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Biomedical subjects

M Sandler

Publications and source records attributed to M Sandler.

At least 271 records · Page 15Linked to original sources
PubMed1975

Monoamine metabolites and related compounds in human amniotic fluid: assay by gas chromatography and gas chromatography-mass spectrometry.

Some catecholamine metabolites and related compounds have been identified in amniotic fluid obtained by transabdominal amniocentesis at various stages of pregnancy, including 4-hydroxy-3-methoxymandelic acid, 4-hydroxy-3-methoxyphenylglycol, 4-hydroxy-3-methoxyphenylcetic acid, p-hydroxypheny lacetic acid, p-hydroxphenyllactic acid and N-benzoylglycine (hippuric acid). Analysis was by gas chromatography with electron capture detection and by gas chromatography-mass spectrometry. Two of these compounds were determined quantitatively, free 4-hydroxy-3-methoxphenylglycol and p-hydroxyphenllactic acid: the concentration of the former increased with advancing pregnancy and that of the latter tended to decrease. Conjugated 4-hydoxy-3-methoxyphenylglycol could not be determined with accuracy as appreciable amounts of the unconjugated compound were found in the snail extract used for enzymatic hydrolysis. Assay of 4-hydroxy-3-methoxyphenylglycol in amniotic fluid is likely to be of diagnostic importance in the prenatal diagnosis of congenital neuroblastoma. Although 4-hydroxy-3-methoxyphenylethanol, 3, 4-dihydroxymandelic acid and 3, 4-dihydroxyphenylacetic acid were specifically looked for in amniotic fluid, they could not be detected.

Amniocentesis↗
PubMed1975

The influence of nerve growth factor, potassium depolarization and dibutyryl (cyclic) adenosine 3',5'-monophosphate on explant cultures of chick embryo sympathetic ganglia.

Optimal nerve growth factor (NGF) and potassium concentrations for the culture of explants of single chick embryo sympathetic ganglia in Leighton tubes are described. NGF increases ganglionic monoamine oxidase (MAO; E.C.1.4.3.4) activity in a dose dependent fashion with maximum effects at a concentration of about 8 U/ml NGF. Peak activity compares closely with values seen in chick ganglia in vivo. Potassium-induced depolarization (45 mM K-+) also increases MAO activity; but the extent of the increase depends upon (NGF concentration, for there is little or no increase at high NGF concentrations. Dibutyryl adenosine 3',5'-cyclic monophosphoric acid (db cyclic AMP) can mimic the potassium-induced increase in MAO.

Animals↗
PubMed1975

The effect of hydrocortisone and adrenocorticotrophic hormone on monoamine oxidase and tyrosine hydroxylase in explant cultures of embryonic chick sympathetic ganglia.

Sympathetic ganglia from 13- to 15-day-old embryonic chicks were cultured for up to 2 days in Leighton tubes. The influence of hydrocortisone and ACTH added to the culture medium on the enzymes monoamine oxidase (MAO) and tyrosine hydroxylase was studied. Hydrocortisone (5 times 10(-5)M) had no effect on tyrosine hydroxylase but increased MAO activity by up to 46 percent over control values under conditions of low or zero nerve growth factor (NGF) concentration. ACTH also increased ganglionic MAO activity, the effect again depending on NGF concentration. This time the maximal response (an increase of 50 percent over controls) was seen at high NGF concentrations. This response was similar to the effect of 1 mM dibutyryl cyclic AMP, and was blocked by 1 times 10-5 M propranolol and 10 muM prostaglandin E(1). ACTH only slightly increased tyrosine hydroxylase activity and this effect was due to a small (18 percent) increase in sympathetic neurone number. Guanosine 5-diphosphate (0.5 mM) was found to increase tyrosine hydroxylase activity by 57 percent and this effect was blocked by the presence of ACTH.

Adrenocorticotropic Hormone↗
PubMed1975

Is there an increase in monoamine-oxidase activity in depressive illness?

In a group of depressed patients who had either been treated with or considered suitable for monoamine oxidase (M.A.O.) inhibitor therapy, a highly significant decrease in conjugated tyramine output was observed after an oral tyramine load compared with normal controls. However, there was no difference in conjugated isoprenaline output between the two groups after isoprenaline ingestion, even though this amine is almost solely metabolised by what is likely to be the same conjugation mechanism. Whilst some explanation in terms of altered gut motility is conceivable, it seems more likely that the apparent deficit in tyramine conjugation in depression represents an increase in functional M.A.O. activity. Consequently, this enzyme would metabolise a greater proportion of available amine, causing a proportionately large decrease in the smaller conjugate pool.

Administration, Oral↗
PubMed1975

Urinary phenolic acid and alcohol excretion in the newborn.

Mean urinary excretion values of some phenolic acids and alcohols have been measured by gas chromatography in 44 neonates (36 males, 6 females) during the first 2 days and days 3-7 of life, and the effect of prematurity and jaundice assessed. 4-Hydroxy-3-methoxymandelic acid (VMA) output rises immediately after birth in term but not in preterm infants. A similar increase in homovanillic acid (HVA) output was restricted to nonjaundiced term babies; in nonjaundiced preterm babies there was a steady rise during the first week. The ratio of HVA to VMA output was higher in these infants than in adults, suggesting a more rapid turnover of dopamine than adrenaline and noradrenaline. Unlike adult values, both HVA and VMA excretion values were directly related to urine volume, an observation perhaps related to renal immaturity. An unexplained reduction in HVA output in jaundiced as opposed to nonjaundiced infants was observed in the first 2 days of life. The ratio of 4-hydroxy-3-methoxyphenylglycol to VMA was about the same as in the adult. p-Hydroxyphenyl-lactic acid (p-HPLA), because of its superior stability, was measured in preference to p-hydroxyphenylpyruvic acid as an index of tyrosyluria. An output of 1 mg p-HPLA/24 h is proposed as the upper limit of normal. Prematurity was associated with a significant rise in p-HPLA output. A dramatic increase in excretion of this acid was noted in jaundiced, compared with nonjaundiced infants, presumably a manifestation of general enzyme immaturity.

Alcohols↗