Biomedical subjects
D L Clark
Publications and source records attributed to D L Clark.
Partsch operation for the treatment of a dentigerous cyst.
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Impacted third molar and dentigerous cyst.
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Open reduction and fixation of compound comminuted fracture of the mandible.
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Metabolic stability and tumor inhibition of bombesin/GRP receptor antagonists.
Small cell lung cancers (SCLC) synthesize and secrete bombesin/gastrin releasing peptide (BN/GRP). The autocrine growth cycle of BN/GRP in SCLC can be disrupted by BN/GRP receptor antagonists such as [Psi13,14]BN. Here several BN analogues were solid-phase synthesized and incubated with intact SCLC cells at 37 degrees C in RPMI medium in a time-course fashion (0-1080 minutes) to determine enzymatic stability. The proteolytic stability of the compounds was determined by subsequent HPLC analysis. The metabolic half-life ranged from 154 minutes to 1388 minutes for the six analogues studied. [Psi13,14]BN was found to be very stable to metabolic enzymes (T1/2 = 646 mm) and also inhibited SCLC xenograft formation in vivo in a dose-dependent manner. When [Psi13,14]BN was incubated with NCI-H345 cells, it inhibited 125I-GRP binding with an IC50 value of 30 nM. These data suggest that BN/GRP receptor antagonists such as [Psi13,14]BN may be useful for the treatment of SCLC.
Cine-computed tomography of cor triatriatum.
A case of cor triatriatum in a 51-year-old man was demonstrated by rapid acquisition cine-CT (CCT). The CCT findings are compared with cardiac catheterization and two-dimensional echocardiography.
Development of postrotatory nystagmus time constants.
Models of the slow phase portion of postrotatory nystagmus in the adult include time constants which describe primary and secondary nystagmus. The cupular time constant (T1) is believed to reflect the activity of the cupula of the semicircular canal, while the adaptation time constant (Ta) defines the rate of change of the baseline firing rate. Values for T1 and Ta have been published for the adult. In this study 37 normal infants under one year of age and 12 children, 3 to 13 years of age were examined for postrotatory nystagmus, and values for the two time constants were determined. The cupular time constant does not change with age and is concluded to be at an adult level at birth. This is correlated with the relative maturity of ear morphology at birth. The adaptation time constant increases from 79.5 sec at one month of age to 260.7 sec at 12-13 years of age, implying that maturation of adaption is a relatively slow process.
A simple analog computer model of ventricular depolarization.
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Behavioral and nystagmus response of a hyperkinetic child to vestibular stimulation.
A five-year-old boy, referred for hyperkinetic behavior, was tested for vestibular function before and after a four-week regime of controlled semicircular canal stimulation. Hyperkinetic behavior was assessed both during and after the four-week treatment period. Initial testing showed that semicircular canal function was normal, but that two measurable central nervous system mechanisms representing integration of the sensory signal were not at a normal level. Behavioral instruments demonstrated an improvement in symptoms of hyperkinetic behavior. It is postulated that the behavioral improvement resulted from an increase in task-relevant arousal in the reticular formation, accompanied by increased cortical inhibition.