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Biomedical subjects

S Li

Publications and source records attributed to S Li.

At least 1,225 records · Page 68Linked to original sources
PubMed1996

A comparison of continuous versus intermittent light exposure on apoptosis.

PURPOSE: We recently found that continuous light exposure at a moderate intensity triggered apoptosis of photoreceptor cells. Since intermittent light exposure is known to cause more severe retinal damage than is continuous light exposure, we sought to determine if intermittent light exposure also triggered apoptosis of photoreceptor cells. METHODS: Lewis albino rats were reared, for 2 weeks, in cyclic light and dark adapted for 24 hr before light exposure. Rats were exposed to intermittent light or continuous light for 6 or 9 hr, respectively. Light-exposed rats were killed by lethal injection at three timepoints: immediately after light exposure, after 6 hr of dark recovery following light exposure and after 24 hr of dark recovery following light exposure. Retinal damage after light exposure was evaluated by morphology, morphometry, the terminal transferase-mediated biotin dUTP nick end labeling (TUNEL) technique for identification of nicked/cleaved nuclear DNA and agarose gel electrophoresis of retinal DNA. RESULTS: Evaluation of morphology confirmed that intermittent light exposure caused more photoreceptor cell damage than did continuous light exposure of the same duration and intensity. The TUNEL technique showed that photoreceptor nuclei contained nicked or cleaved DNA after either intermittent or continuous light exposure, although more TUNEL-positive nuclei were observed after intermittent exposure. Agarose gel electrophoresis of retinal DNA showed internucleosomal DNA fragmentation, which is associated with apoptosis in samples from intermittent light exposure. CONCLUSIONS: These data demonstrated that intermittent light exposure triggered apoptosis in more photoreceptor cells than did continuous light exposure of the same intensity and duration.

Animals↗
PubMed1996

Interaction of diagnostic ultrasound with synthetic oligonucleotide-labeled perfluorocarbon-exposed sonicated dextrose albumin microbubbles.

The purpose of this study was to determine, first, whether the albumin on perfluorocarbon-exposed sonicated dextrose albumin microbubbles has retained its known ability to bind antisense oligonucleotides (DNA utilized to inhibit viral replication and intimal hyperplasia). The binding kinetics of synthetic antisense oligonucleotides to perfluorocarbon-exposed sonicated dextrose albumin microbubbles as well as to room air-containing sonicated dextrose albumin microbubbles were compared. Second, the effect of diagnostic ultrasound on this binding is unknown. The ability of diagnostic ultrasound to release synthetic antisense oligonucleotides from perfluorocarbon-exposed sonicated dextrose albumin microbubbles also was tested in vitro and in vivo in three dogs. Synthetic antisense oligonucleotides exhibited binding to perfluorocarbon-exposed sonicated dextrose albumin microbubbles much like that of native albumin but did not bind uniformly with room air-containing sonicated dextrose albumin microbubbles. Diagnostic ultrasound resulted in significant partitioning of synthetic antisense oligonucleotides into non-bubble containing regions after insonation in vitro as well as deposition of greater amounts of synthetic antisense oligonucleotides in the insonated kidney after intravenous injections of synthetic anti-sense oligonucleotide-labeled perfluorocarbon-exposed sonicated dextrose albumin microbubbles. We conclude that perfluorocarbon-exposed sonicated dextrose albumin microbubbles, unlike room air-containing sonicated dextrose albumin microbubbles, have bioactive albumin on their surface that can bind synthetic antisense oligonucleotides and then release them in the presence of diagnostic ultrasound.

Animals↗
PubMed1996

[Relationship between glaucoma and quality of life].

PURPOSE: Assessment of the relationship between visual impairment of glaucoma and quality of life, and to explore the factors which affect quality of life of patients with glaucoma. METHODS: Sixty patients with chronic angle close glaucoma and open angle glaucoma were measured by the scale of quality of life for diseases with visual impairment. RESULTS: Scores of quality of life were significantly associated with visual function of glaucoma (r = 0.66, P = 0.000), the factors which affect quality of life were visual impairment, sex and occupation. CONCLUSION: The visual impairment of glaucoma may decline quality of life of patient. Evaluation of quality of life of patient. Evaluation of quality of life affords a new index for choosing strategies of glaucoma screening and therapies.

Adolescent↗
PubMed1996

[Changes in hematoporphyrin in patients with gastric and hepatic carcinoma and their clinical significance].

The fluorescence spectroscopy of porphyrin molecule in blood was determined with photoluminescence fluorescence spectroscope in 139 patients with gastric carcinoma, 76 with hepatic carcinoma, 110 with gastric ulcer and chronic gastritis, 168 with liver cirrhosis and 33 normals as controls. The results showed that the peaks of Zinc porphyrin and protoporphyrin in patients with cancer were significantly higher than those in patients with benign disease, the peak of protoporphyrin being two to three times higher in the former groups of patients than that in the latter (P < 0.01). Protoporphyrin could be used as a marker to screen and diagnose gastric and hepatic carcinoma.

Biomarkers, Tumor↗
PubMed1996

Cardiac cytotoxic mechanism mediated by antibodies against myocardial mitochondrial ADP/ATP carrier in patients with dilated cardiomyopathy.

OBJECTIVE: To investigate mechanism of the antibody-mediated cardiac cytotoxicity and clinical significance in dilated cardiomyopathy (DCM), and study the effects of the antibodies against the myocardial mitochondrial ADP / ATP carrier from sera of patients with dilated cardiomyopathy on the guinea pig ventricular myocytes. PATIENTS AND METHODS: This study included 18 patients with DCM (12 men and 6 women), with mean age of 43 years. Control group included 18 health donors, (9 men and 9 women), with mean age of 32 years. The antibodies against the ADP / ATP carrier and cell membrane 52 000 peptide were examined by immunoblotting. The antibody-mediated cardiac cytotoxicity was studied with the cytotoxic test and whole cell patch-clamp technique. RESULTS: The antibodies against myocardial mitochondrial ADP / ATP carrier and cell membrane 52 000 peptide were positive in 18 patients with DCM, while negative in controls. The antibodies induced cytotoxic damage with time-dependent and enhanced Ca-current in cardiac myocytes. The increasing amplitude of peak Ca(2+)-current was 100 pA-840 pA (n = 8) in different dilution of the antibodies. The effect of the antibodies might be inhibited by verapamil, and were null in controls (n = 4). CONCLUSIONS: The above findings suggest that an increase in the antibody-mediated Ca(2+)-current of cardiac myocytes is related to the cytotoxic damage in dilated cardiomyopathy.

Adult↗
PubMed1996

Stereotactic intratumour irradiation with nuclide for craniopharyngiomas.

OBJECTIVE: Craniopharyngiomas is a kind of intractable tumor in neurosurgery. Since the radical excision is very difficult and occasionally hazardous because of its deep location and close neighbouring to critical cerebral structures, it is necessary to look for a simple and effective method. PATIENTS AND METHODS: Stereotactic intratumour irradiation with instillation of nuclide colloid was performed in 220 patients with craniopharyngiomas (altogether 265 times), of whom, 130 were male and 90 female. Their ages ranged from 5 to 69 years. The syndromes of optic path's impairment were present in all of the patients. CT or MRI scan showed cystic tumour in 125 patients, solid and cystic in 80 and solid in 15. No severe complications and death were related to the operation. RESULTS: 150 patients were followed up for 2 months to 7 years (average 3.5 years). Tumours disappeared in 92 patients (61.4%), decreased dramatically in 20 (13.4%), decreased less than 50% in 19 (12.6%), and increased in 15 (10%); and there were 4 deaths (2.6%). CONCLUSIONS: Stereotactic intratumour irradiation with instillation of nuclide colloid is effective in the patients with craniopharyngiomas. Beta-emitting isotopes (P-32 and Y-90) are the preferred internal radiation source because of their limited penetration of the energy released and the greater ease of handling. A calculated dose of 20 000 rads to the cyst wall is recommended.

Adolescent↗
PubMed1996

Experience in prevention of serious complications of laparoscopic cholecystectomy.

OBJECTIVE: To study the causes and prevention of the complications of laparoscopic cholecystectomy (LC). PATIENTS AND METHODS: Based on experience with 2 428 cases, the following should be paid attention to when dissecting and separating adhesions around the gallbladder and of the Calot's triangle. The best method for the prevention of mistaking the common bile duct (CBD) for the cystic duct is to find the junction of the cystic infundibulum and duct, separate the gallbladder wall along the infundibulum, and transect the cystic duct at the junction with the infundibulum. If dense adhesions around the gallbladder or of the Calot's triangle are met with, LC should be abandoned and open the cholecystectomy (OC) should be used instead. In separating the Calot's triangle, blunt dissection should be used to avoid burning the extrahepatic bile duct (EHBD), and blind hemostasis should be avoided. If the cystic artery lies in the upper part and the back of the cystic duct, the cystic duct should be dissected out, clipped and cut first, then the cystic artery be dealt with. If the cystic artery is in the front part of the pedicle of the gallbladder, the artery should be separated, clipped and cut first. Injury to the adjacent organs may be avoided by using electric coagulating hook correctly and avoiding accidental damage to the viscera, and keeping from viscera injury due to current chemotaxis in the closed cavity of the body. RESULTS: A total of 2427 patients were cured. One patient died of frequent episodes of supraventricular tachycardia and pneumonia on the 21st day after LC. CONCLUSION: If LC surgeons follow the above said principles of LC technique. LC is very safe for patients with benign diseases of the gallbladder.

Adolescent↗
PubMed1996

Cataract extraction and intraocular lens implantation with anterior vitrectomy in children.

OBJECTIVE: Extracapsular cataract extraction (ECCE) with selective intraocular lens (IOL) implantation has been the choice of the treatment for children with cataracts. With regard to surgical technique, ECCE with anterior segment vitrectomy has shown some success in reducing complications. Formation of a secondary membrane and opacity of the posterior capsule, however, are still major postoperative complications. To reduce these complications, we modified current surgical procedures with minimal incisions and manipulations. PATIENTS AND METHODS: ECCE with anterior segment vitrectomy was performed using Storz Protage's system in 84 eyes of 58 children ranging in age from 14 months to 14 years. Of 70 eyes of children aged above 3 years, IOLs were implanted simultaneously. Vision improvement and incidence of postoperative complications were compared with other standard procedures to determine the benefits of the operation for children with cataracts. After the anterior capsule was opened by continuous circular capsulorhexis or envelope-form capsulectomy, the lens cortex was excised. Subsequently, the IOL was implanted into the bag. RESULTS: Nine-30 months follow-up showed that all of the central area of the posterior capsule remained clear except one eye in which a secondary membrane was partially formed on the anterior surface of vitreous. No other operative or postoperative complications occurred. CONCLUSIONS: The results indicate that the modified procedure is beneficial in the prevention of secondary cataract formation and other postoperative complications in a short term follow-up, however, a long-term follow-up is warranted to evaluate its role in pediatric cataract surgery.

Adolescent↗
PubMed1996

[Early corneal topographic changes after intraocular lens implantation].

OBJECTIVE: The study was designed to investigate the early post-operative effect of the incision of extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation on the whole corneal curvature. METHODS: TMS-1 Topographic System was used to record the changes in corneal refractive power and topography of 42 eyes within 3 months following the surgery through a 11 mm stepped limbal incision. RESULTS: The corneal topographic map showed that a vertical dumbbell configuration centered at the corneal top presented, the vertical corneal curvature at various radial distances steepened after the operation, the steepening at radial distance of 2.5 mm was much greater than that of 1.5 and 3.5 mm and the steepening at the upper cornea was greater than that at the corresponding lower cornea. The postoperative vertical corneal steepening gradually flattened and the refractive power decreased. CONCLUSION: The topographic map early after ECCE with IOL implantation presents a flattening change of vertical corneal steepening corresponding to a with-the-rule astigmatism which decreases gradually.

Aged↗
PubMed1996

[A study of human keloid with electron spin resonance].

Electron spin resonance (ESR) was used to examine human keloid, normal connective tissue and skin. The results showed that more oxygen free radicals were identified in keloid, less in normal connective tissue while no free radicals were found in skin. The author discussed the significance of the occurrence of oxygen free radicals and its relation with keloid and suggested that reduction or elimination of production of oxygen free radicals by its scavenger may be of help in preventing the excessive growth of scar tissue.

Connective Tissue↗
PubMed1996

Inhibitory effects of isoproterenol on PAF-induced endothelial cell permeability and morphological changes.

Using a model to study vascular permeability under hydrostatically perfused bovine pulmonary artery endothelial cell (EC) monolayers and a software to automatically analyse cell morphological parameters in a computer image workstation, the effects of isoproterenol (IPN) on platelet-activating factor (PAF)-induced changes in EC monolayer permeability and cell morphological parameters were studied. Albumin has the fortifying effect on endothelial barrier function. After treatment of EC monolayer with 10(-8) mol/L PAF, trans-monolayer permeability increased, cell surface area decreased, and intercellular space enlarged. As pretreatment with 10(-4) mol/L IPN, PAF-induced EC permeability increment and morphological changes were blocked. The results suggest that EC contraction and intercellular gap expansion are important mechanisms for PAF-induced high vascular permeability. IPN inhibits the effects of PAF via stabilization of EC morphology and prevention of intercellular gap formation.

Adrenergic beta-Agonists↗
PubMed1996

Value of nasal radiographs in nasal trauma management.

OBJECTIVE: To assess the value of routinely acquiring plain nasal radiographs in patients following nasal trauma both clinically and cost effectively. DESIGN: A questionnaire was devised to determine the factors that influence physicians to order nasal x-rays and whether or not the results of these radiographs influence management. SETTING: The questionnaire was distributed to the otolaryngology staff and residents, emergency physicians, and family physicians affiliated with the University of Toronto. METHODS: Descriptive statistics were employed. MAIN OUTCOME MEASURES: Percentages of reasons for ordering nasal x-rays and their part in treatment management. RESULTS: The commonest reasons for ordering nasal x-rays in these cases included perceived severity of injury and detection of unsuspected facial fractures, as well as presumed need for medicolegal documentation. CONCLUSIONS: Nasal x-rays are not of substantial medicolegal value and do not play a role in the treatment of the patient. Nasal radiographs are not a cost-effective investigation in the management of trauma to the nose, and their routine use should be abandoned.

Cost-Benefit Analysis↗