Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites.

We use a combination of variable-temperature high-resolution synchrotron X-ray powder diffraction measurements and Monte Carlo simulations to characterize the evolution of two different types of ferroic multipolar order in a series of cyanoelpasolite molecular perovskites. We show that ferroquadrupolar order in [C3N2H5]2Rb[Co(CN)6] is a first-order process that is well described by a four-state Potts model on the simple cubic lattice. Likewise, ferrooctupolar order in [NMe4]2B[Co(CN)6] (B = K, Rb, Cs) also emerges via a first-order transition that now corresponds to a six-state Potts model. Hence, for these particular cases, the dominant symmetry breaking mechanisms are well understood in terms of simple statistical mechanical models. By varying composition, we find that the effective coupling between multipolar degrees of freedom-and hence the temperature at which ferromultipolar order emerges-can be tuned in a chemically sensible manner. This article is part of the theme issue 'Mineralomimesis: natural and synthetic frameworks in science and technology'.

PDGF-C is a new protease-activated ligand for the PDGF alpha-receptor.

Platelet-derived growth factors (PDGFs) are important in many types of mesenchymal cell. Here we identify a new PDGF, PDGF-C, which binds to and activates the PDGF alpha-receptor. PDGF-C is activated by proteolysis and induces proliferation of fibroblasts when overexpressed in transgenic mice. In situ hybridization analysis in the murine embryonic kidney shows preferential expression of PDGF-C messenger RNA in the metanephric mesenchyme during epithelial conversion. Analysis of kidneys lacking the PDGF alpha-receptor shows selective loss of mesenchymal cells adjacent to sites of expression of PDGF-C mRNA; this is not found in kidneys from animals lacking PDGF-A or both PDGF-A and PDGF-B, indicating that PDGF-C may have a unique function.

The effectiveness of oral iodized oil in the treatment and prophylaxis of endemic goiter.

In a longitudinal study carried out for 2 yr in the Darfur region, western Sudan, 2316 school children received a single dose of 2 capsules of iodized oil (400 mg iodine) orally, and 1161 school children received 1 ml of the same preparation im (475 mg iodine); 2393 school children served as controls. One year after treatment, goiter prevalence was reduced from 67.0% to 36.0% among the children who had received oral iodized oil and from 71.0% to 42.0% in those who received it im. The prevalence in the control group did not change. The prevalences in each group were approximately the same 2 yr after treatment. Urinary iodine excretion increased after treatment and remained significantly higher than the initial value during the trial. In subjects from rural Darfur, serum T4 levels were increased 1 yr after treatment with oral iodized oil (P less than 0.001) and im iodized oil (P less than 0.01), and remained high in the former (P less than 0.05) but not in the latter. This increase was accompanied by reduction of serum T3 and TSH levels. Sialadenitis occurred in 3.7% of the children who received oral iodized oil. Thyroid antibodies were not detected before treatment, but microsomal antibodies were detected in 2 of the 128 subjects studied who received iodized oil orally. Comparable results occurred when oral and im iodized oil were given to 841 individuals covering a wider age range. It is concluded that a single oral dose of iodized oil is effective in the correction of iodine deficiency, reducing the goiter size and preventing the recurrence of goiter for at least 2 yr.

Peptide hormone markers in screening for endocrine tumors in multiple endocrine adenomatosis type I.

In three families with the multiple endocrine adenomatosis type I (MEA I) trait, 51 members were investigated by measurement of circulating peptide hormones as tumor markers. Twenty-five of 51 members (49 percent) were considered to be affected by MEA I disorders. The incidence rose with age (75 percent in generation II). Both sexes were affected equally. Hyperparathyroidism was present in 20 of 25 affected members (80 percent), and pituitary tumors (prolactinomas) were found in four of 25 (16 percent). Endocrine pancreatic tumors were found in nine of 25 affected members (36 percent), but when "probable" tumors (seven) are included the frequency rises to 72 percent. Hyperparathyroidism was found in all except one member with proved lesions in other organs. Among patients with proved and possible endocrine pancreatic tumors, elevated serum levels of gastrin and pancreatic polypeptide were frequently found, 78 percent and 67 percent, respectively, and we suggest that serum gastrin and pancreatic polypeptide levels are the most useful screening markers at present for pancreatic lesions in MEA I.

Placebo--the forgotten drug.

The placebo effect is seen in patients who have been the target of intervention believed to lack specific action. This effect seems to be an important, and possibly the only, contribution to the positive effect of alternative medicine sometimes reported. The risks involved in the uncritical utilization of the placebo effect are, however, great and must be carefully considered. Most of the information available on this effect has been obtained from double-blind studies in connection with the introduction of new drugs. Depending on the kind of effect that is expected, improvements of up to 30% or more can be noted. Many attempts have been made to explain the nature of the placebo effect. Thus it has been suggested that a placebo acts by decreasing anxiety. Another explanation is that a placebo acts by meeting the expectations of the patient. It has also been proposed that the human placebo response has characteristics of a conditioned response.

Investigation on trichothecene-stimulated lipid peroxidation and toxic effects of trichothecenes in animals.

Three experiments were performed with mice intoxicated with trichothecene-contamined feed or directly into the stomach. Lipid peroxidation was estimated by the TBA value from liver samples, but since such a test seldom provided reliable results, lipid hydroperoxides and total carbonyl were also analyzed. The formation of aldehydes and ketones was compared in vivo and in vitro. The same investigations were conducted on chickens, rainbow trouts and numerous fur animals suspected of chronic intoxication by trichothecenes. The vitamin A concentration was used as a parameter to detect alterations caused in chickens by trichothecenes. Our investigation provided evidence that lipid peroxidation is associated with trichothecene poisoning. The T-2 toxin, even in small concentrations, seems to induce strong lipid peroxidation. When DON and 3-AcDON were given together at a dosage of 180 micrograms/kg feed, 1 week's feeding caused clear lipid peroxidation in mice. Particular attention should be paid to the fact that mycotoxins may already be present in the feed before any experiment is conducted.