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Biomedical subjects

X T Niu

Publications and source records attributed to X T Niu.

14 recordsLinked to original sources
PubMed2001

[Trace elements and extracellular matrix].

OBJECTIVE: To investigate the effects of trace elements on the metabolism of extracellular matrix and explore the physiological and pathological mechanism of trauma. METHODS: Based on the experimental and clinical data, it was studied that the action of trace elements in the metabolism of extracellular matrix in trauma repairing. RESULTS: During wound healing, the trace elements were the components of many kinds of enzymes, carriers and proteins. They took part in the synthesis of hormones and vitamins as well as the transmission of information system. They activated many different kinds of enzymes and regulate the levels of free radicals. The trace elements had the complicated effects on the synthesis, decompose, deposition and reconstruction of collagen and other extracellular matrix. CONCLUSION: The trace elements play an important role in regulating the metabolism of extracellular matrix.

Collagen↗
PubMed2000

[Clinical observation on changes of fibroblast growth factor in burn wounds].

OBJECTIVE: To investigate the changes of fibroblast growth factor (FGF) in burn wounds. METHODS: The FGF expression in the center of wound granulation, the edge of wound, the healed part of wound, the normal skin of patients, and the heal course of second degree burn wounds were detected by immunohistochemical methods. RESULTS: The expression intensity of FGF was different in the different sites of third degree burn wounds. The highest contents of FGF was in the center granulation of burn wounds, the less was in the borderline of wound and healed skin, and the least was in the healed skin. FGF expression mainly concentrated in the middle layer of wound, and almost no FGF expression in normal skin. The most FGF expression was occurred at 14 days after injury in second degree of burn wound. CONCLUSION: The changes of FGF in wounds are closely related to the wound healing, and rational use of FGF can promote wound healing.

Adult↗
PubMed2000

[Repair of nasal columella defect with long slender tubed flap].

OBJECTIVE: To introduce the clinical application of long slender tubed flap constructed with "bridge" technique in the repair of nasal columella defect. METHODS: From March 1968 to August 1998, 18 cases with complicated nasal columella defects were repaired with long slender tubed flaps. Among the 18 tubed flaps, 13 cases were designed on the medial side of the upper arm and 5 cases on the longer cervical region paralleling the clavicle. The tubed flaps were 2.0 to 2.5 cm wide and 11 to 15 cm long. The length of the "bridge" was 3 to 7 cm. RESULTS: No flap necrosis or other complications occurred. Postoperative follow-up was 3 to 60 months. The reconstructed columellae showed satisfactory contour, good texture and color, and satisfactory resistance to injury. CONCLUSION: By using the "bridge" technique, tubed flap can be made long and slender enough to provide relatively abundant tissue with adequate circulation and delicate contour. Combined with strict case selection, long slender tubed flaps can bring excellent functional and cosmetic outcomes in the repair of nasal columella defects including those with partial defect of the nasal tip, ala, septum, or defect of adjacent soft tissue. However, this method is relatively time-consuming.

Adolescent↗
PubMed1994

Protein crystallization in space.

The microgravity environment of space is an ideal place to study the complicated protein crystallization process and to grow good-quality protein crystals. A series of crystal growth experiments of 10 different proteins was carried out in space on a Chinese re-entry satellite FSW-2 in August, 1992. The experiments were performed for about two weeks at a temperature of 18.5 +/- 0.5 degrees C using a tube-like crystallization apparatus made in the Shanghai Institute of Technical Physics, Academia Sinica. More than half of 48 samples from 6 proteins produced crystals, and the effects of microgravity on protein crystal growth were observed, especially for hen-egg white lysozyme and an acidic phospholipase A2 from the venom of Agkistrodon halys Pallas. Analyses of the crystallization of these two enzymes in this mission showed that the microgravity environment in space may be beneficial to improve size, external perfection, morphology, internal order, and nucleation of protein crystals. Some of these positive microgravity effects were also demonstrated by the growth of protein crystals in gelled solution with the above two enzymes. A structural analysis of the tetragonal lysozyme crystal grown in space is in progress.

Ancrod↗
PubMed1994

Protein crystal growth in microgravity.

Protein crystal growth is quite important for the determination of protein structures which are essential to the understanding of life at molecular level as well as to the development of molecular biotechnology. The microgravity environment of space is an ideal place to study the complicated protein crystallization and to grow good-quality protein crystals. A number of crystal-growth experiments of 10 different proteins were carried out in August, 1992 on the Chinese re-entry satellite FSW-2 in space using a tube crystallization equipment made in China. A total of 25 samples from 6 proteins produced crystals, and the effects of microgravity on protein crystal growth were observed, especially for an acidic phospholipase A2 and henegg-white lysozyme which gave better crystals in space than earth-grown crystals in ground control experiments. The results have shown that the microgravity in space favors the improvement of the size, perfection, morphology and internal order of the grown protein crystals.

Crystallization↗
PubMed1990

Immunogenic potential of carpal implants.

This study investigated whether a cellular or a humoral-mediated immunologic response to silicone carpal prostheses could be detected in animals previously sensitized to silicone. Silicone carpal prostheses were emulsified in Freund's complete adjuvant (FCA). This emulsion was injected into guinea pigs weekly for 6 weeks. Controls received only FCA. Four weeks later a carpal prosthesis was implanted. Histology showed the implanted prosthesis encapsulated by fibrous tissue in sensitized animals, with a mononuclear infiltrate within the fibrous periprosthetic capsule consistent with a cellular immune response. Skin testing of the sensitized animals showed a true correlate response to the silicone antigen challenge, whereas no response was observed in the control group. The passive cutaneous anaphylaxis reaction in sensitized animals was positive, emphasizing that the antigen-antibody response was passively transferred. Tissue adjacent to the silicone implant in sensitized animals revealed an IgG deposition around the silicone particles by the fluorescent antibody technique. Control animals showed none of these reactions. These results indicate that microparticulate matter from carpal implants can possibly initiate both a cellular immunologic response and the production of a circulating antibody.

Animals↗
PubMed1987

Effect of dietary supplementation with vitamin A on arterial healing in rats.

The effect of dietary supplementation with vitamin A on the healing of rat aortas was studied. Rats were divided into two groups: rats fed a standard chow and rats fed the chow supplemented with 150 IU vitamin A palmitate/g diet. Seven rats from each group were fed with the above diets for 7 days, killed with ether, and the abdominal aorta excised and assayed for hydroxyproline content and collagenase activity. Ten rats from each group were fed for 7 days on the above diets and then underwent a longitudinal aortotomy which was sutured with prolene sutures under pentobarbital anesthesia. The rats were maintained on their respective diets for 7 days and then killed with ether, their abdominal aorta was excised and both the segment with the arteriotomy and the adjacent distal normal segment were analyzed for hydroxyproline content and collagenase activity. Seven rats from each group were fed with the above diets and then underwent transverse division of the abdominal aorta and reanastomosis using nylon sutures under pentobarbital anesthesia. Rats were maintained on their respective diets throughout the postoperative period. Seven days later, all rats were killed with ether and the bursting strength of the aortic anastomoses was measured. The results showed that vitamin A supplementation in non-operated animals had no significant effect on aortic hydroxyproline content or collagenase activity. In rats undergoing longitudinal aortotomy and suture, there was a significant increase in hydroxyproline content both at the healing arteriotomy and at the adjacent non-wounded aorta in the vitamin A-supplemented group. There was also a significant increase in bursting strength of the healing aortic anastomosis in the vitamin A-supplemented rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The role of thromboxane in experimental inadvertent intra-arterial drug injections.

Inadvertent intra-arterial injection of drugs produces a well-defined clinical syndrome whose pathophysiology remains unclear. This study was designed to determine the role of the inflammatory mediator, thromboxane, in intra-arterial drug injections. The rabbit ear model, as described by Kinmonth and Sheppard, was used. Five of the experimental groups were treated with specific or nonspecific thromboxane blocking agents and two groups served as controls. Immunohistochemical staining of the control ears showed elevated levels of thromboxane within the first 6 hours postinjury. The specific thromboxane blocking agents, methimazole and Aloe vera, showed almost complete blockade of thromboxane production. The percentage of ear survival was significantly greater in the group treated with topical Aloe vera (p less than 0.05) and even greater survival was achieved in the combined Aloe vera/methimazole group (p less than 0.01). On the basis of these results, we have begun treatment of such injuries with specific and nonspecific thromboxane blocking agents.

Animals↗
PubMed1987

Control of burn wound sepsis: a comparison of in vitro topical antimicrobial assays.

The Minimal Inhibitory Concentration (MIC) and the Nathan's Agar Well Diffusion (NAWD) tests are bacterial antimicrobial susceptibility predictors. Some suggest that the NAWD is not as reliable as the MIC test. We compared the MIC and NAWD tests as to how well they agree to bacterial sensitivity or resistance and predicted clinical outcome of burn wound infections. Using 65 bacterial isolates from burned patients, the MIC and NAWD tests agreed in 60.0% of the isolates (vs. a perfect agreement of 100%, p less than 0.001), implying that these tests are not interchangeable. From 18 burned patients treated with nitrofurazone or mafenide acetate, 28 infectious isolates were evaluated. The outcome of these infections was correctly predicted by NAWD in 92.8% and the MIC in 72.0% of the cases (p less than 0.05). It seems that for burns treated with topical antimicrobials, the NAWD is a more reliable predictor of bacterial susceptibility.

Bacteria↗
PubMed1985

Effect of dimethyl sulfoxide and glycerol on acute bowel ischemia in the rat.

After a 30 minute period of superior mesenteric artery occlusion in adult rats, there was a significant decrease in peritoneal inflammatory reaction, ileus, peritoneal adhesion formation, and histologically proved bowel wall necrosis in animals given intravenous dimethyl sulfoxide at the end of the ischemic period. In contrast, control rats given normal saline solution intravenously demonstrated severe inflammatory reaction, ileus, hemorrhagic peritoneal fluid, extensive adhesion formation, and areas of bowel wall necrosis. Intravenous glycerol did not have the beneficial effect seen with dimethyl sulfoxide. Neither compound was effective when given intraperitoneally. We conclude that intravenous dimethyl sulfoxide has a significant protective effect in rats with acute intestinal ischemia due to the superior mesenteric artery occlusion in the rat.

Animals↗
PubMedDate not supplied

In vivo comparison of two silver sulfadiazine antimicrobial agents on burn wound infection.

A controversy exists with regard to the relative efficacy of two preparations of silver sulfadiazine (AgSD), Silvadene and Flint's Silver Sulfadiazine Cream. We compared the susceptibility of Staphylococcus aureus and clinical Gram-positive cocci, Gram-negative rods, and mixed floral isolates by the Nathan's agar well diffusion method and found no differences. However, when S aureus-infected rat burn wounds were treated with these antimicrobial creams over a period of ten days, Silvadene significantly lowered bacterial counts, whereas results after treatment with Flint's Silver Sulfadiazine Cream were no different from those of the control group, which received no treatment. These data imply that Silvadene controls S aureus-generated burn wound infections better than the Flint product.

Animals↗
PubMedDate not supplied

Therapeutic efficacy of timentin and augmentin versus silvadene in burn wound infections.

Successful closure of thermal injuries, by either skin graft or delayed wound closure, largely depends on the ability to control the number of bacteria in the wound. The purpose of this study was to investigate the efficacy of two new antimicrobial agents, ticarcillin and clavulanate (Timentin) and amoxicillin and clavulanate (Augmentin), in the infected thermal injury. The therapeutic results were compared with the model treated with the standard topical silver sulfadiazine (Silvadene). Seventy-six Sprague-Dawley rats received a 20% full-thickness thermal injury and were then divided into six treatment groups. Three of the groups were inoculated topically with 10(8) Pseudomonas aeruginosa/ml, and three of the groups received topical inoculation of 10(8) Staphylococcus aureus/ml. The groups inoculated with P. aeruginosa received either intraperitoneal Timentin, topical Silvadene, or placebo treatment. The groups inoculated with S. aureus were treated with either enteral Augmentin, topical Silvadene, or placebo. The animals received 10 days of therapy and underwent tissue biopsies on alternate days. Statistical analysis showed that the level of bacteria in the wounds compared with the control group was significantly (p less than 0.05) decreased for both antibiotics tested as measured by quantitative wound biopsies. These studies demonstrate the efficacy of systemic Timentin and Augmentin in the infected thermal injury.

Amoxicillin↗
PubMedDate not supplied

Prevention of duodenal ulcer formation in the rat by dietary vitamin A supplementation.

We have shown previously that supplemental vitamin A (Vit. A) increases the early inflammatory response to wounding and enhances the collagen content of the intestine of normal and injured rats. We now report the effect of dietary supplementation with Vit. A on the prevention of duodenal ulcer (DU) in rats caused by intragastric administration of cysteamine-HCl. A major way cysteamine-HCl induces DU formation is by enhancing gastric acid secretion. Adult male rats were divided into two groups: (1) rats fed a standard rat Chow (Purina) (15 IU Vit. A/g diet) containing two to three times the National Research Council recommended daily allowance for Vit. A for normal rats; (2) rats fed the same supplemented with 150 IU of Vit. A palmitate per/g Chow. One week later, all rats were given 1 ml of cysteamine-HCl (135 mg) intragastrically. The rats were maintained on their respective diets. Two days later, all rats were killed with ether, the stomach and duodenum excised, and examined for the presence of ulcers. No gastric ulcers were found in either group. There was a statistically significant decrease in the incidence of DUs in the Vit. A-supplemented group when compared to the control group (p less than 0.01) 48 hr following cysteamine-HCl administration; 32% of the Vit. A-supplemented rats developed a DU whereas 74% of rats fed standard Chow had DUs. Most rats had a single DU in the first part of the duodenum, occasionally a second ulcer was noted in the same area. Dietary supplementation with Vit. A had no effect on gastric acid production. In conclusion, our data show that Vit. A dietary supplementation is effective in preventing formation of DUs caused by cysteamine-HCl administration to rats. This effect does not appear to be due to reduction of gastric acid output.

Animals↗