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Biomedical subjects

C C Johnson

Publications and source records attributed to C C Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1982

Diet and exercise in middle-aged men.

Effects of an anaerobic exercise program on serum lipids and lipoproteins in sedentary male subjects were studied for 12 weeks. No dietary changes were made, and individuals were encouraged to maintain their body weight. Increase in lean body weight, decrease in percent body fat, and unchanged total body weight occurred in subjects participating in the resistive weight training program, while the men's serum cholesterol and low-density lipoprotein-cholesterol decreased and their high-density lipoprotein-cholesterol increased. Lipid profile improvements were attributed to exercise.

Adult↗
PubMed1980

Regulation of rat ovarian cell growth and steroid secretion.

A cultured rat ovarian cell line (31 A-F(2)) was used to study the effect of growth factors (epidermal growth factor [EGF] and fibroblast growth factor [FGF]), a survival factor (ovarian growth factor [OGF]), a hormone (insulin), and an iron-binding protein (transferring) on cell proliferation and steroid production under defined culture conditions. EGF and insulin were shown to be mitogenic (half-maximal response at 0.12 nM and 0.11 muM, respectively) for 31A-F(2) cells incubated in serum-free medium. EGF induced up to three doublings in the cell population, whereas insulin induced an average of one cell population doubling. FGF, OGF, and transferrin were found not to have any prominent effect on cell division when incubated individually with 31A-F(2) cells in serum-free medium. However, a combination of EGF, OGF, insulin, and transferrin stimulated cell division to the same approximate extent as cells incubated in the presence of 5 percent fetal calf serum. EGF or insulin did not significantly affect total cell cholesterol levels (relative to cells incubated in serum-free medium) when incubated individually with 31A-F(2) cells. However, cell cholesterol levels were increased by the addition of OGF (250 percent), FGF (370 percent), or a combination of insulin and EGF (320 percent). Progesterone secretion from 31A-F(2) cells was enhanced by EGF (25 percent), FGF (80 percent), and insulin (115 percent). However, the addition of a mitogenic mixture of EGF, OGF, insulin, and transferrin suppressed progesterone secretion 150 percent) below that of control cultures. These studies have permitted us to determine that EGF and insulin are mitogenic factors that are required for the growth of 31A-F(2) cells and that OGF and transferrin are positive cofactors that enhance growth. Also, additional data suggest that cholesterol and progesterone production in 31A-F(2) cells can be regulated by peptide growth factors and the hormone insulin.

Animals↗
PubMed1979

Physiological and behavioral effects of chronic exposure to 2450-MHz microwaves.

Long-Evans male adult rats were exposed for sixteen weeks to 2450-MHz CW microwaves at an average power density of mW/cm2. The resulting dose rate was 1.23 (+/- 0.25SEM) mW/g. The animals were exposed eight hours a day, five days a week, for a total of 640 h in a monopole-above-ground radiation chamber while housed in Plexiglas holding cages. Daily measures of body mass and of food and water intakes indicated no statistically significant effects of microwave irradiation. Biweekly stabilimetric tests immediately after exposure revealed a significant depression of behavioral activity by 15 microwave-exposed rats as compared with 15 sham-exposed animals. Measures of locomotor activity based on revolutions of a running wheel, which were obtained during 12-h periods between each 8-h exposure, showed no significant effect of irradiation. Blood sampled after 2, 6, 10, and 14 weeks of exposure indicated slight alterations of sulfhydryl groups, and of red and white blood-cell counts. Measures of levels of 17-ketosteroids in urine at weeks 1, 5, 9, and 12 of exposure, and mass of adrenals, heart, and liver at the end of the sixteen-week period of exposure, revealed no indications of stress.

Animals↗
PubMed1978

Epicanthus and epiblepharon.

There are four recognized types of epicanthus: epicanthus supraciliaris, epicanthus palpebralis, epicanthus tarsalis, and epicanthus inversus. Epiblepharon is a congenital anomaly that may appear in upper or lower eyelids. In the lower lids it tends to regress spontaneously and must be differentiated from congenital entropion, because treatment of the two conditions is not the same. Epiblepharon is considered herein with epicanthus because of similarity in treatment, especially in the case of epicanthus tarsalis. Epiblepharon of the upper eyelids may be considered to be essentially an exaggeration of epicanthus tarsalis. Epicanthus tarsalis and epiblepharon of the upper eyelids are treated by making a new fold in the upper lid and performing a V-Y plasty at the inner canthus. Epiblepharon of the lower lid is similarly treated if it does not spontaneously regress.

Blepharoptosis↗
PubMed1978

Instrumentation for monitoring oxygen consumption using a replenishment technique.

An instrument to measure patient oxygen consumption simply and accurately has been built using a replenishment technique. Oxygen is added to the patient's exhaled gas until its oxygen concentration is the same as the oxygen concentration of the inhaled gas. The rate at which oxygen is added is a measure of the patient's oxygen consumption. Bench tests show that oxygen consumption is measured with an accuracy of +/- 2.3 percent and human tests show an accuracy of +/- 5.9 percent. The instrument interfaces easily with a mechanical ventilator and is readily accepted by the clinician.

Humans↗
PubMed1976

A microelectronic pH sensor.

This paper presents preliminary data on a new integrated circuit microelectronic pH sensor. The device is extremely miniaturized by the use of integrated circuit technology, and uses the intrinsic hydrogen ion selective properties of the gate insulator material. In order to make the device compatible with aqueous solution monitoring, the silicon dioxide-silicon nitride gate insulator structure is used. The integrated circuit chip was designed, processed, and packaged by a variety of techniques which protect all metal parts from the aqueous solution. Test data are reported on leakage current, sensitivity, reproducibility, linearity, stability, response time, and life. The results indicate that this type of pH sensor may have many significant advantages for biomedical research and application.

Biomedical Engineering↗
PubMed1975

Structure of the muscles of the upper eyelid.

The human and monkey orbicularis muscle has fibers that are more uniform in size and structure than those of rectus muscles. They have distinct myofibrils, a moderate number of mitochondria, and a well-developed transverse T-tube system. The levator muscle also has relatively uniform fibers, but the myofibrils are less distinct than those of the orbicularis. Especially noteworthy is the unusual arrangement whereby Muller muscle arises directly from the undersurface of the levator muscle, causing an intimate intermingling of smooth and striated fibers. Muller muscle then inserts on the tarsus, whereas the levator muscle extends by an aponeurosis into the septa of the orbicularis muscle. In surgical specimens from patients with ptosis, the levator fibers show varying degrees of abnormality, whereas Muller fibers are normal.

Adolescent↗
PubMed1975

Trancutaneous determination of aortic blood-flow velocities in man.

A transcutaneous ultrasonic Doppler technique for measurement of aortic blood-flow velocities has been developed and compared to more established techniques in order to evaluate its potential usefulness. It is possible by this method to quantitate blood velocity in both the ascending aorta and the aortic arch with ease and reliability. Ultrasonic access to the aorta from the suprasternal notch proved adequate in more than 90 per cent of the normal subjects examined. If further clinical trials prove as encouraging, this technique may be of significant value for patient monitoring and cardiac diagnosis.

Aorta↗