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Biomedical subjects

B E Haskell

Publications and source records attributed to B E Haskell.

11 recordsLinked to original sources
PubMed1991

Complement component C1q activity and ascorbic acid nutriture in guinea pigs.

When guinea pigs are fed tissue-saturating amounts of ascorbate, C1q concentrations are significantly higher than in those animals fed only enough ascorbate for adequate growth and for the prevention of scurvy. C1q is the recognition protein of the classical complement pathway, a system of blood proteins that constitutes an important part of host defense against pathogens. The observed effect of ascorbate nutriture on C1q concentrations is consistent with the known role of ascorbic acid in hydroxyproline biosynthesis. C1q is a hydroxyproline-containing protein with structural similarities to collagen.

Analysis of Variance↗
PubMed1987

Effect of retinoic acid on nerve growth factor receptors.

Retinoic acid (RA), a naturally occurring metabolite of vitamin A, increased the number of receptors for nerve growth factor (NGF) in cultured human neuroblastoma cells (LA-N-1), as indicated by an immunofluorescence assay of cell surface receptors and by specific binding of 125I-NGF to solubilized receptors. Analysis of 125I-NGF binding showed that RA increased the number of both high affinity and low affinity receptors for NGF without affecting the equilibrium dissociation constants. Neurite outgrowth similar to that produced by NGF occurred following RA-treatment in LA-N-1 cells, in the SY5Y subclone of SK-N-SH human neuroblastoma cells and in explanted chick dorsal root ganglia (DRG). Whether morphological changes following RA treatment are directly related to the increase in NGF receptors is unknown. Data presented here are consistent with literature reports that RA modifies cell surface glycoproteins, including those that act as cell surface receptors for epidermal growth factor and insulin.

Cell Line↗
PubMed1987

The effect of vitamin C nutriture on complement component C1q concentrations in guinea pig plasma.

This study shows that guinea pigs fed 100 times the amount of vitamin C needed for growth and for prevention of scurvy have elevated levels of complement component C1q. C1q is a plasma protein rich in hydroxyproline, an amino acid whose biosynthesis requires ascorbate. C1q is essential for host defense against pathogens, both as a component of the classical complement pathway and as an opsonin in the phagocytosis process. We measured C1q in vitamin C-depleted guinea pigs that had been repleted for 4 wks with the following daily doses of ascorbate (mg/100 g body wt): 0.50 (suboptimal), 2.0 (adequate), 10 (ample) and 50 (tissue saturating). We measured C1q in three ways: indirectly by quantifying protein-bound hydroxyproline and directly by hemolytic assay and by immunodiffusion against anti-C1q. Regardless of the method, plasma C1q was 30-50% higher in animals fed tissue-saturating ascorbate than in those fed adequate or suboptimal amounts of the vitamin (p less than 0.05, one-way analysis of variance, least significant difference test). These data confirm and significantly extend earlier work that provided indirect evidence for a relationship between C1q and ascorbate nutriture in the guinea pig. They are consistent with a possible relationship between ascorbate nutriture and host defense.

Animals↗
PubMed1987

The subjective perception of workload in low-time private pilots: a preliminary study.

Control of pilot workload may prevent performance failure of VRF pilots in adverse weather. Measurement of workload and the prediction of performance failure are the first steps. Twelve low-time non-instrument rated pilots were progressively tasked with flight maneuvers under simulated instrument meteorological conditions to the point of performance failure. For each of 3 simulated flights, 14 maneuvers, presented in groups, were performed. Perceived workload was reported by the Subjective Workload Assessment Technique. We obtained 500 workload scores. Workload scores varied significantly between the groups of maneuvers. Instrument landing system approaches had the highest workloads, with descents the second highest. Workload scores were significantly higher when associated with performance failure. The Subjective Workload Assessment Technique proved to be a sensitive workload measure. It showed some promise as a predictor of performance breakdown.

Adult↗
PubMed1978

The neurotoxicity of valine deficiency in rats.

When valine, an essential amino acid, was withdrawn from the diet of weanling rats, the animals rapidly developed a unique pattern of neurological symptoms characterized by head retraction, staggering and aimless circling. At necropsy degenerative changes were most prominent in the neurons of the red nuclei, brain stem structures which modulate motor function. To explore the pathogenesis of the neurotoxicity associated with valine deficiency, we fed rats purified diets deficient in valine alone or in valine plus other branched chain and neutral amino acids, and we examined brain tissues by light microscopy. Motor disfunction and red nuclei damage occurred only in rats fed diets lacking valine alone and not in rats fed diets lacking all three branched chain amino acids. These results suggest that the neurotoxicity of valine deficiency results from amino acid imbalance rather than from lack of dietary valine per se.

Animals↗