Plasma LH progesterone concentrations in the turkey hen during the ovulatory cycle

Progesterone and luteinizing hormone (LH) were measuured in the plasma of Large White turkey hens at frequent intervals during the ovulatory cycle and during the periods when ovulations did not occur. The hormones were quantitated at the beginning and the end of the reproductive season to follow the change in patterns and concentrations of these hormones. Radioimmunoassay procedures were used to assay both hormones. Both progesterone and LH reached a peak amount at about 8 to 2 hours before ovulation. At no time did the progesterone peak precede that of LH. On the other hand, the peak of progesterone was observed to last somewhat longer than the LH peak. Progesterone and LH concentrations demonstrated no peak during the non-ovulatory periods. The patterns of both hormones at the end of the reproductive season was about the same as at the beginning of the season, but with lower concentrations.     

Effect of split doses of N-methyl-N-nitrosourea on DNA repair synthesis in cultured mammalian cells

DNA repair was measured in human fibroblasts, mouse C3H 10 T 1/2 fibroblsts and rat hepatocytes by the non-semi-conservative incorporation of [3H]-TdR during DNA repair synthesis using liquid scintillation techniques. Confluent monolayers of these cells grown on cover slips were exposed to split doses (125 or 250 microgram/ml) of the mutagenic and carcinogenic alkylating agent MNU and DNA repair synthesis compared with that produced by a single dose (500 microgram/ml). No significant difference in DNA repair capacity was detected in the three cell lines treated with a single dose or split doses of MNU.     

Cardiovascular responses of Oriental and Caucasian men to alcohol: some psychological correlates

After drinking a small dose of alcohol, Orientals flushed, their heart rates increased and their diastolic pressures decreased; Caucasians' skin reflectance did not change, but their heart rates and systolic blood pressures decreased. In both groups, flushing was associated with an increase in feelings of vigor. Other mood correlates depended on condition.     

Chamber bioaerosol study: human emissions of size‐resolved fluorescent biological aerosol particles

Humans are a prominent source of airborne biological particles in occupied indoor spaces, but few studies have quantified human bioaerosol emissions. The chamber investigation reported here employs a fluorescence‐based technique to evaluate bioaerosols with high temporal and particle size resolution. In a 75‐m³ chamber, occupant emission rates of coarse (2.5–10 μm) fluorescent biological aerosol particles (FBAPs) under seated, simulated office‐work conditions averaged 0.9 ± 0.3 million particles per person‐h. Walking was associated with a 5–6× increase in the emission rate. During both walking and sitting, 60–70% or more of emissions originated from the floor. The increase in emissions during walking (vs. while sitting) was mainly attributable to release of particles from the floor; the associated increased vigor of upper body movements also contributed. Clothing, or its frictional interaction with human skin, was demonstrated to be a source of coarse particles, and especially of the highly fluorescent fraction. Emission rates of FBAPs previously reported for lecture classes were well bounded by the experimental results obtained in this chamber study. In both settings, the size distribution of occupant FBAP emissions had a dominant mode in the 3–5 μm diameter range.     

The role of oncostatin M in animal and human connective tissue collagen turnover and its localization within the rheumatoid joint

OBJECTIVE: To study the interaction of interleukin-1alpha (IL-1alpha) and oncostatin M (OSM) in promoting cartilage collagen destruction. METHODS: Bovine, porcine, and human cartilage and human chondrocytes were studied in culture. The levels of collagenase (matrix metalloproteinase 1 [MMP-1]) and tissue inhibitor of metalloproteinases 1 (TIMP-1) were measured by bioassay and enzyme-linked immunosorbent assay (ELISA). The levels of OSM in rheumatoid synovial fluid were measured by ELISA. RESULTS: When combined with OSM, IL-1alpha, IL-1beta, and tumor necrosis factor alpha released proteoglycan and collagen from cartilage. OSM was the only member of the IL-6 family to have this effect. Human tendon also responded to IL-1alpha and OSM. OSM increased the production of MMP-1 and TIMP-1 but when combined with IL-1alpha, synergistically promoted MMP-1 production in human chondrocytes and synovial fibroblasts. High levels of OSM were found in human rheumatoid synovial fluids, and confocal microscopy showed that OSM was produced by macrophages in rheumatoid synovial tissue. CONCLUSION: These results highlight an important new mechanism by which there is irreversible loss of collagen from cartilage.     

Effect of topical butyrate on rectal epithelial kinetics and mucosal enzyme activities

Public awareness and misunderstandings of lactose intolerance are at an all-time high. Many people erroneously believe they are lactose intolerant or develop gastrointestinal symptoms after intake of lactose. Consequently, lactose-containing foods such as milk and other dairy foods may be eliminated unnecessarily from the diet. Because these foods are a major source of calcium, low intake of them can compromise calcium nutriture. This, in turn, can increase the risk of major chronic diseases such as osteoporosis (porous bones) and hypertension. This review is intended to help dietetics professionals alleviate clients' fears about lactose intolerance and recommend dietary strategies to improve tolerance to lactose. Scientific findings indicate that the prevalence of lactose intolerance is grossly overestimated. Other physiologic and psychologic factors can contribute to gastrointestinal symptoms that mimic lactose intolerance. Scientific findings also indicate that people with laboratory-confirmed low levels of the enzyme lactase can consume 1 serving of milk with a meal or 2 servings of milk per day in divided doses at breakfast and dinner without experiencing symptoms. Several dietary strategies are available to help lactose maldigesters include milk and other dairy foods in their diet without experiencing symptoms.     

In vitro selection of dopamine RNA ligands

RNA aptamers that specifically bind dopamine have been isolated by in vitro selection from a pool of 3.4 x 10(14) different RNA molecules. One aptamer (dopa2), which dominated the selected pool, has been characterized and binds to the dopamine affinity column with a dissociation constant of 2.8 microM. The specificity of binding has been determined by studying binding properties of a number of dopamine-related molecules, showing that the interaction with the RNA might be mediated by the hydroxyl group at position 3 and the proximal aliphatic chain in the dopamine molecule. The binding domain was initially localized by boundary experiments. Further definition of the dopamine binding site was obtained by secondary selection on a pool of sequences derived from a partial randomization of the dopa2 molecule. Sequence comparison of a large panel of selected variants revealed a structural consensus motif among the active aptamers. The dopamine binding pocket is built up by a tertiary interaction between two stem and loop motifs, creating a stable framework in which five invariant nucleotides are precisely arrayed. Minimal active sequence and key nucleotides have been confirmed by the design of small functional aptamers and mutational analysis. Enzymatic probing suggests that the RNA might undergo a conformational change upon ligand binding that stabilizes the proposed tertiary structure.