Alpha gliadin antibody levels: a serological test for coeliac disease

The diagnostic value in coeliac disease of circulating antibodies to casein, crude gliadin, and alpha gliadin was assessed using an adaption of the enzyme linked immunosorbent assay system. alpha Gliadin was the only antigen which consistently separated 26 patients with untreated coeliac disease from 26 normal controls and 13 patients with chronic inflammatory bowel disease. The mean assay index for the 26 patients was 3.1 (SD 1.2) compared with 1.05 (0.5) for the normal controls and 1.1 (0.6) for patients with chronic inflammatory bowel disease. The alpha gliadin antibody levels of six patients with coeliac disease who had maintained a gluten free diet for at least two years were not significantly higher than normal (1.0 (0.4)). The validity of the test was determined in 90 consecutive patients who were being investigated for the presence of coeliac disease. Levels of alpha gliadin antibody were raised in 36 out of 44 patients found to have histologically proved coeliac disease and in six out of 46 subjects whose jejunal mucosa was normal. Serial alpha gliadin concentrations were measured in 12 patients with coeliac disease who had repeat jejunal biopsies performed six months after starting a gluten free diet. The levels of antibody fell in seven of the eight patients whose jejunal mucosa improved on maintaining the diet. They remained raised in four patients who did not adhere to the diet and whose mucosa did not improve. Although a test measuring alpha gliadin antibodies is unlikely to replace jejunal biopsy in the diagnosis of coeliac disease it may be useful in screening for the disease among outpatients.

Definition of four HLA-A2 subtypes by CML typing and biochemical analysis

The population of HLA-A2-positive individuals, currently considered serologically homogeneous, can be divided into three subtypes on the basis of antigen recognition by various HLA-A2-specific cytotoxic T lymphocytes (CTLs). When these three types of HLA-A2 antigens were analyzed biochemically, they were found to be distinct. Isoelectric focusing (IEF) of HLA antigens digested with neuraminidase (NANAse) suggested that the difference(s) reside in the polypeptide backbone of the HLA-A2 heavy chain. Biochemical analysis distinguishes three distinct categories of HLA-A2 antigens: (1) a major subtype, designated HLA-A2.I, (2) a minor subtype, designated HLA-A2.II, possessing a more basic isoelectric point (IEP) and (3) a minor HLA-A2 subtype more acidic in its IEP than HLA-A2.I, designated HLA-A2.III. A fourth HLA-A2 subtype could be defined by discordance between cell-mediated lympholysis (CML) typing and biochemical analysis. The latter HLA-A2 antigen was defined as a variant by CTL, but was biochemically indistinguishable from the major subtype HLA-A2.I.

A chemiluminescence assay specific for the microsomal metabolite, benzo[a]pyrene-7,8-dihydrodiol

It is possible to assay for trans-7,8-dihydroxy 7,8-dihydrobenzo[a]-pyrene (BP-7,8-dihydrodiol) in complex metabolite mixtures produced during microsomal metabolism of benzo[a]pyrene (BP) because only the BP-7,8-dihydrodiol metabolite will produce significant chemiluminescence (CL) in the NaOCl-H2O2 singlet oxygen-generating system. The limiting CL sensitivity is 30 pmol in a 1-ml CL reaction mixture. CL assays for BP-7,8-dihydrodiol in microsomal reaction solutions gave concentrations identical with those determined by calibrated high-performance liquid chromatography.

Anterior to posterior variations in the concentration of somatostatin-like immunoreactivity in human basal ganglia

Serial coronal sections were cut from frozen right cerebral hemispheres from five normal human brains. From each section samples of caudate nucleus, putamen, internal and external globus pallidus and substantia nigra were removed. Sampling was such that the entire structure was removed from each slice. The concentration of somatostatin-like immunoreactivity, expressed as units per mg protein, was found to vary between nuclei, and to vary along the anterior to posterior axis of some nuclei. Highest concentrations were found in the caudate nucleus, with the head and tail containing greater amounts than the body. The high concentrations in the head of the caudate may be due to contamination of samples of this region with adjacent nucleus accumbens. In a separate series of cases, the nucleus accumbens was shown to be considerably higher concentrations of somatostatin-like immunoreactivity than the head of the caudate. Concentrations in the putamen tended to decrease along the anterior to posterior axis. In the external globus pallidus, levels of somatostatin-like immunoreactivity showed the most striking changes along the anterior to posterior axis, rising 2.5 fold in the first three samples, and then falling 4 fold in the more posterior sections. The internal globus pallidus had generally lower concentrations, and these varied in a pattern opposite to that in the external globus pallidus. Levels in the substantia nigra were low compared to those in caudate and putamen.

Chronic middle ear disease and auditory perceptual deficits: is there a link?

Data are presented indicating a correlation between chronic recurrent otitis media of early childhood and in increased likelihood of subsequent auditory processing deficits in a group of children referred for evaluation of impaired learning. Helpful appendices are added for a better understanding a central auditory processing skills.

CELL DOUBLING TIME IN THE APICAL MM OF ELONGATING LATERAL ROOTS OF VICIA FABA L

Cell doubling time was determined in several ways in the apical mm of newly emerged, 0·2, 1 and 4 cm long lateral roots of Vicia faba L. and in every case it tended to decrease with increase in root length. Similar values were obtained in the roots of each length investigated when cell doubling time was calculated from the rate of passage of cells into the period of DNA synthesis (S) in both control and colchicine treated roots and from the rate of accumulation of cells in metaphase in the presence of colchicine, assuming cell number increased exponentially, i.e. colchicine had not affected the rate of entry of cells into mitosis or S during the 3 to 6 h period over which measurements were taken. A discrepancy was found, however, between the values determined for cell doubling time obtained from these rates and those calculated on the basis of the method devised by Evans and his co-workers (Evans, Neary and Tonkinson, 1957). Possible reasons for such a discrepancy are discussed.