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Biomedical subjects

J C Cheng

Publications and source records attributed to J C Cheng.

At least 73 records · Page 4Linked to original sources
PubMed1998

Postoperative bleeding with factor VII deficiency: case report.

Factor VII deficiency was diagnosed during haematological investigation of a patient with multiple occurrences of postoperative bleeding after surgical extraction of an impacted upper left canine. The bleeding was eventually stopped with local measures without resorting to blood product transfusion which may have been necessary if local measures had failed to control bleeding. Abnormalities were also found in subsequent blood profiles and coagulation tests in other members of the patient's family.

Adolescent↗
PubMed1997

Osteopenia in adolescent idiopathic scoliosis. A primary problem or secondary to the spinal deformity?

STUDY DESIGN: A cross-sectional study to assess the lumbar spinal and proximal femoral bone mineral density in girls aged 12, 13, or 14 years with adolescent idiopathic scoliosis and to compare them with bone mineral densities of an age-matched control group. OBJECTIVES: To determine whether there is an association of osteopenia with idiopathic scoliosis, to compare bone mineral density in patients with scoliosis in different age groups with healthy controls, and to correlate bone mineral density with scoliotic parameters, including the pattern and magnitude of the curve. SUMMARY OF BACKGROUND DATA: Routine radiographs allow very limited assessment of osteopenia. Therefore, only a few studies have compared osteopenia in patients with scoliosis with that in healthy individuals. New techniques allow a more reliable quantification of the bone mineral state in adolescent idiopathic scoliosis. Available series in the literature either had a small sample population with inadequate controls or examined a large age range. METHODS: Using a dual energy x-ray absorptiometer, bone mineral density was measured in the predominant trabecular bone area, i.e., the lumbar spine (L2-L4) and bilateral proximal femur, in 81 girls aged 12, 13, or 14 years old with idiopathic scoliosis of various degrees of severity. Results were compared with those of 220 age-matched healthy control girls. RESULTS: In all three age groups, scoliotic patients had significantly lower bone mineral density in all measured regions than that in the control individuals (student's t test). Sixty-eight percent of the scoliotic individuals had a significantly reduced bone mineral density. Differences in bone mineral density between bilateral hips (paired t test) were not statistically significant either in scoliotic patients or in healthy control individuals. No differences in body weight, body height, or menarche status were found between the scoliotic and control individuals. Correlation studies showed that, in scoliotic patients, the values of bone mineral density did not correlate with the curve degree or curve pattern. CONCLUSIONS: There is a persistently lower bone mineral density in patients between 12 years and 14 years of age with idiopathic scoliosis. The decreased bone mineral density occurred in patients with idiopathic scoliosis before the age of 12 years, with no further progression from the age 12 to age 14, and did not correlate with the scoliosis degree or pattern. These findings suggest that the osteopenia in idiopathic scoliosis may be related to the primary etiology of the disease rather than secondary to the asymmetrical mechanical forces associated with the back deformities.

Absorptiometry, Photon↗
PubMed1997

Cellular differentiation regulated by gibberellin in the Arabidopsis thaliana pickle mutant.

The plant growth regulator gibberellin (GA) has a profound effect on shoot development and promotes developmental transitions such as flowering. Little is known about any analogous effect GA might have on root development. In a screen for mutants, Arabidopsis plants carrying a mutation designated pickle (pkl) were isolated in which the primary root meristem retained characteristics of embryonic tissue. Expression of this aberrant differentiation state was suppressed by GA. Root tissue from plants carrying the pkl mutation spontaneously regenerated new embryos and plants.

Arabidopsis↗
PubMed1997

[Closed reduction and percutaneous pinning for acute type III extension- Supracondylar fracture of distal humerus in children.].

GOAL OF SURGERY: Closed reduction of acute type III (according to Gartland) supracondylar extension fractures of the distal humerus and unicondylar pin fixation. INDICATIONS: Type III and unstable type II supracondylar fractures. CONTRAINDICATIONS: Swelling of the elbow. Compartment syndrome. PREOPERATIVE WORK UP: Radiographs of both elbows in the anterior-posterior and lateral projections. POSITIONING AND ANAESTHESIA: Supine with arm on arm board. General anaesthesia. SURGICAL TECHNIQUE: Closed reduction through manipulation under fluoroscopic control. Fixation with 2 Kirschner wires introduced percutaneously through the lateral condyle. Long arm cast for 4 to 5 weeks. POSTOPERATIVE MANAGEMENT: Radiographs on the first postoperative day, 1 week later and at time of cast and pin removal 4 to 5 weeks postoperatively. At that time active mobilisation of the elbow is started. Follow-up for 1 to 2 years is recommended. POSSIBLE COMPLICATIONS: Damage of ossific nucleus of physis. Damage to neurovascular structures. Wire migration. Pin tract infection. RESULTS: Out of 82 children (mean age 6.5 years) 73 had a follow-up of more than 6 months. 80.8% had good or excellent results. 15.1% had a decrease of the carrying angle of more than 10 degrees (4.1% more than 20 degrees ). There were 2 pin tract infections and 1 iatrogenic transient ulnar palsy.

English Abstract↗
PubMed1997

Subtalar realignment in congenital clubfoot using the Cincinnati approach.

GOAL OF SURGERY: Surgical correction of clubfoot through an extensive and meticulous posterior, lateral, medial, subtalar, and plantar release. INDICATIONS: Failed conservative treatment of clubfoot at 6 months of age. CONTRAINDICATIONS: Previous failed surgery with a different incision. PREOPERATIVE WORK UP: Radiographs of both foot and ankle in the anterior-posterior and lateral projections. POSITIONING AND ANAESTHESIA: Supine. Tourniquet. General anaesthesia. Free draping above the knee. SURGICAL TECHNIQUE: Through a Cincinnati incision the Achilles tendon is exposed and lengthened and the posterior capsule excised. The talofibular and the calcaneofibular ligaments are incised and released. The plantar aponeurosis is divided and the small plantar muscles are detached. Finally a medial release is achieved having excised the abductor hallucis muscles. Release of the dorsal talonavicular joint capsule. In severe cases the calcaneoucuboid joint must also be released. The corrected position is maintained with Kirschner wires. POSTOPERATIVE MANAGEMENT: Long leg cast with the knee bent at 90 degrees . Cast changed after 10 to 14 days. Eight weeks postoperatively removal of cast and Kirschner wires and prescription of a Dennis-Brown boot to be worn for 12 to 18 months. POSSIBLE COMPLICATIONS: Injury to neurovascular structures. Pin tract infection. Tightness, loosening or slipping of cast. Inadequate correction and damage to articular surfaces. RESULTS: From 1985 to 1992 60 infants (70 feet) were operated. Average follow-up was 5 years (1 to 7). Assessment of clinical and functional results was based on the Magone rating system: 60% excellent, 18.6% good, 11% fair results were obtained; 2 infants had a minor skin breakdown, 7 were undercorrected and 2 were overcorrected.

Journal Article↗
PubMed1997

The cutometer and ultrasonography in the assessment of postburn hypertrophic scar--a preliminary study.

Sixteen patients with various degrees of postburn hypertrophic scars were evaluated by ultrasonography and elastometry. An Aloka Echo Camera (SSD-500) with a 7.5 MHz probe and a Cutometer SEM 575 skin elastometer were used. Serial monthly examinations were performed using both pieces of equipment. In some patients, more than one scar was assessed. The assessments were correlated with clinical grading of the progress of the scars. It was noted that ultrasonography was very sensitive in the localization of scar tissues, distinguishing them from normal skin, assessment of thickness and also delineation of the extent of scar tissues. The subcutaneous part of the scar could be assessed. Cutometer SEM 575 is a new machine that applies a gentle suction to the skin to measure its viscoelasticity. It is sensitive, the inter-observer variation is low, and it could be used for the grading of a scar. These two assessment techniques compliment other methods of scar assessment and will prove useful when assessment of response to treatment is required.

Adult↗
PubMed1997

Pigmented villonodular synovitis of the shoulder after anterior capsulolabral reconstruction.

Pigmented villonodular synovitis (PVNS) is a proliferative disorder of the synovium affecting joints, bursae, or tendon sheaths. PVNS is further classified into diffuse and localized forms and rarely affects the shoulder. We report a case of nodular synovitis of the shoulder after arthroscopic and open anterior capsulolabral reconstruction. The histopathology and treatment of a nodular form of PVNS of the shoulder is discussed.

Adult↗
PubMed1997

Knee arthroscopy in Chinese children and adolescents: an eight-year prospective study.

In the period January 1985 to December 1992, 69 Chinese boys and 20 Chinese girls (average 14.6 years, age range 6 to 16 years) with a total of 92 involved knees underwent examination under anaesthesia and knee arthroscopy. Two thirds of the patients were engaged in sports activities. A haemarthrosis was present in 51 patients. In one patient, Staphylococcus aureus was shown, and in two children a serous-purulent aspirate grew Mycobacterium tuberculosis. The lateral meniscus was torn in four knees and the medial meniscus in six. An intact discoid lateral meniscus was found in five girls. Three partial anterior cruciate ligament (ACL) tears, three complete ACL tears and two posterior cruciate ligament tears were diagnosed. One child had an osteochondral defect of the lateral femoral condyle accompanying an ACL and a lateral meniscal tear. Nonspecific synovitis of unknown etiology was diagnosed in six patients who had presented subacutely with at least a 2-month history of a symptomatic monoarticular knee effusion with low grade local inflammation and no history of major trauma. The synovitis gradually resolved over a 6- to 10-month period after arthroscopy. Knee arthroscopy in children and adolescent patients is safe, gives a high diagnostic accuracy, and allows treatment of a variety of intraarticular conditions. This study also demonstrates that the range of intraarticular knee problems found in Chinese children and adolescents differs from that described in their Western counterparts.

Adolescent↗
PubMed1997

Auditory ERPs during rhyme and semantic processing: effects of reading ability in college students.

Event-related potential (ERP), reaction time (RT), and response accuracy measures were obtained during the phonological and semantic categorization of spoken words in 14 undergraduates: 7 were average readers and 7 were reading-impaired. For the impaired readers, motor responses were significantly slower and less accurate than were those of the average readers in both classification tasks. ERPs obtained during rhyme processing displayed a relatively larger amplitude negativity at about 480 ms for the impaired readers as compared to the average readers, whereas semantic processing resulted in no major group differences in the ERPs at this latency. Also, N480 amplitude was larger during semantic relative to phonological classification for the average readers but not for the impaired readers. Results are compared to a previous study of reading-impaired children on the same tasks.

Adolescent↗
PubMed1997

Sonographic evaluation of hip effusion in children. Improved visualization with the hip in extension and abduction.

PURPOSE: To assess the difference in the sonographic appearance of hip effusions when the hip was placed in the extended and abducted position as compared to a neutral position. MATERIAL AND METHODS: Twenty-one consecutive children (aged 2-14 years) with hip pain or limping were examined for hip effusions by means of ultrasound. The capsule-femoral-neck distance, the presence of joint fluid, and the shape of the anterior capsule were compared in hips in slight extension and abduction with those in hips in a neutral position. RESULTS: Of the 11 positive hip effusions, the maximal distance between the capsule and femoral neck was significantly larger (p < 0.005) in the extended and abducted hip position than in the neutral hip position, with a mean difference of 1.6 mm. Convex bulging of the anterior capsule was more confidently diagnosed in 3 hip effusions in the extended and abducted hip, and better visualization of fluid between the capsule and femoral neck was achieved in 4 joint in this posture. CONCLUSION: The study demonstrated an improvement in the sonographic detection of hip effusion in the extended and abducted position compared to the neutral position.

Adolescent↗
PubMed1997

Giant cell tumor of bone. Prognosis and treatment of pulmonary metastases.

Giant cell tumor of bone is a challenging clinicopathologic entity. Despite its benign designation, it has the capacity to recur locally and develop rare pulmonary metastases. Between 1945 and 1991, 104 patients with histologically benign giant cell tumors of bone, 5 of which metastasized to the lung, were treated at the authors' institution. In these cases, histologic materials from the lung were identical to those found in the primary bone lesion. The primary bone lesions were treated with local curettage (3), wide resection (1), and wide resection with prosthesis placement (1). The patients were observed for a mean of 12.6 years (range, 5-38 years). Four of the 5 patients experienced local recurrences (average time interval, 34 months), with 3 patients experiencing 2 or more recurrences. The average time to lung metastasis was 23 months; 1 patient presented initially with pulmonary findings. Four patients underwent surgical resection of pulmonary metastases. All 4 patients are alive with no disease progression, despite incomplete pulmonary resections in 2 patients. Locally aggressive disease and multiple recurrences appear to be risk factors for pulmonary metastases in benign giant cell tumor of bone. Pulmonary metastases occurred within the first few years after discovery of primary bone tumors. Radiographs and computed tomographs of the chest are recommended to rule out this complication in patients with local recurrences. Resection of pulmonary metastasis is recommended. Long term survival is not incompatible with persistent pulmonary lesions.

Adult↗
PubMed1997

EMF genes regulate Arabidopsis inflorescence development.

Mutations in EMBRYONIC FLOWER (EMF) genes EMF1 and EMF2 abolish rosette development, and the mutants produce either a much reduced inflorescence or a transformed flower. These mutant characteristics suggest a repressive effect of EMF activities on reproductive development. To investigate the role of EMF genes in regulating reproductive development, we studied the relationship between EMF genes and the genes regulating inflorescence and flower development. We found that APETALA1 and AGAMOUS promoters were activated in germinating emf seedlings, suggesting that these genes may normally be suppressed in wild-type seedlings in which EMF activities are high. The phenotype of double mutants combining emf1-2 and apetala1, apetala2, leafy1, apetala1 cauliflower, and terminal flower1 showed that emf1-2 is epistatic in all cases, suggesting that EMF genes act downstream from these genes in mediating the inflorescence-to-flower transition. Constitutive expression of LEAFY in weak emf1, but not emf2, mutants increased the severity of the emf phenotype, indicating an inhibition of EMF activity by LEAFY, as was deduced from double mutant analysis. These results suggest that a mechanism involving a reciprocal negative regulation between the EMF genes and the floral genes regulates Arabidopsis inflorescence development.

Alleles↗
PubMed1997

Bone mineral acquisition in low calcium intake children following the withdrawal of calcium supplement.

Our recent 18-month calcium supplementation trial demonstrated a significant increase in radial bone mineral mass in 7-year-old children with calcium intake approximately 300 mg/day (Am J Clin Nutr 1994; 60: 744-50). The persistence of higher bone mass after cessation of calcium supplementation is unknown. This is a follow-up study to investigate the lasting effect of calcium supplementation on bone acquisition. Subjects were 159 Chinese children aged 8.7 years. Distal one-third radial bone mineral content (BMC) and bone width (BW) were measured by single-photon absorptiometry. After 12 months, the significant difference in mean +/- SD percentage radial BMC disappeared between the study and control groups (7.34 +/- 6.77% vs 8.67 +/- 6.46%, p > 0.05). Dietary calcium intakes were similar between the groups. During the supplementation phase, the study group had 17.9% greater BMC gain than that of controls. In the follow-up phase, however, the study group had 16.1% less BMC gain than that of controls. It appears that an increased acquisition rate during the supplementation phase was almost balanced by a reduced acquisition rate during follow-up phase. Moreover, throughout the entire 30-month period, the overall BMC acquisition rates of the study and control groups were 25% and 23.8%, respectively. Hence, the overall acquisition rate of the study group was only 5% higher than that of controls. Therefore, the effect of calcium supplementation on bone mineral gain appears to reflect a transient reduction in bone turnover rate. Longer-term calcium trials are necessary to confirm whether a sustainable higher calcium intake throughout childhood will enhance peak bone mass.

Body Height↗
PubMed1997

Dual-energy X-ray absorptiometry predicts bone formation in lower limb callotasis lengthening.

The rate of regenerate bone mineral content (BMC) acceleration was studied using dual-energy X-ray absorptiometry (DEXA) in callotasis lengthening of the lower limb. Eleven youngsters (age range 5-17 years) undergoing callotasis lengthening for congenital, post-traumatic or post-infective conditions were studied longitudinally. Patients were initially scanned once a week until completion of the lengthening phase, and at 2-week intervals thereafter until removal of the fixator. They were subsequently followed up at regular intervals on an outpatient basis for up to 2 years after removal of the fixator (average, 14 months). The BMC accretion slopes exhibited by the patients and the rate of new bone formation allowed the identification of three groups. In the fast formation group, the rate of new bone formation was 0.3-0.6% per day. In the moderate formation group the rate of new bone formation is 0.1-0.3% per day, while in the poor formation group the rate of new bone formation is < 0.1% per day. From the analysis of time graphs, a direct correlation emerged between early bone formation and subsequent bone mineral content accretion. Measurement of BMC during callotasis lengthening in the lower limb allows precise monitoring of the process. It may prove useful to prevent complications occurring after removal of the fixator at an unduly early stage, such as plastic deformation and fracture through the regenerate bone. It may be used to predict the bone formation rate in a given patient, and to implement measures to try to influence it.

Absorptiometry, Photon↗
PubMed1997

Change of foot size with weightbearing. A study of 2829 children 3 to 18 years of age.

The change of foot length and width with age has been reported in a few anthropometric studies in the literature. However, the relationship with body height rarely is reported, and the dynamic effect of weightbearing on foot size has not been documented. In this series, 2829 children 3 to 18 years of age of equal gender distribution were included in the study. The foot length and width on weightbearing and nonweightbearing were measured with a special precision electronic caliper. The foot length and width were found to increase linearly from the age of 3 years until 12 years in girls and 15 years in boys. This was followed by a phase during which the increase plateaued. The foot length and width increased significantly on weightbearing at all ages in both genders with a mean of 2.1 to 4.4 mm or 3.1% to 4.8%, respectively. The foot length and width also were found to correlate significantly with the body height in both genders, with a correlation coefficient of 0.96 to 0.98. No significant differences were found between the sizes of the dominant and nondominant foot in either gender.

Adolescent↗
PubMed1996

Cloning and nucleotide sequencing of the protease gene of Vibrio vulnificus.

The gene (vvp) encoding a thermolabile protease of Vibrio vulnificus was cloned and sequenced. The transcription start point was also determined by primer extension. The product of this gene is very likely the secretory neutral metalloprotease that has been purified and characterized previously.

Amino Acid Sequence↗
PubMed1996

Expression of DC8 is associated with, but not dependent on embryogenesis.

DC8 is a late embryogenesis-abundant (LEA) protein gene isolated from carrot (Daucus carota). Deletion analysis of the DC8 promoter was performed to determine the sequences required for ABA and seed-specific regulation of DC8 transcription. To investigate the mechanism of DC8 expression during seed development, chimeric gene constructs containing DC8 promoter fragments fused to a promoterless beta-glucuronidase gene (DC8:GUS) were introduced into carrot, tobacco (Nicotiana tobacum) and Arabidopsis thaliana plants. Seed-specific DC8 expression patterns was conserved among the three plant species. However, differences among the species in the patterns of DC8 expression in the embryo and endosperm that correlated with differences in the rates of embryo and endosperm growth were found. Lack of correspondence between DC8 activation and embryo development among the seeds of the three species suggests that DC8 expression, which is associated with seed maturation, is not coupled to the embryo development program. The presence of DC8 activity in carrot callus and endosperm is consistent with the notion that DC8 expression is independent of embryo morphogenesis. A similar DC8 activity time-course during callus induction and seed development suggests that explantation and 2,4-D treatment initiates a course of events similar to that in the carrot ovule. After fertilization, two pathways one leading to embryo development and another to seed maturation are initiated, but they are not closely linked. As a result we find DC8, part of the maturation program, being activated at different embryonic stages in different plant species.

Arabidopsis↗