Search

The proportion of sickle haemoglobin (HbS) was determined in 170 sickle-cell-trait individuals; 75 (44.1%) individuals had HbS% > 38%, 54 (31.8%) had HbS% between 31% and 38% and 41 (24.1%) had HbS% < 31%. There was positive correlation between HbS% and haemoglobin concentration, packed cell volume, mean corpuscular haemoglobin, mean corpuscular volume and target cell percentage. Multiple regression analysis indicated that measurement of haemoglobin concentration, mean corpuscular haemoglobin and target cell percentage could be used to predict the HbS%.

Ulceration of the large intestine, induced in New Zealand white rabbits by the administration of 1% w/v degraded carrageenan for periods of up to nine weeks, was studied by a combination of histochemical and chemical procedures for the identification of O-acylated sialic acid. The onset of the disease was rapid, visible faecal blood being observed within five days. Caecal ulceration was diffuse throughout the mucosa being more prominent and frequent on the transverse folds. In some cases large, discrete ulcers were observed in the rectal portion of the lower colon, while in a small number of cases there were ulcers at the caecal end of the upper colon. The ulceration was characterized by oedema, congestion, haemorrhage, inflammation and mucosal ulceration. The inflammatory exudate consisted of macrophages, lymphocytes, a few plasma cells and, in animals treated for a long period, aggregates of eosinophils. The ulceration was associated with a marked reduction in the proportion of the caecal epithelial glycoprotein sialic acids which were neuraminidase-resistant and/or substituted in the side chain. Histochemical studies indicated that changes in side chain substitution were more marked at the margins of the ulcers and could be observed in sections of colon that showed no evidence of ulceration.

Rabbits fed freely with a 1% aqueous solution of degraded carrageenan developed a progressive colitis characterized after five days by severe inflammation and mucosal ulceration of the caecum. Histochemical and chemical studies indicated that there was a marked reduction in intracellular mucin and in the proportion of the epithelial glycoprotein sialic acids with substituents in the side chain and at position C4. Changes in the O-acylated sialic acids occurred rapidly and, apparently, prior to either mucosal ulceration or a significant inflammatory response. Following the removal of carrageenan from the diet, there was evidence of progressive healing characterized by re- epitheliazation and a reduction in the inflammatory response until, at 12 days, the mucosa was comparatively normal. Healing was accompanied by an apparent increase in intracellular mucin and in the proportion of the epithelial glycoprotein sialic acids with substituents in the side chain and at position C4. Animals sacrificed 20 days after withdrawal of the carrageenan showed a renewal of ulceration characterized by an active inflammatory process, congestion, haemorrhage, and an inflammatory exudate consisting of a massive aggregation of eosinophils together with lymphocytes and plasma cells. This was accompanied by a reduction in the proportion of side chain and C4 substituted sialic acids.