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Biomedical subjects

J C Cheng

Publications and source records attributed to J C Cheng.

At least 91 records · Page 5Linked to original sources
PubMed1996

The hypertrophic scar and microcirculation properties.

Blood-flow measurements of microcirculation were used as a quantitative indicator for scar assessment and healing. A laser doppler flowmeter (LDF), giving an integrated instantaneous flux value through a measured volume of skin, was used for the measurements. It has been postulated that the degree of hypertrophy after thermal injury correlates with the degree of microvascular regeneration. This study looked quantitatively at microcirculation in normal and scarred skin of different clinical grading and investigated the comparative responses to changes in local temperature stimuli. An attempt is made to define microcirculation using the parameters of Vasodilation Index (Dli) and Vasomotion Intensity (% Vsm) as respective responses to a rise in local temperature of the skin from 36 degrees C to 44 degrees C. The improvements in both Dli and % Vsm with healing of scar relate to the degree of microvascular regeneration, which in turn correlates with the clinical assessment.

Adolescent↗
PubMed1996

Mechanical properties of normal skin and hypertrophic scars.

The non-linear viscoelastic properties of skin tissue were characterized by modulus of elasticity E, which represents stiffness, and percentage extension (strain, xi) at load intensities of 20, 40 and 100 gm. The latter property is a measure of the extensibility for both normal skin and hypertrophic scar. A quasi-static extensometer applies a standard rate of extension to the skin and its mechanical properties were obtained from 15 Chinese patients with burn injuries of superficial to full skin thickness burns. Clinical evaluation of hypertrophic scar is qualitative and depends on colour, thickness and hardness or firmness. Using mechanical properties assists in the characterization by providing a quantitative indicator. Higher scar grading is synonymous with increased stiffness and decreased extensibility. Correlation with clinical assessment was achieved with these in vivo viscoelastic properties.

Adolescent↗
PubMed1996

Late cognitive brain potentials, phonological and semantic classification of spoken words, and reading ability in children.

Event-related potential (ERP), reaction time, and response accuracy measures were obtained during rhyming and semantic classification of spoken words in 10 average (mean age 11.64 years) and 9 impaired reading (mean age 12.10 years) children. The behavioral measures of classification did not distinguish the groups. In the ERPs, rhyme processing produced more pronounced group differences than did semantic processing at about 480 ms, with a relatively more negative distribution for the impaired readers at centroparietal sites. At about 800 ms in both classification tasks, the impaired readers displayed a late positivity that was delayed in latency and of larger amplitude at frontal sites than that for the average readers. The ERP findings suggest that the categorization of spoken words for meaning and sound result in increasingly more aberrant correlates of these processing demands in reading-impaired children.

Adolescent↗
PubMed1996

A follow-up study on the effects of calcium-supplement withdrawal and puberty on bone acquisition of children.

Recent calcium supplementation trials in children have confirmed a positive but moderate effect of calcium intake on bone mineral accretion. However, the lasting effect of a higher bone mineral mass after calcium-supplement withdrawal is not known. This is an 18-mo follow-up study conducted after an 18-mo controlled calcium supplementation trial to study the persistent effect of higher bone mineral mass in children. Radial bone mineral mass was determined by single-photon absorptiometry; lumbar spine and femoral neck bone mineral mass were evaluated by dual-energy X-ray absorptiometry in 84 healthy Hong Kong children at age 8.5 y and these evaluations were repeated at age 10 y. Pubertal status was determined by Tanner staging. At the end of the follow-up, the differences in percentage gains in lumbar spine bone mineral content (12.1 +/- 8.2% compared with 14.9 +/- 10.05%, P = 0.24) and lumbar spine area (8.6 +/- 5.1% compared with 9.4 +/- 5.5%, P = 0.47) between the study and control groups disappeared. Dietary calcium intakes during follow-up were similar for the two groups (555 and 640 mg/d, P = 0.23). In multiple-regression analyses, pubertal status was the strongest correlate of bone acquisition and linear growth in the study period. In conclusion, higher percentage gains in bone mineral mass in childhood by calcium supplementation for 18 mo were reversible. Our study showed that the benefits of calcium supplementation disappear after treatment is withdrawn. Longer-term calcium trials are necessary to determine whether peak bone mass can be modified through sustained supplementation so that appropriate calcium intakes can be determined.

Absorptiometry, Photon↗
PubMed1996

Refinement of the modified-relative-dose-response test as a method for assessing vitamin A status in a field setting: experience with Indonesian children.

The modified-relative-dose-response (MRDR) test, which has been used extensively throughout the world for assessing vitamin A status, has been simplified. The major methodologic change resulting from the current studies in Indonesia is the use of graded standard doses of 3,4-didehydroretinyl acetate (DRA) based on the age range of the population of interest. Instead of a dose of 0.35 mumol/kg body wt, standard doses of 5.3 mumol for children younger than 6 y, 7.0 mumol for children between 6 and 12 y of age, and 8.8 mumol for adults and children > 12 y of age are suggested for field use. The acceptable time between administering the oral dose and obtaining a blood sample was validated as being 4-7 h in a group of children (n = 84) by taking two blood samples per child between 3 and 7 h after dosing with DRA. Furthermore, DRA in vitamin E-containing corn oil, with or without the addition of 4.6 mmol all-rac-alpha-tocopheryl acetate/L, was found to be stable for > or = 18 mo at 2 degrees C and at -20 degrees C, but not at 22 degrees C or at 37 degrees C. When DRA was stored in amber glass vials, stability was affected more by temperature than by exposure to room light. In keeping with earlier studies in adults, the ratio of 3,4-didehydro-retinol to retino tends to be independent of body weight. Indeed, slower growing children (ie, those with lower weight-for-age) may have a somewhat better vitamin A status than their heavier counterparts.

Adult↗
PubMed1996

Anthropometric measurements and body proportions among Chinese children.

There are significant racial differences in body proportions. Such data are not readily available for Chinese children. This article reports a cross section study of body proportions of 2193 Hong Kong Chinese children, ages 4 to 16 years, with equal gender distribution. Standing height, sitting height, and arm span were measured with standard equipment and methodology. Lower segment height was calculated as the difference between standing height and sitting height. Statistical analysis of the results showed a high linear correlation of the standing height with arm span, sitting height, and lower segment height, with a correlation coefficient ranging from 0.965 to 0.983 for both genders. When expressed as the ratio of standing height to arm span, the value was relatively constant and changed only linearly from 1.03 to 1 in girls and 1.03 to 0.98 in boys ages 4 to 16 years. The ratio of sitting height to lower segment height varied from a mean of 1.4 to 1.14 in boys and 1.36 to 1.18 in girls ages 4 to 16 years. The Chinese children were found to have a proportional limb segmental length relative to the trunk that differed significantly from the proportionally longer limbs in whites and blacks.

Adolescent↗
PubMed1996

Thumb duplication at the metacarpophalangeal joint. Management and a new classification.

Duplication at the metacarpophalangeal joint level (Wassel Type IV) is the most common type thumb duplication (polydactyly), accounting for 50%. It can be subdivided into 4 types: (A) hypoplastic (12%), (B) ulnar deviated (64%), (C) divergent (15%), and (D) convergent (complex) (9%). Type D has the most complex bone and soft tissue anomalies and is most likely to have residual deformities. A surgical protocol emphasizing early operation within 1 year of age, 1 stage osteotomy, meticulous collateral ligament repair, and abductor pollicis brevis tendon reattachment is presented. Twenty-one cases with an average followup of 5.25 years were reviewed. The cosmetic and functional results were satisfactory. Of a score system of 20 points, the mean score was 17.9. All except 1 patient had a stable metacarpophalangeal joint. Fifteen patients had a good range of movement, and 17 patients are satisfied with the outcome of surgery. Scar hypertrophy occurred in 2 patients.

Adolescent↗
PubMed1996

Paediatric sports injuries in Hong Kong: a seven year survey.

OBJECTIVE: To ascertain the epidemiological characteristics of sports injuries in children in Hong Kong. METHODS: Retrospective review of all cases seen in the Sports Injury Clinic of the Prince of Wales Hospital, Shatin, Hong Kong, in the period May 1984 to December 1990. The variables studied were age at presentation, gender, side of the body injured, anatomical location of the injury, type and severity of injury, sport played, level (school, recreational, amateur and professional) and frequency of sports participation, length in years of sports practice, and initial management of the injury. RESULTS: Of the 2293 patients seen, 238 were youngsters (54% boys) 16 years old or younger. Ball games accounted for the greatest number of injuries, with 37 children taking part in basketball, 28 in soccer, 12 in volleyball, and 31 children taking part in a variety of other ball games. Of the remaining children, the single largest group was practising track and field, with sprinting and middle distance running accounting for 42 injuries, and 28 children were injured while cycling. Most of the injuries (85%) were classified as non-serious, but 15% of children presented with a total of 21 fractures, two joint dislocations, five concussions, and seven torn knee ligaments. CONCLUSIONS: Children sports participation in Hong Kong, although not at high level and not as widespread as in the West, accounts for significant morbidity. These injuries should be carefully monitored to ascertain whether they result in any detrimental long term effects.

Adolescent↗
PubMed1996

Carcinomatous perforation of the sigmoid colon presenting as a thigh mass.

We report a patient presenting with a left psoas abscess causing necrotizing fasciitis of the upper thigh. The patient underwent exploration of the left thigh through a medial approach, confirming necrotizing fasciitis of the adductor compartment and the femoral triangle. The infective process also involved the left psoas. This was explored retroperitoneally through a left pararectal laparotomy incision. Further exploration revealed a carcinomatous ulcer of the sigmoid colon. Despite active resuscitation, antibiotic therapy, and further debridement, the patient died three days after admission.

Aged↗
PubMed1995

Humeral avulsion of glenohumeral ligaments as a cause of anterior shoulder instability.

The avulsion of the glenohumeral ligament labral complex at the glenoid (Bankart lesion), as well as ligamentous laxity are well known causes of anterior shoulder instability. A lesser known entity, the humeral avulsion of glenohumeral ligaments (HAGL), was studied to determine its incidence and its role in anterior glenohumeral instability. Sixty-four shoulders with the diagnosis of anterior instability were prospectively evaluated by arthroscopy for intraarticular pathology, including Bankart, capsular laxity, and HAGL lesions. Six shoulders were found to have HAGL lesions (9.3%), 11 shoulders with generalized capsular laxity (17.2%), and 47 shoulders with Bankart lesions (73.5%). In patients with documented anterior instability without a demonstratable "primary" Bankart lesion, a HAGL lesion should be ruled out. This lesion is readily recognized arthroscopically, and an appropriate repair of this lesion can restore anterior stability to the patient. The pathological anatomy of the HAGL lesion and our treatment of this lesion is discussed.

Adolescent↗
PubMed1995

A randomized double-blind controlled calcium supplementation trial, and bone and height acquisition in children.

There is limited information relating Ca intake to bone and height acquisition among Oriental children who consume little or even no milk. The present controlled study investigated the acquisition of bone mass and height of Chinese children with an initial Ca intake of approximately 567 mg/d who were supplemented to about 800 mg/d. Eighty-four 7-year-old Hong Kong Chinese children underwent an 18-month randomized, double-blind, controlled Ca-supplementation trial. The children were randomized to receive either 300 mg elemental Ca or a placebo tablet daily. Bone mass of the distal one-third radius was measured by single-photon absorptiometry, lumbar spine and femoral neck were determined using dual-energy X-ray absorptiometry. Measurements were repeated 6-monthly. Baseline serum 25-hydroxycholecalciferol concentration and physical activity were also assessed. Baseline Ca intakes of the study group and controls were respectively 571 (SD 326) and 563 (SD 337) mg/d. There were no significant differences in baseline serum 25-hydroxycholecalciferol concentration (P = 0.71) and physical activity (P = 0.36) between the study and control groups. After 18 months the study group had significantly greater increases in lumbar-spinal bone mineral content (20.9 v. 16.34%; P = 0.035), lumbar-spinal area (11.16 v. 8.71%; P = 0.049), and a moderately greater increment in areal bone mineral density of the radius (7.74 v. 6.00%; P = 0.081) when compared with the controls. The results confirm a positive effect of Ca on bone mass of the spine and radius but no effects on femoral-neck and height increase. A longer trial is warranted to confirm a positive Ca effect during childhood that may modify future peak bone mass.

Absorptiometry, Photon↗
PubMed1995

Closed reduction and percutaneous pinning for type III displaced supracondylar fractures of the humerus in children.

From 1985 to 1991, 623 cases of supracondylar fracture of the humerus in children were admitted to one center, of which 403 were analyzed in detail. Of these, 180 cases were classified as Gartland type III extension fractures, and 111 were treated via primary closed reduction and percutaneous smooth Kirschner wire pinning, of which 82 were followed up for an average of 3.5 years and were studied in detail clinically and radiologically. There were two cases of superficial pin tract infection and one of ulnar nerve palsy associated with the pinning. Nineteen fractures (10.5%) had an initial nerve palsy related to the injury. All recovered completely from 4 weeks to 40 weeks postinjury. Only one of nine cases (5%) with absent radial pulse required exploration. Eighty percent of all cases had excellent or good function according to the Flynn criteria of elbow assessment. The most important factor correlating with the final varus deformity was found to be the difference in Baumann's angle between the injured and the normal side after closed reduction and pin fixation. The results of cross pinning in eight cases were not found to be different from those of the lateral pinning group (74 cases). Ipsilateral fracture of the same limb occurred in 4.4% of the cases, the majority being a fracture of the distal radius. The average anesthetic time for the procedure was 54 min, and the average hospital stay was 2.9 days. Our study shows that cross or lateral percutaneous pinning was found to be effective in the treatment of Gartland type III extension fractures with a high success rate and minimal complications.

Bone Wires↗
PubMed1995

RML1 and RML2, Arabidopsis genes required for cell proliferation at the root tip.

New cells are produced from the meristematic tissues located at the shoot and root tip throughout the life of higher plants. To investigate the genetic mechanism regulating meristematic activity, we isolated and characterized four single-gene, recessive mutants in Arabidopsis thaliana called root meristemless (rml). Complementation tests identified two RML loci; RML1 maps to chromosome IV and RML2 maps to chromosome III. These mutants produce normal embryonic roots that either did not undergo or experienced limited cell division following germination, resulting in primary roots of less than 2.0 mm in length. Mutants can produce lateral and adventitious roots, which can grow to a length comparable to the embryonic root and arrest, indicating that the growth arrest is unrelated to the embryonic dormancy process. Neither the addition of growth regulators to the media nor the removal of shoots can rescue mutant roots from growth arrest, indicating that the mutant phenotype is not caused by a shortage of known growth regulators or by a transmissible shoot inhibitor. Normal cell division ability in mutant embryo, shoot, and callus cells indicates that the RML gene functions are not part of the general cell division processes; rather, they are involved specifically in activating the cell division cycle in the root apical cells.

Arabidopsis↗
PubMed1995

Percutaneous Kirschner-wire pinning for severely displaced distal radial fractures in children. A report of 157 cases.

Distal radial fractures are common in children. Recent outcome studies have cast doubt on the success of treatment by closed reduction and application of plaster. The most important risk factor for poor outcome is translation of the fracture. If a distal radial fracture is displaced by more than half the diameter of the bone at the fracture site it should be classified as high risk. We performed percutaneous Kirschner-wire pinning on 157 such high-risk distal radial fractures in children under 16 years of age. The predicted early and late failure rate was reduced from 60% to 14% and only 1.5% of patients had significant limitation of forearm movement of more than 15 degrees in the final assessment at a mean of 31 months after operation. There were no cases of early physeal closure or deep infection.

Adolescent↗
PubMed1995

Hip reconstruction for femoral head loss from septic arthritis in children. A preliminary report.

Seven children (8 hips) with Choi's Type IV-B sequelae of septic arthritis of the hip underwent an unconventional reconstruction technique using a vascular-pedicled iliac crest graft to replace the destroyed femoral head and neck. The average age at surgery was 3.5 years, and the mean followup 7 years. Graft incorporation was observed in all patients; however, severe graft resorption was found in 1 hip, and mild resorption in 4 hips. The method of internal fixation of the iliac crest graft was not ideal and will require modification. Excellent femoral head-neck substitution with graft hypertrophy and remodeling was seen in 3 hips. In 7 hips (88%), vertical hip stability was achieved and a good range of hip motion was maintained. All children adapted very well to the operative procedures. At the final followup, the symptoms were those of limb-length discrepancy; pain was not a symptom.

Arthritis, Infectious↗
PubMed1995

Changes in tyrosine-phosphorylated p190 and its association with p120 type I and p100 type II rasGAPs during myelomonocytic differentiation of human leukemic cells.

A M(r) 190,000 protein (p190) functions as a GTPase-activating protein (GAP) for Rho and Rac family proteins, which are involved in regulating cytoskeletal actin and membrane ruffling. Tyrosine-phosphorylated p190 also complexes with rasGAP, a regulator of Ras activity, thus possibly linking Ras and Rho pathways. Leukemic cells induced to differentiate along myelomonocytic lineages have increased filamentous actin (as evidenced by phalloidin staining) and extended pseudopodia, and become irregularly shaped and flattened, suggesting altered Rho and Rac function. We, therefore, hypothesized that changes in p190 and its association with rasGAP are an integral part of these shape changes. During phorbol 13-myristate 25-acetate-induced monocytic differentiation of HL60 promyelocytic and RWLeu4 chronic myelogenous leukemic cells, the total amount of p190 decreases rapidly but returns to initial levels by 12 h. In RWLeu4, this was accompanied by commensurate changes in p190 tyrosine phosphorylation and association with p120 type I rasGAP. Association of p190 and type I rasGAP was demonstrated by immunoprecipitation with antibodies to either protein. An additional band at M(r) 100,000 (p100) was detected in immunoprecipitates after 12 h of phorbol 13-myristate 25-acetate treatment. Reverse transcription-PCR and immunoblot analyses suggest that p100 is type II rasGAP, an alternatively spliced product of p120 type I rasGAP. p100 was expressed only in response to direct protein kinase C activators, but all classes of differentiation agents increased tyrosine-phosphorylated p190. Rho and Rac are known to be involved in regulating actin polymerization. The results presented here show that the association of p190 with type I rasGAP parallels increases in actin polymerization and cell adhesion. This suggests a role for p190-rasGAP interactions in phorbol 13-myristate 25-acetate-induced cytoskeletal reorganization.

Base Sequence↗
PubMed1995

Nephrotic syndrome and acute renal failure associated with hepatitis A virus infection.

Acute renal failure has been documented in association with hepatitis A virus (HAV) infection. This report describes a temporal relationship between HAV infection and immune complex mesangial proliferative glomerulonephritis associated with nephrotic syndrome. Animal experimental data have already shown that this is indeed a histological lesion associated with HAV infection. This case report is the first English documentation associating HAV infection with immune complex mesangial proliferative glomerulonephritis.

Acute Kidney Injury↗