Arteriovenous malformation of the stomach

A patient with chronic anemia is presented who radiologically showed prominent rugae of the stomach. Angiography demonstrated an arteriovenous malformation with a large feeding artery and prominent draining veins.     

The effect of total parenteral nutrition (TPN) on the enteroinsular axis in the rat

The effect of 6 days of total parenteral nutrition (TPN) on the enteroinsular axis was studied in vivo and in vitro in the rat. During the TPN period, blood samples were taken from control and TPN animals to determine the comparative pattern of GIP release. Glucose, insulin and GIP responses to oral glucose (OGTT) were compared in TPN and control rats. The effect of glucose and GIP on insulin release from the isolated perfused pancreas of the same animals was investigated to determine if TPN altered the sensitivity of the beta cell. In conjunction with these studies the number and distribution of GIP-containing cells were compared in control and TPN animals. TPN resulted in no change in basal levels of glucose, insulin and IR-GIP. An exaggerated insulin response to OGTT occurred after TPN whereas the glucose response was reduced. The IR-GIP response to glucose was normal following TPN. The isolated perfused pancreas showed a 30% increase in insulin release in response to GIP after TPN. The insulin response to glucose appeared normal as did the number and distribution of GIP cells. Fluctuations in GIP and insulin levels in control animals were diurnal in nature, whereas IR-GIP levels in TPN animals remained near fasting levels. It was hypothesized that the increase in beta cell sensitivity to GIP may be causally connected to the exposure of the pancreas to chronically low levels of GIP during TPN.     

Sequence variation at the major histocompatibility complex locus DQ beta in beluga whales (Delphinapterus leucas) [published erratum appears in Mol Biol Evol 1995 Nov;12(6):1174]

Genetic variation at the Major Histocompatibility Complex locus DQ beta was analyzed in 233 beluga whales (Delphinapterus leucas) from seven populations: St. Lawrence Estuary, eastern Beaufort Sea, eastern Chukchi Sea, western Hudson Bay, eastern Hudson Bay, southeastern Baffin Island, and High Arctic and in 12 narwhals (Monodon monoceros) sympatric with the High Arctic beluga population. Variation was assessed by amplification of the exon coding for the peptide binding region via the polymerase chain reaction, followed by either cloning and DNA sequencing or single-stranded conformation polymorphism analysis. Five alleles were found across the beluga populations and one in the narwhal. Pairwise comparisons of these alleles showed a 5:1 ratio of nonsynonymous to synonymous substitutions per site leading to eight amino acid differences, five of which were nonconservative substitutions, centered around positions previously shown to be important for peptide binding. Although the amount of allelic variation is low when compared with terrestrial mammals, the nature of the substitutions in the peptide binding sites indicates an important role for the DQ beta locus in the cellular immune response of beluga whales. Comparisons of allele frequencies among populations show the High Arctic population to be different (P < or = .005) from the other beluga populations surveyed. In these other populations an allele, Dele-DQ beta*0101-2, was found in 98% of the animals, while in the High Arctic it was found in only 52% of the animals. Two other alleles were found at high frequencies in the High Arctic population, one being very similar to the single allele found in narwhal.      

A comparison of the ability of serum and monoclonal antibodies to gastric inhibitory polypeptide to detect immunoreactive cells in the gastroenteropancreatic system of mammals and reptiles

Summary A monoclonal antibody raised to gastric inhibitory polypeptide (GIP) has been compared with conventional rabbit and guinea-pig antisera to GIP. Four staining methods were tested and of these the peroxidase antiperoxidase (PAP) method proved to give the best results with both the mouse and rabbit antibodies. The monoclonal antibody, when used to stain pancreatic tissue, gave negative results whereas a distinct population of gut endocrine cells was readily demonstrable, suggesting that GIP is not a constituent of the mammalian pancreas. The monoclonal antibody was found to be the most sensitive for immunocytochemistry achieving the titre of 1:10⁶ in rat gut. A C-terminal specific antibody, with a high affinity and avidity to GIP, it was clearly the preferred antibody for immunocytochemical studies.     

Cytoplasmic streaming in Chara corallina studied by laser light scattering.

An apparatus is described by means of which the power versus frequency spectrum of the photomultiplier current can be obtained for laser light scattered by streaming cytoplasm in the algal cell Chara corallina. A Doppler peak is noted in the spectrum which is abolished when cytoplasmic streaming is arrested by electrical stimulation. For 5 cells of Chara, this simple laser-Doppler velocimeter gave streaming velocities (46-7 mum s-1, S.D. +/- 4-8 at 20 degrees C) similar to those obtained for the same cells using the light microscope (44-3 mum s-1, S.D. +/- 5-3 at 20 degrees C). A narrow distribution of streaming velocities is indicated. The technique described provides a rapid, quantitative assay of the in vivo rheological properties of cytoplasm.