Pattern of epithelium formation in human and guinea-pig skin (author's transl)

Comparative histometry of human and guinea-pig epidermis revealed that in the latter development of the (subcorneal) superficial epithelium is significantly less, and that of the (mostly follicular) deep epithelium is markedly more pronounced than in man.     

Pharmacokinetics of the new antiasthma and antiallergy drug, azelastine, in pediatric and adult beagle dogs

The plasma concentrations and relative bioavailability of azelastine hydrochloride (AZ) and its desmethyl metabolite (DAZ) after a single and 10 once-a-day oral doses of 2.5 mg kg-1 AZ were determined in adult male and female and pediatric male and female beagle dogs. The pediatric and adult dogs were 4-6 weeks and 1-2 years of age, respectively. An analysis of variance (ANOVA) was performed on the bioavailability parameters among all groups and between the first and last doses. No statistically significant (p < 0.05) sex-related differences in the bioavailability parameters were observed. The peak concentration (Cmax) of AZ, especially after the first dose, was significantly higher in pediatric dogs than that in adult dogs, whereas following the multiple AZ administrations, the bioavailability parameters for the last dose were similar in the two age groups. The apparent volume of distribution (Vss) of AZ suggested that the drug was extensively distributed into tissue in adult as well as in pediatric dogs. The Vss was considerably smaller in pediatric dogs, which may explain the higher Cmax in this age group. The bioavailability of the metabolite in adult dogs after multiple administration of AZ was higher than that in pediatric dogs. Although some differences in the parameters among the groups are statistically significant, they do not appear to have any biological significance. Therefore, similar AZ dosages may be required in pediatric and in adult populations to achieve optimum therapeutic drug levels.     

A correlative study on the mechanism of adaptive cytoprotection against ethanol-induced gastric lesion formation in rats

The protective effect of mild irritants against the subsequent gastric injury induced by necrotizing agents has been termed 'adaptive cytoprotection'. In this study, the possible pathway and mechanisms of adaptive cytoprotection induced by 20% ethanol were investigated. An ex-vivo gastric chamber preparation was used. The gastric mucosa was exposed to 20% ethanol before subsequent administration of 100% ethanol 15 min later. Subdiaphragmatic vagotomy or drug pretreatment was carried out in order to elucidate the mechanisms of adaptive cytoprotection by 20% ethanol. The results showed that 20% ethanol pre-exposure significantly protected the gastric mucosa against damage caused by 100% ethanol. This protective action was completely abolished by atropine or lidocaine pretreatment, whereas vagotomy and hexamethonium failed to have a significant influence. The cytoprotective effect, however, was independent of the gastric secretory volume, titratable acid content, luminal soluble mucus level and gastric mucosal blood flow. Exposure of only half the gastric mucosa to the mild irritant resulted in the protection of both sides of the mucosa. All these findings indicate that the adaptive cytoprotection of 20% ethanol involves the participation of chemoreceptors and muscarinic receptors in the gastric mucosa. An internal enteric reflex arc, with transmission of signals within the gastric mucosa, may also contribute to the cytoprotective process of the mild irritant.     

Evidence of vertical transmission of Ross River and Sindbis viruses (Togaviridae: Alphavirus) by mosquitoes (Diptera: Culicidae) in southeastern Australia

Ross River and Sindbis viruses were isolated from Aedes camptorhynchus adults reared from immatures collected from a salt marsh in coastal Victoria, indicating the existence of field vertical transmission. These first isolations of an arbovirus from adult mosquitoes reared from field-collected immatures in Australia indicates one mechanism for arbovirus maintenance in temperate regions.     

Subacute combined degeneration of the spinal cord: MR findings

The authors present the initial and follow-up MR findings in a patient with subacute combined degeneration of the spinal cord, a complication of vitamin B12 deficiency, and a rare cause of demyelination of the dorsal and lateral columns of the spinal cord. Initial study showed high intensity in the dorsal columns of the cervical and thoracic spinal cord on T2-weighted image. Five months after treatment, the abnormal signal intensity was noted to have decreased.     

Genetic analysis of salt tolerance in arabidopsis. Evidence for a critical role of potassium nutrition

A large genetic screen for sos (for salt overly sensitive) mutants was performed in an attempt to isolate mutations in any gene with an sos phenotype. Our search yielded 28 new alleles of sos1, nine mutant alleles of a newly identified locus, SOS2, and one allele of a third salt tolerance locus, SOS3. The sos2 mutations, which are recessive, were mapped to the lower arm of chromosome V, approximately 2.3 centimorgans away from the marker PHYC. Growth measurements demonstrated that sos2 mutants are specifically hypersensitive to inhibition by Na+ or Li+ and not hypersensitive to general osmotic stresses. Interestingly, the SOS2 locus is also necessary for K+ nutrition because sos2 mutants were unable to grow on a culture medium with a low level of K+. The expression of several salt-inducible genes was superinduced in sos2 plants. The salt tolerance of sos1, sos2, and sos3 mutants correlated with their K+ tissue content but not their Na+ tissue content. Double mutant analysis indicated that the SOS genes function in the same pathway. Based on these results, a genetic model for salt tolerance mechanisms in Arabidopsis is presented in which SOS1, SOS2, and SOS3 are postulated to encode regulatory components controlling plant K+ nutrition that in turn is essential for salt tolerance.