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Biomedical subjects

D Fang

Publications and source records attributed to D Fang.

105 records · Page 6Linked to original sources
PubMed1985

Gap-junctional communication in a communication-defective and in a communication-competent teratocarcinoma cell line.

We examined the gap-junctional communication properties of a communication-defective cell line R5/3 and its communication-competent revertant H2T12. For these studies, we carried out microelectrode impalements to monitor ionic coupling and dye coupling. Our dye-injection experiments revealed that the H2T12 cells are much more efficient in dye coupling than the R5/3 cells. This latter observation is in agreement with the previous finding that the H2T12 cells are much better metabolically coupled than the R5/3 cells. With ionic coupling measurements, however, both cell lines exhibited similar levels of cell-cell coupling. The R5/3 cells demonstrated an ionic coupling coefficient of 0.19 +/- 0.011 (S.E.M.) and H2T12 a coupling coefficient of 0.25 +/- 0.009 (S.E.M.). These results in conjunction with observations from other studies indicate that the different experimental approaches for monitoring gap-junctional communication may have different levels of sensitivity for detecting as opposed to measuring the level of cell-cell coupling.

Cell Communication↗
PubMed1983

Long-term results of lumbar intervertebral disc prolapse.

A series of 40 patients is presented at least ten years following anterior spinal fusion for intervertebral disc prolapse. The proportion of patients who had complete relief or only isolated transient symptoms at the five-year review (67.5%) showed only a very slight fall over the years (65.0%). The union rate was shown to improve with time. There was no clear evidence that anterior spinal fusion led to accelerated degeneration of adjacent intervertebral discs. The significance of posterior extension of the fusion is discussed.

Adult↗
PubMed1983

Tuberculosis of the upper cervical spine.

Six patients, aged between 3 and 51 years, with tuberculosis of the upper cervical spine were studied. Prominent features of the disease included pain and stiffness, paralysis, swelling of the retropharyngeal soft tissue, osteolytic erosions, and atlanto-axial subluxation. Cure was obtained with antibiotics, transoral decompression and C1-2 fusion.

Adolescent↗
PubMed1982

The treatment of thoracolumbar spinal injuries with paresis by conservative versus surgical methods.

18 patients with cord or root involvement in thoracolumbar injuries underwent posterior spinal surgery, including 11 Harrington instrumentations. 11 similar patients were treated conservatively. Surgery offered no definite advantage for neural recovery, nor did it curtail the duration of hospitalisation. However, it significantly decreased post-traumatic kyphotic deformity and improved the vertebral alignment. Morbidity and implant failure were noted in 27% of the operated cases. It would appear that operative stabilisation of the thoracolumbar injuries of the spine is indicated in selected cases where there is a risk of significant post-traumatic kyphotic deformity with gross vertebral body displacement.

Adult↗
PubMed1981

The treatment of unstable intertrochanteric fractures of the hip: a prospective trial of 150 cases.

We report a prospective clinical trial of 150 cases for the treatment of unstable intertrochanteric fracture of the neck of the femur. Three methods were tested in our series--skeletal traction with a tibial pin, medial displacement osteotomy and valgus osteotomy--with 50 patients in each group. Our results showed no significant difference between those treated with the Dimon and Hughston osteotomy and those treated by the Sarmiento osteotomy. Conservative treatment of skeletal traction for unstable fracture was found to be well tolerated by the Chinese patient. A low mortality and morbidity rate was found in this series with an overall infection rate of 4 per cent.

Aged↗
PubMedDate not supplied

A new immune escape mutant of hepatitis B virus with an Asp to Ala substitution in aa144 of the envelope major protein.

A new hepatitis B virus (HBV) mutant with an Asp to Ala substitution in aa144 of the envelope major protein was identified from the blood samples of two persistently infected patients. They were born to HBsAg-positive carrier mothers. The patients had been immunized with HBV vaccine after birth, under a standard schedule of 3 injections at 0, 1 and 6 months, but failed to be protected. The mutant was stable and was present in the blood samples collected at 1 and 4 years of age from patient 105. To study the antigenic differences, two expression plasmids, pExpW (wild type) and pExpM (mutant), were constructed, and HBsAgs were expressed in COS-M6 cells. The binding activities of the HBsAg from pExpW and pExpM were compared with anti-a-epitope monoclonal antibody and with anti-HBs polyclonal antibody, respectively, by radioimmunoassay. The results showed that the binding activity of HBsAg of pExpM was distinctly lower than that of pExpW, and the HBV mutant with envelope major protein144Asp-->Ala was shown to be a new immune escape variant.

Alanine↗
PubMedDate not supplied

Varus deformity following lateral humeral condylar fractures in children.

Lateral humeral condylar fractures are quite common in children. This article shows that varus deformity is a common sequela following such injuries. Twenty-four patients were studied, with a mean follow-up of 4.8 years. A loss of carrying angle, seen in 10 cases, occurred with comparable frequency in undisplaced (50%) and displaced (39%) fractures. The deformity was usually mild, averaging 10 degrees in the undisplaced fractures and 9.6 degrees in the displaced fractures treated with open reduction. We conclude that varus deformity is common in this injury, and occurs whether or not the fracture is displaced.

Adolescent↗
PubMedDate not supplied

Application of the new stereological probes to the study of the melanosome in Cloudman S91 melanoma cells.

The relationship between melanosome size and number and melanin content has been investigated in Cloudman S91 melanoma cells growing in vitro using both "model-based" and "design-based" stereological procedures. Cells were cultured for 4 days, harvested at daily intervals, and resin-embedded for light and electron microscopy; one aliquot of each sample of cells was assayed to determine its melanin content. By comparing their volume-weighted mean nuclear volume and their number-weighted mean nuclear volume, we have found that the nuclei of Cloudman melanoma cells form a fairly homogeneous population. The volume fraction and absolute volume of premelanosomes (VVpm, cell and Vpm) and mature melanosomes (VVmm, cell and Vmm) were all found to decrease progressively throughout the period of culture as did the number of premelanosomes (Npm) and mature melanosomes (Nmm). Whilst the volume-weighted mean volume of individual stage I and stage II premelanosomes, (VVipm), remained fairly constant at about 10 nm3, the volume of individual stage III and IV mature melanosomes showed significant variation ranging between about 13 nm3 and 32 nm3. The melanin content of the cells decreased progressively over the 4 days of culture. There were, however, considerable variations in both the average melanin content per unit volume of mature melanosomes, in the range 170-600 fg/micron3, and in the melanin content per individual mature melanosome, in the range 3-12 fg. Our findings show that stereological techniques can provide unbiased and sensitive tools for the study of the morphological basis of melanogenesis; their value will become even more evident when they are combined with techniques for the localization of melanogenic enzymes and their substrates.

Cell Count↗
PubMedDate not supplied

Spinal pseudarthrosis in ankylosing spondylitis.

Spinal pseudarthrosis is an important mechanical complication in longstanding ankylosing spondylitis. Thirty-five patients with 40 lesions were studied. Three lesions through vertebral bodies resulted from complete fractures. The rest occurred at interspaces, more common at the lower thoracic and upper lumbar segments. Double pseudarthrotic lesions were observed in 5 patients. Progressive osteolysis of the anterior elements was prominent, with variable sclerosis, osteophytes, vacuum phenomenon, subluxation and fragmentation. A posterior element weak link, as a bony break or facet joint non-fusion, was an essential component in every lesion, playing an initiating or perpetuating role in its pathogenesis. Mechanical derangement from trauma, severe round kyphosis, spondylodiscitis, hip disease, spinal operation and unusual activities may be contributing factors. Initial treatment is conservative, but 16 patients required operative stabilisation.

Adult↗