A 10-year-old boy with microcephaly, stunted growth, mental retardation, café-au-lait spots and immunodeficiency is described. An older brother of the patient had the same clinical symptoms and a more severe immunodeficiency. Cytogenetic studies in the proband revealed a typical form of chromosome instability with multiple rearrangements of chromosomes 7 and 14. Such abnormalities were also present, though in very low frequencies, in the father and three of the phenotypically normal sibs. The similarity of the symptoms in the two sibs, the close consanguinity of their parents and the results of the cytogenetic studies in the family favour the hypothesis that the disorder is an inherited one. The clinical features and the chromosome aberrations as present in the proband are usually found in chromosomal breakage syndromes, but it was possible to exclude each of the classical chromosomal breakage syndromes on clinical and/or cytogenetic grounds.

This study was undertaken to identify ecological factors that favour opportunistic pathogenic species in the subgingival microflora. In a first approach, human serum as a substitute for gingival exudate, was used for batch-wise enrichment of subgingival plaque. The microflora resulting after 5-6 enrichment steps consisted of black-pigmented and non-black-pigmented Bacteroides species, Peptostreptococcus micros and Fusobacterium nucleatum as the main organisms. It is noted that the same group of species was found to be enriched independent upon the origin of the subgingival plaque sample. It was suggested that these organisms are favoured by the increased flow of gingival exudate during inflammation. The consortium of organisms was capable of selective degradation of serum (glyco-)proteins. Four different types of degradation occurred. After a prolonged period of growth complete degradation of immunoglobulins, haptoglobin, transferrin and complement C3c was observed. Partial degradation of immunoglobulins, haptoglobin, transferrin, albumin, alpha 1-antitrypsin and complement C3c and C4 was generally observed after 48 h of growth. Besides, immunoglobulin protease activity yielding Fc and Fab fragments was found. The consortium was also capable of consuming carbohydrate side-chains as indicated by an altered electrophoretic mobility of the serum glycoproteins.

Basal plasma renin activity (PRA), angiotensin I and II (AI, AII), angiotensin-converting enzyme (ACE) activity and plasma aldosterone (PA) and sodium and potassium concentration were simultaneously measured in 55 healthy recumbent children aged between 1 week and 13 years. A significant (P less than 0.001) age-related decrease for PRA (r = -0.73), AI (r = -0.72), AII (r = -0.51) and PA (r = -0.71) was observed but not for ACE (r = 0.26, P = 0.06). After correction for age the correlation between PRA or PA and AI or AII was still significant (P less than 0.005). The strong correlation between AI and AII in the group as a whole (r = 0.82, P less than 0.001) and also in separate age groups, and an AI to AII ratio which was not different between the various age groups suggest that ACE activity in this age range is not rate-limiting for AII generation.

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This study was undertaken to design a relevant model system with conditions resembling the gingival pocket, in order to identify ecological factors that stimulate the establishment and maintenance of pathogenic subgingival microflora. Human serum as a substitute for gingival exudate was used in continuous culture enrichments of subgingival plaque to enable the selection of slow-growing (D gO.08 h-I ) consortia of microorganisms. After one week of continuous cultivation, species such as Treponema denticola, Peptostreptococcus spp., Lactobacillus catenaforme, Streptococcus spp., Bacteroides spp., Eubacterium spp. and Veillonella parvula became the predominating organisms. The cultures produced a wide variety of mainly cell-bound hydrolytic enzymes which have been associated with periodontal disease. The consortia preferentially consumed carbohydrates as was also indicated by the altered electrophoretic mobility of the serum glycoproteins due to removal of carbohydrate side-chains. Extensive degradation of glycoproteins such as immunoglobulins, haptoglobin, transferrin and a,-antitrypsin was observed. Acetic, butyric and propionic acids were the major products of metabolism suggesting heterolactic fermentation and amino acid catabolism. These products are typical of acidogenesis in anaerobic fermentations. Our results suggest that this in-vitro model can approximate conditions in gingival pockets.Research 20,450-457. Breure AM. (1986). Hydrolysis and acidogenic fermentation of protein and carbohydrates in anaerobic waste water treatment. Ph.D. thesis, Univ. of Amsterdam 7-20. Britz ML, Wilkinson RG. (1982). Leucine dissimilation to isovaleric and isocaproic acids by cell suspensions of amino acid fermenting anaerobes: the Stickland reactions revisited. Canadian Journal of Microbiology 28,291-300. Cheng S-L, Chan ECS. (1983). The routine isolation, growth and maintenance of the intermediatesize anaerobic oral spirochetes from periodontal pockets.