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Biomedical subjects

J C Cheng

Publications and source records attributed to J C Cheng.

At least 109 records · Page 6Linked to original sources
PubMed1995

Ribotyping of clinical Vibrio vulnificus isolates.

Restriction fragment length polymorphism analysis of rRNA genes (ribotyping) was used to differentiate Vibrio vulnificus isolates. Among the 10 restriction enzymes tested, HindIII was shown to provide the most discriminatory patterns. Stul was used for further analysis of strains that were indistinguishable with HindIII. Thirteen clinical V. vulnificus strains were analyzed for their ribotypes with HindIII, as well as Stul when necessary. Four of the clinical strains were isolated from different samples collected from the same patient, and were shown to have identical ribotypes. All the others gave unique ribotypes, indicating the large genetic divergence in V. vulnificus clinical isolates. The ribotype of V. vulnificus by HindIII remained unchanged after successive in vitro and in vivo passages. HindIII gave rise to five bands which were shown in every V. vulnificus strain but not in other vibrio species tested, suggesting that ribotyping with this restriction enzyme may be useful for confirming the identification of this bacterium.

Bacterial Typing Techniques↗
PubMed1994

A developmental study of visual ERP distributions during spatial and phonetic processing.

Ten adults (mean age 19.5 years; S.D. = 1.65) and 10 children (12.2 years; S.D. = 1.28) participated in a choice reaction time study of event-related potential (ERP) correlates of pattern and phonological discriminations of letters. In the form condition, the subjects responded discriminately to letters that did (e.g., b, p) and did not (e.g., f, h) have an enclosed area. Likewise, the subjects responded to letters that did and did not rhyme with "e" in the rhyme task. For both groups, the two late positivities (P600 and P3) were significantly later in the rhyme ERPs than the form as were the RTs associated with the tasks. Distribution and group differences were most notable for the positivity at 380 msec. The P380 distribution did not vary between the conditions for the adults, but there was a more negative distribution in the rhyme condition compared to the form at fronto-central sites for the children. The topographic differences between the form and rhyme tasks at 380 msec were consistent with the involvement of auditory areas in the rhyme task. Generally, however, the children's and adults' wave forms were similar in terms of morphology, peak latency and distribution.

Adolescent↗
PubMed1994

Congenital pseudarthrosis of the ulna.

Congenital ulnar pseudarthrosis is a very rare condition. Two cases are reported in addition to 36 already reported in the English literature. One of the cases reported had a "one-bone forearm" procedure done, with a satisfactory result after 6 years. The second case had a free vascularized fibula graft procedure with restoration of the bony alignment and union after 8 months of follow-up.

Bone Transplantation↗
PubMed1994

Double-blind, controlled calcium supplementation and bone mineral accretion in children accustomed to a low-calcium diet.

A randomized, double-blind, controlled calcium supplementation trial was conducted for 18 mo to determine its effects on bone acquisition and height increment in 162 7-y-old Chinese children (87 boys and 75 girls) with habitually low calcium intakes (280 mg/d). Distal one-third radial bone mineral content (BMC), area bone density (BMC/bone width), and height were evaluated every 6 mo. Baseline dietary intakes, serum 25-hydroxycholecalciferol, and physical activity were determined. The study group received 300 mg Ca/d as calcium carbonate; control subjects received placebo tablets. After 18 mo the study group had significantly greater gains in BMC (16.5% vs 13.97%; P = 0.02) and BMC/bone width (9.45% vs 6.31%; P = 0.0008) than the control subjects. The findings confirm a positive effect of calcium intake on bone acquisition but no effect on height increment. Whether a higher bone mass attained at age 8-9 y would be maintained and beneficial to future peak bone mass requires longitudinal investigation. Further study is warranted to determine calcium requirements for Chinese children.

Body Height↗
PubMed1993

Percutaneous elongation of the Achilles tendon in children with cerebral palsy.

From 1987 to 1990, 45 children with cerebral palsy underwent percutaneous elongation of the Achilles tendon (71 ankles); the mean age was 5.7 years. Most suffered from spastic diplegia or hemiplegia. A three-step cut technique was used, the limb immobilised in a long leg fiberglass cast and immediate weightbearing allowed. Follow up was from 2 to 5 years. Satisfactory results were obtained with significant improvement in walking in 89%.

Achilles Tendon↗
PubMed1993

Response of fingertip circulation to local warming in the injured hand--a study using laser Doppler flowmetry.

A laser Doppler flowmeter was used to assess the fingertip circulation serially in 41 patients with various hand injuries. The "flux value" measures the flow of red cells across the site of assessment and the "fluctuation" represents the pulsatile peak-trough difference in flux value with each cardiac contraction. Local temperature at the fingertip was raised stepwise by a special heater-thermostat from 36 to 44 degrees C. Compared to the normal hand both the flux value and fluctuation in the injured hand are smaller at lower temperatures. The differences narrow down at higher temperatures and the trend reverses above 42 degrees C and remains so on cooling. This may represent abnormal sympathetic tone in the injured hand.

Adolescent↗
PubMed1993

Limb fracture pattern in different pediatric age groups: a study of 3,350 children.

The fracture patterns of 3,350 children with 3,413 limb fractures admitted to one center from 1986 to 1990 were analyzed retrospectively. The overall boy-to-girl ratio was 2.7:1, rising to 5.5:1 in the adolescent group. Distal radius fracture was the most common fracture (19.87%), followed by supracondylar fracture of the humerus (16.64%) and forearm shaft fracture (13.36%). Specific age group breakdown showed that supracondylar fracture of the humerus was the most common fracture occurring in the age groups 0 to 3 years and 4 to 7 years, accounting for 28.94 and 31.18% of all limb fractures, respectively. Fracture of the distal radius occurred in 27.06% of the 8 to 11 year age group and 23.31% of the 12 to 16 year group. Open fractures were uncommon (2.17%), and greenstick fractures were found only in 5.27% of this hospital series. The nondominant arm was found to have more fractures although the number was not statistically significant. Seasonal variation in incidence occurred, with more cases in the summer and autumn months. The open reduction rate in the treatment varied from 10.15% in the 0 to 3 year age group to 33.95% in the 12 to 16 year group. Forty-five percent of the 0 to 3 year age group were discharged from hospital within 24 h, contrasting with 30% in the other age groups. Overall incidence of fractures requiring hospital treatment was estimated to range from 35 per 10,000 in the 0 to 3 year age group to 62, 60, and 57 per 10,000 in the 4 to 7, 8 to 11, and 12 to 16 year groups, respectively.

Adolescent↗
PubMed1993

Pyomyositis and staphylococcal scalded skin syndrome.

Pyomyositis is a rare musculoskeletal infection in non-tropical countries. We report a child who had pyomyositis complicated by staphylococcal scalded skin syndrome. This complication has not previously been described in patients with pyomyositis. Early diagnosis of pyomyositis was made by ultrasound examination, and percutaneous needle drainage under ultrasound guidance was performed. Pus aspirated and blood cultures grew Staphylococcus aureus. No open surgical drainage was required and resolution of the abscess was documented by serial ultrasound examinations.

Child↗
PubMed1993

Translation of the radius as a predictor of outcome in distal radial fractures of children.

We conducted a retrospective analysis of 94 children with fractures of the distal third of the radius, with or without ulnar fractures, treated by primary closed reduction and plaster. The overall failure rate of 29% was due mainly to irreducibility, inability to maintain reduction and eventual limitation of forearm rotation. Age, sex and severity of angulation were not significant, but the direction of angulation and the degree of translation at either the radial or the ulnar fracture sites were significant risk factors. Translation of the radius was the single most reliable predictor of outcome (83% correct). The risk of failure in fractures with translation of the radius of more than half the diameter of the bone was 60%, compared with 8% for fractures with less translation.

Casts, Surgical↗
PubMed1992

Ultrasonography of congenital muscular torticollis.

The sonographic appearance of the sternocleidomastoid muscles of 36 children with congenital muscular torticollis was studied. Sternocleidomastoid tumour was detected in all of them and the images were more complex than described in the literature. A patchy echo-texture was as frequent as a homogeneous echo-texture, and was more common in the younger child. The echo-genicity of the mass could be hyperechoic, isoechoic or hypoechoic relative to normal muscle. A hypoechoic rim surrounding the mass was frequently present. Change of the proportion of the mass relative to the entire muscle-mass complex in different ages matching clinical observations was also noted. These sonographic findings would be important in establishing a sonographic diagnosis. The higher sensitivity of ultrasound in detection of sternocleidomastoid tumour over clinical methods, and the importance of the sonographic findings in the management of congenital muscular torticollis were also discussed.

Child, Preschool↗
PubMed1992

Biomechanical analysis of a step-cut technique for flexor tendon repair.

We compared the strength of a new step-cut technique for flexor tendon repair with that of the widely used Kessler-Tajima technique, giving special attention to the relative contributions of the core and epitendinous sutures. 36 flexor digitorum profundus tendons from human cadavers were used. Corresponding digits from the same donor were paired, and the two tendons of each pair were placed in the Kessler-Tajima and step-cut groups, respectively. Each group had three subcategories of repair: (1) core repair alone; (2) epitendinous repair alone; and (3) full repair. In the Kessler-Tajima repair, the core stitch contributed more to ultimate tensile strength, while the epitendinous stitch contributed more to gap formation resistance. In the step-cut repair, however, the epitendinous stitch contributed more to both measures of strength. The full step-cut repair was 65% stronger in resisting gap formation and had 84% more ultimate tensile strength than the full Kessler-Tajima repair. We attribute the greater strength of the step-cut repair to the additional number of epitendinous loops, which lie perpendicular to the long axis of the tendon.

Cadaver↗
PubMed1992

Activation of proximal tubular Na(+)-H+ exchange by angiotensin II.

Stimulation of Na(+)-H+ exchange by angiotensin II (ANG II) was characterized in renal proximal tubular cells. Rabbit proximal nephron segments were incubated in the presence or absence of ANG II (5 x 10(-10) M), after which brush-border membrane vesicles (BBMV) were isolated and assayed for Na(+)-H+ antiporter activity using the acridine orange technique. Both the affinity (for sodium) and capacity of the carrier were elevated significantly (P less than 0.05) within 15 min of incubation with ANG II. To determine whether the stimulation of transport capacity involved a change in Na(+)-H+ antiporter density in the luminal membrane, binding of tritiated 5-(N-methyl-N-isobutyl)amiloride ([3H]MIA) was measured in BBMV derived from control and ANG II-treated nephron segments, following maximal stimulation. This demonstrated a significant (P less than 0.05) increase in the maximal specific binding (Bmax) of [3H]MIA binding in the ANG II-treated group compared with control, of a magnitude sufficient to account for the observed change in maximal velocity (Vmax). The data indicate that the Vmax effect is caused by an apparent increase in the number (density) of active Na(+)-H+ carriers present in the luminal membrane. Finally, to test the possibility that the observed kinetic change involves an exocytic mechanism, the effect of colchicine on ANG II-stimulated antiporter activity was examined. The increase in Vmax due to ANG II was blocked by the addition of 0.5 mM colchicine to the incubation medium, whereas colchicine alone had no significant effect on the Vmax of Na(+)-H+ kinetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1992

Fetal fracture healing in a lamb model.

A large animal model to assess fetal fracture repair and the ability to close excisional bony defects is presented. Incisional and excisional ulnar fractures were made in 14 midgestation fetal lambs, harvested at serial time points, and subjected to high-resolution low-kilovolt magnification radiographs, magnetic resonance imaging scans, and histologic analysis. Fetal fracture healing was characterized by early closure of excisional defects and rapid fracture healing with minimal or no soft-tissue inflammation or callus formation. Magnetic resonance imaging scans of the fractures revealed a characteristic pattern compatible with the histologic findings, namely, minimal inflammation in soft tissue adjacent to the fracture site. Histologic and magnification radiographic findings indicated that complete bony repair occurred within 21 days in incisional defects and within 40 days in excisional defects. In both cases, healed fetal bone resembled normal bone matrix. Excisional defects, including periosteum, of greater than three times the width of the bony cortex closed rapidly with virtually normal-appearing bony matrix and with minimal or no callus formation.

Animals↗
PubMed1991

Distraction lengthening of the forearm.

Seven patients aged six to 25 underwent progressive distraction lengthening of the forearm. Five had lengthening of the ulna and two of the radius. Four cases had multiple exostoses, two had post-traumatic distal epiphyseal arrests and one had dyschondrosteosis. Two methods were used: the Wagner technique of diaphyseal distraction and bone grafting, or diaphyseal corticotomy and callus distraction without bone grafting. The average lengthening achieved was 3 cm. Review after one to three year's follow-up showed satisfactory improvement in appearance and function in all cases, with minimal complications.

Adolescent↗
PubMed1990

Long-term neurologic outcome in psychogenic water drinkers with severe symptomatic hyponatremia: the effect of rapid correction.

PURPOSE: The purpose of our study was to ascertain the safety of rapidly correcting acute symptomatic hyponatremia in psychogenic water drinkers, particularly in regard to any delayed adverse neurologic sequelae. PATIENTS AND METHODS: We reviewed the medical records of all known psychogenic water drinkers (34) in our hospital from 1977 to 1989. Using seizure as a marker of severity, we identified 13 patients having a total of 27 episodes associated with severe hyponatremia. We evaluated the charts of those patients in detail to assess the mode of treatment, rate of correction, and long-term neurologic outcome. None of the patients experienced respiratory arrest before treatment, which was initiated within 2 hours of seizure. RESULTS: For all 27 episodes, the initial serum sodium level (mean +/- SE) was 110.9 +/- 1.2 mmol/L, and the rate of correction (mean +/- SE) was 1.65 +/- 0.2 mmol/L/hour. All but one episode were corrected "rapidly" (initial correction rate of 0.7 or more mmol/L/hour) to 120 to 130 mmol/L within 12 hours. The absolute change in the serum sodium level was 15.1 +/- 1.2 mmol/L in 12 hours, 21.6 +/- 1.4 mmol/L in 24 hours, and 25.9 +/- 1.4 mmol/L in 48 hours. In no instance did therapy induce hypernatremia. All patients recovered immediately after treatment. There was no clinical or radiologic evidence of adverse neurologic sequelae immediately after treatment or after 6 years of follow-up. CONCLUSION: In this series of male psychogenic water drinkers, early "rapid" correction of acute symptomatic hyponatremia by raising the serum sodium level 15 mmol/L in 12 hours while maintaining an absolute change in the serum sodium level of 26 mmol/L within 48 hours produced no long-term neurologic sequelae.

Adult↗