Adult Intolerance Research Articles

Biogenesis of intestinal lactase-phlorizin hydrolase in adults with lactose intolerance. Evidence for reduced biosynthesis and slowed-down maturation in enterocytes.

Enzymatic activity, biosynthesis, and maturation of lactasephlorizin hydrolase (LPH) were investigated in adult volunteers with suspected lactose intolerance. Mean LPH activity in jejunal biopsy homogenates of these individuals was 31% compared to LPH-persistent individuals, and was accompanied by a reduced level of LPH-protein. Mean sucrase activity in individuals with low LPH was increased to 162% and was accompanied by an increase in sucrase-isomaltase (SI)-protein. Biosynthesis of LPH, SI, and aminopeptidase N (APN) was studied in organ culture of small intestinal biopsy specimens. In individuals with LPH restriction, the rate of synthesis of LPH was drastically decreased, reaching just 6% of the LPH-persistent group after 20 h of culture, while the rate of synthesis of SI appeared to be increased. In addition, maturation of pro-LPH to mature LPH occurred at a slower rate in LPH-restricted tissue. Immunoelectron microscopy revealed an accumulation of immunoreactive LPH in the Golgi region of enterocytes from LPH-restricted individuals and reduced labeling of microvillus membranes. Therefore, lactose intolerance in adults is mainly due to a decreased biosynthesis of LPH, either at the transcriptional or translational level. In addition, intracellular transport and maturation is retarded in some of the LPH-restricted individuals, and this leads to an accumulation of newly synthesized LPH in the Golgi and a failure of LPH to reach the microvillus membrane.

Bird-Egg Syndrome

87 adult patients from our allergy clinic were skin tested with budgerigar and canary feathers, hen's egg white and egg yolk and common inhalant allergens. Of 59 patients found to be atopic, 17 (29%) were concomitantly sensitized to bird dander and egg proteins, 10 of them being symptomatic to bird dander and/or egg exposure. All but 1 of the egg-symptomatic patients were exposed to pet birds. The patients with strong serological reactivity to bird antigens were also exclusively sensitized to egg proteins, in particular to livetins (water-soluble fractions of egg-yolk proteins). Extensive RAST-inhibition studies demonstrated identical patterns of cross-reactivity between bird dander and hen's egg proteins, livetins being the major cross-reacting antigens. This peculiar IgE-mediated allergy is designated as 'bird-egg syndrome'. It is suggested that egg intolerance in adults is mainly due to sensitization to egg-yolk livetins and can be provoked by inhalation of pet bird dander. Thus, it must be distinguished from the common egg-white allergy of atopic children. Our study further underlines the importance of respiratory sensitization in adult food allergy. On the other hand, exposure to cross-reacting antigens by ingestion might also influence the allergic manifestations to inhalant allergens.

Immunology of food intolerance in adults

Immunology of food intolerance in adults

Absence of milk antibodies in milk intolerance in adults.

Milk intolerance, characterized by abdominal bloating, cramps, and diarrhea one to four hours after ingestion of one or two glasses of milk occurs in at least 5% of the adult white population and in over 75% of healthy Negroes. 1 In the majority of these persons, the enzyme which digests the milk sugar, lactose, is deficient, and their symptoms can be reproduced by lactose administration. So-called cow's milk allergy does not seem to play a role in this syndrome since the patients have no other allergic disorders and they are able to tolerate small quantities of milk without symptoms. In the past, serum antibodies to cow's milk or milk fractions in the serum of infants and children had been considered evidence of hypersensitivity to milk, but it is now believed that a true causal relationship between milk antibodies and clinical disease has not been proven. 2 To obtain further information

Absence of Milk Antibodies in Milk Intolerance in Adults

Milk intolerance, characterized by abdominal bloating, cramps, and diarrhea one to four hours after ingestion of one or two glasses of milk occurs in at least 5% of the adult white population and in over 75% of healthy Negroes. 1 In the majority of these persons, the enzyme which digests the milk sugar, lactose, is deficient, and their symptoms can be reproduced by lactose administration. So-called cow's milk allergy does not seem to play a role in this syndrome since the patients have no other allergic disorders and they are able to tolerate small quantities of milk without symptoms. In the past, serum antibodies to cow's milk or milk fractions in the serum of infants and children had been considered evidence of hypersensitivity to milk, but it is now believed that a true causal relationship between milk antibodies and clinical disease has not been proven. 2 To obtain further information

Intestinal lactase deficiency and lactose intolerance in adults

Intestinal lactase deficiency and lactose intolerance in adults