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Biomedical subjects

C E Clark

Publications and source records attributed to C E Clark.

At least 37 records · Page 2Linked to original sources

Cotrel-Dubousset instrumentation.

Cotrel-Dubousset Instrumentation (CDI) presents a diversified posterior implant system applicable in any situation requiring posterior spinal instrumentation. It acts in the three dimensions of the spine, frontal-sagittal-axial. Correct hook site selection and direction provide spinal balance in three dimensions. The double major idiopathic scoliosis is an appropriate model on which to learn the principles of usage of CDI Results of CDI in a wide variety of spinal pathology have been excellent. There is a learning curve for CDI, hook placement being the most significant. Pitfalls and complications can be avoided.

Bone Screws↗

Surgical treatment for malignant exophthalmos of endocrine origin.

Endocrine exophthalmos is a poorly understood disease process thought to be related to a dysfunction of the thyroid-pituitary axis. Initial therapy for symptomatic endocrine exophthalmos is medical. Failure to respond to medical management is heralded by progressive exophthalmos, exposure keratitis, and decreasing visual acuity. The pathophysiologic processes involved and an historical review of the various surgical procedures used are discussed. The results of 28 patients surgically decompressed by a transantral transethmoid approach are presented. Preservation or improvement in visual acuities were observed in all but one patient. Diplopia was generally not improved and may be worsened in some patients.

Adult↗

Effects of toxicants on populations: a qualitative approach II. First order kinetics.

System level effects exhibited by a population subjected to a chronic or an acute dose of toxicant are the emphasis of this study. A three dimensional model of a toxicant and a population, with state variables (the population biomass, the concentration of toxicant in an organism, and the concentration of toxicant in the environment) coupled by a linear dose-response function, is analyzed analytically. One of the main results presents sufficient conditions, in terms of a system level parameter, for the persistence, and for the extinction, of a population exposed to a chronic dose of toxicant. When depuration and degradation are negligible processes, the effects of toxicant accumulation associated with an acute exposure of a population are analyzed in some detail. Both persistence and extinction are shown to be viable behavior modes of a population in this biochemical setting.

Environmental Pollutants↗

Ullrich-Turner syndrome (45,X/46,X,i[Xq]) in a child with a familial inversion of chromosome 3.

We report a girl with shortness of stature and minor anomalies representing a mild form of the Ullrich-Turner syndrome. Cytogenetic studies showed 3 distinct anomalies: 1) a familial pericentric inversion, inv(3) (p25q21)pat, in all cells examined; 2) monosomy X (45,X) in 70% of cells; 3) isochromosome X (46,X,i(Xq)) in 30% of cells. The karyotype designation is: 45,X,inv(3) (p25q21)pat/46,X,i(Xq), inv(3) (p25q21)pat. The pedigree, which was originally interpreted as representing the segregation of a 2;3 translocation, is corrected and updated. Reproductive risks in families with pericentric inversions are discussed.

Body Height↗

Value of serial sonography in the in utero detection of duodenal atresia.

Duodenal atresia can be fatal unless promptly diagnosed and treated surgically. Death occurs in the newborn secondary to emesis, aspiration, and electrolyte imbalance. Serial ultrasound scans were obtained for 2 patients, but duodenal atresia was not detected until 29 and 32 weeks' gestation, respectively. With prior knowledge of an infant with Down syndrome and duodenal atresia, management of fetal distress with subsequent operative delivery can be altered. Early prenatal diagnosis by ultrasonography and subsequent amniocentesis plays an important role in the antenatal and postpartum counseling and management of these patients and neonates.

Adolescent↗

Risk factor analysis of intraventricular hemorrhage in low-birth-weight infants.

Sixty of 63 newborn infants weighing less than 1,250 gm, admitted consecutively to the Intensive Care Nursery during a 15-month period, were prospectively investigated for the incidence of intraventricular hemorrhage by early computerized tomography or by autopsy. Nineteen of the 60 infants had evidence of IVH. The incidence of IVH was correlated with the presence of possible neonatal, obstetrical, asphyxial, or therapeutic risk factors. There was a significant difference in only one of the risk factors: birth outside the perinatal center. Fifteen of 27 outborn infants (56%) developed IVH, whereas only four of 33 inborn infants (12%) developed IVH (P less than 0.001). There were no statistically significant differences in maternal obstetrical risk factors, infant risk factors, or indices of birth asphyxia in the inborn compared with the outborn infants. However, perinatal therapeutic risk factors differed between the two groups. Outborn infants were less likely to have received betamethasone (P less than 0.001), were less likely to have their arterial blood gases monitored and stabilized during the first 20 minutes after birth (P less than 0.001), and were given more bicarbonate (P less than 0.001) and more boluses of fluid intravenously (P less than 0.02). The risk of IVH in very low birth-weight infants may be significantly decreased by therapeutic factors at birth. Maternal transport to a perinatal center and intensive neonatal resuscitation may contribute to decreasing the incidence of intraventricular hemorrhage.

Cerebral Hemorrhage↗

Trisomy 6q25 leads to 6qter in two sisters resulting from maternal 6;11 translocation.

Chromosome banding was used to define a partial duplication of the long arm of chromosome 6 (6q25 leads to 6qter) in two profoundly affected sisters and to identify their phenotypically normal mother and sister as balanced translocation carriers whose karyotypes were interpreted as 46,XX,t(6;11) (q25;q25). Prominent clinical features included profound mental retardation, hypertelorism, micrognathia, down-turned mouth, dental anomalies, clubfeet, webbed neck, late progressive scoliosis, flexion contractures, and low total finger ridge count. By comparison with published reports, it has been possible to establish a trisomy 6q25 leads to 6qter syndrome.

Abnormalities, Multiple↗

Long arm deletion of chromosome 13 with exclusion of esterase D from 13q32 leads to 13qter.

A de novo partial 13q monosomy is reported in a severely affected 8-year-old female with the karyotype 46,XX,del(13)(q32). Abnormal features included mental retardation, delayed development, microcephaly, encephalocele, hearing loss, hypertelorism, ptosis, flat nasal bridge, protruding upper incisors, facial asymmetry, short neck, hypoplastic thumbs, scoliosis and clubfeet. The deletion was demonstrable by R-banding but was not apparent by GTG banding. The locus for esterase D (EC 3.1.1.1) is excluded from the deleted segment 13q32 leads to 13qter.

Abnormalities, Multiple↗