Chalk eating in middle Georgia: a culture-bound syndrome of pica?

BACKGROUND: Although geophagia (earth eating) has been observed and documented in many areas of the world, the specific preference for consuming kaolin is less well known. The ingestion of kaolin, also known as white dirt, chalk, or white clay, is a relatively common type of pica found in the central Georgia Piedmont area. METHODS: We reviewed the literature, made informal contacts with Georgia physicians, and arranged semistructured interviews with 21 individuals with a history of chalk eating; we gathered both quantitative and qualitative information. RESULTS: Kaolin ingestion appears to be a culturally-transmitted form of pica, not selectively associated with other psychopathology. CONCLUSION: Kaolin ingestion appears to meet the DSM-IV criteria for a "culture-bound syndrome."

Specific detection of an interleukin 1- and tumour necrosis factor-activated beta-casein kinase in HeLa and KB cells.

Interleukin 1 (IL-1) and tumour necrosis factor (TNF) activate a novel protein kinase, TIP kinase, which phosphorylates beta-casein in vitro. We have identified and purified to homogeneity a tryptic fragment of beta-casein, called T1, which was phosphorylated by TIP kinase with kinetics similar to those of the intact protein (K[m] = 27 +/- 6 microM). Phosphopeptide maps of in vitro phosphorylated T1 and beta-casein were identical, confirming that T1 contained the main phosphorylation site of the protein. T1 corresponded to residues 114 to 169 of beta-casein. It was phosphorylated by constitutively active protein kinases to a much lesser extent than beta-casein and thus constituted a specific substrate of the cytokine-activated enzyme. This made possible the detection of TIP kinase in extracts of IL-1-stimulated HeLa and KB cells, which had been hampered by high background phosphorylation when beta-casein was used as substrate. Our results show that the use of fragment T1 allows detection of low levels of TIP kinase in crude samples. They also suggest that its activation, which had previously been observed only in connective tissue cells, may be a general response of many cell types to IL-1 or TNF.

Role for p38 mitogen-activated protein kinase in platelet aggregation caused by collagen or a thromboxane analogue.

p38 mitogen-activated protein kinase (MAPK) was identified in platelets on the basis of (a) its reactivity with antibodies to C-terminal and N-terminal peptides, and (b) its ability to activate MAPK-activated protein kinase-2, which phosphorylates the small heat shock protein, hsp27. p38 MAPK was activated in platelets by collagen fibers, a collagen-related cross-linked peptide, thrombin, or the thromboxane analogue U46619. A highly specific inhibitor of p38 MAPK, a pyridinyl imidazole known as SB203580, inhibited the platelet enzyme in vitro (IC50 approximately 0.5 microM). At similar concentrations it also inhibited agonist-stimulated phosphorylation of hsp27 in platelets, and platelet aggregation and secretion induced by minimal aggregatory concentrations of collagen or U46619, but not thrombin. Inhibition of aggregation was overcome by increasing agonist dose. SB203580 might act by inhibiting thromboxane generation, but this was only inhibited by 10-20% at low agonist concentrations. p38 MAPK provides a crucial signal, which is necessary for aggregation caused by minimal concentrations of collagen fibers or U46619. Thrombin or high doses of these agonists generate signals that bypass the enzyme, or render the enzyme no longer rate-limiting.

Specific activation of beta-casein kinase by the inflammatory cytokines interleukin 1 and tumour necrosis factor.

Increases (5-fold) in the rate of phosphorylation of beta-casein were observed in extracts of human gingival fibroblasts that had been stimulated by interleukin 1 (IL-1) or tumour necrosis factor (TNF). The induced kinase was cytosolic and had little activity on alpha-casein. Its chromatographic behaviour on anion-exchange and gel-filtration columns was similar to that of beta-casein kinase, an enzyme detected originally in MRC-5 cells stimulated by IL-1 and TNF. Phosphopeptide maps of beta-casein confirmed that the kinase activated in gingival fibroblasts had the same substrate specificity as beta-casein kinase. In gingival fibroblasts, beta-casein kinase activity was maximum after 15 min of stimulation by IL-1 or TNF, and remained activated for several hours. Activations of small heat-shock protein (hsp27) kinase and mitogen-activated protein (MAP) kinase were also maximum 15 min after stimulation, but decreased to background levels within the next 30 min. Study of the effects of 21 agents other than IL-1 or TNF showed that none activated beta-casein kinase, whereas several activated MAP kinase or hsp27 kinase. beta-Casein kinase was also detected in extracts of bovine articular chondrocytes and human endothelial cells stimulated by IL-1 or TNF. Semi-purified preparations of fibroblast beta-casein kinase were not inactivated by phosphatases in vitro. Our results suggest that it may be involved in responses specific to IL-1 and TNF in a wide range of cell types and that its activation probably involves mechanisms other than its phosphorylation.

Reports of childhood incest by adults with panic disorder or agoraphobia.

A convenience sample of 94 members of an agoraphobia self-help group responded to an anonymous survey on their possible histories of childhood incest. 12 (13%) respondents reported such a history. These results are discussed in terms of hypothesized etiologies of panic disorder and agoraphobia.

Interleukin 1 and tumor necrosis factor stimulate two novel protein kinases that phosphorylate the heat shock protein hsp27 and beta-casein.

We have partially purified and characterized two protein kinases that were strongly activated by interleukin-1 (IL-1) or tumor necrosis factor (TNF) in MRC-5 fibroblasts. The kinases were separated by anion exchange chromatography of cytosolic fractions. They phosphorylated in vitro the small heat shock protein (hsp27) or beta-casein and were stimulated 3- and 4.5-fold, respectively, in cells that had been exposed to IL-1 or TNF for 10 min. They were distinct from the mitogen-activated protein kinases, whose activation by IL-1 or TNF has been reported recently. The hsp27 kinase phosphorylated its substrate on serine residues. Its molecular mass was estimated to be 45-kDa by gel filtration. It is probably involved in the increase in hsp27 phosphorylation seen in intact cells. The beta-casein kinase behaved as a 65-kDa protein. It phosphorylated its substrate on serine and threonine residues and had little activity on alpha-casein. The hsp27 and beta-casein kinases were not activated after stimulation of the cells with phorbol myristate acetate (PMA). In contrast, the MAP kinases were activated to a similar extent (2-3-fold) by the cytokines and by PMA. The hsp27- and beta-casein kinases probably correspond to novel enzymes whose mechanisms of activation may be independent of protein kinase C or MAP kinases.