Biomedical subjects
Publications and source records attributed to J C Cassady.
A large series of patients with intraocular lens implants had an overall 0.98% incidence of retinal detachment (eight detachments in 819 eyes). Within this group, patients with axial lengths of more than 25 mm had a statistically significantly higher incidence of retinal detachment (P = .054).
In order to assess the contribution of fundus examination to the differential diagnosis of acuqired optic neuropathy, five ophthalmologists viewed 163 fundus stereophotographs of nine disease entities as "unknowns." Glaucoma, central retinal artery occlusion (CRAO), and ischemic optic neuropathy (ION) were diagnosed by at least one observer with an accuracy above 80%. The remaining conditions (optic neuritis; compressive, traumatic, and hereditary optic neuropathies) were correctly identified with less than 50% accuracy. Retinal arteriolar attenuation and sheathing were most helpful in differentiating CRAO and ION. Although pathologic disc cupping often identified glaucoma, it was also seen in 20% of eyes with optic atrophy not associated with glaucoma. Excavation was more profound in glaucoma than in nonglaucomatous optic atrophy, the latter demonstrating relatively greater neuroretinal rim pallor. In 6% of nonglaucomatous optic atrophy eyes, however, disc cupping was misdiagnosed as "glaucomatous." Only 11% of eyes with previously documented papillitis or ION left clues that allowed observers to identify preexisting disc swelling.
A five-compartment pharmacokinetic model with two excretory pathways, exhalation and metabolism, based on first order kinetics is used to outline the effect of body build, pulmonary ventilation, and lipid content in blood on uptake, distribution, and clearance of low solubility gases and lipid soluble vapours during and after exposure. The model shows the extent that individual differences have on altering uptake and distribution, with consequent changes in blood concentration, rate of excretion, and toxicity, even when variations in these parameters are within physiological ranges. The model is also used to describe the concentration variation of inhaled substances in tissues of subjects exposed to concentrations with permitted excursions. During the same course of exposure, the tissue concentrations of low solubility gases fluctuate much more than tissue concentrations of lipid soluble vapours. The fluctuation is reduced by metabolism of inhaled substance. These conclusions are recommended for consideration whenever evaluating the effect of excursions above the threshold limit values used in the control of industrial exposures (by excursion factors).
We attempted to reproduce the work of Naeye with regard to the thickness of the muscular media in small pulmonary arteries among victims of the sudden infant death syndrome, using Naeye's methods. In two separate studies, using two slightly different groups of patients and different ocular grids, we observed a statistically significant difference between crib deaths and accidental deaths in hyperplasia of the arterial muscular media, the only parameter not dependent on point-counting. As no investigator has been able to achieve exactly the same results as Naeye in all three parameters, we concluded that point-counting is probably not the method of choice for this determination. Our data for hyperplasia (in the second phase of the study) correlated with those for the retention of periadrenal brown fat and hepatic erythropoiesis in the same patients.
This report reviews the literature on amblyopia therapy from 1970 through 1976. New techniques of screening for amblyopia have been developed during this period. Modification of therapy which includes the use of penalization, prisms, red filter, and home exercises has been reported in the current literature. A summary of the author's personal experience in the treatment of amblyopia at the Bascom Palmer Eey Institute from 1966 through 1976 is presented with the factors that influenced the outcome of this therapy.
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The absence of carnitine in the diet of normal infants results in marked reduction of plasma carnitine levels. In order to evaluate the effects of L-carnitine supplementation of soybean formula, plasma and urine levels of free carnitine and acylcarnitine were compared in infants receiving carnitine-free soybean protein-based formula and the same formula supplemented with 50 and 250 nmol/ml L-carnitine. In infants receiving soybean formula with 50 nmol/ml L-carnitine, the plasma levels of free carnitine were not significantly different from those in infants receiving formula with 250 nmol/ml L-carnitine; however, urine levels of free carnitine were significantly increased when the infants received formula with 250 nmol/ml L-carnitine. In normal full-term infants, supplementation of soybean formula with 50 nmol/ml L-carnitine was sufficient to maintain normal plasma levels that were comparable to breast-fed infants.
To describe the time course of the early development genetic variance for blood pressure, a cohort of twins is being followed from birth to 1 year of age. The present interim report describes systolic and diastolic blood pressure measurements for 102 twin pairs (39 monozygotic (MZ) and 63 dizygotic (DZ) in the newborn period and at 1, 3 and 6 months of age. Mean values for both systolic and diastolic blood pressure were similar regardless of race, sex, zygosity, or chorionicity. Statistically significant genetic variance was detected for systolic blood pressure at 6 months of age but not for diastolic blood pressure at any data point. The data are consistent with the hypothesis that genetic factors that determine within-family similarities of blood pressure may be detected early in life, and support the need for further investigation of both genetic and environmental determinants of blood pressure in young populations.