Ear wax and otitis media in children.

A study was designed to find the prevalence of ear wax in children aged 3 to 10 years and to test the belief that large amounts of wax are unlikely to be seen when otitis media is present. Roughly a quarter of the children had appreciable amounts of wax, and there was a gradual decline in prevalence with age. The amount of ear wax appeared to decrease when otitis media was present. The results did not support removing wax when assessing children''s ears in general practice.     

Seasonal changes in the ruminal microflora of the high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus).

The dominant rumen bacteria in high-arctic Svalbard reindeer were characterized, their population densities were estimated, and ruminal pH was determined in summer, when food quality and availability are good, and in winter, when they are poor. In summer the total cultured viable population density was (2.09 +/- 1.26) X 10(10) cells ml-1, whereas in winter it was (0.36 +/- 0.29) X 10(10) cells ml-1, representing a decrease to 17% of the summer population density. On culture, Butyrivibrio fibrisolvens represented 22% of the bacterial population in summer and 30% in winter. Streptococcus bovis represented 17% of the bacterial population in summer but only 4% in winter. Methanogenic bacteria were present at 10(4) cells ml-1 in summer and 10(7) cells ml-1 in winter. In summer and winter, respectively, the proportions of the viable population showing the following activities were as follows: starch utilization, 68 and 63%; fiber digestion, 31 and 74%; cellulolysis, 15 and 35%; xylanolysis, 30 and 58%; proteolysis, 51 and 28%; ureolysis, 40 and 54%; and lactate utilization, 13 and 4%. The principal cellulolytic bacterium was B. fibrisolvens, which represented 66 and 52% of the cellulolytic population in summer and winter, respectively. The results indicate that the microflora of the rumen of Svalbard reindeer is highly effective in fiber digestion and nitrogen metabolism, allowing the animals to survive under the austere nutritional conditions typical of their high-arctic habitat.     

Utility of peptide-protein affinity complexes in proteomics: identification of interaction partners of a tumor suppressor peptide.

We used a N-biotinylated peptide analog of the C-terminal domain of the tumor suppressor protein, p21cip1/waf1 to elucidate peptide/protein interacting partners. The C-terminal domain of p21cip1/waf1 protein spanning 141-160 amino acid residues is known to bind PCNA and this interaction is important in many biological processes including cell-cycle control. This C-terminal 20-mer efficiently extracts PCNA in the presence of a variety of N- or C-terminally attached affinity tags. Using difference silver stained 2D gels combined with in-gel tryptic digests, we identified the difference spots using MALDI-TOF mass spectrometry-based peptide mass fingerprinting followed by a database search using PROFOUND against NCBIs human nonredundant protein sequence data bank. Identified spots include the p48 subunit of chromatin assembly factor-1, the heat shock 70 protein analog BiP, calmodulin, nucleolin and a spot similar in size to dimeric PCNA. In contrast, microcapillary ion-trap LC-MS/MS analysis of a tryptic digest of entire affinity extracts derived from both control and experimental runs followed by database searches using SEQUEST confirmed the presence of most of the above proteins. This strategy also identified hnRNPA1, HPSP90alpha, HSP40 and T-complex protein 1, a protein similar to prothymosin, and a possible allelic variant of the p21cip1/waf1 protein. The use of N-biotinylated peptide derived from the C-terminal domain of p21cip1/waf1 protein in proteomic analysis exemplified here suggests that peptides obtained from intracellular functional screens could also potentially serve as efficient baits to discover new drug targets.     

Changes in the migration and adhesive activity of polymorphonuclear leukocytes as 1 of the characteristics of Gram-negative bacteria isolated from patients with suppurative lung destruction

The influence of Gram-negative bacteria on the migratory and adhesive activity of polymorphonuclear leukocytes (PMNL) in the peripheral blood of clinically normal donors has been studied by the specially developed method with the use of Boyden chambers. Pseudomonas and enterobacteria have been found to produce complex and various effects on the above-mentioned properties of PMNL. When incubated in fresh serum, Gram-negative bacteria are capable of enhancing the migratory activity of PMNL, this property being least pronounced in P. aeruginosa. The incubation of live bacteria from the authors' collection in the patients' sera or in sera obtained from normal donors and inactivated by heating induces no hemotaxis of PMNL, and P. aeruginosa strains even suppress it under such conditions. The isolated Gram-negative bacteria under study increase the number of highly adhesive PMNL in the population used in this investigation, but P. aeruginosa cultures do not produce such effect.     

Within-tree spatial variation in the leaf monoterpenes of Sequoia sempervirens

Location within a tree was analyzed as a source of variation in Sequoia sempervirens leaf monoterpenes. No differences were found for quantitative composition or total yield/dry wt among lower, middle and upper canopy positions. The awlshaped, spirally arranged leaves of vigorous upper shoots showed small quantitative compositional differences, but not differences in total yield. The intermediate leaf form of young sprouts had the most different monoterpene quantitative composition and about three times the total yield of the above two leaf forms. Analysis of a clonal ring of 17 adult trees resulted in coefficients of variation similar to those for samples collected from different canopy levels of the same shoot. Results revealed the sources and magnitudes of experimental error in comparative studies of this species' leaf monoterpenes, and did not support the concept that somatic mutation provides an important source of variation in a large, long-lived organism such as coast redwood.     

Influence of red pepper and capsaicin on body composition and lipogenesis in rats

Inclusion of red pepper or its active principle ‘capsaicin’ in the diet led to a lowering of total lipids, particularly triglycerides in the liver. The total body fat was lowered in animals fed red pepper or capsaicin but not in animals fed paprika powder which had negligible capsaicin content. Hyperlipogensis and hypertriglyceridemia caused by fructose feeding were significantly were decreased in capsaicin-fed animals. Activities of the key lipogenic enzymes were reduced as reflected by decreased lipogenesis.     

Glycosylation of high-affinity thrombin receptors appears necessary for thrombin binding.

Monosaccharide binding competition, lectin affinity chromatography, and glycosylation inhibitors have been used to determine if glycosylation plays a role in thrombin-receptor interactions. Mannose appeared to specifically inhibit thrombin binding to mouse embryo (ME) and hamster fibroblasts. Concanavalin A bound to antibody-purified receptor fractions, and was used as an affinity ligand to purify receptor fractions that retained thrombin binding activity. Cells treated with tunicamycin (6.25 ng/ml) for 24 h lost approximately 35% of their high-affinity thrombin binding sites, yet binding of receptor monoclonal antibody TR-9 was not affected, indicating that the receptor was present in the membrane, but unable to bind thrombin. Thus thrombin receptor glycosylation may be directly involved in thrombin binding.     

Magnetic circular dichroism studies on the heme and tryptophan components of cytochrome c peroxidase

We have measured the magnetic circular dichroism of cytochrome c peroxidase and some of its derivatives from 250-350 nm. Comparison of the changes observed on conversion to the catalytic intermediate (cytochrome c peroxidase-I) with spectra obtained from horseradish peroxidase and its derivatives and model compounds of protoheme leads us to the conclusion that the observed changes in the magnetic circular dichroism spectra reflect conversion of the heme to the ferryl state. No evidence was found for modification of tryptophan in cytochrome c peroxidase-I.     

Application of avidin-ferritin and peroxidase as contrasting electron-dense markers for simultaneous electron microscopic immunocytochemical labelling of glutamic acid decarboxylase and tyrosine hydroxylase in the rat arcuate nucleus

Summary A pre-embedding immunostaining procedure was developed using ferritin and peroxidase to enable simultaneous electron microscopic localization of two antigens in the same tissue section. This method was used to study the anatomic relationship between glutamic acid decarboxylase (GAD) immunoreactive axons and tyrosine hydroxylase (TH) — containing neurons of the rat arcuate nucleus. The findings provide ultrastructural evidence that GAD-immunoreactive terminals establish symmetric (Gray II) synapses on TH-reactive neurons.