Biomedical subjects
Publications and source records attributed to S M Chung.
Cultured human cells derived from pancreatic, gastric, duodenal, and gall bladder cancers secreted a considerable amount of pancreatic secretory trypsin inhibitor into the culture medium.
The best treatment for diseases of the hip can begin if one diagnoses the disorder as soon as possible after onset. In many cases, successful management of the disease will prevent permanent damage to the hip joint. If injury occurs to the developing hip joint, major hip surgery may be necessary in adult life.
Two hundred patients who had been fitted with binaural hearing aids were chosen as subjects for a questionnaire survey to determine the factors which would influence the use of binaural hearing aids. From the analysis of the 16 factors used which included audiological, physical and social factors, the following results were obtained: (1) A significantly greater proportion of male patients used binaural hearing aids than female patients. (2) A significantly greater proportion of patients with a different hearing loss configuration in the two ears used binaural hearing aids as compared with those with a symmetrical hearing loss. (3) Frequent users of binaural hearing aids were males, who had had additional help to reduce their hearing disability, and had a more severe hearing loss in the better ear. The use of binaural hearing aids in noisy situations and in localising sounds was also investigated.
The cornea has one of the highest acetylcholine (ACh) concentrations of any tissue but the function of the ACh has remained enigmatic. During studies on corneal arachidonic acid metabolism, we observed that ACh stimulates formation of labeled phosphatidic acid in rat corneas whose phospholipids were prelabeled with [14C]arachidonate. ACh did not affect the metabolism of free [14C]arachidonate. [14C]Arachidonyl-phosphatidic acid formation was doubled after 10 min of incubation in the presence of ACh concentrations of 10(-4) M or greater. The stimulation by ACh could be completely blocked by atropine and scopolamine and partially blocked by d-tubocurarine. These studies suggest that intact rat cornea has muscarinic cholinergic receptors and that the enzymes of the inositol phospholipids pathway are present since phosphatidic acid is an obligatory intermediate in that cycle of reactions.
Deoxycholate promotes phospholipase C degradation of endogenous phosphatidyl[3H]inositol (Pl), phosphatidyl[3H]inositol monophosphate (PIP) and phosphatidyl[3H]inositol bisphosphate (PIP2) in rat cornea and human platelets. Hydrolysis of phosphatidyl[3H]inositol significantly lags polyphospho[3H]inositide degradation. Concomitantly, formation of [3H]inositol monophosphate (IP1) lags behind [3H]inositol bisphosphate (IP2) and [3H]inositol trisphosphate (IP3) production. These results demonstrate that rat cornea and human platelet phospholipase C cause a preferential hydrolysis of the endogenous polyphosphoinositides rather than phosphatidylinositol.
The human promyelocytic leukemia cell line HL60 can be induced to differentiate into mature granulocytes by exposure to Me2SO. [1-14C]Arachidonic acid incubated overnight with these cells was incorporated mainly into membrane phospholipids. Stimulation of these cells with the calcium ionophore, A23187, resulted in a rapid release of esterified arachidonic acid from phosphatidylethanolamine and phosphatidylcholine. The released arachidonic acid was metabolized via both the cyclooxygenase and lipoxygenase pathways into three major hydroxylated products, 12-L-hydroxy-5,8,10-heptadecatrienoic acid (HHT), 5(S)-hydroxy-6,8,11,14-icosatetraenoic acid (5-HETE), and 5-(S),12(R)-dihydroxy-6,8,10,14-icosatetraenoic acid (leukotriene B). Arachidonic acid was also incorporated into triacylglycerols and phosphatidylinositol. The lipoxygenase product, 5-HETE, was rapidly esterified into cellular lipids. Thirty minutes after ionophore stimulation, 55% of the total 5-HETE synthesized was esterified into phospholipids and 35% incorporated into acylglycerols. In contrast, the other hydroxylated derivatives of arachidonic acid (HHT and leukotriene B) were not incorporated into acylglycerols or phospholipids. Esterification of hydroxylated metabolites of arachidonic acid into membrane phospholipids may serve to regulate a number of granulocyte functions.
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In a 51/2 year old boy with unilateral coxa vara who died of unrelated causes histological sections were made of the proximal femora and pelvic growth plates. The proximal femora were also perfused to study the pattern of arterial supply. Evidence of active endochondral ossification was not detectable in growth plates of the affected right femur, the clinically and roentgenographically normal left femur and the pelvis, including a Salter Type II fissure fracture. The endochondral ossification defect found in growth plates of the proximal right femur and pelvis was associated with a reduction in the number and caliber of intraosseous arteries supplying the metaphyseal sides of the growth plates in the proximal femur and those supplying the subchondral region and extraosseous medial ascending cervical arteries on the surface of the femoral neck. This deficiency in endochondral ossification resembles a form of dwarfism associated with a coxa vara and a generalized growth plate disorder.
We reviewed eleven patients less than seven years old with fractures of the odontoid process in an effort to establish a more standard form of treatment for the injury and to determine what complications, if any, occur as a result of fractures of the odontoid process in pediatric patients. Our study showed that children with odontoid fractures that are recognized and treated promptly usually do well. The fracture can usually be reduced by passive manipulation or by the "hanging head technique". Support in the reduced position for two to three months in a Minerva jacket or halo cast should be long enough to permit healing. Our study suggests that fractures of the odontoid process in young patients almost always heal.
Thanatophoric dwarfism is a severe form of short-limbed dwarfism in which cardiorespiratory failure uniformly results in death in the neonatal period. Its radiographic features include markedly flattened vertebral bodies with a typical U-shaped deformity, a flat squat pelvis, and short, bowed extremities with flaring and irregularity of the metaphyses. These characteristic features distinguish this entity from the two other most commonly confused congenital short-limbed forms of dwarism--achondroplasia and achondrogenesis. The distinctions are discussed in the text.
To understand why congenital dislocated hip (CDH) was diagnosed late (mean age: nine months) in children admitted to the Children's Hospital of Philadelphia (CHOP), 714 consecutive CHOP admissions, aged zero to two years, and 947 consecutive newborns delivered at the Hospital, University of Pennsylvania (HUP) were examined for CDH. The expected frequency of CDH was found at HUP. At CHOP, the children had a higher incidence of CDH, many with associated congenital anomalies, their hips were more difficult to examine, the hospital records contained few references to hip examinations. Had these children's hips been formally examined at birth, the delay in diagnosis might have been eliminated and treatment might have been easier and more successful.
After the determination of the shear strength and modes of failure of the capital femoral epiphyseal plates in twenty-five pairs of hips obtained post mortem from children five days to fifteen years and ten months old, with the plate intact on one side and with the perichondrial fibrocartilaginous complex removed on the other, the gross and microscopic morphology was studied. The shear strength of the human epiphyseal plate varied with age and was greatly dependent on the surrounding perichondrial complex in infancy and early childhood, but less so in adolescence. When this complex was excised, the strength of the epiphyseal plate was diminished, especially in specimens from younger children. The forces necessary to cause slipping were found to be within the physiological range of the force that would be generated in overweight children, suggesting that purely mechanical factors may play a major role in the etiology of slipped capital femoral epiphysis.
Surgery for Sprengel's deformity can produce less lowering of the scapula than desired and occasionally can result in an injury to the brachial plexus or brachial artery. The method used to produce better correction and to avoid complications was a softening of a clavicle by the morcellization technique of Robinson et al. We feel that the procedure is a simple one which helps to improve the degree of correction and to avoid neurovascular complications. The procedure should be combined with the Woodward correction for Sprengel's deformity.
Manual traction reduction without anesthesia and immediate immobilization in a spica cast were used to treat eighty-five children ranging in age from birth to ten years old who had closed femoral-shaft fractures and no associated injuries. Up to two centimeters of overriding, 30 degrees of anterior angulation, and 15 degrees of medial angulation were accepted. Any angulation in excess of these amounts, or lateral or posterior angulation, was corrected by wedging the cast at the fracture site. Further telescoping of the fracture fragments in the case was attributed to the child pressing the foot against the bottom of the cast and was prevented by removing the sole of the cast. Of the seventy-five children examined two to eighteen years after fracture, none had any residual skeletal deformity or joint stiffness. The length discrepancies of the fractured limbs ranged from 1.7 centimeters of shortening to 0.9 centimeter of overgrowth.
By means of perfusion studies, an analysis was made of the arterial supply to the proximal end of the femur in 150 specimens from autopsied fetuses and children, aged from twenty-six weeks of gestation to fourteen years and eight months old. All died of diseases which did not involve the hip joint. Two anastomotic rings were found: an extracapsular one formed by the medial and lateral femoral circumflex arteries, and a subsynovial intra-articular ring at the articular cartilage-neck junction. The intra-articular rings in males were discontinuous more often than in females. A three-plane analysis of totally-cleared specimens demonstrated that the epiphyseal plate constituted an absolute barrier to blood flow between the epiphysis and metaphysis in all but two of the 124 barium sulphate-perfused specimens examined. A smaller number of ascending cervical arteries crossed the anterior and medial surfaces of the mid-neck in the specimens from three to ten-year-old white children than in those from newborn to two-year-old white and black children. This finding may be important for the etiology of Legg-Perthes disease. No differences with respect to age, sex, or race were found in the arteries of the ligamentum teres.
A grade 4 spondylolisthesis at the level of L-4 and L-5 was detected in a 3-year-old girl who had a spastic gait and focal sensory deficit. There was no history or objective evidence of substantial spinal trauma. A deformity over the lower part of the spine had been noted at 1 year of age and the radiological lesion was more extensive than that found in classical spondylolysis. Consquently, a diagnosis of congenital spondylolisthesis is most acceptable. Treatment via combined posterior and posterolateral fusion following anterior decompression has yielded gratifying results.
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