The presence of the extracellular calcium-sensing receptor on human antral gastrin cells was investigated. Reverse transcription PCR using mRNA isolated from gastrin cellenriched cell cultures identified a product with a sequence identical to part of the human parathyroid-secreting cell calcium-sensing receptor. Immunocytochemistry with an antibody to the extracellular region of the receptor immunostained all gastrin cells (but not mucin or somatostatin cells), and detected appropriate-sized bands in Western blots of whole cell lysates. Increasing extracellular calcium levels from 0.5 to 9 mM stimulated gastrin release in a concentrationdependent manner, with maximal release obtained at 7.2 mM. A known agonist of the calcium receptor, spermine also stimulated gastrin release. Microfluorimetry of identified gastrin cells demonstrated that increasing extracellular calcium resulted in an initial rapid rise in intracellular calcium followed by a plateau level that returned to basal levels immediately after removal of the elevated calcium. The traces were consistent with activation of a receptor-mediated mechanism rather than a concentration-dependent influx of calcium. In conclusion, these data indicate that G cells express the calcium-sensing receptor, and that activation of the receptor may explain the acid rebound phenomenon associated with calcium-containing antacid preparations.

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For an odd prime [Formula: see text], we determine a minimal set of topological generators of the pro-[Formula: see text] Iwahori subgroup of a split reductive group [Formula: see text] over [Formula: see text]. In the simple adjoint case and for any sufficiently large regular prime [Formula: see text], we also construct Galois extensions of [Formula: see text] with Galois group between the pro-[Formula: see text] and the standard Iwahori subgroups of [Formula: see text].

In mRNA samples isolated from a gastrin (G) cell-enriched human antral cell preparation, reverse transcription-polymerase chain reaction identified products encoding part of the alpha 1-subunit of class C and D L-type voltage-dependent Ca2+ channels (VDCCs). Analysis of the polymerase chain reaction products demonstrated a 100% homology with the known human gene sequences. An antibody to the class D alpha 1-subunit immunostained 30-40% of the cultured cells; of these 90% were gastrin immunoreactive. Gastrin release stimulated by terbutaline (beta 2-agonist) and forskolin was abolished by blockade of L-type VDCCs; the effect of 3.6 mM extracellular Ca2+ was only partially reversed. In G cells the rise in intracellular Ca2+ observed in response to increasing extracellular Ca2+ from 0.5 to 3.6 mM was reduced by nitrendipine. These results indicated that human antral cells expressed class C and D L-type VDCCs. Activation of G cells with beta-adrenergic agonists required an influx of extracellular Ca2+ through these channels to stimulate gastrin release. However, activation of L-type channels was not the only mechanism underlying Ca(2+)-stimulated gastrin release.

OBJECTIVE: To attain an objective account of the methods to measure enamel erosion used in 1980–1998 publications, a structured review of the literature was undertaken. METHODS: Inclusion and exclusion criteria were applied to 731 clinical/experimental research and review reportS. Eighty‐five included papers were subsequently rated according to ‘hierarchy of evidence’ guidelines to assess the strength of the report's design and the relevance of the evidence to replicating enamel erosion in vivo in humanS. Scores were assigned to rate each aspect in the guidelines. RESULTS: A total of 16 clinical, 13 review and 56 experimental papers were assessed; 36.4% were published during 1996–1998.Excluding reviews, 16 papers were qualitative and 56 quantitative; 51 used human enamel. Our classification yielded nine groups of methods (five scoring systems and 26 measurement techniques).CTFPHE (Can Med Assoc J 1992; 147: 443) grading of research reports indicated that 2.8% provided evidence grade I; 20.8%, grade IIa; 63.9%, grade III; and 12.5%, grade IV. CONCLUSIONS: There has been a consistent increase in the body of knowledge. The overall quality of publications has not substantially changed over time. Experimental studies were more often quantitative, and quantitative studies had better research designS. No single group of research methods had obviously superior research designs.

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It is a general principle that objects coming from semi-simple, simply connected (split) groups have explicit presentations like Serre's presentation of semi-simple algebras and Steinberg's presentation of Chevalley groups. In this paper we give an explicit presentation (by generators and relations) of the Iwasawa algebra for the first congruence kernel of a semi-simple, simply connected Chevalley group over Zp, extending the proof given by Clozel for the group Γ 1 (SL 2 (Zp)), the first congruence kernel of SL 2 (Zp) for primes p > 2 .

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