Meal-induced increase in plasma gastrin immunoreactivity in the rhesus monkey (Macaca mulatta)

The hormonal response to food intake in rodents, dogs, and humans involves gastrin and cholecystokinin, structurally related peptides present in plasma, gut, and brain. In order to determine the time course of plasma gastrin response in a nonhuman primate, six overnight-fasted adult male rhesus monkeys were offered a meal of bananas (11g) and peanut butter (1 Tbsp) or a fresh water bottle in a crossover design. All animals completely consumed the meal within 10 min. Compared to non-fed control levels, plasma gastrin was significantly elevated (52 ± 11 pM vs. 32 ± 9 pM, means ± S. E. M.) from 10 to 45 min post-ingestion, but returned to near basal fasted level by 120 min. Levels of gastrin in tissue samples (n = 2) were highest in the antrum of the stomach, with decreasing amounts measured in the upper and lower duodenum, respectively. The results demonstrate that the plasma concentration and response to a meal of rhesus monkey gastrin are similar to those of other mammalian species. However, the high concentrations of gastrin found in duodenum are thus far unique to Macaca mulatta and humans.     

Identification of differentially expressed sequences in pre-embryogenic tissue of oilseed rape by suppression subtractive hybridisation (SSH)

A subtracted cDNA library comprising of 576 clones were constructed to isolate differentially expressed sequences in the pre-embryogenic tissue (PEC) of winter oilseed repe. After differential screening, only 16 clones were identified as potential positives. Eventually, only three clones: BNPE DG3, BNPE AE4 and BNPE EG1 were confirmed by Northern analysis as upregulated in␣PEC of the oilseed rape embryogenic culture. This is the first study to report Ae4, Dg3 and Eg1 sequences as preferentially expressed in the oilseed␣rape PEC and associated with the induction of somatic embryogenesis in B.napus secondary embryogenesis. Ae4 encodes a putative proline-rich protein, Dg3 encodes a lipid transfer-like protein and Eg1 encodes a napin, member of the BNMNAP subfamily.     

The Ethics of Research on Less Expensive,Less Effective Interventions: A Case for Analysis

The Kennedy Krieger lead paint study is a landmark case in human experimentation and a classic case in research ethics. In this paper I use the lead paint study to assist in the analysis of the ethics of research on less expensive, less effective interventions. I critically evaluate an argument by Buchanan and Miller who defend both the Kennedy Krieger lead paint study and public health research on less expensive, less effective interventions. I conclude that Buchanan and Miller’s argument is flawed but that does not mean that research designed to find less effective interventions cannot be justified in some situations. Based on my analysis, I suggest questions to ask when considering such research and I offer some principles to guide us. In the process, light is shed on the various debates and issues raised by the lead paint study; e.g. standards of care, researchers’ responsibilities to research subjects, the distinction between treatment and research and the question of what it is that legitimizes public health research. Merle Spriggs is supported by a grant from the Alfred Felton Bequest which is managed by ANZ Trustees.     

Kinetic advantage for transport into hamster intestine of glucose generated from phlorizin by brush border beta-glucosidase

Phlorizin, labeled with tritium only in the glucose moiety, was used as substrate for the beta-glucosidase present in brush border membranes from hamster intestine in order to study, simultaneously, the kinetics of hydrolysis and the fate of the [3H]glucose liberated by the enzyme. The [3H]glucose seems to experience the same hydrolase related transport into the intestinal villi as the hexoses liberated from the common disaccharides byu their respective hydrolases. The released [3H]glucose accumulation rate is only partially inhibited by unlabelled glucose added to the medium as either the free sugar or as the precursors sucrose, lactose or glucose 1-phosphate, and then only when these sugars are present at very high levels. Furthermore, glucose oxidase, added to the medium as a glucose scavenger, has no effect on the uptake rate of the phlorizin hydrolase-liberated sugar. These and other findings are presented as evidence that, under conditions where the Na+-dependent glucose carrier is more than 97% inhibited by phlorizin, the glucose derived from the inhibitor, like the hexoses from disaccharides, has a kinetic advantage for transfer into the intestinal tissue.     

Requirement of protein synthesis for the induction of ribonucleoside diphosphate reductase mRNA in Escherichia coli

Summary An RNA-DNA hybridization assay was used to quantitate the ribonucleoside diphosphate reductase mRNA synthesis (nrd mRNA) to show that gene expression was dependent on protein synthesis. The increased nrd mRNA synthesis induced by inhibition of DNA synthesis was eliminated by simultaneous inhibition of protein synthesis. It was further found that protein synthesis is required not only initially but continuously during DNA inhibition for increased expression of nrd mRNA synthesis.