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Biomedical subjects

J M Scott

Publications and source records attributed to J M Scott.

At least 199 records · Page 11Linked to original sources
PubMed1975

Nutritional stability of various naturally occurring monoglutamate derivatives of folic acid.

The nutritional stabilities of four major dietary folates were studied as their corresponding monoglutamates and were compared to pteroylglutamate (folic acid) itself. The study of the monoglutamyl rather than polyglutamyl forms was justified since the former are formed during the course of digestion and also addition of extra glutamyl residues is unlikely to affect the types of nutritional instability associated with these derivatives. Since ability to support growth in Lactobacillus casei is known to reflect nutritional activity in man this organism was used in the stability studies. It was found that pteroylglutamate and 5-formyltetrahydropteroylglutamate had nutritional stabilities of the order of weeks although the stability of the former was decreased by phosphate. Surprisingly 10-formyltetrahydropteroylglutamate was nutritionally more stable than expected, possibly due to its conversion to the more stable oxidized 10-formylpteroylglutamate or to the reduced 5-formyl derivative. In contrast 5-methyltetrahydropteroylglutamate was much less stable nutritionally than expected.Unsubstituted tetrahydropteroylglutamate was most unstable nutritionally but in contrast to the other derivatives examined it was more stable under acidic than basic conditions. Ascorbate was found to be a far superior stabilizing agent than 2-mercaptoethanol at comparable concentrations.

Ascorbic Acid↗
PubMed1975

Oedema of the umbilical cord and respiratory distress in the newborn.

Oedema of the umbilical cord, defined as visible oedema in a cord wish a minimal cross sectional area of 1-3 cm-2, is found in 10 per cent of deliverieo. It is seen more frequently in cetain complications of pregnancy such as abrupti placentage, maternal diabetes, macerated intrauterine death and in conditions affectint the infant including prematurity, rhesus isoimmunization, respiratory distress syndrome (RDS) and transient respiratory distress (TRD). There is a higher incidence in infants delivered by Caesarean section. There is no significant association between cord oedema and either fetal distress or neonatal asphyxia nor is there any correlation with maternal hypertension or oedema. The mechanism of production of the odema is discussed; low oncotic pressure, raised hydrostatic pressure in the placenta and umbilical cord, and an increase in total water in the feto-placental unit are considered. The presence of oedema of the cord may reflect similar changes in the lungs which antenatally predispose aninfant whose pathway for production of surfactant is immature to develop RDS and the mature infant to develop TRD. The value of cord oedema as a warning sign is stressed.

Abruptio Placentae↗
PubMed1974

Studies on derivation of transcobalamin 3 from granulocytes. Enhancement by lithium and elimination by fluoride of in vitro increments in vitamin B12-binding capacity.

Unsaturated vitamin B(12)-binding capacity (UBBC) of human serum is not reproducibly measurable because it increases variably in vitro in relation to time, temperature, and, in the case of plasma, anticoagulant present before removal of cells. This variable increase proved to be due to variable release in vitro of transcobalamin III (TC III) from granulocytes. UBBC increase was greatest (up to fourfold normal levels) in the presence of lithium, which is the heparin salt used in many laboratories doing UBBC studies. In vitro increase was least when blood was collected in EDTA at 0 degrees C and immediately centrifuges at 0 degrees C (T(0) sample); results equivalent to T(0) were obtained at room temperature even after several hours delay when 47 mM fluoride was present; either cold temperature or 47 mM fluoride appeared to prevent TC III release from granulocytes. The measured levels of the three transcobalamins with T(0) methods of collection, which presumably reflect most closely the in vivo circulating levels, suggest that TC I and TC III in normal plasms are of the same order of magnitude and together normally comprise less than 10% of the UBBC. Approximately 90% of the UBBC content of sonicates of peripheral blood granulocytes and of bone marrow aspirates of normal individuals appears to be TC III, with the rest being TC I. Thus, normal myelocytes, like normal granulocytes, appear to contain mainly TC III. No TC II was present in any of the sonicates. The general practice in most laboratories has been to determine serum UBBC. Because in vitro increments of up to 119% were found to occur in serum, this practice should be replaced by collection using methods that prevent such increments. Blood collected in EDTA-47 mM NaF had a stable, reproducible UBBC with no significant in vitro increment with time.EDTA-NaF UBBC was 640+/-168 (range 380-921 pg B(12) bound/ml plasma) for 12 normal adult men and 809+/-232 (range 505-1208) for normal adult women. It presumably approximates circulating UBBC and is substantially below the serum UBBC mean of 935+/-262 (range 611-1506 for the same 12 men) and 1273+/-355 (range 811-2306 for the same 10 women).

Adult↗