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Biomedical subjects

L Dai

Publications and source records attributed to L Dai.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Time effect of restraint stress-induced suppression of lymphocyte transformation].

In the present study, restraint, which caused no direct tissue damage, was selected as a method of stress to investigate time effect of stress-induced suppression of lymphocyte transformation in rats. The lymph node and spleen extract or the serum from rats restrained for 3, 6, 12, 18 h or 12, 24, 48, 72, 96 h after restraint, with concanavalin A (Con A), was added to the lymphocyte suspension of rat mesenteric lymph node and was incubated for 72 h. The optical density (OD) value indicating the level of lymphocyte transformation was determined by colorimetric assay of methylthiazol tetrazolium bromide (MTT). The results are as follows. (1) The lymph node and spleen extract or the serum from the rats restrained for 3 or 6 h did not markedly affect the lymphocyte transformation. (2) The lymph node and spleen extract or the serum from the rats restrained for 12 h or 18 h significantly inhibited the lymphocyte transformation and stronger inhibition occurred at 18 h. (3) Up to 96 h after restraint, the suppressive effect of the lymph node or spleen extract on the lymphocyte transformation still existed, but the suppression of the serum on the lymphocyte transformation almost disappeared. These results suggest that the restraint of rats may cause lymphoid tissues to produce some immune suppressive protein of stress, which is released into blood leading to a generalized suppression of cellular immunity.

Animals↗
PubMed1999

[The therapeutic effect of ligustrazin and salvia miltiorrhiza on the gene expression of alpha1 (I) and alpha1 (III) procollagen in rat pulmonary fibrosis].

OBJECTIVE: To evaluate the effect of ligustrazin and salvia miltiorrhiza on collagen gene expression in rat pulmonary fibrosis (PF). METHODS: The tested animals were divided into 7 groups: normal control, untreated animal groups (day 7, 14 and 29), Ligustrazin, Salvia Miltiorrhiza and hydrocortisone groups. Treatment was started from day 15 to day 28. HE stain and in situ hybridization with alpha(1) (I) and alpha(1) (III) procollagen (PC) cDNA probes were applied to rat lungs on day 29. The results were quantified by a feature analysor. RESULTS: All the three drugs were effective, ligustrazin the best (P < 0.01), salvia miltiorrhiza the second (P < 0.01). In untreated groups both alpha(1) (I) and alpha(1) (III) PC mRNA reached the maximum on day 7. Alpha(1) (I) PC mRNA still kept high on day 29 while alpha(1) (III) PC mRNA had decreased to normal. In ligustrazin group alpha(1) (I) PC mRNA decreased to normal (P > 0.05) but in salvia miltiorrhiza and hydrocortisone groups it was still above normal level (P < 0.01). In all groups alpha(1) (III) PC mRNA had decreased to normal on day 29. CONCLUSIONS: Inhibitive effect of ligustrazin on alpha(1) (I) PC mRNA may play an important role in treating PF. The effect of salvia miltiorrhiza is less than ligustrazin.

Animals↗
PubMed1999

[Disc degeneration and cervical instability].

OBJECTIVE: To evaluate disc degeneration and segmental instability in the cervical spine by comparing the magnetic resonance imaging assessment of disc degeneration with conventional plain radiographic evaluation with cervical segmental instability. METHODS: Two hundred sixty consecutive patients with suspected cervical spine disorders were analyzed for horizontal and angular displacements on lateral flexion and extension radiographs and disc degeneration on T(2)-weighted magnetic resonance images of the cervical vertebrae. RESULTS: In all intervertebral levels, the grade of disc degeneration increased significantly (P < 0.01) with age. Cervical instability was identified in 151 segments (14.5%) and correlated with Grade 1 and Grade 2 degeneration in the intervertebral discs (P < 0.01). CONCLUSIONS: Cervical segmental instability may indicate early degeneration of intervertebral disc in the cervical vertebrae.

Adult↗
PubMed1999

[Radiculopathy after cervical laminectomy].

OBJECTIVE: To investigate radiculopathy after multilevel laminectomy in patients with cervical compression myelopathy and underlying mechanism. METHODS: We retrospectively reviewed 287 consecutive patients with cervical compression myelopathy treated by multilevel cervical laminectomy and identified 37 patients (12.9%) with postoperative radiculopathy. There were 27 men and 10 women, with an average age of 56 years at time of surgery. The diagnosis was either cervical spondylosis (25 patients) or ossification of the posterior longitudinal ligament (12 patients). RESULTS: Radiculopathy was observed from 4 hours to 6 days after surgery. The most frequent patterns of paralysis were C(5) and C(6) root involvements of the motor-dominant type. All patients showed complete recovery in 2 weeks to 3 years (average, 5.4 months). Follow up results showed that the recovery rate was negatively related to the duration of complete recovery of postoperative radiculopathy (r = -0.832, P < 0.01) and the patients with spondylotic myelopathy had a significantly better clinical recovery rate than those with ossification of the posterior longitudinal ligament (t = 2.960, P < 0.01). CONCLUSIONS: Postoperative radiculopathy is complicated with posterior cervical decompression and associated with tethering effect upon the nerve root. More logical procedures for prevention of postoperative radiculopathy are decompression through an anterior decompressive procedure in conjunction with a spinal fusion, which may achieve stabilization and directly remove all of the anterior spinal cord compression at multiple levels.

Adult↗
PubMed1999

[The significance of endometrial biopsy during luteal median phase in diagnosis of luteal function].

OBJECTIVE: To investigate the significance of progesterone profile and endometrial biopsy during luteal median phase in diagnosis of luteal function. METHODS: The progesterone profile during median luteal phase and endometrial histology during median and late luteal phase of 53 infertile women with infertile and recurrent abortion for unknown reasons were studied. RESULTS: Retarded endometrial development occurred in the median luteal phase in 24 of the 53 cases, 9 of which lasted into the late phase. The average progesterone profile of these patients was markedly lower compared with the control group (P < 0.05). However, the average progesterone profile remained normal in the other 13 cases, in whom, RED got normalized in the late luteal phase. Endometrial biopsies taken during the median and late luteal phase from the rest of 29 cases were normal. CONCLUSIONS: In patients with retarded endometrial development during the full luteal phase, luteal function was decreased, but in patients with retarded endometrial development only during the median luteal phase, luteal function appeared to be normal.

Abortion, Habitual↗
PubMed1998

Disc degeneration and cervical instability. Correlation of magnetic resonance imaging with radiography.

STUDY DESIGN: An imaging study was designed to evaluate disc degeneration and segmental instability in the cervical spine. OBJECTIVES: To compare the magnetic resonance imaging assessment of disc degeneration with the conventional plain radiographic evaluation of cervical segmental instability. SUMMARY OF BACKGROUND DATA: No studies have been conducted to investigate the association of disc degeneration with cervical instability. METHODS: Two hundred sixty consecutive patients with suspected cervical spine disorders were analyzed for horizontal and angular displacements on lateral flexion and extension radiographs and disc degeneration on T2-weighted magnetic resonance images of the cervical vertebrae. RESULTS: In all intervertebral levels, the grade of disc degeneration increased significantly (P < 0.01) with age. Cervical instability was identified in 151 segments (14.5%) and correlated with Grade 1 and Grade 2 degeneration in the intervertebral discs (P < 0.01). CONCLUSIONS: Cervical segmental instability may indicate early degeneration of intervertebral disc in the cervical vertebrae.

Adult↗
PubMed1998

The relationship between vertebral body deformity and disc degeneration in lumbar spine of the senile.

This study provides an investigation of the relationship between vertebral deformities and disc degeneration in patients with senile osteoporosis using biomechanical and medical imaging methods. The finite element analysis showed that stress concentration in the central area of the vertebral body is much decreased with disc degeneration, indicating that load transmission has been altered. Radiography and MRI suggested that vertebral deformities are related to the height and degeneration of the disc just below this vertebral body. When a disc has decreased height or degeneration, the vertebral body just above it is less likely to be deformed for patients with spinal osteoporosis.

Aged↗
PubMed1998

Radiculopathy after laminectomy for cervical compression myelopathy.

Postoperative radiculopathy is a complication of posterior cervical decompression associated with tethering of the nerve root. We reviewed retrospectively 287 consecutive patients with cervical compression myelopathy who had been treated by multilevel cervical laminectomy and identified 37 (12.9%) with postoperative radiculopathy. There were 27 men and ten women with a mean age of 56 years at the time of operation. The diagnosis was either cervical spondylosis (25 patients) or ossification of the posterior longitudinal ligament (12 patients). Radiculopathy was observed from four hours to six days after surgery. The most frequent pattern of paralysis was involvement of the C5 and C6 roots of the motor-dominant type. The mean time for recovery was 5.4 months (two weeks to three years). The results at follow-up showed that the rate of motor recovery was negatively related to the duration of complete recovery of postoperative radiculopathy (gamma=-0.832, p < 0.01) and that patients with spondylotic myelopathy had a significantly better rate of clinical recovery than those with ossification of the posterior longitudinal ligament (t=2.960, p < 0.01). Postoperative radiculopathy may be prevented by carrying out an anterior decompression in conjunction with spinal fusion, which will achieve stabilisation and directly remove compression of the cord at multiple levels.

Adult↗
PubMed1998

Diagnosis and treatment of acute central cervical cord injury.

OBJECTIVE: To clarify the diagnosis and management of acute central cervical cord injury. METHODS: Eighty-nine patients with acute cervical central cord injury were retrospectively reviewed. Sixty-three patients were treated conservatively and 26 were treated surgically. There were two acute deaths. Eighty-seven patients were followed up for 3 months to 15 years. RESULTS: Their average neurological score (ASIA) was increased from 41.7 at admission to 83.1 at follow-up. CONCLUSIONS: Acute central cervical cord injury should be differentiated from complete spinal cord injury, cervical myelopathy, cruciate paralysis and C8 nerve root injury. When compression of nerve tissue or cervical instability is identified, operative intervention should be indicated. The prognosis is less optimistic in the patients with severe primary injury and at old age.

Adult↗
PubMed1998

[Construction of PCNA antisense RNA expression vector and its antitumorigenic effect on human gastric cancer cell].

OBJECTIVE: To observe the effect of proliferating cell nuclear antigen (PCNA) antisense RNA on the growth characteristics of human gastric cancer cell. METHODS: An eukaryotic expression vector pDR-PCNA with human PCNA gene insert in reverse direction was successfully constructed. The human gastric cancer cell line SGC-7901 was transfected with pDR-PCNA by lipofectamine. RESULTS: Growth rate, protein and RNA biosynthesis and DNA contents in S-phase and G2/M-phase of the transfected SGC-7901 were significantly suppressed in comparison with those of the parental cell line. CONCLUSION: PCNA antisense RNA can significantly suppress the in vitro growth of gastric cancer cell line.

Cell Division↗
PubMed1998

Heterotopic ossification of the hip after spinal cord injury.

OBJECTIVE: To analyse the risk factors of heterotopic ossification after spinal cord injury. METHODS: Of 104 patients with spinal cord injury, 47 (45.2%) were complicated by heterotopic ossification of the hip. These patients with heterotopic ossification were compared with 57 patients without heterotopic ossification. RESULTS: Statistical analysis showed that complete paraplegia, spasticity and pressure sore were significantly (P < 0.05) or highly significantly (P < 0.01) related to heterotopic ossification formation. The coexistence of two or three of these factors in the paraplegic patients was found to significantly (P < 0.01) enhance the risk of heterotopic ossification formation. CONCLUSION: When the spinal cord injured patients have single or multiple risk factors, they should be predicted for susceptibility of heterotopic ossification.

Adult↗
PubMed1998

[Comparing the bronchodilating effects of ipratropium bromide and theophylline].

OBJECTIVE: To compare the bronchodilating effects of ipratropium bromide and theophylline in chronic obstructive pulmonary disease(COPD). METHOD: In 26 patients, mean peak forced expiratory volume in 1 second(FEV1) were measured at the time before and 30 minute, 1, 2, 3, 4, 5, 6 hours after the drugs were administered in a double-blind, placebo-controlled crossover method. RESULT: The mean peak of FEV1, increased over baseline were 34% and 19% respectively, for ipratropium bromide and theophylline (P < 0.01), and the reaching duration were 1-2 hours and 2-3 hours, the proportion of patients attaining at least a 15% (P < 0.01) increase in the FEV1, responders were 19% and 50% (P < 0.01) respectively, for ipratropium bromide and theophylline. The average FEV1, increased during the 6-hours observation period were 18% for ipratropium bromide and 8% for theophylline (P < 0.01). The mean duration of FEV1 > 15% was 3.6 and 1.6 hours respectively. CONCLUSION: Ipratropium bromide nebulized is a more potent bronchodilator than the oral theophylline in patients with chronic airflow obstruction.

Adult↗
PubMed1998

[Gene expression of messenger RNA coding for procollagen and tumour necrosis factor-alpha in lungs undergoing bleomycin-induced pulmonary fibrosis].

OBJECTIVE: mRNA for tumour necrosis factor-alpha(TNF-alpha) and procollagen I [pro alpha 1(I)] and III (pro alpha 1(III) was measured in bleomycin treated mice to evaluate their roles in pulmonary fibrosis. METHOD: 30 male Wistar rats were divided into normal control group and groups treated by bleomycin on days 3, 7, 14, 21, 30. Each group included 5 rats, and the rats were treated by single intratracheal instillation with sterile saline solution or with 5 mg/kg body weight of bleomycin. The rats were sacrificed at different days, and total RNA from the lungs of bleomycin or saline solution instilled rats was extracted. Expression of TNF-alpha, pro alpha 1 (I) and pro alpha 1 (III) mRNA was measured by dot blot and Northern blot hybridization. RESULT: The levels of TNF-alpha mRNA in lungs of bleomycin groups on days 3,7 were significantly higher than those of control group (t = 10.33 and 12.54 respectively; P < 0.01). The levels of pro alpha 1 (I) and pro alpha 1(III) mRNA in lungs of bleomycin group on day 7 were higher than those of control group(t = 10.56 and 24.23 respectively; P < 0.01), After reaching the peak levels in two weeks, the levels of pro alpha 1(III) mRNA in lungs of bleomycin group on day 30 declined slowly to approximately the values of normal control group (t = 1.95; P > 0.05); but the levels of pro alpha 1(I) mRAN on day 30 after bleomycin administration were higher than those of control group (t = 16.67; P < 0.01). The mRNA coding pro alpha 1(I) and pro alpha 1(III) in lungs of rats had two mRNA species. CONCLUSION: The results suggested that the metabolism of mRNAs for pro alpha 1 (I) and pro alpha 1 (III) may be preferentially perturbed, and that increase of collagen gene expression in the transcriptional level might be involved in the mechanism of collagen accumulation. The increased expression of TNF-alpha gene may play an important role in the early events of bleomycin-induced pulmonary fibrosis.

Animals↗
PubMed1998

Lumbar spinal stenosis: a review of biomechanical studies.

OBJECTIVE: To investigate the biomechanical aspects of etiology, pathology, clinical manifestation, diagnosis and surgical treatment of the lumbar spinal stenosis. METHODS: A series of biomechanical methods, such as three-dimensional finite element models, three-dimensional kinematic measurement, cadeveric evaluation, and imaging assessment was applied to correlate lumbar biomechanics and lumbar spinal stenosis. Surgery of lumbar spinal stenosis has been improved. RESULTS: The stresses significantly concentrate on the posterolateral part of the annulus fibrosus of disc, the posterior surface of vertebral body, the pedicle, the interarticularis and the facet joints. This trend is intensified by disc degeneration and lumbar backward extension. Posterior element resection has a definite effect upon the biomechanical behavior of lumbar vertebrae. The improved operations proved satisfactory. CONCLUSION: Stress concentration in the lumbar vertebrae is of importance to the etiology of degenerative lumbar spinal stenosis, and disc degeneration is the initial key of this process. Then these will be aggravated by backward extension. Functional radiography and myelography are of assistance to the diagnosis of the lumbar spinal stenosis. For the surgical treatment of the lumbar spinal stenosis, destruction of the posterior element should be avoid as far as possible based upon the thorough decompression. Maintaining the lumbar spine in flexion by fusion after decompression has been proved a useful method. When developmental spinal stenosis is combined with disc herniation, discectomy through laminotomy is recommend for decompression.

Humans↗
PubMed1997

GC rich DNA oligonucleotides with narrow minor groove width.

Investigation of the width of the minor groove using 500 MHz NMR spectroscopy in three closely related 11-mer B-DNA duplexes shows that the minor groove is narrow in a GC rich oligonucleotide, and that a narrow minor groove is not something endemic to DNAs with persistent repetitions of adenine nucleotides (A-tract DNA). The width of the groove is dictated by local sequence contexts and independent of neighboring A-tract DNA.

Base Composition↗
PubMed1997

Meniscal injury in children: long-term results after meniscectomy.

Twenty-four children who underwent open total meniscectomy were reviewed and followed-up for an average of 16.1 years (range 6-33 years). There were 7 boys and 17 girls aged between 7 and 16 years (average 12.5 years). Excellent and good results were noted in 62.5% of the patients. Eighty-seven of the children showed radiographic degeneration of the knee joint. This study in a Chinese population indicates that meniscectomy is not a benign procedure in children, and total meniscectomy should be avoided as far as possible.

Adolescent↗
PubMed1997

Acute central cervical cord injury presenting with only upper extremity involvement.

Twenty-four patients with acute central cervical cord injury with motor and sensory impairment involving only the upper extremities are described; none had any abnormality in the lower extremities. They were all treated conservatively with one exception in whom an anterior decompression was performed. Seventeen had complete recovery of motor function; the remaining 7 had some weakness of the palmar interosseous muscles. The time to recovery was from 2 weeks to 4 months. Sensory recovery took from 4 to 6 months after injury. This type of injury is caused by damage to the anterior and posterior horn cells in the cervical cord.

Accidental Falls↗