Three-dimensional culture of rat exocrine pancreatic cells using collagen gels

Rat pancreatic cells were dissociated using a combined enzyme and EDTA method, grown on a plastic surface and then overlayed with collagen gel. Our studies have shown that exocrine pancreatic cells grown in this way have the ability to rearrange themselves into a three-dimensional organoid structure in which well defined epithelial lumina have been identified by ultrastructural and light microscopic examination. This in vitro system has advantages in examining the cytodifferentiation of pancreatic cells and may be exploited in studying pancreatic carcinogenesis.     

Cells involved in the immune response. XXX. An evaluation of the different assays to demonstrate rabbit spleen plaque-forming cells. Enhancement of the assay by anti-target cell antibodies

Four different procedures for the detection of rabbit spleen plaque-forming cells (PFC) directed toward the sheep erythrocyte (SRBC) antigen were evaluated in terms of their sensitivity. These included the conventional localized hemolysis in gel (LHG) assay, the thin-layer LHG assay, the LH assay using a monolayer of the target SRBC erythrocytes and the localized hemolysis in liquid phase (Cunningham) assay. The latter assay consistently proved to be the most sensitive assay. The sensitivity of this latter assay was further improved by incorporating preformed IgG or IgM antibodies directed toward the target erythrocytes, in subhemolytic concentrations, into the assay. This antibody-enhanced plaque assay in liquid medium is 20-50 times more sensitive than the conventional LHG assay.     

Axon-myelin sheath relations of oligodendrocyte unit phenotypes in the adult rat anterior medullary velum

Axon-oligodendrocyte relations of Rip-immunolabelled and dye-injected oligodendrocyte units are characterised in the adult rat anterior medullary velum (AMV). Each oligodendrocyte unit comprised the oligodendrocyte cell body, processes and the internodal myelin segments they support. Oligodendrocyte units corresponded to classically described type I/II or type III/IV unit phenotypes which respectively myelinated discrete populations of small and large diameter axons, delineated by a myelinated fire diameter of 2-4 microns (diameter of the axon plus its myelin sheath). Within units, mean fibre diameter was directly related to mean internodal length and inversely related to the number of myelin sheaths in the unit. The relationship between fibre diameter and internodal length was retained in units which myelinated axons of different diameters, indicating that axon diameter was an important determinant of the longitudinal dimensions of myelin sheaths. We also show that type III/IV units maintained a far greater volume of myelin than type I/II units. It was concluded that type I/II and III/IV oligodendrocytes represent two functionally and morphologically distinct phenotypes whose distribution densities were determined by the diameter and spatial dispersion of axons.     

Virological and serological diagnosis of cytomegalovirus infection in bone marrow allograft recipients

To detect cytomegalovirus (CMV) infections, a total of 1,074 cultures of urine, saliva, or blood were collected weekly from 43 consecutive patients undergoing allogeneic bone marrow transplantation. Twenty-three patients were seronegative before transplant and primary infection occurred in 2 (9%). Twenty patients were initially seropositive and recurrent infections occurred in 5 (25%). Three patients in the recurrent group had proven CMV pneumonitis; viraemia was detected in two recipients, while the third had CMV isolated only from bronchial lavage fluid. The serological response of the 43 patients was defined by testing 559 serial sera for specific IgG and IgM antibodies by radioimmunoassay. Passive acquisition of IgG antibodies from blood products was found in 78% of initially seronegative recipients. One patient with primary infection responded in a pattern typical of immunocompetent individuals with long-term production of specific IgG and transient production of specific IgM antibodies. The second patient also had a typical response, but this was delayed until several weeks after the start of virus excretion. In patients with recurrent infections, specific IgM production did not correlate with episodes of virus excretion. Three of five such patients failed to mount a specific IgM response, and these were the only patients in the study to develop CMV pneumonitis. We conclude that CMV infection in bone marrow recipients can only be diagnosed by detection of virus; therefore, the ability of these patients to mount humoral immune responses should not be relied upon for diagnostic purposes.     

The static elastic properties and chemical composition of the rat aorta in spontaneously occurring and experimentally induced hypertension: the effect of an anti-hypertensive drug.

The static elasticity and scleroprotein content of the aorta have been measured in 24 Okamoto spontaneously hypertensive rats aged 22-25 weeks, and 24 Wistars of the same age in which hypertension had been induced by nephrectomy and treated with a steroid. From the age of 4 weeks half the animals in each group were treated with a diuretic drug. By the age of 15 weeks caudal artery systolic blood pressure was significantly lower than control values in both drug-treated groups and remained so until death. Both types of hypertension were associated with larger diameter, thicker-walled and heavier aortas than those in the drug-treated animals. Vessels from Okamoto animals contained more collagen than those from the Wistars, although the collagen content was unchanged by drug treatment. Neither drug nor strain had any clear-cut affect on elastin content. In spite of these differences in wall thickness and chemical composition, values of the functional stiffness of the aorta measured over a wide range of pressure were similar in all four groups of animals. Using a simple model of the aorta in which elastin and collagen bear stress in parallel we find that the relationship between vessel composition and static incremental elastic modulus (structural stiffness) is similar in both models of hypertension and is not changed by drug treatment in spite of the consequent reduction in blood pressure.     

Serum-Mediated Resistance Induced with Immunogenic Preparations of Salmonella typhimurium

Serum obtained from animals immunized with attenuated Salmonella typhimurium strain RIA, heat-killed bacterial suspensions, or immunogenic ribosomal preparations was capable of passively conferring protection on normal recipient mice to challenge infection with virulent S. typhimurium strain SR-11. Protection was measured by the ability of a recipient animal to reduce the total number of challenge organisms significantly below that found in challenged control mice. Intraperitoneal administration of 0.1 ml of pooled sera was more effective than 0.05 ml in transferring resistance. The transfer of equivalent amounts of immune serum subcutaneously did not result in demonstrable resistance. In all cases in which serum transfer was effective, resistance was maximal at 5 days, greatly diminished by 10 days, and gone by 15 days post-transfer. Pooled serum obtained from normal donor mice or 0.2 ml of serum from mice hyperimmunized with immunogenic ribonucleic acid preparations did not possess the capacity to confer demonstrable resistance on normal recipients.     

Effects of ethanol on murine aggression assessed by biting of an inanimate target

The effects of acutely administered ethanol (0, 0.5, 1.0 and 2.0 g/kg, IP) were studied in a tube-restraint/target biting model of aggressive responding using naive group-and individually-housed male Swiss mice. Behavioural measures were the latency to the first bite and the biting frequency. In saline-injected control animals, the levels of responding were significantly higher in group-housed than isolated mice. Animals given alcohol exhibited a dose-dependent suppression of biting frequency, and an increase in biting latency. Mice experienced in the tube-testing situation showed reduced baseline levels of biting, but alcohol produced similar effects to those in naive mice. There was no evidence of a biphasic action of alcohol.     

The impact of newspaper advertising on a regional antenatal health campaign

In 1981 the West Midlands Health services undertook a publicity campaign aimed at helping women to understand more about keeping healthy during pregnancy and encouraging them to seek early ante-natal care. A series of full page advertisements on ante-natal care were placed in local newspapers in the Region. Set out here are the findings of two studies of the impact of the publicity campaign. The first shows how far people's knowledge of what to do during pregnancy was altered by the publicity, and the second shows what people thought of the advertisements themselves and the further information sent to them on request.     

Precision Tracing of Household Dengue Spread Using Inter- and Intra-Host Viral Variation Data,Kamphaeng Phet,Thailand

Dengue control approaches are best informed by granular spatial epidemiology of these viruses, yet reconstruction of inter- and intra-household transmissions is limited when analyzing case count, serologic, or genomic consensus sequence data. To determine viral spread on a finer spatial scale, we extended phylogenomic discrete trait analyses to reconstructions of house-to-house transmissions within a prospective cluster study in Kamphaeng Phet, Thailand. For additional resolution and transmission confirmation, we mapped dengue intra-host single nucleotide variants on the taxa of these time-scaled phylogenies. This approach confirmed 19 household transmissions and revealed that dengue disperses an average of 70 m per day between households in these communities. We describe an evolutionary biology framework for the resolution of dengue transmissions that cannot be differentiated based on epidemiologic and consensus genome data alone. This framework can be used as a public health tool to inform control approaches and enable precise tracing of dengue transmissions.     

Aneurysmal subarachnoid hemorrhage during pregnancy: a comprehensive and systematic review of the literature

Neurosurgical Review - Aneurysmal subarachnoid hemorrhage (aSAH) is an emergent condition requiring rapid intervention and prolonged monitoring. There are few recommendations regarding the...