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Biomedical subjects

Y L Ding

Publications and source records attributed to Y L Ding.

12 recordsLinked to original sources
PubMed2001

[Aneurysmal model induced by elastase].

OBJECTIVE: To induce the aneurysms by corrosion of aneurysmal wall with elastase, imitating clinical intracranial aneurysms patho-morhologically. METHODS: The elastase-corroded arterial segments were transplanted onto lateral walls of carotid arteries. Follow-up and pathological examination of the aneurysms were made at two weeks and one month after construction. RESULTS: The aneurysms formed by the transplantation of elastase-corroded arterial segments were found persistent or enlarge a little within one month. The aneurysms were purplish red and easy to rupture when exposed. The walls were deprived of elastic layer, and constructed by thin connective tissue. CONCLUSIONS: The aneurysms made by transplanting elastase-corroded arterial segments are simple to built, while morphological and pathological characteristics are demonstrated good clinical mimicry, we believe our aneurysm model may well substitute the most popularly used aneurysms made of venous pouches.

Aneurysm↗
PubMed1995

Cellular source, activation and inhibition of dental plaque collagenase.

Dental plaque is the major aetiological factor in periodontal diseases and contains several proteolytic enzymes. The origin of these proteinases is, however, poorly studied. This study was undertaken to characterize collagenase present in dental plaque of adult periodontitis patients. Vertebrate-type rather than bacterial-derived collagenase activity was detected in extracts of both supra- and subgingival dental plaque extracts of adult periodontitis patients. Dental plaque collagenase was found to exist predominantly in autoactive form. Dental plaque collagenase from periodontally healthy individuals existed in latent from. Latent dental plaque collagenase from periodontitis lesions could be activated by a 95 kD chymotrypsin-like proteinase from Treponema denticola and human leukocyte cathepsin G but not by human plasmin. Incubation of purified latent leukocyte collagenase with whole cells of Fusobacterium nucleatum, Eubacterium saburreum, Prevotella buccae and Porphyromonas gingivalis, however, did not result to the activation of the enzyme. Doxycycline in vitro inhibited dental plaque collagenase with an IC50-value of 20 microM. Dental plaque collagenase degraded more efficiently type I and II collagens than type III collagen. Western-blot analysis with specific anti-human neutrophil collagenase-antibody revealed that both in supra- and subgingival dental plaque extracts dental plaque collagenase had undergone proteolytic conversion from an 80 kD proform to a 58 kD active form which is associated with catalytic autoactivity as measured by functional collagenase assay. This reflects proteolytic activation of leukocyte collagenase in dental plaque probably by other proteases derived from potent periodontopathogenic bacteria such as T. denticola or other PMN proteases such as cathepsin G.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Limulus hemocyte transglutaminase. Its purification and characterization, and identification of the intracellular substrates.

To investigate further the molecular events of the intracellular coagulation cascade in limulus hemocytes, a transglutaminase (TGase), which may be involved in the formation of a stabilized gel, was purified and characterized. Through the purification procedures consisting of six steps, 1.6 mg of TGase with a specific activity of 940 amine incorporation unit/mg was obtained from 32.4 g of Tachypleus tridentatus hemocytes. The purified TGase gave a single band on SDS-polyacrylamide gel electrophoresis with a molecular mass of 86 kDa, and demonstrated mammalian-type II TGase-like enzymatic properties. The TGase activity was Ca(2+)-dependent and was inhibited by primary amines, EDTA, and SH-reagents. Moreover, two major potential substrates for TGase were identified in the hemocyte lysate by using dansylcadaverine (DCA) incorporation in the presence of 10 mM CaCl2 and 10 mM dithiothreitol. Of these protein substrates, an 80-kDa protein contained a large number of proline residues, amounting to about 22% of the total amino acids. On the other hand, an 8.6-kDa protein abundantly present in the hemocytes was characterized as a Cys-rich protein consisting of 81 amino acid residues and a calculated molecular mass of 8,671. The entire amino acid sequence of this protein was established. Also, the 8.6-kDa protein was readily cross-linked intermolecularly by TGase, forming multimers as large as pentamers. We speculate that like plasma factor XIIIa, limulus TGase and its two protein substrates in the hemocytes may play an important role in the defense of this animal against invading microorganisms.

Amino Acid Sequence↗
PubMed1989

Recent advances in burn wound management in China.

The latest advances in burn wound management in China may be summarized as follows: 1. Escharectomy, tangential excision and skin grafting is being performed widely in moderate and small deep burns especially in functional sites; immediate flap transfer after débridement for deep third degree burns; tangential excision, escharectomy and large sheet skin grafting along the division lines of the face for deep facial burns. 2. Micro-skin grafting--a new operative method used in China was introduced to manage extensive deep burns. 3. Softened freeze-dried glutaraldehyde preserved skin, chlorhexidine-alcohol refrigerated porcine skin, frozen amniotic membrane--all are effective as burn dressings. 4. The new methods of prolonging the survival time of allo- and xeno-skin grafts are used with ultraviolet rays, medicinal herbs and in vitro treatment with triamcinolone acetonide. 5. No remarkable rejection occurred after application of composite skin grafts to burn wounds. 6. The time of culturing epidermal cells has been shortened to 5-13 days. Preliminary successful results were obtained in patients after transplantation of cultured epidermal cell plate or cell emulsion dropped into the holes of allo-skin grafts. No rejection occurred for 50 days up to 16 months after allo-transplantation of epidermal cell plate. 7. Silver norfloxacin, zinc sulphadiazine and cerium nitrate/silver sulphadiazine had a strong bacteria inhibiting action and promoted wound healing.

Anti-Bacterial Agents↗
PubMed1987

Extensive scalds following accidental immersion in hot water pools.

The scalds produced by immersion in hot water pools were extensive, usually of superficial depth on the upper parts of the body and deep dermal or full thickness skin loss on the lower parts. Blisters appeared rather slowly, within 2 days post-burn and often dispersed spontaneously. The estimated burned area on admission may thus be smaller than found subsequently. This study showed that the volume of fluid required for adequate resuscitation during the first post-burn day may be only 1.5 ml/kg/% BSA burned. Deep dermal burns were treated preferably by early tangential excision and grafting. The full thickness skin loss was treated by escharectomy and skin grafts.

Adolescent↗
PubMed1983

Clinical and histological observations on the application of intermingled auto- and porcine-skin heterografts in third degree burns.

Escharectomy and skin grafting with both homograft and porcine skin has become an effective method in treating massive third degree burns. Seventeen patients and 21 operations of intermingled transplantation of auto- and fresh porcine skin heterografts after escharectomy of the severe burn wounds have been carried out since March 1973. Clinical and histological data are summarized, among which we observed the 'fusing phenomena' of auto- and porcine skin heterografts in 6 patients. Vascularization, 'turning red', viability and rejection as well as ways to improve the results of the grafting method are discussed. No vascular communication between fresh porcine skin and the host wound has been observed during the early postoperative period. The cause of 'turning red' is a reddish transudation between the graft and the host wound seen through the thin porcine skin. Based on histological observations, porcine skin is viable after transplantation. With nutritional support apparently coming from the underlying plasma and tissue fluid. Eventually the process of rejection is similar to that of homograft Better results are found with porcine skin grafts 0.4-0.5 mm in thickness placed 0.5-0.75 cm apart. In order to avoid large sloughing wound surfaces less than 20 per cent area of porcine skin coverage is advisable.

Adolescent↗