Isozyme Variation among 40 Frankia Strains

Forty Frankia strains belonging to the Alnus and Elaeagnus host specificity groups and isolated from various plant species from different geographical areas were characterized by the electrophoretic separation of isozymes of eight enzymes. All the enzyme systems that were investigated showed large variation. Diaphorases and esterases gave multiple band patterns and confirmed the identification of specific Frankia strains. Less variability was observed with enzymes such as phosphoglucose isomerase, leucine aminopeptidase, and malate dehydrogenase, which allowed for the delineation of larger groups of Frankia strains. Cluster analysis, based on the pair-wise similarity coefficients calculated between strains, delineated three large, dissimilar groups of Frankia strains, although each of these groups contained a large amount of heterogeneity. However, numerous Frankia strains, mainly from the Alnus host specificity group, demonstrated a perfect homology for all the enzymes tested.     

Laminin-nidogen complex. Extraction with chelating agents and structural characterization

Large quantities of intact laminin-nidogen complex could be extracted from a mouse tumor basement membrane with a physiological buffer containing EDTA. Analysis of the purified complex demonstrated that the two proteins occur in an equimolar ratio and that anchoring of these complexes to the extracellular matrix requires divalent cations. Reversible dissociation of the complex was achieved with 2 M guanidine X HCl and has been used for purification of the individual components. Electron microscopy and binding studies using laminin fragments demonstrated that nidogen interacts specifically with the center of the cross-shaped laminin molecule as represented by the short-arm structure fragment 1. The complex was also useful to confirm and refine a previously proposed dumb-bell structure of nidogen and to prepare and characterize the cell-binding fragment 8 from the long arm of laminin.     

Circannual and Circa-Hemiannual Rhythms of Basal and Stimulated Gastric Secretion in Conscious Cats

Conscious cats equipped with a gastric fistula and a denervated Heidenhain pouch were submitted to weekly measurements of the basal and pentagastrin-stimulated gastric secretion for 1 to 14 years. Rhythms of basal secretion were documented in 37 cats for the group studies, in 25 cats only for the individual studies which required at least whole year data. Twelve-month or 6-month rhythms were detected for each variable studied, i.e. volume, acid, pepsin, fucose and uronic acid outputs in the group studies, with peaks for volume, acid and pepsin in Winter, peaks for uronic acid in Spring and Fall indicating different rhythms for oxyntic, chief and mucous cells. Individual studies detected rhythms in 25% of the analyses, and demonstrated male and female and cat to cat differences. Spectral analysis in 3 cats confirmed the differences in the individual rhythms with prominent peaks differing from 365 days in 50% of the cases. Chronopharmacological responses to pentagastrin were documented for volume, acid and pepsin outputs in 5 male and 6 female cats. Group analysis detected a Winter acrophase for volume and acid secretion and a Summer acrophase for pepsin secretion. Analysis of the stimulated response data showed interindividual variation but a higher percentage of detection for rhythms, i.e. 38% for all variables and 50% for pepsin secretion. Different rhythms in acid and pepsin secretion documented in individual studies could provide the basis of a better understanding of the discrepancies reported in the literature concerning the seasonal incidence of peptic ulcer disease.     

ADENYLATE CYCLASE IN HELIX AND APLYSIA GANGLIA: CHARACTERISTICS OF ITS STIMULATION BY A PEPTIDE-CONTAINING NERVOUS SYSTEM EXTRACT

Abstract— A crude particulate fraction, prepared from the central ganglia of Helix or Aplysia , contains levels of adenylate cyclase activity comparable to those in mammalian brain. This activity can be stimulated up to 50-fold by NaF, and 4- to 10-fold by guanyl nucleotides such as GTP and guanylylimidodiphosphate (Gpp(NH)p). A peptide-containing extract from Helix or Aplysia nervous system also stimulates the adenylate cyclase, by 50-400°. In contrast, a number of peptides known to occur in vertebrate and invertebrate nervous system are without effect. The adenylate cylase stimulation by the endogenous molluscan peptide-containing extract may be receptor-mediated, but the effect is not enhanced in the presence of guanyl nucleotides: in this respect it differs from many other hormone-sensitive adenylate cyclases. The endogenous extracts prepared from Helix and Aplysia each stimulate both Helix and Aplysia adenylate cyclases, suggesting that the putative cyclase-linked receptors may be similar in the two species. Furthermore, the active components in the extracts from Helis and Aplysia appear to be similar, since preliminary evidence suggests that they may interact with the same adenylate cyclase-linked receptor in particulate fraction from Helix ganglia.     

H-2 typing of mice genetically selected for high or low antibody production

H and L inbred mouse strains were derived from animals selected respectively for the production of high and low titers of agglutinins against xenogeneic erythrocytes. L was found to beH-2 ^s . H was found to beH-2K ^d ,D ^q , with anI region derived from another (probably unknown) haplotype.     

Derivation of the first clinical diagnostic models for dehydration severity in patients over five years with acute diarrhea

Diarrheal diseases lead to an estimated 1.3 million deaths each year, with the majority of those deaths occurring in patients over five years of age. As the severity of diarrheal disease can vary widely, accurately assessing dehydration status remains the most critical step in acute diarrhea management. The objective of this study is to empirically derive clinical diagnostic models for assessing dehydration severity in patients over five years with acute diarrhea in low resource settings. We enrolled a random sample of patients over five years with acute diarrhea presenting to the icddr,b Dhaka Hospital. Two blinded nurses independently assessed patients for symptoms/signs of dehydration on arrival. Afterward, consecutive weights were obtained to determine the percent weight change with rehydration, our criterion standard for dehydration severity. Full and simplified ordinal logistic regression models were derived to predict the outcome of none (<3%), some (3–9%), or severe (>9%) dehydration. The reliability and accuracy of each model were assessed. Bootstrapping was used to correct for over-optimism and compare each model’s performance to the current World Health Organization (WHO) algorithm. 2,172 patients were enrolled, of which 2,139 (98.5%) had complete data for analysis. The Inter-Class Correlation Coefficient (reliability) was 0.90 (95% CI = 0.87, 0.91) for the full model and 0.82 (95% CI = 0.77, 0.86) for the simplified model. The area under the Receiver-Operator Characteristic curve (accuracy) for severe dehydration was 0.79 (95% CI: 0.76–0.82) for the full model and 0.73 (95% CI: 0.70, 0.76) for the simplified model. The accuracy for both the full and simplified models were significantly better than the WHO algorithm (p<0.001). This is the first study to empirically derive clinical diagnostic models for dehydration severity in patients over five years. Once prospectively validated, the models may improve management of patients with acute diarrhea in low resource settings.