Biomedical subjects

C Glass

Publications and source records attributed to C Glass.

43 records · Page 3Linked to original sources

PubMed1985

Uptake of high-density lipoprotein-associated apoprotein A-I and cholesterol esters by 16 tissues of the rat in vivo and by adrenal cells and hepatocytes in vitro.

The uptake of high-density lipoprotein (HDL)-associated apolipoprotein A-I and cholesterol esters was estimated in 16 tissues of the rat using rat HDL doubly labeled with nondegradable tracers; covalently attached 125I-tyramine-cellobiose traced apo-A-I, and [3H]cholesteryl linoleyl ether traced cholesterol esters. Both labels remained associated with the HDL fraction in the plasma, adequately traced their unlabeled counterparts, and were well trapped at their sites of uptake. Cholesteryl ether was taken up at a greater fractional rate than apo-A-I by adrenal, ovary, and liver: 7-fold, 4-fold, and 2-fold greater, respectively. The rates of uptake of cholesteryl ether and apo-A-I were about equal in the other tissues (except kidney). The disproportionate uptake of HDL cholesteryl ether relative to HDL apo-A-I was also observed in primary cultures of rat adrenal cells and hepatocytes. Uptake of both moieties in both cell types showed saturability. Both the absolute rate of uptake of [3H]cholesteryl ether and the ratio of ether uptake to apo-A-I uptake were greater in adrenal cells than in hepatocytes, consonant with the in vivo observations. Very similar results were obtained using HDL biologically labeled with [3H]cholesterol esters. The disproportionate uptake of [3H]cholesteryl ether was not significantly decreased by depletion of apo-E from the HDL nor by reductive methylation of the apo-E to block its recognition by receptors. However, apo-A-I uptake was decreased, suggesting that apo-E mediates the uptake of particles containing apo-A-I but does not contribute to the disproportionate uptake of [3H]cholesteryl ether.

Adrenal Glands↗

PubMed1985

Familiarity, spatial frequency and task determinants in processing laterally presented representations of faces.

Laterally presented portraits were judged as familiar or unfamiliar (Experiments 1 and 2), or were processed in a target matching task (Experiment 3). Exposure durations (100 or 190 msec.) were varied between (Experiments 1 and 2) or within (Experiment 3) the experiments. Clear and degraded faces appeared either randomly intermingled (Experiment 1) or in blocked sequences (Experiments 2 and 3). In Experiment 3 familiar and unfamiliar stimuli also appeared in blocks. Stimulus degradation was achieved by coarse quantization of the image into blocks, so replacing relevant high-spatial-frequencies (the features) by spurious information, preserving only the original lower-spatial-frequency components. Left hemisphere mediation was strongest and most consistent with long exposures and random sequences of clear and degraded stimuli. Right hemisphere mediation tended to appear with shorter exposures and degraded stimuli presented in blocks. Though the interactions were often complex, the general pattern of results was consistent with the analytic-holistic processing dichotomy.

Discrimination Learning↗

PubMed1985

Sequence and expression of a human type II mesothelial keratin.

Using mRNA from cultured human mesothelial cells, we constructed bacterial plasmids and lambda phage vectors that contained cDNA sequences specific for the keratins expressed in these cells. A cloned cDNA encoding keratin K7 (55 kD) was identified by positive hybrid selection. Southern Blot analysis indicated that this sequence is represented only once in the human genome, and Northern Blot analysis demonstrated that the gene encoding K7 is expressed in abundance in cultured bronchial and mesothelial cells, but only weakly in cultured epidermal cells and not at all in liver, colon, or exocervical tissue. The predicted amino acid sequence of this keratin has revealed a striking difference between this keratin and the type II keratins expressed in epidermal cells: whereas all of the epidermal type II keratins thus far sequenced have long nonhelical termini rich in glycine and serine, this mesothelial type II keratin has amino and carboxy terminal regions that are unusually short and lack the inexact repeats of glycine and serine residues.

Amino Acid Sequence↗

PubMed1984

Lipoprotein synthesis and secretion by cultured rat hepatocytes. Parallel inhibition of secretion of VLDL, HDL and albumin by monensin.

The biosynthesis and secretion of very-low-density lipoproteins (VLDL) and high-density lipoproteins (HDL) by cultured normal rat hepatocytes was investigated with particular emphasis on its modification by monensin. This acidic ionophore coordinately inhibited the rates of secretion of the several VLDL apolipoproteins and the VLDL lipids, suggesting an effect late in the process of biosynthesis and secretion, probably at the stage of exiting from the Golgi apparatus. The secretion of immunoreactive albumin into the medium was comparably inhibited, implying that the pathway and mechanisms involved in albumin secretion may be closely similar to those for VLDL synthesis and secretion. Secretion of phospholipids and of apolipoproteins E and A-I in the HDL fraction increased progressively with time over 18 h in control incubations but was strongly inhibited by monensin. During extended incubation with monensin at high concentrations (10 microM), there was a net release to the medium of a number of hepatocyte proteins, including some that comigrated with apolipoprotein A-I and apolipoprotein C, making it appear that monensin increased the secretion of these apolipoproteins. However, using labeled amino acids, it was shown by autoradiography and by immunoprecipitation that secretion of newly-synthesized, radioactive apolipoprotein A-I and apolipoprotein C was actually inhibited by monensin. These results are compatible with the conclusion that HDL synthesis and secretion may occur by mechanisms closely related to those for synthesis and secretion of albumin and VLDL.

Amino Acids↗

PubMed1983

Dissociation of tissue uptake of cholesterol ester from that of apoprotein A-I of rat plasma high density lipoprotein: selective delivery of cholesterol ester to liver, adrenal, and gonad.

The metabolic fate of homologous high density lipoprotein (HDL) was studied in the rat, tracing the apoprotein A-I (apo A-I) and cholesterol ester moieties simultaneously. The apo A-I was labeled with covalently linked 125I-labeled tyramine cellobiose, which accumulates in the cells degrading the apoprotein; [3H]cholesterol ethers, which cannot be hydrolyzed or mobilized after uptake, were incorporated into the lipid core of reconstituted HDL to reflect the fate of the cholesterol esters. Several lines of evidence, including direct comparison with biologically labeled HDL, are presented to support the validity of this approach. The liver was the major organ of cholesterol ether uptake, accounting for 65% of the total; the adrenal gland and ovary were the most active organs per gram (wet) of weight. Uptake of cholesterol ether was 7-fold greater than that of apo A-I in adrenal, 4-fold greater in the ovary, and greater than 2-fold greater in the liver. The remaining tissues took up apo A-I and cholesterol ethers at more nearly equal rates. Transfer of HDL-associated cholesterol ethers and 125I-labeled apo A-I to other lipoprotein fractions was not observed; thus, the results reflect direct uptake from HDL itself. Whereas uptake of low density lipoprotein appears to involve endocytosis of intact particles, uptake of HDL in at least some rat tissues involves additional, more complex, transfer mechanisms.

Adrenal Glands↗

PubMedDate not supplied

Pressure support ventilation: reducing the work of breathing during weaning.

Pressure support ventilation decreases the work of breathing by providing the patient with positive airway pressure during the inspiratory phase. The use of this type of ventilatory support is likely to increase over the next few years for patients, especially during the weaning period. By understanding how pressure support ventilation works and what patient parameters need to be monitored, the critical care nurse can help patients decrease respiratory muscle fatigue during weaning and thus decrease the weaning time for these patients.

Critical Care↗

PubMedDate not supplied

Nurses' ability to achieve hyperinflation and hyperoxygenation with a manual resuscitation bag during endotracheal suctioning.

OBJECTIVE: To examine nurses' ability to deliver 1.5 times the ventilated tidal volume at 100% FIO2 with a manual resuscitation bag during endotracheal suctioning. DESIGN: Prospective, descriptive. SETTING: Six adult critical care units in a large university-affiliated medical center. SUBJECTS: One hundred nurses randomly selected from the six adult intensive care units. OUTCOME MEASURES: Nurses' manual resuscitation bag delivery of tidal volume and oxygen, as well as bagging rate, number of breaths delivered, and number of suction catheter passes performed. Patients' heart rate, mean arterial pressure, and arterial oxygen saturation. RESULTS: The mean FIO2 delivered was 0.71 (range 0.24 to 0.97). Oxygen liter flow and nurses' delivered minute ventilation predicted 24% of the variance in FIO2 delivered. Mean bagging rate was 31 compressions per minute. The mean volume per breath delivered was 626 cc, which resulted in achievement of 57% of the standard (1128 cc). Volume achieved was related to patient lung compliance, but not related to nurses' experience, unit of employment, hand strength, or size. CONCLUSIONS: Nurses observed were unable to meet the standard for volume or oxygen delivery. However this did not affect the patient's heart rate, mean arterial pressure, or SaO2.

Adult↗