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Biomedical subjects

T Wang

Publications and source records attributed to T Wang.

At least 505 records · Page 28Linked to original sources
PubMed1997

[Correlation between the serum levels of interleukin-2 and soluble interleukin-2 receptor and the response to immunosuppressive therapy in severe aplastic anemia patients].

OBJECTIVE: To explore factors influencing the effectiveness of immunosuppressive therapy in severe aplastic anemia (SAA). METHODS: The serum levels of interleukin-2 (IL-2) and soluble IL-2 receptor (sIL-2R) of 22 SAA patients and 15 normal controls were measured by immunoenzyme assay. RESULTS: Comparing with the normal controls, 40.9% and 63.6% of the SAA patients had higher serum levels of IL-2 (>840ng/L) and of sIL 2R (>320 x 10(3) U/L), respectively. Those who had higher IL-2 levels and higher sIL-2R levels got better responses to cyclosporin A(CsA) and CsA plus antilymphocyte globulin (ALG). CONCLUSION: The serum levels of IL-2 and sIL-2R were correlated with the responsiveness to immunosuppressive therapy in SAA patients and might be useful for directing treatment.

Adolescent↗
PubMed1997

Timing of the expression of enamel gene products during mouse tooth development.

In order to understand the mechanisms involved in tooth development it is important to define the timing for tissue-specific gene expression. A consequence of ameloblast cell differentiation is the sequential expression of tissue-specific genes whose products form the enamel extracellular matrix. The ameloblast phenotype has been characterized as consisting of two major classes of proteins: amelogenins and non-amelogenin proteins such as anionic enamel proteins (enamelins, tuft proteins, tuftelin, sulfated proteins) and enamel proteases. The postulated functions for the anionic enamel proteins are as nucleators for hydroxyapatite crystal formation while amelogenins control the crystal size, growth and orientation. While the amelogenins have been well characterized, detailed knowledge for anionic enamel proteins has been sparse. In the present study, we designed experiments to characterize one of the anionic enamel proteins from mouse molars, tuftelin, and to determine the timing of expression of this protein during molar tooth development. Our results showed the initial detection of tuftelin transcripts within proliferating inner enamel epithelial cells at very early stages of tooth development (13 days of embryonic development equivalent to the bud stage of tooth development). These data provide direct evidence that invalidates previous dogmas that enamel proteins were synthesized by polarized, non-dividing, fully differentiated ameloblast cells. In addition, tuftelin was found to be synthesized also by dental papilla mesenchyme cells suggesting that this protein is not enamel-specific. These data taken together open the possibility that the tuftelin present in the dentino-enamel junction could be secreted by both, preodontoblast cells and preameloblast cells. It might also suggest a possible different role for tuftelin than nucleator of hydroxyapatite crystals.

Amelogenin↗
PubMed1997

Future clinical research with icodextrin-containing solutions.

Icodextrin-based solutions have been investigated for over ten years and are commercially available in some countries in Europe. Although many studies have been described using icodextrin, we believe that there are many interesting areas remaining for clinical research with icodextrin-based PD solutions. Included in these are the careful examination of the kinetics of icodextrin during the 14-16 hour daytime exchange in CCPD, new studies investigating fluid absorption during icodextrin exchanges, and finally, the potential use of icodextrin in an early start dialysis regime. We look forward to seeing the results from these very interesting studies.

Absorption↗
PubMed1997

Time dependence of solute removal during a single exchange.

The viability of long-term peritoneal dialysis (PD), especially once residual renal function is lost, has been challenged since recently recommended weekly targets of Kt/V of 2.1 and creatine clearance (Ccr) of 70 L/1.73 m2 may be difficult to reach. This study demonstrates the theoretical possibility of achieving these targets in PD patients even without residual renal function. A 6-hour dwell study was performed in 68 PD patients with frequent dialysate and plasma sampling using 2 L of 1.36% (n = 13), 2.27% (n = 9), or 3.86% glucose dialysate (n = 46) with 131I albumin as an intraperitoneal volume marker. Alterations in fluid balance, Kt/V, and Ccr with dwell time (t) as well as the impact of peritoneal fluid absorption on peritoneal fluid and solute removal were evaluated. Kt/V and Ccr did not follow an exponential function with t and, in fact, decreased after 4-5 hours, especially in high transporters. All patients could achieve either weekly Kt/V (especially low transporters) or Ccr target (especially high transporters) if they are treated with automated PD. Calculations showed that eliminating fluid absorption could increase mean fluid removal by 43%-179%, increase mean Kt/V by 17%-32%, and mean Ccr by 16%-30% (depending on the solution used and the patient's peritoneal transport pattern) during a 6-hour dialysis exchange. We reached the following conclusions: (1) Kt/V(urea) and Ccr are markedly time-dependent during a single exchange due to the substantial impact of peritoneal absorption and may, in fact, decline after 4 hours, especially in high transporters. (2) Extrapolating Kt/V and Ccr values from short dwell times [i.e., peritoneal equilibration test (PET) results] to long dwell times will overestimate the peritoneal clearances. (3) Enough fluid removal must be considered as an important target of adequate dialysis along with small solute clearances. (4) If fluid absorption could be eliminated, most continuous ambulatory peritoneal dialysis (CAPD) patients could achieve the recommended Kt/V and/or Ccr targets even without residual renal function.

Absorption↗
PubMed1997

[Injury effects of nicotine on isolated rat common carotid artery].

OBJECTIVES: To investigate the injured effects of nicotine on isolated rat common carotid artery and to supply experimental proofs for vascular vessel and organ transplantation. METHODS: Asins relaxing and contractile functional test of isolated vascular vessel and scanning electron microscopy techniques, we observed the influence of nicotine on the contractile and the relaxing function of isolated artery and the intact of the intima. RESULTS: Lower concentrations of nicotine (6 x-10 mol/L-6 x 10(-6) mol/L) produced a concentration-dependent constrictor response of 18%-41% relative to those induced by norepinephrine (NE, 10(-7) mol/L), whereas removal of endothelium reduced nicotine-induced constrictions to 5%-21%. Higher concentrations of nicotine (6 x 10(-5) mol/L-6 x 10(-3) mol/L) not only injured contractile function of vascular smooth muscle but also caused severe damage to the intima. Various concentrations of nicotine all inhibited acetylcholine-induced relaxation response. CONCLUSIONS: Nicotine not only has cytotoxicity to vascular vessel but also results in vasoconstrictor effects which depend upon endothelium intact, probably by inhibiting the release of endothelium-derived relaxing factor.

Animals↗
PubMed1997

[Expression of mitogen-activated protein kinase in hypertrophic myocardium in SHRsp].

OBJECTIVE: To explore whether myocardial mitogen-activated protein kinase (MAPK) play an important role in hypertensive cardiac remodeling. METHODS: We compared myocardial MAPK activity by phosphocellular method and its localization and distribution by immunohistology in hypertrophic myocardium in SHRsp at age of 34 weeks (34 w group) and 54 weeks (54 w group) with age matched WKY served as control. RESULTS: SHRsp was compared with WKY. The heart weight to body weight ratio was significantly increased in both groups. Myocardial MAPK activity increased 1.81 fold in the 34 w group and 1.46 fold in the 54 w group. MAPK expressed abundantly in hypertrophic myocardium, mainly localized in interstitial cells. CONCLUSION: MAPK might be a major pathway of transducing hypertrophic signals.

Animals↗
PubMed1997

[Clinical application of retrograde island flap carrying plantar metatarsal arteries as pedicle].

The skin and soft tissue defects or ulceration of the wight-bearing part of the sole was difficult to repair with medial plantar island flap, but would be treated with retrograde island flap carrying plantar metatarsal arteries as pedicle. Ten flaps were applied in 9 patients. They had either indolent ulcer or skin defect secondary to excision of painful corn or callosities of the front part of the sole. The flaps were 3 cm to 5 cm long and 3 cm to 4 cm wide, and they all survived following retrograde transfer. The patients were followed up for 1 to 10 years. It was found that the patients could bear weight on the operated foot and could walk without pain or lameness. The flaps were resistant to abrasion from long-time walking. It was concluded that this kind of flap was best suitable to repair the ulcers and defects over the front part of the sole despite there were some minor shortcomings such as the size of the flaps available was small and the donor site required split skin graft for coverage.

Adolescent↗
PubMed1997

[Dumbbell-shaped double-leaf flap for the repair of penetrating wound of palm with tissue defect].

The penetrating wound of palm with the defect of tissues was usually caused by blunt crushing of gun-shot injury. It was difficult to treat clinically. In order to repair the skin defect of palm and dorsum in one operation, 2 kinds of dumbbell-shaped double-leaf flap were desigened. From February 1993 to March 1996, 5 cases with penetrating wound of palm were treated by this method in which the interosseous posterior artery flap in 4, and the superficial epigastric flap in 1. There were 4 males and 1 female with the ages ranging from 15 to 47 years old. The results were as follows: total survival of the flap in 4 cases and partial necrosis of skin margin of the distal leaf in 1 case. The appearance and function of the flap were satisfactory after a follow-up from 4 months to 3 years. It was concluded that the interosseous posterior artery flap had a long vascular pedicle with its constant anatomical distribution, and the 2nd stage of division of the pedicle of the flap was not necessary. It was a perfect flap in repairing the penetrating wound of the palm with small skin defect. The superficial epigastric flap was cumbersome in appearance and was necessary to divide the pedicle of the flap in 2nd staged operation. It was suitable in repairing the penetrating wound with large skin defect. Regarding the operative technique, a meticulous debridement and the appropriate flap area were required, and the blood vessel of the flap should not be compressed by the surrounding tissues. The advantages of this operation provided a simple method to handle, high rate of survival, and one-staged operation.

Adolescent↗
PubMed1997

[Preliminary investigation of treatment of ulnar nerve defect by end-to-side neurorrhaphy].

In the repair of the defect of peripheral nerve, it was necessary to find an operative method with excellent therapeutic effect but simple technique. Based on the experimental study, one case of old injury of the ulnar nerve was treated by end-to-side neurorraphy with the intact median nerve. In this case the nerve defect was over 3 cm and unable to be sutured directly. The patient was followed up for fourteen months after the operation. The recovery of the sensation and the myodynamia was evaluated. The results showed that: the sensation and the motor function innervated by ulnar nerve were recovered. The function of the hand was almost recovered to be normal. It was proved that the end-to-side neurorraphy between the distal stump with the intact median nerve to repair the defect of the ulnar nerve was a new operative procedure for nerve repair. Clinically it had good effect with little operative difficulty. This would give a bright prospect to repair of peripheral nerve defect in the future.

Adult↗
PubMed1997

[Clinical application of implantation of vascular bundle into silicone tube to bridge the peripheral nerve defect].

In order to improve the therapeutic effect of non-neural tissue in bridging the peripheral nerve defect and increase the blood supply of the implant, the silicone tube was chosen to bridge the gap, and the vessel bundle was inserted into the tube. The procedures were performed as following: resected the pseudoneuroma and enveloped the proximal and the distal ends in a silicone tube, and then sutured the epineurium and the tube wall with 7/0 stitch. In patients, eleven cases with fifteen nerves were treated, including seven median nerves, five ulnar nerves and three radial nerves. The lengths of the nerve defects were within 3 cm in 13 nerves and 3 cm-5 cm in 2 nerves. They were followed up from one to five years and the result was excellent (M4S4) in 8 nerves, good (M3S3) in 3 and poor (M1S1) in 2. It was discussed that the indication for the procedure should be included: the nerve defect could not be sutured directly, and the patient would not agree to use his own nerve for graft.

Adolescent↗
PubMed1996

Results of MDR-1 vector modification trial indicate that granulocyte/macrophage colony-forming unit cells do not contribute to posttransplant hematopoietic recovery following intensive systemic therapy.

To formally test the hypothesis that the granulocyte/macrophage colony-forming unit (GM-CFU) cells can contribute to early hematopoietic reconstitution immediately after transplant, the frequency of genetically modified GM-CFU after retroviral vector transduction was measured by a quantitative in situ polymerase chain reaction (PCR), which is specific for the multidrug resistance-1 (MDR-1) vector, and by a quantitative GM-CFU methylcellulose plating assay. The results of this analysis showed no difference between the transduction frequency in the products of two different transduction protocols: "suspension transduction" and "stromal growth factor transduction." However, when an analysis of the frequency of cells positive for the retroviral MDR-1 vector posttransplantation was carried out, 0 of 10 patients transplanted with cells transduced by the suspension method were positive for the vector MDR-1 posttransplant, whereas 5 of 8 patients transplanted with the cells transduced by the stromal growth factor method were positive for the MDR-1 vector transcription unit by in situ or in solution PCR assay (a difference that is significant at the P = 0.0065 level by the Fisher exact test). These data suggest that only very small subsets of the GM-CFU fraction of myeloid cells, if any, contribute to the repopulation of the hematopoietic tissues that occurs following intensive systemic therapy and transplantation of autologous hematopoietic cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Selective blockade of peripheral delta opioid agonist induced antinociception by intrathecal administration of delta receptor antisense oligodeoxynucleotide.

Previous studies have shown that intrathecal (i.t.) administration of antisense, but not mismatch, oligodeoxynucleotides (ODNs) to the cloned delta opioid receptor (DOR) can inhibit the antinociceptive actions of i.t. delta (delta), but not mu (mu) or kappa (kappa), opioid agonists. As a major portion of spinal opioid receptors are localized on the central terminals of the small afferent fibers, we hypothesized that the effects of antisense ODNs given i.t. might be the result of actions at the level of the cell body in the dorsal root ganglion (DRG). This possibility was investigated by assessing the antinociceptive actions of an i.t. or intrapaw (ipaw) administered mu (morphine), delta ([D-Ala2, Glu4]deltorphin) or kappa (CI977) opioid agonist in rats treated with i.t. saline or antisense or mismatch ODNs to the DOR (12.5 micrograms, twice-daily for 3 days). The opioid agonists produced significant antinociception in the 5% formalin-flinch test following either i.t. or ipaw administration. DOR antisense ODN treatment blocked the antinociceptive actions of both i.t. or ipaw [D-Ala2, Glu4]deltorphin without affecting the antinociceptive actions of i.t. or ipaw morphine or CI977. Radioligand binding studies with [3H]naltrindole (NTI), a delta selective antagonist, indicated an approximate 50% decrease in delta opioid receptors in the lumbar spinal cord following i.t. DOR antisense, but not mismatch, ODN treatment. DOR antisense or mismatch ODN treatment did not affect nu or kappa radioligand binding in lumbar spinal cord. These data suggest the possibility that peripheral proteins can be targeted with i.t. antisense ODNs providing significant opportunities for the exploration of the physiological and pathological significance of these substances.

Analgesics, Opioid↗
PubMed1996

Evaluation of microcapsule permeability via inverse size exclusion chromatography.

Inverse aqueous size exclusion chromatography (SEC) was adopted to measure the permeability of microcapsules (hollow hydrogel spheres with diameter < 1 mm) using dextran molecular weight standards. Alginate/poly(L-lysine)/alginate microcapsules were chosen as a column substrate. Data from column SEC experiments were verified by kinetic studies of solute size exclusion. The permeability of tested microcapsules was modified by the reaction time with 0.05wt.% poly(L-lysine) (PLL). The exclusion limit of the microcapsules prepared at 5-min reaction time was found to be 100,000, while the microcapsules that were allowed to react with PLL for 20 min became less permeable and their exclusion limit was approximately 50,000. Based on relationships between solute size and molecular weight, the exclusion limits determined with dextrans were converted to the size and approximate molecular weight of protein presumably excluded by the capsular membrane at "ideal" conditions. The results from both column SEC and batch experiments suggest that the standard alginate/PLL/alginate capsules are permeable to immunoglobulins of IgG class. Unlike other techniques which utilize only a limited number of solutes, inverse SEC enables one to examine the capsule permeability to a homologous series of molecular weight standards. Inverse SEC also provides an opportunity to evaluate the properties of a large series of capsules directly by comparing their calibration curves. In addition, undesirable enthalpic effects in permeability studies with globular proteins as test solutes can be minimized or eliminated by using the inert molecular weight standards such as polysaccharides.

Alginates↗