Biomedical subjects
Publications and source records attributed to Z B Chen.
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BACKGROUND: Currently screw fixation of the scaphoid is a well-established method to treat unstable scaphoid fractures. PATIENTS AND METHODS: Between June 1995 and December 2000, 68 patients with an unstable acute scaphoid fracture were treated with screw fixation; 46 patients were reexamined on an average 35 months postoperatively. Range of motion and grip strength (Jamar dynamometer) were measured. The total data rating resulted from the Krimmer wrist score. RESULTS: The subjective results were evaluated with the DASH questionnaire. The average postoperative pain score was documented with a visual analogous pain scale from zero to 100 (VAS 0-100). X-rays as well as computed tomography were performed postoperatively. The average range of motion was 124 degrees for extension/flexion (92% of the opposite site), 57 degrees for radial/ulnarduction (=90%), and 177 degrees for pronation/supination (=98%). Postoperative strength was 47 kg (=90% of the opposite site). The postoperative pain score was 13 (0-100) after stress and 2 during resting conditions. Bony consolidation was reached in 44 cases. The Krimmer wrist score demonstrated a very good result in 39 cases, a good result in 5 cases, and a satisfactory result in 3 cases. The average DASH score was 8.3 points. CONCLUSIONS: The results demonstrate the reliability of internal screw fixation as treatment for acute scaphoid fractures. Functional results as well as subjective satisfaction of the patients are very good. Postoperative CT scans help to evaluate exact bony consolidation, position of the screw, and postoperative morphology of the scaphoid.
This study aims to induce an efficient expansion of cytotoxic T-lymphocytes (CTL) from peripheral blood mononuclear cells (PBMCs) using dendritic cells (DC) transfected with hepatocellular carcinoma (HCC) messenger RNA (mRNA) for adoptive immunotherapy of HCC. Dendritic cells are generated from PBMCs. HCC mRNA is isolated either from HepG-2 cells or from tumour tissue from three HCC patients, and then amplified using the polymerase chain reaction (PCR). Expansion of CTLs is achieved from PBMCs induced by DCs transfected with HCC mRNA and cytotoxicity is measured using a crystal violet staining assay. The proportion of CD3+, CD4+ and CD8+ cells is determined using flow cytometry. Dendritic cells transfected with the total HCC mRNA stimulated antigen-specific cytotoxic T-cell responses that are capable of recognising and killing autologous tumour cells in vitro. The cytotoxic activity was inhibited by treatment with anti-CD3, anti-CD8 and anti-MHC class I monoclonal antibodies, but not with anti-CD4 and MHC class II antibodies. In conclusion, HCC mRNA-transfected DCs may represent a broadly applicable vaccine strategy to induce potentially therapeutic CTL responses in HCC.
OBJECTIVE: To investigate the protective effect of tumor necrosis factor-alpha(TNF-alpha) on spinal motor neurons after peripheral nerve injury. METHODS: Twenty Wistar rats were divided into two groups, the right sciatic nerves of 20 Wistar rats were transected, the proximal stumps were inserted into a single blind silicone tube. 16 microliters of normal saline(NS) and TNF-alpha(30 U/ml) were injected into the silicone tubes. After 2 weeks, the 4th, 5th lumbar spinal cord were taken for examination. Enzyme histochemical technique and image analysis were used to show acetylcholinesterase(AChE) and nitric oxide synthase(NOS) activity of spinal motor neurons. RESULTS: The number of AChE and NOS staining neurons were 8.65 +/- 1.98 and 5.92 +/- 1.36 in the experimental group and 6.37 +/- 1.42 and 8.67 +/- 1.45 in the control group respectively, there were significant difference between the two groups(P < 0.01). CONCLUSION: It suggests that TNF-alpha has protective effect on motor neurons after peripheral nerve injury.
Paclitaxel is an anticancer agent with low aqueous solubility. More extensive clinical use of this drug is somewhat delayed due to lack of appropriate delivery vehicles. An attempt was made to adopt an o/w emulsion as the drug carrier which incorporated paclitaxel in the triacylglycerol stabilized by a mixed-emulsifier system. A suitable formulation was found in this study: 0.75 mg/ml paclitaxel, 10% (w/v) oil blend, 4% (w/v) EPC, 3% (w/v) Tween 80 in 2.25% (w/v) glycerol solution. The formulated emulsion has very good stability when stored at 4 degrees C, and the paclitaxel containment efficiency can be maintained above 95% and the mean emulsion diameter around 150 nm for at least 3 months. Paclitaxel-emulsion displayed cytotoxicity against HeLa cells with IC50 at 30 nM. The average life span of ascitic-tumor-bearing mice was prolonged significantly by the treatment of paclitaxel-emulsion (P<0.05). The formulated emulsion is a promising carrier for paclitaxel and other lipophilic drugs.
Substance P (SP) in the dose range 0.75-1.5 nmol exerts a potent stimulatory effect on ventilation after microinjection into the rat ventrolateral medulla oblongata (VLM; n. reticularis lateralis, n. paragigantocellularis lateralis). A significant but less pronounced effect is also seen in the dorsal medulla (DM; n. tractus solitarius). Somatostatin (0.6-1.8 nmol) inhibited ventilation and induced apnoea after microinjection into the VLM but not the DM. Serial microinjections of the two peptides showed a reciprocal antagonistic action in the VLM but not in the DM. The apnoea-inducing effect of SOM was blunted by SP while SOM reduced the ventilatory stimulation induced by SP. Extracellular single unit recordings were performed following the microiontophoretic application of SP and/or SOM to respiratory-related and non-respiratory-related neurons in the VLM and DM. Although a heterogeneous population of neurons were recorded from, the majority of respiratory-related units in the VLM responded with excitation to SP and inhibitory to SOM. A direct interaction between the peptides was seen in some respiratory-related units. The neurons not responding to either of the peptides were usually non-respiratory. Dorsal to the VLM, the type of response to the two peptides was less likely to be antagonistic and a wider distribution of response types were recorded. The results indicate a direct physiological antagonism between SP and SOM regarding their effects on respiratory regulation elicited in the VLM.
The effect of substance P (SP) and the SP antagonist [D-Pro2,D-Trp7,9]-SP on basal ventilation was investigated in halothane-anesthetized rats. Microinjections of SP (0.4-1.5 nmol) into the ventrolateral medulla oblongata (VLM), (nuclei gigantocellularis, facialis, ambiguus, and reticularis lateralis) or into the dorsomedial medulla oblongata (DM, nucleus tractus solitarius) and its ventral surroundings dose dependently increased tidal volume (VT) and/or minute ventilation. In sensitive areas, the ventilatory stimulation was initiated within minutes, peaked around 8-10 min, and slowly returned to normal over 30-45 min after the injection. In the VLM sites, the increase in VT was generally accompanied by a decrease in respiratory frequency (f), whereas in the DM, f increased in parallel with VT. Furthermore, within the VLM, the respiratory response patterns differed with the definite location of the SP injection. A shortening of inspiratory time was observed in the ventromedial part, the ventrolateral portion of the nucleus paragigantocellularis and ventral to the nucleus facialis. In contrast, a lengthening of expiratory time was seen when SP was injected or applied more laterally along the ventral portion of nucleus facialis and near or directly on the ventral medullary surface. Application of [D-Pro2, D-Trp7,9]SP before or after SP completely antagonized the excitatory effects of SP on ventilation. The SP antagonist administered into the VLM decreased the ventilatory response to hypoxic breathing but caused no change during hyperoxic conditions.
Local injections of the tetradecapeptide somatostatin (SOM) into the brain stem region were performed in anesthetized and decerebrate rats. SOM administration (0.6-1.8 nmol) into the nucleus paragigantocellularis and the nucleus reticularis lateralis of the ventrolateral medulla oblongata induced ventilatory depression and apnea. The occurrence of apnea was dose dependent and attributed to the anesthetic depth, and it was seen within 60-240 s after injection. In anesthetized rats the apnea was seen as a termination or a continuous decrease in tidal volume while respiratory frequency remained unaltered. SOM-induced apnea was caused by depression of central inspiratory drive. SOM injections into the dorsal medulla were ineffective in eliciting apnea, although a ventilatory depression but no apnea was induced in the awake unanesthetized state. In addition to its effect on basal ventilation, SOM administration in the ventrolateral medulla resulted in a blunted ventilatory response to hypoxic and hypercapnic stimuli in anesthetized rats. We conclude that SOM has potent inhibitory effects on respiration that are specifically located in the nucleus paragigantocellularis and the nucleus reticularis lateralis.
The home made UADF after Bastiani's pattern was mechanically tested in our lab on fracture of cadaveric femurs. For comparison, the same test was also carried out with conventional semicircular external fixator. The results showed that the rigidity and stability of fixation closely related with the diameter of the bone-pin used. The diameter of the treated pins used in UADF was one time larger than that of the round pin used in conventional semicircular external fixator. The compression rigidity of the former frame was 3.5 times stronger than that of the latter one; the extent of displacement of the fragments happened in the former frame was much less than that occurred in the latter one. Clinical Application of UADF. on fracture of tibia and fibula in 31, of femur in 8, knee arthrodesis and osteotomy of tibia and fibula one in each, brought bony healing on successfully. It is apparent that the UADF is multifunctional, universal and adaptable in use, leading to success.
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