Gordon Dale

An improved method for the determination of acetylcholinesterase activity in rectal biopsy tissue from patients with hirschsprung's disease

A method is described for the assay of acetylcholinesterase in tissue samples using the selective cholinesterase inhibitor, lysivane (10-(alpha-diethylaminopropyl) phenothiazine hydrochloride). Significantly increased enzyme activity is found in rectal biopsy specimens from patients with Hirschsprungs disease (p less than 0.001) indicating the diagnostic usefulness of the assay.

DIAGNOSTIC VALUE OF RECTAL MUCOSAL ACETYLCHOLINESTERASE LEVELS IN HIRSCHSPRUNG'S DISEASE

Acetylcholinesterase (AChE) activity was measured in rectal biopsy specimens obtained from 68 children aged between 2 days and 14 1/2 years in whom Hirschsprungs disease was suspected. The diagnosis was subsequently established in 12; in these, the mean AChE activity was found to be 30.5 X 10(-7) units/g tissue (range 16.9 to 63.0). The 56 non-Hirschsprung cases had a mean of 5.0 X 10(-7) units/g tissue (S.D. 2.2), the highest value in this group being 10.9. The results were unaffected by age, sex, nature of biopsy procedure, or the presence of blood. It is suggested that the assay of AChE activity in rectal biopsy material is a simple and quick procedure that is useful in the diagnosis of Hirschsprungs disease.

DIAGNOSIS OF HIRSCHSPRUNG'S DISEASE BY QUANTITATIVE BIOCHEMICAL ASSAY OF ACETYLCHOLINESTERASE IN RECTAL TISSUE

Acetylcholinesterase activity was measured in rectal-biopsy specimens obtained from nineteen children. Seven children in whom the diagnosis of Hirschsprungs disease was established were found to have a significantly higher enzyme activity than the twelve in whom this diagnosis was excluded. The estimation may prove to be of value in the diagnosis of Hirschsprungs disease.

Molecular forms of acetylcholinesterase in Hirschsprung's disease

We describe changes in the levels of different molecular forms of acetylcholinesterase in four cases of Hirschsprungs disease linked to the transition from aganglionic to normal bowel. In addition changes in a control case with histologically normal bowel is reported. In all patients with Hirschsprungs disease there is a marked increase in the level of the tetrameric form of the enzyme in the aganglionic region. The changing level of this form of the enzyme correlates well with the histochemical appearance suggesting that quantitative measurement of this molecular species might form the basis of an improved diagnostic test for the disease.

Plasma amino acid changes in the postsurgical newborn during intravenous nutrition with a synthetic amino acid solution.

Plasma amino acid concentrations during the therapeutic use of a crystalline amino acid solution are presented and discussed. In an attempt to avoid potentially dangerous hyperaminoacidemia, a maximum infusion rate of 350 mg nitrogen/kg/day was chosen. This resulted in the majority of the amino acids remaining within two standard deviations of normal mean,3 although levels of aspartate, glutamate, proline, valine, and isoleucine are in excess of this limit. No amino acid level is as much as one standard deviation below the mean, the lowest in this respect being lysine. A moderate increase in nitrogen provision is probably desirable to improve weight gain, but this solution would result in undesirable increases in these amino acid concentrations.

A 7-year study of the diagnostic value of rectal mucosal acetylcholinesterase measuremnt in Hirschsprung's disease

Over a 7-year period, 213 children were investigated for failure to pass meconium or for chronic constipation. Of these, 45 were confirmed to have Hirschsprungs disease; in this group the acetylcholinesterase activity in rectal biopsy tissue was significantly increased (P less than .001; mean 34.2, 95% confidence limits, 8.6 to 95.2) units g-1 when compared with the non-Hirschsprungs group (mean 6.6, 95% confidence limits, 2.0 to 15.9 units g-1). By expressing the acetylcholinesterase activity as a percentage of the total cholinesterase activity it is possible to compensate for evaporative weight loss and the combination of these two measurements improves the overall diagnostic value of the test. There were no false-positive and only two false-negative results.

Biochemical consequences of intravenous nutrition in the newborn.

Publisher Summary The management of severe nutritional failure by the development of intravenous infusions that provide not only sufficient calories for energy requirements, but also amino acids and other nutrients is known variously as intravenous nutrition, parenteral nutrition, intravenous hyperalimentation, parenteral feeding, and hyperalimentation. The increasing use of intravenous nutrition has revealed a variety of complications. Many of the problems encountered are associated with the intravenous catheter and the high sepsis rate is a major cause of concern. A number of metabolic complications are also reported. The newborn infant, with its relatively high metabolic rate, its requirements for growth, and its limited calorie stores is particularly susceptible to the effects of starvation. Glucose, fructose, alcohols, fat emulsions, and amino acid are the energy-providing intravenous infusate and their effects are discussed in the chapter. Alterations in hydrogen ion regulation may be encountered in infants receiving total intravenous nutrition. Disorders of hydrogen ion regulation such as hyperosmolar acidosis, lactic acidosis, hypophosphatemia, essential fatty acids, and trace element deficiencies are also discussed.

SCREENING FOR NEUROBLASTOMA

Some natural occurring flavonoids have weak antithrombotic properties and several flavonoids inhibit aspects of arachidonic acid metabolism and alter platelet, neutrophil, and lymphocyte function. FAA has been reported to enhance natural killer cell activity in mice,3A and Smith et al5 found that FAA induces haemorrhagic necrosis of transplantable cancers in mice. We have noted haemorrhage at sites of tumour implantation in rats given a single non-toxic dose of FAA (1-5 g/m2). We suspect that ’FAA prevents the growth of transplanted tumours in mice primarily by altering a platelet function needed for establishment of tumour growth. Because of the effect of FAA upon ristocetin-induced platelet agglutination, FAA may inhibit platelet adhesion and/or platelet plug formation mediated by von Willebrand factor. Its possible role as an anticancer (antimetastatic) agent apart, FAA may prove useful in the prevention and/or management of other diseases in which platelet adhesion or aggregation plays a part.

The characterisation of molecular forms of acetylcholinesterase in Hirschsprung's disease

Aganglionic rectal tissue from patients with Hirschsprungs disease contains four forms of acetylcholinesterase; the major component has a sedimentation coefficient in the region of 10.0S. Results from gel filtration confirm these findings and, when used in conjunction with the sedimentation data, allow the determination of the molecular mass of these forms. The four species of acetylcholinesterase include: monomer, G1, 74 kDa dimer, G2, 131 kDa; tetramer G4, 275 kDa and an asymmetric form, A12, 811 kDa. Evidence is provided which shows that the major form, G4 interacts with the detergent Triton X-100. Selective measurement of G4-AChE using a suitable assay may provide the basis for improving the existing means of diagnosis of Hirschsprungs disease.