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Biomedical subjects

L Y Dai

Publications and source records attributed to L Y Dai.

At least 19 recordsLinked to original sources
PubMed2001

Orientation and tropism of lumbar facet joints in degenerative spondylolisthesis.

The orientation and tropism of the lumbar facet joints at L4-5 level was assessed by magnetic resonance imaging (MRI) in 53 patients with degenerative L4-5 spondylolisthesis and 53 age- and sex-matched normal control subjects. The degree of disc degeneration at the L4-5 level and of vertebral slip on lateral radiographs was also evaluated. Patients with degenerative spondylolisthesis had more sagittally orientated facet joints (P < 0.01) and more significant facet joint tropism (P < 0.05) than normal control subjects. For patients with degenerative spondylolisthesis, the facet joint tropism was significantly correlated with the degree of disc degeneration (P < 0.05). The results suggest that morphological abnormalities of the lumbar facet joints are a predisposing factor in the development of degenerative spondylolisthesis.

Adult↗
PubMed2001

Direct repair of defect in lumbar spondylolysis and mild isthmic spondylolisthesis by bone grafting, with or without facet joint fusion.

Forty-six patients with lumbar spondylolysis and mild isthmic spondylolisthesis were managed with direct repair of the defect with or without facet joint fusion in the affected segment. There were 24 males and 22 females, ranging in age from 15 to 56 years (average, 38.2 years). These patients had experienced clinical symptoms due to spondylolysis for between 4 months and 20 years (average, 5.3 years). Of 46 patients, 28 had no spondylolisthesis, 11 had Meyerding grade I vertebral slippage and 7 had grade II. Direct repair of 98 defects was performed on these patients. Twenty-six patients, in whom the disc adjacent to the defect was determined as degenerative by magnetic resonance imaging (MRI), simultaneously underwent facet joint fusion; 17 in one segment and 9 in two segments. The average period of follow-up was 50 months (24-92 months). Ninety-four defects achieved bony healing. As a result, 28 patients were graded as having an excellent outcome, 15 good, and 3 fair. Bone grafting in the defects achieves union between the loose lamina and the anterior element of lumbar vertebrae, and reconstructs the anatomic structure and physiologic functions of the lumbar vertebrae. There was no significant difference in outcome between the spondylolytic/spondylolisthetic patients with non-degenerative disc, who were treated with direct repair of defect only, and those with degenerative disc, who additionally underwent a fusion procedure (P > 0.05). The present series demonstrates a satisfactory result and a high rate of bony healing of the pars defect by this operative procedure in patients with lumbar spondylolysis and mild isthmic spondylolisthesis. Preoperative assessment of the disc degeneration with MRI is of great assistance in making the protocol choice of whether to opt for fusion.

Adult↗
PubMed2001

Acute central cervical cord injury: the effect of age upon prognosis.

In this clinical study, a total of 89 consecutive patients with acute cervical cord injury was analysed retrospectively. There were 29 patients aged 60 years and over, accounting for 32.6% of all the cases. All the patients were followed up from 1 to 15 years, with an average of 6 years and 4 months. Among the patients of 60 years and over, 27 (93.1%) had both upper and lower extremities involved, compared with 40 (66.7%) of those under 60 years (P<0.05). Also among the older group, 24 had radiographic findings of severe cervical spinal degeneration, a higher incidence than in the patients under 60 years (P<0.05). There were two deaths in patients of 60 years and older. The average American Spinal Injury Association (ASIA) scores in both the younger and older groups at final follow-up were significantly larger (P<0.01) than on admission, but the age of the patients was negatively correlated with the ASIA scores both on admission (P<0.05) and at final follow-up (P<0.01). The ASIA score was significantly lower (P<0.01) in patients aged 60 years and over than in those younger than 60 years both on admission and at final follow-up. Patients aged 60 years and over with acute central cervical cord injury have a poorer prognosis although they may experience significant neurological improvement.

Acute Disease↗
PubMed2001

Remodeling of the spinal canal after thoracolumbar burst fractures.

Thirty-one patients with thoracolumbar burst fractures, seven untreated, 16 treated nonoperatively, and eight treated operatively, were analyzed retrospectively and followed up for 3 to 7 years. The initial and final degrees of neurologic deficit and the stenotic ratio of the spinal canal were recorded. Stenotic ratio significantly decreased from the first examination (range, 12.3%-74.5%; average, 26.2%) to the final followup (range, 5.4%-46.5%; average, 19.2%), but there were no differences of the percentage of remodeling between patients who were untreated and those treated nonoperatively and operatively. The recovery rate was highly significantly related to the stenotic ratio at first examination. Nonoperative management may be considered for treatment of patients who are neurologically intact or only slightly impaired with thoracolumbar burst fractures.

Adult↗
PubMed2000

Surgical treatment of nonunited fractures of the odontoid process, with special reference to occipitocervical fusion for unreducible atlantoaxial subluxation or instability.

Fifty-seven consecutive patients treated surgically for nonunited fractures of the odontoid process were reviewed. All patients presented late, exhibiting neurological deficits subsequent to nonunion. Delay in presentation was between 6 and 120 months (mean 32 months) after the original injury, due to missed diagnosis or inappropriate management. Seven patients who were reduced in traction underwent a Gallie atlantoaxial fusion. In the remaining 50 patients who were unreducible, an occipitocervical arthrodesis was performed. They were followed up for a minimum of 2 years, except one who died from postoperative respiratory failure. All patients obtained a solid bony union, including two in whom nonunion occurred following atlantoaxial fusion, and occipitocervical fusion was added as a rescue. Thirty-eight patients achieved excellent neurological recovery, nine still had some disability, five retained their neurological deficits and two reported a deterioration. In two patients, a recurrence in a traumatic episode was experienced long after a resolution. Our findings demonstrate that occipitocervical arthrodesis is preferable for unreducible subluxation or instability of atlantoaxial articulation in nonunion of odontoid fractures.

Adolescent↗
PubMed2000

Disc degeneration in patients with lumbar spondylolysis.

The grade of intervertebral disc degeneration in 73 symptomatic patients with lumbar spondylolysis was evaluated with magnetic resonance imaging to assess the prevalence of disc degeneration. The results were compared with those of age- and sex-matched asymptomatic control populations and with patients with clinical back pain symptoms but without spondylolysis. The relationship between disc degeneration and age of patients, the duration and severity of clinical symptoms, and the grade of vertebral slip was evaluated. A five-point grading scale based on T2 signal intensity recommended by Gibson et al. was used to evaluate the degree of disc degeneration. The grade of disc degeneration below the spondylolytic defect in the patients was highly significantly related to the age of patients (p < 0.01) and was more severe than in the controls (p < 0.01), but there was no difference of disc degeneration above the defect between the patients and the controls (p > 0.05). Furthermore, the grade of disc degeneration below the spondylolytic defect in the patients was highly significantly correlated with the duration of clinical symptoms (p < 0.01), although it was not associated with the severity of clinical symptoms or the grade of vertebral slip (p > 0.05). The results suggest that the degree of disc degeneration at the spondylolytic level is a more important determinant for choice of the fusion procedure than the age of the patients or the grade of vertebral slip, and that preoperative magnetic resonance examination is of great importance to evaluation of disc degeneration.

Adolescent↗
PubMed2000

Immediate early gene 2 of human cytomegalovirus increases interleukin 2 receptor-alpha gene expression.

Previously, we demonstrated that the cytomegalovirus (CMV) immediate early 2 (IE2) gene product upregulates interleukin-2 receptor-alpha (IL-2R alpha) gene expression. To further define this effect, we used a series of IL-2R alpha promoter truncations to identify that the primary site of CMV IE2 activity was in the region between -281 and -273 of the IL-2R alpha promoter, an area without known transcription factor activity. Deletion of known transcription factor enhancer elements resulted in a similar decrease in IE2-driven promoter activation. This unique sequence from the IL-2R alpha promoter was shown to drive a minimal promoter in the presence of IE2. These studies identify a new transcription factor binding site in the IL-2R alpha promoter, which may be specifically responsive to the CMV IE2 gene product. These studies also suggest that one mechanism whereby CMV infection may result in organ transplant rejection is through increased IL-2R alpha expression.

Base Sequence↗
PubMed1999

Fractures of the patella in children.

Fractures of the patella are relatively rare injuries for children. Fourteen patients with patellar fractures were reviewed. There were 12 boys and two girls with the age ranging between 9 and 15 years and an average of 11.4 years. Sleeve fractures were the most common type of patellar fractures observed (eight cases), followed by transverse fractures (four cases) and comminuted fractures (two cases). All the fractures were treated with open reduction and followed up for 2 to 20 years. Overall results were good in 13 patients, and flexion limitation of the knee was seen in one. Fractures of the patella in children are characterised by sleeve fractures. The prognosis of the patients treated with open reduction is generally good.

Adolescent↗
PubMed1998

Osteoporosis in Colles fracture.

Previous studies of bone density in patients with Colles fracture have been inconclusive. We measured bone density at the second metacarpal in 36 postmenopausal women with Colles fracture. The patients were found to have highly significant (P < 0.01) or significant (P < 0.05) differences in the parameters of bone density compared with controls matched for age. The results suggest that osteoporosis is of definite relevance to the etiology of Colles fracture in postmenopausal women.

Aged↗
PubMed1998

The relationship between osteoarthritis and osteoporosis in the spine.

The degree of osteoarthritis and osteoporosis in the lumbar spine has been compared in patients with spinal osteoarthritis and osteoporotic fractures and in a normal control group of 252 elderly subjects, to investigate the relationship between osteoarthritis and osteoporosis in the spine. The two indices were highly significantly different in the three groups (p<0.01). The degree of osteoarthritis in the osteoarthritic patients was higher (p<0.01) than in the fracture patients and the normal control subjects, while the degree of osteoporosis in the fracture patients was higher than in osteoarthritic patients and normal controls (p<0.01). These data support the conclusion that osteoarthritis and osteoporosis in the spine are inversely related.

Aged↗
PubMed1997

Cytomegalovirus modulates transcription factors necessary for the activation of the tumor necrosis factor-alpha promoter.

Several studies have demonstrated that cytomegalovirus (CMV) infection increases expression of the tumor necrosis factor (TNF) gene. This effect is mediated, in part, by an effect of the CMV immediate early 1 (IE1) gene product on the TNF promoter. To further analyze these interactions, we used plasmids with TNF promoter truncations to determine the site within the promoter where the CMV IE1 gene product mediates its effect. The site was localized to a 40-base pair segment that contains a cAMP response element (CREB). Deletion of the cAMP response element increased basal promoter activation but had little effect on IE1-induced activation. Additional studies demonstrated that the cAMP element is flanked 5' by a PU.1 site and 3' by an NF-kappa B site, both of which increase expression of the TNF promoter. These sequences demonstrated IE1 responsiveness. We next determined the relevance of these observations for normal human cells by infecting human alveolar macrophages with CMV. In these studies we evaluated expression of NF-kappa B, PU.1 and CREB by gel shift assay at immediate early times after infection. We found that CMV infection increased the binding activity of NF-kappa B and PU.1 and decreased the binding activity of CREB. CMV infection also increased expression of the TNF gene in alveolar macrophages. These observations suggest that CMV increases TNF gene expression, in part, by altering the binding activity of transcription factors that regulate gene expression.

Base Sequence↗
PubMed1996

Cytomegalovirus modulates interleukin-6 gene expression.

Complications after lung transplantation include the development of rejection and an increased incidence of infection, particularly with cytomegalovirus (CMV). Several recent studies have suggested that interleukin (IL)-6 may be used to detect both infection and rejection after lung transplantation. In addition, IL-6 may play a role in the development of bronchiolitis obliterans after transplantation. Because CMV is also associated with the development of bronchiolitis obliterans after transplantation, we determined whether CMV induces IL-6 gene expression. We demonstrated that CMV infection increased both IL-6 protein and mRNA in peripheral blood mononuclear cells. We also demonstrated that the CMV immediate early 1 gene product increased expression of the IL-6 promoter. This effect of the CMV immediate early 1 gene product was dependent upon the presence of specific transcription factor binding sites in the IL-6 promoter. These studies demonstrate that CMV may be an important cofactor in the development of rejection and infection after transplantation through its effects on IL-6.

Cells, Cultured↗
PubMed1996

Lumbar disc herniation in patients with developmental spinal stenosis.

Lumbar spinal stenosis and lumbar disc herniation are usually regarded as two pathogenetically different conditions, but in the literature lumbar disc herniation in patients with developmental spinal stenosis has been rarely documented. In a clinical retrospective study, 42 lumbar disc herniations with developmental spinal stenosis were reported and analyzed. Discectomy was performed after laminotomy. The patients were followed-up for an average of 4.4 years (range 2-7 years). The preoperative symptoms disappeared completely in 28 patients, in 13 patients some degree of backache remained although their nerve root pain had been relieved, and in 1 patient intermittent claudication reappeared after 6 years resolution of their preoperative pain. We conclude that when developmental spinal stenosis is combined with disc herniation, discectomy through laminotomy rather than laminectomy is usually sufficient for decompression.

Adult↗
PubMed1996

Multiple non-contiguous injuries of the spine.

Forty-seven patients with multiple non-contiguous injuries of the spine were reviewed retrospectively, giving an incidence of 5.4 per cent of 875 spinal injuries. Thirty-three were men and 14 women with an age range of between 16 and 78 years. Twenty-three were treated operatively. The multiple non-contiguous injuries had a more complicated mechanism of injury and tended to be more severe injuries than single-level injuries as they were combined more frequently with injuries of other parts of the body. Being aware of this combination of injuries leads to an earlier diagnosis. Operative reconstruction is recommended.

Adolescent↗
PubMed1994

[Long-term results of meniscectomy].

The long-term results after total meniscectomy in 60 patients have been reviewed with an average follow-up period of 16.1 years (10 to 33 years) and 58.3% excellent and good results were demonstrated. Statistical analysis showed that the late results were related to the time of follow-up and not associated with the length of history before operation. Radiological degeneration of the knee was seen in 87.5% of the patients, while no relationship between the degeneration and the clinical results was found. It is indicated from this retrospective study that the menisci are of so great importance in biomechanics that total meniscectomy should be as far as possible avoided.

Adolescent↗
PubMed1994

[Histological investigation of the ligamentum flavum].

The micro- and ultrastructures of the human ligamentum flavum were investigated. It was found that the ligamentum flavum is made of chiefly of elastic fibers. This kind of structure provides a basis for the important physiological functions of the ligamentum flavum. So the load is transmitted between the vertebrae and spinal stability is maintained by means of this ligament. Then clinical relevance was discussed.

Adult↗
PubMed1994

Radiographic measurement of the prevertebral soft tissue of cervical vertebrae.

The radiographic measurement of the prevertebral soft tissue of cervical vertebrae was performed in 87 normal adults. According to the results of the measurement, 10 mm and 20 mm were used as the upper limit normal values of the retropharyngeal and retrotracheal space respectively. We conclude that although the widened soft tissue space is of diagnostic significance, diagnosis should be made on the basis of analysis of the injury history, clinical manifestation and imaging examination.

Adult↗