Biomedical subjects

Hui Xu

Publications and source records attributed to Hui Xu.

At least 163 records · Page 9Linked to original sources

PubMed2002

Column switching-back flushing technique for the analysis of aromatic compounds in gasoline.

A simple method, based on the technique of capillary column switching-back flushing, has been developed for the detailed analysis of aromatic compounds in gasoline. The sample was first separated on a 30-m long OV-2330 polar precolumn and then backflushed onto a nonpolar analytical column. The early eluting components from the precolumn and the components of interest (aromatic compounds plus heavier compounds) eluting from the analytical column are all directed to the same flame ionization detection system through a T piece, which permits the quantitative analysis of aromatic hydrocarbons in gasoline by a normalization method using correcting factors. The switching time window of the method is +/-5 s, resulting in easier operation and higher reliability. The reproducibility of the quantitative analysis was < or = 3% RSD for real gasoline samples.

Benzene Derivatives↗

PubMed2002

Thermosetting gels with modulated gelation temperature for ophthalmic use: the rheological and gamma scintigraphic studies.

For ophthalmic drug delivery, Pluronic F127 solutions have a phase transition temperature too low for them to be instilled into the eye at room temperature. Refrigerator storage is usually required to make administration easier, whereas the potential irritation of cold to the sensitive ocular tissues may result in poor topical bioavailability. The purpose of this study is to develop a thermosetting gel with a suitable phase transition temperature by combining Pluronic analogs and to examine the influence of incorporating mucoadhesive polysaccharide, sodium hyaluronate (HA-Na), on the ocular retention of the gel. Dynamic rheological method and single photon emission computing tomography (SPECT) technique were used to ex/in vivo evaluate the thermosetting gels, respectively. An optimized formulation containing 21% F127 and 10% F68 increased the phase transition temperature by 9 degrees C as evaluated by elasticity modulus compared to that of individual 21% F127 solution. Rheological behaviors of the Pluronic solutions showed that the combined Pluronic formulation was free flowing liquid below 25 degrees C and converted to a firm gel under the physiological condition. Furthermore, this formulation possessed the highest viscosity both before and after tear dilution at 35 degrees C. Gamma scintigraphic data demonstrated that the clearance of the thermosetting gel labeled with 99mTc-DTPA was significantly delayed with respect to the phosphate buffered solution, and at least a threefold increase of the corneal residence time was achieved. However, no further improvement in the ocular retention was observed when adding HA-Na into the thermosetting gel due to the substantially decreased gel strength.

Animals↗

PubMed2002

[Influence of high-frequency electric surgical knife on healing of abdominal incision, experimental and clinical studies].

OBJECTIVE: To study the influence of high-frequency electric surgical knife on abdominal incision healing. METHODS: Two hundred and forty Wistar rats were randomly divided into two groups of 120 rats to undergo abdominal incision by high-frequency electric knife or common lancet respectively. Each of these two groups was redivided into four subgroups that were injected hypodermically with 0.2 ml of quantitative mixture of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa at the concentrations of 0.24 x 10(2) bacteria (10(2) group), 4.49 x 10(4) bacteria (10(5) group), and 4.11 x 10(7) bacteria (10(8) group) respectively, and normal saline of the same volume (10(0) group). Eight days after the operation, the rats were killed. The infection rate of the operational wound was observed and the tissues around the wounds were examined pathologically. On the basis of the animal experiment, 220 patients undergoing abdominal operation above type II were randomly allocated into one of following three groups: high-frequency electric knife (EK) group (93 cases, high-frequency electric knife was used to cut the abdominal tissues and electro-coagulation was used for hemostasis), electro-coagulation (EC) group (55 cases, the abdominal tissues were cut with common lancet and electro-coagulation was used for hemostasis) and control group (72 cases, common lancet and silk thread suture were used). The healing of wound was observed after operation. RESULTS: Four rats died of anesthetic accident; the other 236 rats were killed 8 days after. The wound infection rates were 23.33% and 6.60% in the experimental 10(0) group and the control 10(0) group respectively (chi(2) = 3.28, P > 0.05); 37.04% and 13.33% in the experimental 10(2) group and the control 10(2) group respectively (chi(2) = 4.31, P > 0.05), 50.00% and 24.14% in the experimental 10(5) group and the control 10(5) group respectively (chi(2) = 4.22, P > 0.05); and 63.33% and 36.67% in the experimental 10(8) group and the control 10(8) group respectively (chi(2) = 4.27, P > 0.05). Clinical observation showed a delayed wound healing rate of 17.20% (16 cases) in EK group, 16.36% (11 cases) in EC group, and 2.86% (2 cases) in the control group. There was a statistically significant difference in delayed wound healing rate between the EK and control groups (chi(2) = 8.57, P < 0.01) and between the EC and control groups (chi(2) = 5.66, P < 0.05). However, no significant difference in the delayed wound healing rate was seen between the EK and EC groups (chi(2) = 0.017, P > 0.05). CONCLUSION: High-frequency electric knife remarkably delays the healing of abdominal incision. Its application should be minimized so as to reduce the possibility of postoperative complications.

Abdomen↗

PubMed2002

Development and characterization of anti-Gal B cell receptor transgenic Gal-/- mice.

BACKGROUND: The successful clinical application of pig-to-primate xenotransplantation is currently limited by the development of an acute vascular rejection, which is thought to involve an induced humoral immune response to the galactose alpha1,3 galactose (alpha-Gal) antigen. Successful xenotransplantation may require the development of novel methods for removal or neutralization of anti-Gal antibodies and anti-Gal-producing B cells. The large diversity of the B-cell repertoire makes it difficult, however, to isolate and study anti-Gal B-cell development. METHODS: We have established a transgenic mouse model for investigating anti-Gal B cells by introducing a transgene encoding both heavy and light chains for an anti-Gal IgM antibody into an alpha-galactosyltransferase-deficient (Gal-/-) background. We have characterized the frequency, phenotype, and function of transgenic anti-Gal B cells by multiparameter flow cytometric analysis and ELISA. RESULTS: ELISA analysis of serum from animals with the transgene in an alpha-galactosyltransferase-deficient background (Tg Gal-/-), from transgenic animals with a heterozygous alpha-galactosyltransferase background (Tg Gal-/+), and from nontransgenic alpha-galactosyltransferase-deficient littermates (Gal-/-) demonstrated elevated expression of anti-Gal antibodies in Tg Gal-/- mice compared with nontransgenic Gal-/- animals and a lack of transgene expression in the Tg Gal-/+ mice. Anti-Gal antibody expression in Tg Gal-/- mice could be increased by immunization with an ovalbumin-Gal glycoconjugate in vivo and through stimulation with lipopolysaccharide in vitro. Multiparameter flow cytometric analysis indicates that 50% to 80% of splenic and peritoneal B cells expressed the transgene and excluded endogenous immunoglobulin gene rearrangements. The majority of these B cells expressed anti-Gal receptors on the surface, as identified by staining with a fluorescein isothiocyanate-bovine serum albumin-Gal glycoconjugate. FACS analysis of the Tg Gal-/- B cells identified them as a population of CD21highCD23lowIgMhigh marginal zone B cells in the spleen and CD5-CD23low B1 cells in the peritoneal cavity. CONCLUSIONS: These observations suggest that this model can be used to study the regulation of anti-Gal B cells and can establish a reliable source of functional anti-Gal B cells, which could be used to test the effectiveness of alpha-Gal-specific immunosuppressive reagents.

Animals↗

PubMed2002

Neuropeptide Y inhibits the hyperexcitability of type A neurons in chronically compressed dorsal root ganglion of the rat.

Our recent data revealed adrenergic sensitivity in chronically compressed dorsal root ganglion (DRG) of rats. As neuropeptide Y (NPY) is a common sympathetic co-transmitter, we investigated the effect of NPY on injured DRG neurons. The expression of NPY Y1 and Y2 receptors and the effect of NPY on chronically compressed DRG neurons were studied using in situ hybridization and extracellular single fiber recording in vitro, respectively. After DRG compression, the expression of Y1 receptor was distinctly increased in large and medium-sized DRG neurons, while Y2 receptor was increased in small DRG neurons. NPY inhibited both the spontaneous activity and the excitatory effect of norepinephrine in injured DRG A-neurons. The results suggest a possibility that NPY may inhibit the hyperexcitability of injured DRG A-neurons via increased Y1 receptor following chronic compression.

Action Potentials↗

PubMed2002

Oxidative stress increases internal calcium stores and reduces a key mitochondrial enzyme.

Fibroblasts from patients with genetic and non-genetic forms of Alzheimer's disease (AD) show many abnormalities including increased bombesin-releasable calcium stores (BRCS), diminished activities of the mitochondrial alpha-ketoglutarate dehydrogenase complex (KGDHC), and an altered ability to handle oxidative stress. The link between genetic mutations (and the unknown primary event in non-genetic forms) and these other cellular abnormalities is unknown. To determine whether oxidative stress could be a convergence point that produces the other AD-related changes, these experiments tested in fibroblasts the effects of H(2)O(2), in the presence or absence of select antioxidants, on BRCS and KGDHC. H(2)O(2) concentrations that elevated carboxy-dichlorofluorescein (c-H(2)DCF)-detectable ROS increased BRCS and decreased KGDHC activity. These changes are in the same direction as those in fibroblasts from AD patients. Acute treatments with the antioxidants Trolox, or DMSO decreased c-H(2)DCF-detectable ROS by about 90%, but exaggerated the H(2)O(2)-induced increases in BRCS by about 4-fold and did not alter the reduction in KGDHC. Chronic pretreatments with Trolox more than doubled the BRCS, tripled KGDHC activities, and reduced the effects of H(2)O(2). Pretreatment with DMSO or N-acetyl cysteine diminished the BRCS and either had no effect, or exaggerated the H(2)O(2)-induced changes in these variables. The results demonstrate that BRCS and KGDHC are more sensitive to H(2)O(2) derived species than c-H(2)DCF, and that oxidized derivatives of the antioxidants exaggerate the actions of H(2)O(2). The findings support the hypothesis that select abnormalities in oxidative processes are a critical part of a cascade that leads to the cellular abnormalities in cells from AD patients.

Acetylcysteine↗

PubMed2002

The role of IL-12 in the induction of intravenous tolerance in experimental autoimmune encephalomyelitis.

Intravenous administration of autoantigen is an effective method to induce Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). IL-12 is a potent Th1 stimulator and an essential cytokine in the induction of EAE. The role of IL-12 in the induction of i.v. tolerance is not clear. In this study, we induced tolerance by i.v. administering myelin basic protein (MBP) peptide Ac1-11 (MBP1-11) in EAE. We observed significant suppression of IL-12 production by the lymph node cells of MBP1-11-injected mice. To see whether the low level of IL-12 is the cause or effect of tolerance, we administered IL-12 to the EAE mice at the time of i.v. MBP1-11 injection. Exogenous IL-12 abrogated the suppression of clinical and pathological EAE by i.v. tolerance. IL-12 blocked the suppressive effect of i.v. tolerance on the proliferative response to MBP1-11 and MBP1-11-induced production of IL-12 and IFN-gamma. Furthermore, IL-12 completely blocked the i.v. tolerance-induced type 1 T regulatory cell response. These data suggest that i.v. administration of autoantigen results in the suppression of endogenous IL-12 and the consequent switching of the immune response from an immunogenic to a tolerogenic form.

Animals↗

PubMed2002

Development of a melanoma-specific adenovirus.

Concerns regarding the hepatotoxicity of adenovirus for cancer gene therapy have led to attempts to engineer viruses for tissue-specific gene expression and tissue-specific replication. The Tyrex2 (a tandem murine melanocyte-specific enhancer) system was used to express luciferase, purine nucleoside phosphorylase (PNP), and the essential adenoviral gene E1A. In nonmelanoma cell lines, the CMV promoter/enhancer (CMV p/e) was 969 times stronger than the Tyrex2 construct, whereas in melanoma cells it was only 2.6 times stronger. An adenovirus with Tyrex2 regulating PNP (Ad2Tyr2-PNP) was tested for cytotoxicity. In melanoma cells, treatment with Ad2Tyr2-PNP plus the prodrug 6-methylpurine deoxyriboside (6-MPDR) resulted in 90% cytotoxicity by day 4. In non-melanoma cell lines, only the CMV p/e resulted in significant cytotoxicity. We compared the intrinsic E1A promoter/enhancer (E1A p/e) system with the melanoma-specific constructs and found that the Tyrex2 system achieved higher levels of luciferase than the E1A p/e in all melanoma lines tested. In non-melanoma cell lines, the E1A p/e is 12.4 times stronger than the Tyrex2 construct. Tyrex2 was then used to regulate adenoviral E1A expression to construct a melanoma-specific replicating adenovirus. We were unable to achieve selective replication. As E1A is a known transactivator of the adenovirus major late promoter (MLP), we studied the ability of the MLP to express a transgene in the context of tissue-selective E1A expression. We were able to demonstrate high levels of luciferase activity with this construct; however, selectivity was lost. Melanoma-specific adenovirus expression was achieved with the Tyrex2 construct, and this led to melanoma-specific cytotoxicity by the potent PNP suicide gene. Selective melanoma-specific replication was not successful. The MLP may be a useful promoter in the context of a tissue-specific replicating adenovirus.

Adenoviridae↗

PubMed2002

Combined use of regulatory elements within the cDNA to increase the production of a soluble mouse single-chain antibody, scFv, from tobacco cell suspension cultures.

In order to facilitate production and secretion of a soluble form of a small, single-chain antibody ScFv (32 kDa) in tobacco cell suspension culture, several modifications were made simultaneously to the antibody cDNA that included elements that have been shown to regulate the expression of proteins in plants. The scFv cDNA was initially ligated into a binary vector under the control of the CaMV 35S promoter and the T7 terminator for expression in tobacco suspension culture. Subsequently, modifications were engineered into the cDNA for enhancement of scFv production. These included the following: (i) the signal peptide (SP) of the tobacco pathogenesis-related protein PR1a which was added in-frame to the N-terminal end of scFv cDNA; (ii) a 5'-nontranslated region from the tobacco etch virus (TEV leader sequence), which was fused to the N-terminal end of the SP; and (iii) the endoplasmic reticulum retention signal peptide KDEL, which was added to the C-terminal end of the scFv protein. Using a modified disruption method involving pectinase, the highest expression of total scFv (344 ng scFv/g cell) occurred when the plant leader sequence, the TEV sequence, and the KDEL peptide were all present in the expression construct. Although the addition of the KDEL sequence significantly increased the total yield of protein 5.4-fold, it did not increase the overall amount of protein secreted. These studies indicate that while the SP is very important in promoting secretion of the scFv, it had little influence on increasing scFv secretion levels even when both the TEV and the KDEL sequences significantly increased overall protein levels.

Animals↗

PubMed2002

GammadeltaT cells regulate the development of hapten-specific CD8+ effector T cells in contact hypersensitivity responses.

It has been reported that gammadeltaT cells are required for transfer of contact hypersensitivity responses by hapten-primed T cells. The mechanism by which they do so, however, remains to be elucidated. To specifically investigate the role of gammadeltaT cells in the development of contact hypersensitivity, this study employed Tdelta gene knockout mice that are deficient in gammadeltaT cells but are normal in the development of alphabetaT cells. The result indicates that contact hypersensitivity responses were significantly greater in gammadeltaT cell deficient mice than in wild-type mice. Similar results were obtained when wild-type mice were depleted of gammadeltaT cells with antibody treatment before hapten sensitization. Depletion of CD4+ T cells did not affect the increased contact hypersensitivity response in gammadeltaT cell deficient mice, suggesting that the effect of gammadeltaT cells is on CD8+ T cells and does not require CD4+ T cells. Further experiments demonstrated that primed CD8+ T cells from the deficient mice exhibited significantly higher CTL activity. The cytokine profile of CD4+ T cells was not significantly altered. Transfer of primed lymph node cells from hapten-primed gammadeltaT cell deficient mice elicited a similar level of contact hypersensitivity in naive wild-type and the deficient recipient mice, indicating that gammadeltaT cells have little effect on the elicitation of primed T cells and contact hypersensitivity responses. We conclude that gammadeltaT cells downregulate contact hypersensitivity responses to hapten sensitization by limiting the development of hapten-specific CD8+ effector T cells during sensitization and that this effect is independent of CD4+ T cells.

Animals↗

PubMed2002

Neuroprotective effects of hyperthermic preconditioning on infarcted volume after middle cerebral artery occlusion in rats: role of adenosine receptors.

OBJECTIVE: There are still only a limited number of studies regarding the neuroprotective effects of hyperthermic preconditioning on regional brain ischemia or regarding the role of adenosine A1 receptors in such pretreatment. We examined the effects of hyperthermic pretreatment on infarcted volume after middle cerebral artery occlusion (MCAO), as well as the contribution of A1 receptors, to the responses in rats. DESIGN: Prospective, randomized animal study. SETTINGS: An animal research laboratory in a medical university. SUBJECTS: Male Wistar rats (200-250 g). INTERVENTION: All animals were anesthetized with isoflurane during each pretreatment, as well as for MCAO. The animals were assigned as follows: (i) sham-control group (n = 8), which was maintained at normothermia (37 +/- 0.2 degrees C pericranial temperature) for 15 mins, then kept in an awake state for 0.5, 3, 6, 18, 24, or 48 hrs before 2-hr MCAO; (ii) hyperthermia group (n = 8), which was subjected to 42 +/- 0.5 degrees C for 15 mins, and then received the same treatment as the sham group; (iii) DPCPX (a selective central adenosine receptor antagonist)-treated control group, which was given the agent before normothermia pretreatment, then kept for a recovery time of 0.5 or 24 hrs (n = 8 in each group) before MCAO; (iv) DPCPX plus hyperthermia-treated group, which was administered the agent at the same dose as the control before hyperthermic exposure, then selected for each recovery time (n = 8 in each group) before MCAO; (v) DPCPX-ischemic group, to which the agent was administered before MCAO (n = 8); and (vi) vehicle-ischemic group, in which peanut oil as a vehicle, instead of DPCPX, was injected before MCAO (n = 8). Values are expressed as mean +/- se. Statistical analysis was done by analysis of variance, followed by Scheffe's F test, Mann-Whitney U test, or the chi-square test as appropriate (p <.05). MAIN RESULTS: The infarcted volume in hyperthermic animals kept for 18 or 24 hrs before the occlusion procedure was significantly smaller than in the sham controls, but not in rats kept for 0.5, 3.0, 6.0, and 48 hrs. DPCPX partially reversed the reduction in infarcted volume that was induced by hyperthermic preconditioning after focal ischemia, whereas the agent itself did not affect the volume after ischemia. CONCLUSION: These data indicate that hyperthermic pretreatment reduces the effects on MCAO-induced cerebral infarction, possibly via a partial mediation of the central adenosine receptors in the brain. The results also suggest a need for further studies to define the relationship between heat shock proteins and central adenosine receptors in preconditioning.

Animals↗

PubMed2002

Pharmacological protection of synaptic function, spatial learning, and memory from transient hypoxia in rats.

Hypoxia significantly reduced cholinergic theta activity in rat CA1 field and intracellular theta in the CA1 pyramidal cells, recorded in hippocampal slices. The hypoxic responses of the hippocampal CA1 pyramidal cells to a brief hypoxia consisted of a short period of "synaptic arrest", observed as an elimination of excitatory postsynaptic current under voltage clamp and recovered immediately as oxygenation was reinitiated. The hypoxic synaptic arrest was not associated with reduced postsynaptic responses of the pyramidal cells to externally applied L-glutamate, suggesting that the synaptic arrest might result from a presynaptic mechanism. The hypoxic synaptic arrest was abolished in the presence of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a specific adenosine A(1) receptor antagonist. Blocking adenosine A(1) receptors also eliminated effects of hypoxia on the hippocampal CA1 field theta activity and intracellular theta of the CA1 pyramidal cells. In behaving rats, brief hypoxia impaired their water maze performance in both the escape latency and probe tests. The impairment was prevented by intralateral cerebroventricular injections of DPCPX. These results suggest that hypoxia releases adenosine and produces an inhibition of synaptic transmission and intracellular signal cascade(s) involved in generation/maintenance of hippocampal CA1 theta activity. This protection of synaptic efficacy and spatial learning through adenosine A(1) receptor antagonism may represent an effective therapeutic strategy to eliminate functional interruption due to transient hypoxic episodes and/or chronic hypoxia secondary to compromise of respiratory function.

Animals↗

PubMed2002

Nitric oxide-independent effects of tempol on sympathetic nerve activity and blood pressure in DOCA-salt rats.

The role of sympathetic nerves and nitric oxide (NO) in tempol-induced cardiovascular responses was evaluated in urethane-anesthetized sham and deoxycorticosterone acetate (DOCA)-salt-treated (DOCA-salt) rats. Tempol (30-300 micromol/kg iv), a superoxide (O) scavenger, decreased renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), and heart rate (HR) in DOCA-salt and sham rats. The antioxidants tiron and ascorbate did not alter MAP, HR, or RSNA in any rat. Tempol responses were unaffected after sham rats were treated with N(G)-nitro-L-arginine (L-NNA, 13 mg/kg). In DOCA-salt rats, L-NNA reduced tempol-induced depressor responses but not the inhibition of HR or RSNA. Tempol did not significantly decrease MAP, HR, or RSNA after hexamethonium (30 mg/kg iv) treatment in any rat. Dihydroethidine histochemistry revealed increased O levels in arteries and veins from DOCA-salt rats. Tempol treatment in vitro reduced O levels in arteries and veins from DOCA-salt rats. In conclusion, tempol-induced depressor responses are mediated largely by NO-independent sympathoinhibition in sham and DOCA-salt rats. There is an additional interaction between NO and tempol that contributes to depressor responses in DOCA-salt rats.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗

PubMed2002

Synthesis and insecticidal activity of novel 4beta-halogenated benzoylamino podophyllotoxins against Pieris rapae Linnaeus.

Twelve new 4beta-halogenated benzoylamino compounds (7.1-7.12) of podophyllotoxin have been synthesized, and their structures were confirmed by IR, 1H-NMR, MS spectra as well as CHN elemental analysis. These compounds showed delayed insecticidal activity against 5th instar larvae of Pieris rapae Linnaeus in vivo, when tested by a leaf-dipping method at a concentration of 250ppm. By preliminary qualitative structure-activity relationship analysis, we found the following results: 1) Compounds 7.2, 7.5-7.9 were more potent than the nature parent product in the mortality after 15 d against P. rapae in vivo. Especially compounds 7.5 and 7.6 bearing meta- and para-chlorobenzene substituents respectively, were the most potent of these compounds; 2) Substitution on the benzene ring moiety of 4beta-benzoylamino podophyllotoxin (PPT) with Cl, Br, I at the para or at the meta position yielded compounds which were as potent or more potent than those containing the corresponding substituting group at the ortho position. 3) Substitution on the benzene ring moiety of 4beta-benzoylamino podophyllotoxin with I either at the ortho, meta or para position yielded less potent compounds (7.10-7.12) when compared with PPT.

Animals↗

PubMed2002

Relationship between drug effects and particle size of insulin-loaded bioadhesive microspheres.

AIM: To formulate and characterize insulin-loaded adhesive microspheres (MP) and evaluate drug effects of MP with various sizes, 120, 350, and 1000 nm in diameter, in the alloxan-induced diabetic rats. METHODS: Insulin-loaded MP were formulated by an ionotropic gelation procedure. Particle size distributions were determined by photon correlation spectroscopy and optical microscopy. The factors that influenced the particle sizes and loading capacity were investigated, and the release properties were assessed in vitro. The hypoglycemic effect was investigated by monitoring the plasma glucose level of the alloxan-induced diabetic rats after oral administration. RESULTS: All the MPs with three sizes formulated were in the desired size range, and the loading capacity was 15.3 %+/-1.7 % (120 nm), 32.4 %+/-2.4 % (350 nm), and 53.3 %+/-2.7 % (1000 nm) respectively. The particle size also had an influence on the release property of the MPs. Half an hour later, 25 %+/-4 % (120 nm), 18.3 %+/-2.4 % (350 nm), and 8.6 %+/-1.3 % (1000 nm) of insulin were released. MP with different sizes had various degree of hypoglycemic effects after 10 h (P<0.05 vs control insulin solution). The plasma glucose level of 350 nm size particles remarkably decreased 15 h later (P<0.05 vs 120 nm) or 35 h later (P<0.01 vs others). The relative pharmacological availability was 10.2 %+/-0.5 % (120 nm), 14.9 %+/-1.3 % (350 nm), and 7.3 %+/-0.8 % (1000 nm) respectively. Particles of 350 nm showed a comparatively higher availability (P<0.05). CONCLUSION: Adhesive CS-MP were helpful in increasing the relative pharmacological bioavailability of insulin, and a distinct advantage of proper particle size helped to increase the drug effects.

Animals↗

PubMed2002

[An experimental study on the cograft of auto-microskin and allo-dermal matrix].

OBJECTIVE: To explore the promoting effects of cograft of auto-microskin and allo-dermal matrix on burn wound healing. METHODS: Forty-six patches of full skin loss wounds were made in the backs of 6 small white swines. Auto-microskin and meshed acellular allo-dermal matrix were simultaneously prepared. The 46 wounds were averagely divided into test (T) and control (C) groups. The wounds in T group were covered with auto-microskin and allo-dermal matrix (1:4) and split-thick allo-porcine skin. While the wounds in C group were grafted with autoskin and allo-dermal matrix. RESULTS: The skin survival rate exhibited no difference between C and T groups (P > 0.05). There was similar histological exhibition in the two groups after skin grafting. The structure of collagen fibres appeared integrated, clear with regular arrangement and steady diameter at 8 - 20 post-operative weeks. Simultaneously, it was revealed by histological examination that normal vascular structure could be identified in the grafted skin and that inflammatory reaction ameliorated gradually and that epithelium combined well with dermis. It was also found that the epidermal papillar across the basement membrane fixed well to allo-dermis. The skin appeared smooth, elastic and functioned well at 5 months after skin grafting. CONCLUSION: The grafted skin survived well after the cograft of auto-microskin and allo-dermal matrix, which might be ideal covering material for the major deep burn wound healing.

Animals↗

PubMed2002

[Clinical evaluation of the effects of rhGH on the management of severely burned patients].

OBJECTIVE: To investigate the effectiveness and the safety of clinical use of rhGH in the management of severe burn patients. METHODS: Two hundred burn patients aged 20 - 25 yrs with TBSA from 20% to 50% and admitted within 5 postburn days (PBD) were enrolled in this study. The patients were divided into operation and non-operation groups. Furthermore, each group was randomly divided into control (N), treatment with rhGH in dosage 0.2 IU/Kg/d (A) and treatment with rhGH in dosage 0.4 IU/kg/d (B) groups. The general data, the metabolism of protein and glucose, the immune function, the urine biochemistry, the wound healing rate and hospital stay days recorded and compared among all groups. RESULTS: Plasma protein was increased, the immune function recovered early, the wound healing time was shortened obviously, the wound healing rate was increased evidently and the hospital stay days were decreased significantly in the treatment groups (A and B groups) compared with the N group. The body weight of burn patients remained unchanged in N group. Nevertheless, the plasma levels of glucose and insulin were increased and the urine output of potassium, sodium and chloride decreased in N group compared with those in A and B groups. Moreover, the levels of all these indices in B group were higher than those in A group, whereas side effects were more common in B group than in A group. In addition, the incidence of adverse reaction was higher in operation group than that in non-operation group. CONCLUSION: rhGH could effectively promote protein synthesis, enhance systemic immune function, accelerate wound healing and shorten hospital stay days in severely burned patients. But attention should be paid to appropriate dosage and duration of use.

Adult↗

PubMed2002

[Important factors controlling rates of N2O emission and CH4 oxidation from forest soil].

In this study, laboratory incubation experiments were conducted to determine the effect of pH, soil water content, temperature, NH4+ and NO3- on N2O emission and CH4 oxidation of mixed broad-leaved Korean pine forest soil. Results showed that there were significant correlations between N2O emission rate, CH4 oxidation rate and soil pH and temperature under certain lab conditions. Meanwhile, the significant positive correlation between N2O emission rate and CH4 oxidation rate was also observed. The results suggested temperature and pH could be the most important factors controlling the rates of N2O emission and CH4 oxidation of a forest soil under this experiment conditions.

Methane↗