MC3T3-E1 cells in multilayer stage or calcification stage without any effect on proliferation. Locally administrated SMB may affect the differentiation of osteoblasts in vivo.

3T3 Cells↗
PubMed1994

The major kidney AE1 isoform does not bind ankyrin (Ank1) in vitro. An essential role for the 79 NH2-terminal amino acid residues of band 3.

The AE1 (band 3) protein mediates the exchange of anions across the erythrocyte plasma membrane and, via association with the adapter molecule, ankyrin (Ank1), forms the major link between the membrane and the underlying spectrin cytoskeleton. The major kidney isoform of AE1 (kAE1), a protein that is otherwise identical to erythroid AE1 but lacks the NH2-terminal 79 amino acids, is localized to the basolateral plasma membrane of acid-secreting (alpha-type) intercalated cells of distal nephron. It has been proposed that this polarized distribution of kAE1 is due, at least in part, to its association with the ankyrin-spectrin cytoskeleton. In this study, we have used cell-free binding assays to investigate the interaction of anion exchangers with an Ank1 fragment, R13-H, that contains the AE1 binding site. Microsomes from cells expressing full-length erythroid AE1 bound 125I-labeled R13-H, revealing the presence of both high (Kd = 12.5 nM) and low (Kd = 166 nM) affinity sites. This binding was specific, as evidenced by the failure to observe high affinity binding of 125I-R13-H to microsomes from cells transfected with vector alone or with AE1m, a mutant lacking the approximately 400 amino acid NH2-terminal cytoplasmic ankyrin binding domain. Using this assay, we could detect no high affinity association between kAE1 and 125I-R13-H. We conclude that the NH2-terminal 79 amino acids play an essential role in high affinity and specific binding of AE1 to Ank1.

Amino Acids↗
PubMed1994

Effects of tetracyclines on neutrophil, gingival, and salivary collagenases. A functional and western-blot assessment with special reference to their cellular sources in periodontal diseases.

The characterization and regulation of matrix metalloproteinases (MMPs) have been studied to determine their role(s) in periodontal tissue destruction. Progress in elucidating the roles of MMPs in periodontal tissue destruction has led to a new concept involving the chemotherapeutic inhibition on MMPs, a therapeutic strategy which less than a decade ago was considered "a difficult and perhaps impossible task." Tetracyclines/doxycycline (DOXY) and their chemically modified nonantimicrobial derivatives (CMTs) are known to inhibit the matrix metalloproteinases, especially preferring human neutrophil collagenase (MMP-8), and prevent the oxidative activation of procollagenases. We characterized by Western blotting the molecular forms and cellular sources of gingival tissue, dental plaque, gingival crevicular fluid (GCF), and salivary MMPs associated with periodontitis. Also the molecular forms of tissue inhibitors of matrix metalloproteinases (TIMP-1 and TIMP-2) in periodontitis were studied by Western blot. Neutrophil (PMN)-derived MMPs were found to predominate in periodontitis, and phospholipase C present in increased amounts in periodontitis sites was found to be a potential inducer of PMN degranulation. We further studied the effects of DOXY on molecular forms of different latent and active MMPs purified from different cellular sources (PMNs, fibroblasts, keratinocytes) and present in vivo in oral exudates (gingival extracts, GCF, and saliva). DOXY inhibition of activated (oxidatively or proteolytically) MMPs were not associated with MMP fragmentation. Michaelis-Menten plots of initial rates of degradation of soluble type I collagen revealed an apparent Km value of 0.3-0.6 microM for MMP-8, and 75 microM DOXY inhibited MMP-8 in a manner which did not result in changes in apparent Km value but did prevent the initial degradation reaching Vmax providing evidence for noncompetitive inhibition. Treatment of patients with long-term DOXY medication results in decreased MMP-8 activities/levels in gingival tissue, crevicular fluid, and saliva, but not fragmentation of MMP-8 in vivo. These data further support and extend the key role of PMN-MMPs in periodontitis, and the activities of these PMN MMPs can be inhibited directly by therapeutic levels of DOXY.

Blotting, Western↗
PubMed1994

Linkage analysis of a candidate locus (HLA) in autosomal dominant sacral defect with anterior meningocele.

Sacral defect with anterior meningocele (SDAM) is a type of caudal dysgenesis. It is present at birth and becomes symptomatic later in life, usually because of obstructive labor in females, chronic constipation, rectal fistula and abscess, or meningitis. The inheritance is autosomal dominant. HLA has been implicated in caudal dysgenesis because of analogy with disorders of the T-locus complex, a tail length determining gene in mice which is linked to the major histocompatibility complex, H-2. Members of a 5-generation family with sacral defect and anterior meningocele (SDAM) were typed with polymorphic markers (dinucleotide repeats D6S89, D6S105, D6S109, and TCTE1) linked to HLA. Two-point and multipoint analysis exclude the HLA region as the location for the SDAM gene in this family.

Abnormalities, Multiple↗
PubMed1994

The cytoplasmic domain of myelin glycoprotein P0 interacts with negatively charged phospholipid bilayers.

The intracellular COOH-terminal domain of the glycoprotein, P0, has been proposed to be involved in the formation of the major dense line of peripheral myelin. We have addressed this hypothesis by generating and subsequently isolating a peptide fragment that contains 65 of the 69 residues of the cytoplasmic region of rat P0. This peptide, termed P0(intra), bound to artificial phospholipid vesicles and caused their rapid aggregation. The peptide-induced aggregation of membrane bilayers appeared to result from ionic interactions, since P0(intra) vesicle association was decreased by 1) reducing the phosphatidylserine content of the membranes, 2) increasing the NaCl concentration of the surrounding buffer, or 3) elevating the divalent cation concentration within the buffers. Cationic disc gel electrophoresis of P0(intra) revealed at least four charge isoforms of the peptide. Treatment of sciatic nerve slices with phorbol ester prior to isolation of P0(intra) increased the amount of the more negatively charged species, suggesting that at least some of the charge heterogeneity of the peptide can be attributed to differing phosphorylation states. The ability of P0(intra) to bind to phospholipid bilayers implies that the cytoplasmic domain of P0 may be responsible for the formation and maintenance of the myelin major dense line.

Animals↗
PubMed1994

Retrograde conduction properties after catheter radiofrequency ablation of atrioventricular accessory pathways.

UNLABELLED: A total of 208 atrioventricular (AV) accessory pathways in 200 patients were abolished by catheter radiofrequency current ablation. The antegrade AV conduction was normal after the ablation. Approximately 66% of the patients experienced retrograde AV conduction dissociation, which is independent of the age, gender and antegrade conduction properties of accessory pathways (manifest or concealed). Retrograde conduction dissociation is more prevalent than decremental conduction in patients with left free (80% vs. 17%, P < 0.001) or right free (78.6% vs. 21.4%, P < 0.01) wall pathways. Eleven patients (5.5%) showed recurrence after an average of 213 days follow-up. The recurrence of right free wall pathways (21.4%) is much more common than that of left free wall (2.5%) and posteroseptal (4.8%) pathways. The recurrence in those with decremental conduction after the initial successful ablation is higher than that of patients with retrograde AV dissociation (8.8% vs. 3.8%, P < 0.01), and most of them required a second ablation session. CONCLUSION: most of the patients, especially those with free wall accessory pathways, will have retrograde conduction dissociation after the successful radiofrequency catheter ablation. Electrophysiological studies should be carefully performed on patients with decremental retrograde conduction after the ablation.

Adolescent↗
PubMed1994

Predictors of early and late recurrence of atrioventricular accessory pathway conduction after apparently successful radiofrequency catheter ablation.

The correlation between electrophysiologic parameters and recurrence in 239 patients who underwent successful catheter ablation for an accessory pathway mediated tachycardia was analysed. Pathway conduction recurred in 15 patients (6.3%) after a mean follow-up of 7.3 months. Recurrence was most common in patients with right free wall pathways (17.1%). Accessory pathway conduction resumed in 18.9% of patients with decremental ventriculo-atrial (VA) conduction post-ablation compared with those patients without VA conduction (3.4%) (P < 0.001). Recurrence was common also in patients with repeated return of accessory pathway conduction during the ablation procedure (40% vs. 1.3%, P < 0.01). The patients in whom these observations are made should be monitored closely for recurrence of accessory pathway conduction post-ablation.

Adult↗
PubMed1994

Gene transfer for transplantation. Prolongation of allograft survival with transforming growth factor-beta 1.

OBJECTIVE: The authors tested the ability of plasmid gene transfer to express transforming growth factor-beta 1 (TGF-beta 1), prolong allograft survival, and evaluate promoter effects on gene expression. SUMMARY BACKGROUND DATA: Delivery of immunosuppressants directly to allografts using gene transfer and gene therapy approaches may inhibit immune activation while avoiding the systemic toxicity of conventional immunosuppression. Candidate genes include soluble cytokines, which could be expressed at low levels throughout the graft while inducing a local immunosuppressive effect. Transforming growth factor-beta 1 is a soluble cytokine that has pleiotropic immunosuppressive effects. METHODS: Cardiac grafts from syngeneic (CBA/J, H-2k) or allogenic (C57BL/6, H-2b) donors were placed into CBA/J recipients. Purified plasmid DNA-encoding murine TGF-beta 1 or beta-galactosidase (Lac Z) under the control of RSV, SV40, MMTV, or pancreatic elastase promoters was injected into grafts at surgery. The Lac Z expression was determined by histologic examination and TGF-beta 1 expression by graft survival. Cytotoxic T lymphocyte and flow cytometric analyses were performed to evaluate the immunosuppressive effects of TGF-beta 1 in vitro. RESULTS: Plasmid DNA-encoding TGF-beta 1 prolonged survival from 12.6 +/- 1.1 days to 26.3 +/- 2.5 days (p < 0.02, Student's t test). The SV40 promoter was superior to the MMTV promoter in its ability to prolong survival. The effects of the plasmids were specific because Lac Z, antisense TGF-beta 1 inserts, or pancreatic elastase promoter did not prolong allograft survival. Histologic examination demonstrated Lac Z expression at least 14 days post-transplant in myocardial cells. Both RSV and SV40 promoters were effective in this respect, while a control null promoter was not. Toxicity testing showed that gene transfer of TGF-beta 1 did not alter survival or histology of syngeneic grafts. In addition, plasmids and purified TGF-beta 1 protein were not toxic to myoblasts in vitro. Recombinant TGF-beta 1 inhibited cytotoxic T lymphocyte generation and altered T cell surface receptor expression and subset expansion in vitro. CONCLUSION: Gene transfer/therapy with plasmid DNA encoding TGF-beta 1 in vivo achieves immunologic effects that prolong allograft survival. Multiple promoters effectively induce plasmid expression, which is achieved in cardiac myocytes for at least 2 weeks without toxicity or adverse systemic effects. Transforming growth factor-beta 1 inhibits immune responses by different mechanisms, revealed by in vitro analysis of T cell cytolytic function, subset distribution, and receptor display.

Animals↗
PubMed1994

In vivo inhibition of human neutrophil collagenase (MMP-8) activity during long-term combination therapy of doxycycline and non-steroidal anti-inflammatory drugs (NSAID) in acute reactive arthritis.

We studied the in vivo effect of long-term doxycycline treatment combined with NSAID on human interstitial collagenases, other matrix metalloproteinases, serine proteinases, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and lactoferrin from saliva and serum during the course of acute reactive arthritis (ReA). Collagenase activity and serine proteases (elastase-like, cathepsin G-like and trypsin-like activities) of saliva (n = 10) and gelatinase, lactoferrin and TIMP-1 of saliva (n = 10) and serum (n = 10) samples before and after 2 months doxycycline treatment, combined with NSAID, were studied by quantitative SDS-PAGE assay, ELISA assay and by spectrophotometric assay. The cellular source and molecular forms of salivary collagenase were characterized by immunoblotting using specific antisera. We found that activities of total and endogenously active interstitial collagenase reduced significantly. The salivary collagenase was found to originate from neutrophils. No fragmentation of either pro 75-kD and active 65-kD MMP-8 was detected after 2 months doxycycline treatment. However, during 2 months doxycycline and NSAID treatment no reduction of salivary and serum gelatinase, lactoferrin and TIMP-1-levels and salivary serine protease activities were detected. The in vivo inhibition of collagenase (MMP-8) activity during long-term doxycycline therapy in human saliva containing inflammatory exudate of ReA patients may contribute to the reduced tissue destruction observed in recent clinical and animal model studies in arthritides during long-term doxycycline/tetracycline treatment.

Adult↗
PubMed1994

Use of mivacurium during laparoscopic surgery: effect of reversal drugs on postoperative recovery.

We studied the influence of mivacurium on the recovery profile following outpatient laparoscopic tubal ligation in 60 healthy, nonpregnant women. After administration of midazolam 2 mg intravenously (IV), anesthesia was induced with fentanyl, 2 micrograms/kg, and thiopental, 4 mg/kg, IV. When the patient became unresponsive (loss of eyelid reflex), either succinylcholine 1 mg/kg, IV (Group I), or mivacurium 0.2 mg/kg, IV (Groups II and III), was administered to facilitate tracheal intubation. Anesthesia was maintained with isoflurane (0.5%-2% inspired concentration) in combination with 67% N2O in oxygen. Muscle relaxation was maintained in all three groups with intermittent bolus doses of mivacurium, 2-4 mg, IV. In Group III, residual neuromuscular block was reversed with a combination of neostigmine, 2.5 mg, and glycopyrrolate, 0.5 mg, IV, at the end of the operation. In the postanesthesia care unit (PACU), patients in Group III had a significantly increased incidence of postoperative nausea and vomiting compared to Group II. The use of succinylcholine (versus mivacurium) was also associated with more frequent postoperative nausea and vomiting. However, these emetic sequelae did not delay postoperative recovery times. In addition, a comparable number of patients in each treatment group required analgesic medication for postoperative pain. Although patients who received succinylcholine complained of significantly more neck pain during the 24-h period after discharge, nausea, vomiting, and shoulder pain were similar in all three groups during this period. We conclude that neostigmine and glycopyrrolate may contribute to the development of postoperative emesis when used for reversal of residual neuromuscular block.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Propofol infusion during regional anesthesia: sedative, amnestic, and anxiolytic properties.

We examined the plasma concentrations and resultant clinical effects produced by four different propofol bolus infusion regimens in 98 healthy males undergoing elective urologic procedures under regional anesthesia. Patients were randomly assigned to one of four propofol dosage groups. In Groups 1-4, loading doses of propofol equal to 0.2, 0.4, 0.5, or 0.7 mg/kg intravenously, respectively, were followed by fixed-rate propofol infusions of 0.5, 1, 2, or 4 mg.kg-1.h-1, respectively, during the regional block procedure. Sedation (sleepiness) was assessed independently by the patient and a blinded observer using 100-mm visual analog scales. Intraoperative amnesia was assessed using picture recall. Sedation scores increased in a dose-dependent fashion (13 +/- 19, 21 +/- 19, 45 +/- 28, and 73 +/- 26 mm at 30 min in Groups 1-4, respectively). Within a given dosage group, sedation scores were stable during the maintenance infusion period. Mean plasma propofol concentrations increased with higher propofol infusion rates (0.16 +/- 0.3, 0.18 +/- 0.1, 0.47 +/- 0.2, and 1.1 +/- 0.8 microgram/mL at 30 min in Groups 1-4, respectively). However, significant variability was observed among individual patient sedation scores and plasma propofol concentrations. Anxiety scores decreased in all four propofol infusion groups during the maintenance period. Hemodynamic variables and hemoglobin oxygen saturation values were similar in all four treatment groups. Recovery from propofol's central effects was rapid after discontinuation of the propofol infusion, and the incidence of side effects was low. Recall of intraoperative events was more commonly observed in the lower-dosage groups (86%, 96%, 58%, and 13% of patients in Groups 1-4, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Effect of topical eutectic mixture of local anesthetics on pain response and analgesic requirement during lithotripsy procedures.

We sought to determine whether topically applied eutectic mixture of local anesthetics (EMLA) would decrease analgesic requirement during extracorporeal shock wave lithotripsy (ESWL). Fifty-nine healthy out-patients undergoing elective ESWL using an unmodified Dornier HM-3 lithotriptor were randomly assigned to receive either a topical EMLA or placebo cream applied to the skin of the flank overlying the kidney 90 min prior to the ESWL procedure. Patients were given five test shocks at each of five different energy levels: 10, 12, 15, 18, and 20 kV. Patients evaluated the average pain at each stimulus level using a visual analog scale. Overall pain scores were significantly lower in EMLA-treated patients at 18 and 20 kV (P < 0.05). EMLA cream was significantly more effective at decreasing cutaneous pain in male than in female patients. However, during the lithotripsy procedure, EMLA cream had no significant effect on the intraoperative requirement for intravenous alfentanil, hemodynamic variables, recovery times, or postoperative side effects. Although the topical application of EMLA cream produced cutaneous analgesia, these data suggest that it failed to produce any opioid-sparing effect during the immersion lithotripsy procedure.

Adult↗
PubMed1994

Expression of biologically active monomeric form of human M-CSF in baculovirus infected silkworm, Bombyx mori.

The human macrophage colony stimulating factor (hM-CSF) in its monomeric form has been over-produced in BmN cells and in silkworm larvae infected with the recombinant baculovirus Bm284M-CSF. The recombinant monomeric M-CSF (rhM-CSF) exhibited the activity of 8-14 x 10(4) units/ml of cell culture medium. When the insect larvae were infected with the recombinant virus, the maximum rhM-CSF was expressed 4-5 days post infection with an activity of 3 x 10(6) units/ml hemolymph. The monomeric rhM-CSF was purified to homogeneity through three steps of purification. A pilot purification yielded 1 mg of homogeneous monomeric rhM-CSF from 10 larvae. The purified rhM-CSF monomers gradually dimerized in vitro. In contrast, the crude or the semi-purified monomers did not dimerize in vitro, indicating that the presence of an unknown moiety in the rhM-CSF preparations obtained from hemolymph interfered with dimerization.

Alkylation↗