The importance of the pylorus as a regulator of solid and liquid emptying from the stomach

The role of the pylorus in the control of gastric emptying of liquids and digestible solids was investigated in the present study by pylorus excision in six pigs. The pylorus was left intact in another six pigs. Antro-pyloro-duodenal motility was recorded by a sleeve sensor and side holes. Liquid emptying was significantly more rapid in pylorus excised than in pylorus intact animals, during intraduodenal infusion of isosmolar dextrose (712 mL vs 107 mL), fatty acid (402 mL vs 46 mL), amino acids (752 mL vs 112 mL), 25% dextrose (392 mL vs 51 mL) and 3 normal saline (705 mL vs 157 mL). In pylorus excised animals, in contrast to pylorus intact animals, the manometric pattern of isolated pyloric pressure waves at the distal stomach was rarely seen (P < 0.05). In a second series of experiments, pylorus excised animals emptied significantly more (P < 0.04) meat over 120 min (181 g) than pylorus intact animals (80 g), but the proportion of particle sizes emptied was unaltered. In the pig, localized pyloric contractions are important for retardation of gastric emptying when nutrient or hyperosmolar solutions enter the duodenum. By contrast, the pylorus is unimportant in determining the size of solid particles emptied from the stomach.     

Relationship of the hematopoietic cycle to the combined activities of a stimulator and a short-lived inhibitor

Substances that circulate in the blood following drug-induced bone marrow aplasia produce a biphasic curve of DNA synthesis in cells in liquid and semisolid cultures which reflect relative concentrations of these growth regulators of hematopoiesis. This net effect magnified by induced marrow failure in human, rat, and mouse is a sinusoidal curve that is the reciprocal of the WBC. Generated in the bone marrow, humoral stimulating activity (HSA) produces peak growth of colonies in agar (CFU-GM) during the proliferative phase of bone marrow recovery, whereas humoral inhibitory activity (HIA), present at the time of marrow maturation, suppresses colony growth. Split femurs from rats given cyclophosphamide (CY) and killed at regular intervals condition media that affect DNA synthesis in a fashion similar to that of HSA-HIA in the rats' sera. In Dexter cultures, HSA is derived from the adherent rather than the hematopoietic cell, whereas HIA is produced by that nonadherent cell. Animals treated with a lethal dose of busulfan (BU) produce large amounts of HSA in vivo until death. Those transplanted with adherent bone marrow cells depleted of hematopoietic cells on day 1 after BU also die, whereas those given nonadherent marrow cells survive and generate HIA at the time of bone marrow recovery. HSA and media conditioned by bone marrow stromal cells causes an increase in spleen colonies (CFU-S), as does HIA. These studies support the contention that the net effect of putative regulators of hematopoiesis, measured in the drug-perturbed state, consist of a constantly present stimulator emanating from bone marrow stroma, and a variable inhibitor produced by maturing hematopoietic bone marrow cells.     

Simian virus 40-transformed adherent cells from human long-term marrow cultures: cloned cell lines produce cells with stromal and hematopoietic characteristics

Adherent cells from long-term marrow cultures from 23 individuals were transformed with wild-type simian virus 40 (SV40). After transformation, cloned cell lines were developed that even after rigorous subcloning invariably produced both stromal cells and round cells. The stromal cells expressed cytoskeletal filaments similar to those of long-term marrow culture adherent cells and produced interstitial and basal lamina collagen types. The round cells had the electron microscopic appearance of primitive hematopoietic cells and when examined with cytochemical stains and monoclonal antibodies to hematopoietic differentiation antigens had reaction patterns suggestive of cells from several lineages. Most round cells expressed the pan- hematopoietic T-200 determinant, and lesser percentages expressed the early T cell antigens CD-1 and CD-3, HLA-DR determinants, the monocytic antigen recognized by Leu M3, and the myeloid antigens detected by monoclonal antibodies 1G10 and 12.8. In addition, when plated in semisolid medium in the presence of a source of colony-stimulating activity, up to 11% of the cells formed colonies consisting of blastlike cells that also expressed hematopoietic cell surface determinants. The data suggest that adherent cells in long-term marrow cultures contain a cell that after transformation by SV40 obligately produces cells with hematopoietic as well as stromalike features.     

Cloning and nucleotide sequence of a mouse erythrocyte beta-spectrin cDNA

A rabbit monospecific antibody for mouse beta-spectrin was used to screen a mouse anemic spleen cDNA expression library. A mouse beta- spectrin cDNA clone was isolated and identified by its ability to make mouse beta-spectrin-like antigens in Escherichia coli. This clone was used to probe total RNA from various mouse tissues. Anemic spleen RNA showed two strongly hybridizing RNA species of approximately 6 and 8 kb. Two very faintly hybridizing bands of about 6 kb and 10 kb could also be seen in total mouse brain RNA. All of these bands could be detected after hybridization under both stringent and nonstringent conditions. This suggests that erythroid beta-spectrin may also be expressed in the brain. No bands could be detected in kidney, liver, or spleen RNA. Southern blot analysis of mouse genomic DNA showed a single hybridizing band after digestion with several restriction endonucleases even under nonstringent conditions. Nucleotide sequencing of the cDNA insert revealed almost complete identity between the N-terminus of the deduced amino acid sequence of the cDNA clone and the C-terminal 15 amino acids of a peptide derived from the beta-8 repeat unit of human erythrocyte beta-spectrin. The deduced amino acid sequence contained most of the conserved amino acids characteristic of the 106 amino acid repeat unit first found in human alpha-spectrin and thus provides the first evidence for a complete 106 amino acid repeat unit structure in beta-spectrin.     

Autologous bone marrow transplantation using unfractionated cells cryopreserved in dimethylsulfoxide and hydroxyethyl starch without controlled-rate freezing

To develop a simplified method of bone marrow (BM) cryopreservation, changes were made in the standard method in three areas: the cryoprotectant, the method of cell freezing, and the storage temperature. Unfractionated BM cells from 60 patients were cryopreserved in 300-mL aliquots in both dimethylsulfoxide (DMSO) and hydroxyethyl starch (HES), a combination known to preserve granulocytes successfully. The cells were frozen without rate-controlled freezing by simple immersion into a -80 degrees C freezer where they remained until the time of reinfusion. The 60 patients underwent 72 autologous transplants after three high-dose chemotherapy regimens: 30 received high-dose carmustine in combination, five received high-dose busulfan and cyclophosphamide, and 37 received high-dose aziridinylbenzoquinone. The BM was infused for more than 30 minutes after rapid thawing at 37 degrees C. The mean post-thaw nucleated cell recovery was 96% +/- 11.6%, and Trypan blue dye exclusion was 82.2% +/- 9.2%. The mean postthaw CFU-GM and BFU-E recoveries were 81.9% +/- 39.0% and 90.5% +/- 41.2%. Complete count recovery occurred in 68 of 72 transplants. Median times to a WBC count greater than 1,000/microL, a granulocyte count greater than 1,000/microL and a platelet count greater than 20,000/microL were 15, 21, and 15 days, respectively. Risk factors for delayed recovery were not found. Unfractionated BM cells can be successfully cryopreserved in the DMSO/HES mixture rapidly and inexpensively, without rate-controlled freezing or storage at liquid nitrogen temperatures.     

Functional differences between two Fc receptor ITAM signaling motifs

Most Ig receptors exist as multi-subunit complexes with a unique ligand binding alpha chain and a common signaling FcR gamma-chain. The myeloid Fc gamma RIIa (CD32) appears unique among FcR because both ligand- binding and signaling capacity are found in the alpha chain. Within the cytoplasmic tails of Fc gamma RIIa and FcR gamma-chain similar, but not identical, activatory motifs (ITAMs) have been defined, in which tyrosines play an important role. Previously, Fc gamma RIIa-ITAM was shown to be critical for both proximal and distal activatory functions in IIA1.6 B-cell transfectants. Triggering of interleukin-2 (IL-2) release and antigen presentation was absent in Fc gamma RIIa, but not in FcR gamma-chain receptor complexes. We now assessed the capacity of Fc gamma RIIa wild-type and Fc gamma RIIa/gamma chimeric molecules to trigger IL-2 production and antigen presentation by B cells. Both of these functions could solely be triggered by receptors containing the FcRIIa was capable of functional interaction with FcR gamma-chain, thus reconstituting the capacity to trigger IL-2 release and antigen presentation. These data document qualitative differences between Fc receptor ITAMs.     

Impact of insulin glargine and lixisenatide on β‐cell function in patients with type 2 diabetes mellitus: A randomized open‐label study

It is known that β‐cell function can be enhanced by direct stimulation of insulin secretion or by induction of β‐cell rest, but whether both strategies can complement each other has not yet been examined. A total of 28 people with type 2 diabetes (glycated haemoglobin 7.8% ± 0.5%) were treated with either lixisenatide or titrated insulin glargine, followed by their combined administration, each over 4 weeks. First‐ and second‐phase insulin secretion during an intravenous glucose challenge were calculated. First‐ and second‐phase insulin secretion were not increased with glargine alone, but increased after addition of lixisenatide ( P < .001). Lixisenatide alone increased first‐ and second‐phase insulin secretion ( P < .01). Addition of insulin glargine tended to further increase first‐phase insulin secretion (P = .054), as well as insulin and C‐peptide concentrations ( P < .05). Second‐phase insulin secretion was not affected by the addition of glargine. The sequence of initiating lixisenatide or glargine had no effect on the final measures of glycaemia or insulin secretion. Thus, lixisenatide and, to a lesser extent, insulin glargine, increase glucose‐stimulated insulin secretion in an additive manner.     

Human platelet aggregation by murine monoclonal antiplatelet antibodies is subtype-dependent

Twenty murine monoclonal antibodies (MoAbs) generated against different human platelet antigens induced clumping of human platelets in plasma and buffer. Whereas one MoAb could agglutinate platelets, clumping for 19 MoAbs was blocked by metabolic inhibitors, indicating that these induce platelet activation. Fifteen MoAbs were of IgG1, two of IgG2a, and two of IgG2b subtype. F(ab')2 fragments of these did not evoke an aggregatory response, but specifically inhibited aggregations by and binding of their respective intact MoAbs to platelets. Single-platelet counting technology indicated that the MoAbs bind through their antigen- binding and Fc domains mainly to the surface of the same platelet, rather than cause interplatelet-binding. Despite these similarities, the mechanism of action was nevertheless subtype-dependent. Aggregation induced by all IgG1 antibodies could consistently be prevented by blocking the Fc gamma II-receptor, whereas aggregations induced by all IgG2 antibodies still occurred with blocked Fc-receptor, provided functional complement was present. We therefore conclude that platelet activation by MoAb-binding is initiated by antigen recognition followed by an Fc domain-dependent step, which involves the Fc gamma II-receptor for IgG1-type MoAbs and complement-binding for IgG2-type MoAbs. Thus, antibodies of different subtypes can aggregate platelets via different pathways.     

Peripheral blood progenitor cell transplantation in lymphoma and leukemia using a single apheresis

Myeloablative treatment and peripheral blood progenitor cell (PBPC) transplantation are increasingly used for lymphomas and leukemias. We have sought to optimize conditions for priming, collection, and engraftment of the leukapheresis product. Fifty-four consecutive adult patients were eligible, 31 with high-grade non-Hodgkin's lymphoma of poor prognosis, 12 with Hodgkin's disease in chemosensitive relapse, and 11 with poor prognosis acute lymphoblastic leukemia. Filgrastim was administered after routine chemotherapy with VAPEC-B or HiCCOM to mobilize PBPC. A rapidly increasing white blood cell count was used to predict the time of peak PBPC release and plan leukapheresis. Forty- five patients underwent leukapheresis. A median of 14 L of blood was processed at a single apheresis. A median of 2.4 x 10(8)/kg mononuclear cells (MNCs), 1.04 x 10(6)/kg granulocyte-macrophage colony-forming cells (GM-CFCs), and 10.6 x 10(6)/kg CD34+ cells were obtained. Slightly fewer MNCs were obtained from the heavily pretreated Hodgkin's disease group. There were no other significant differences in the size or composition of the leukapheresis harvest in the three patient groups. Forty patients underwent high-dose therapy and PBPC transplantation. Filgrastim was administered by daily subcutaneous injection until the absolute neutrophil count was > or = 1 x 10(9)/L for 2 consecutive days. Rapid and sustained hematopoietic engraftment occurred in all patients. The median time to achieve a neutrophil count > or = 0.5 x 10(9)/L was 9 days (range, 8 to 16 days); to achieve a platelet count > or = 20 x 10(9)/L was 10 days (range, 6 to 88 days); and to achieve a platelet count > or = 50 x 10(9)/L was 15.5 days (range, 10 to 100 days). Neutrophil recovery was faster than that of a historical control group treated with autologous bone marrow transplantation and filgrastim, but platelet recovery times were halved in the PBPC group. There was no secondary engraftment failure. Requirements for blood and platelet transfusions, antibiotic use, and parenteral nutrition were similar in the three patient groups. The median number of days in the hospital was 13 (range, 10 to 55) in the PBPC patients, compared with 19 (range, 14 to 51) in the historical controls. Leukapheresis yields (MNC, GM-CFC, and CD34+ cell numbers) were not useful for predicting the times to engraftment. We have shown that sufficient PBPC for transplantation can be obtained at a single leukapheresis after mobilization with routine chemotherapy and filgrastim in patients with non-Hodgkin's lymphoma, Hodgkin's disease, and acute lymphoblastic leukemia, even those heavily pretreated.(ABSTRACT TRUNCATED AT 400 WORDS)