Brain development in neonatal rats nursing asparagine-deprived dams.

A possible requirement for dietary asparagine during lactation was investigated by measuring any adverse effect of maternal asparagine deprivation on the body growth and brain development of nursing rat pups. Each dam was given 7 pups to nurse. Three groups of 5 dams each were deprived from the 1st (T1), 8th (T2), or 15th (T3) day of lactation until weaning (day 22); at weaning, the pups of each group weighed approximately 10% less than those of asparagine-fed controls. Brain development was also affected: the cerebra of T3 pups contained less cholesterol and cerebrosides than control pups, indicating decreased myelination. Both T2 and T3 pups required more trials in a water maze to acquire a learned behavior than control pups. T1, T2, and T3 pups also displayed higher seizure thresholds. The groups of pups whose brains contained the lowest amounts of myelin lipids (T3) were those who displayed the greatest deviation in behavior from the control pups. Thus, the development of neonatal rat brain is sensitive to even mild or transient forms of malnutrition, and a requirement for dietary asparagine during lactation seems evident.

Evidence for hydroxyacyl-ceramides and hydroxyacyl-cerebrosides in female rhesus monkey gingiva.

Materials believed to be hydroxyacyl-ceramides (HO-Cer) and hydroxyacyl-cerebrosides (HO-Ceb) have been analyzed by high performance liquid chromatography (HPLC) from the glycolipid components of six female rhesus monkey gingivae. These recovered materials show identical behavior by (HPLC) with authentic standards.

Gingival fluid fucose to protein ratios as indicators of the severity of periodontal disease.

Total fucose and protein was measured in gingival fluid samples collected from 16 human subjects. A significantly higher total protein concentration was found for the control (clinically normal) group when compared to the experimental (severe clinical inflammation) group. This is probably due to the higher gingival flow rate found in the experimental group. The total fucose analyses showed no statistical difference between both groups, but when fucose to protein ratios were studied, a significantly higher ratio was found for the experimental group when compared to the controls. This probably represents the breakdown of plasma and tissue glycoproteins which may occur as a result of inflammation.

An asparagine requirement in young rats fed the dietary combinations of aspartic acid, glutamine, and glutamic acid.

The effect of dietary asparagine on rat growth was investigated. Diets were formulated with L-amino acids so as to contain asparagine, aspartic acid, glutamine and/or glutamic acid in all possible combinations and then fed to weanling rats for 3 weeks. Of the four, only asparagine was found to be essential for optimal growth, and it was essential regardless of the presence or absence of any dietary combination of these related amino acids. In selected dietary groups, the unbound asparagine levels were measured in various tissues over an 8-day period. Muscle asparagine levels were reduced for asparagine-deprived animals over the entire period studied; brain levels were decreased only after 7 days of dietary depletion, while hepatic levels were unaffected by dietary asparagine deprivation. In a related series, animals were more drastically depleted of asparagine by combining dietary deprivation with asparaginase treatment, causing a rapid decrease in cellular concentration of asparagine, which affected protein and DNA synthesis for those organs undergoing hyperplastic growth. Thus, asparagine may be rate limiting to protein synthesis for this extreme case as well as during dietary asparagine deprivation, which also decreased intracellular levels of unbound asparagine and led to irreversible deficits in development.

Concentrations of asparagine in tissues of prepubertal rats after enzymic or dietary depletion of asparagine.

Growth of weanling rats was significantly depressed after 8 days of asparagine depletion produced by dietary means or by asparaginase treatment. Moreover, the concentration of free asparagine was significantly lowered in forebrain, skeletal muscle, liver, kidney, spleen and small intestines 3 h after an asparaginase injection, but remained lowered only in forebrain and skeletal muscle after 8 days of enzymic or dietary depletion of asparagine.