Automatic flush feeding pumps.
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Enteral Nutrition↗
Biomedical subjects
S A Jones
Publications and source records attributed to S A Jones.
In-vivo measurements of blood flow velocity profiles in canine ilio-femoral anastomotic bypass grafts.
In-vivo velocity profiles were recorded with a 20 MHz 80-channel pulsed Doppler ultrasound velocimeter in canine end-to-side ilio-femoral anastomotic grafts. The geometries were obtained from casts of the anastomotic region, and flow rates were measured with electromagnetic flow probes. Three cases reported here include a "standard" geometry, which was similar to previously studied in vitro models, a stenosed geometry, and a case with below average flow rate. Observed flow features include separation at the hood and toe, movement of the floor stagnation point, and skewed profiles in the proximal outflow segment. Out-of-plane curvature and lateral displacement of the anastomosis inlet appear to have a strong effect on the flow fields. In addition, compliance affects the instantaneous flow rates within the proximal and distal branches.
Anastomosis, Surgical↗
Measurements of velocity and wall shear stress inside a PTFE vascular graft model under steady flow conditions.
The flow field inside a model of a polytetrafluorethylene (PTFE) canine artery end-to-side bypass graft was studied under steady flow conditions using laser-Doppler anemometry. The anatomically realistic in vitro model was constructed to incorporate the major geometric features of the in vivo canine anastomosis geometry, most notably a larger graft than host artery diameter. The velocity measurements at Reynolds number 208, based on the host artery diameter, show the flow field to be three dimensional in nature. The wall shear stress distribution, computed from the near-wall velocity gradients, reveals a relatively low wall shear stress region on the wall opposite to the graft near the stagnation point approximately one artery diameter in axial length at the midplane. This low wall shear stress region extends to the sidewalls, suture lines, and along the PTFE graft where its axial length at the midplane is more than two artery diameters. The velocity distribution inside the graft model presented here provides a data set well suited for validation of numerical solutions on a model of this type.
Anastomosis, Surgical↗
In situ hybridization demonstration of albumin mRNA in B6C3F1 murine liver and hepatocellular neoplasms.
In situ hybridization was used to detect albumin mRNA in normal liver and hepatocellular neoplasms in 20 male B6C3F1 mice between 17 and 24 months of age. Positive signals for albumin were observed consistently in the cytoplasm of hepatocytes in normal liver, particularly in periportal areas. No signals were observed in other cells, such as Kupffer's cells, mesenchymal cells, or bile duct epithelium. Of hepatocellular adenomas, 11/11 (100%) stained positively for albumin mRNA, whereas 14/15 (93%) of primary hepatocellular carcinomas showed positive expression. Albumin mRNA was also detected in extrahepatic metastases of hepatocellular carcinoma, including 9/15 (60%) of pulmonary neoplasms and 5/12 (42%) of metastases at other sites. The pulmonary metastases of hepatocellular carcinoma frequently exhibited a glandular, papillary, or sarcomatous histologic appearance. The presence of albumin in these tumors, lacking characteristic hepatocellular phenotype, is a potential determinant of hepatic lineage. We conclude that in situ hybridization for albumin mRNA in mice is a useful tool in the differential diagnosis of hepatocellular carcinoma, particularly in the case of pulmonary metastasis. This technique may also enable recognition of hepatocyte differentiation in glandular structures with phenotypic features of biliary cells, as seen in mixed hepatocellular-cholangial neoplasms.
Adenoma, Liver Cell↗
Dissection of the molecular mechanism of action of GW5638, a novel estrogen receptor ligand, provides insights into the role of estrogen receptor in bone.
The estrogen receptor (ER) mixed agonists tamoxifen and raloxifene have been shown to protect against bone loss in ovariectomized rats. However, the mechanism by which these compounds manifest their activity in bone is unknown. We have used a series of in vitro screens to select for compounds that are mechanistically distinct from tamoxifen and raloxifene in an effort to define the properties of an ER modulator required for bone protection. Using this approach, we identified a novel high affinity ER antagonist, GW5638, which when assayed in vitro functions as an ER antagonist, inhibiting the agonist activity of estrogen, tamoxifen, and raloxifene and reversing the "inverse agonist" activity of the pure antiestrogen ICI182,780. Thus, GW5638 appears to function as an antagonist in these in vitro systems, although in a manner distinct from other known ER modulators. Predictably, therefore, GW5638 alone displays minimal uterotropic activity in ovariectomized rats, but will inhibit the agonist activity of estradiol in this environment. Unexpectedly, however, this compound functions as a full ER agonist in bone and the cardiovascular system. These data suggest that the mechanism by which ER operates in different cells is not identical, and that classical agonist activity is not required for the bone protective activity of ER modulators.
Animals↗
The value of direct immunofluorescence as a diagnostic aid in dermatomyositis--a study of 35 cases.
Dermatomyositis (DM) in a inflammatory disorder of skeletal muscle and skin closely related to other connective tissue diseases; however, to date, no conclusive immunofluorescence (IMF) data are available for the disorder. The aim of this study was therefore to analyse retrospectively the clinical, histological and direct IMF findings for a group of 35 patients who had presented during an 8-year period. Clinically, 29 of the patients had the typical cutaneous features of DM, while 16 had evidence of myositis based on electromyographic or muscle biopsy findings; six developed malignant tumours during the study period, three of which proved fatal. Cutaneous histopathology findings were compatible with the diagnosis of DM in 18 cases, with evidence of a lupus band in six. Direct IMF showed a lupus band at the basement membrane zone in 19 (with IgM, IgG or C3), with colloid bodies in seven. Serologically, only nine were antinuclear antibody positive, one extractable nuclear antibody positive and all 35 anti-Jo-1 negative. Eight had other circulating autoantibodies, namely thyroid (three), gastric parietal cell (two), smooth muscle (two) and rheumatoid factor (one). Our findings suggest that direct IMF can be a useful adjunct in the investigation of patients with DM, and may prove helpful in diagnosis when both the histopathology and serology are inconclusive.
Adolescent↗
Chemokine receptor specific for IP10 and mig: structure, function, and expression in activated T-lymphocytes.
A human receptor that is selective for the CXC chemokines IP10 and Mig was cloned and characterized. The receptor cDNA has an open reading frame of 1104-bp encoding a protein of 368 amino acids with a molecular mass of 40,659 dalton. The sequence includes seven putative transmembrane segments characteristic of G-protein coupled receptors. It shares 40.9 and 40.3% identical amino acids with the two IL-8 receptors, and 34.2-36.9% identity with the five known CC chemokine receptors. The IP10/Mig receptor is highly expressed in IL-2-activated T lymphocytes, but is not detectable in resting T lymphocytes. B lymphocytes, monocytes and granulocytes. It mediates Ca2+ mobilization and chemotaxis in response to IP10 and Mig, but does not recognize the CXC-chemokines IL-8, GRO alpha, NAP-2, GCP-2. ENA78, PF4, the CC-chemokines MCP-1, MCP-2, MCP-3, MCP-4, MIP-1 alpha, MIP-1 beta. RANTES, 1309, eotaxin, nor lymphotactin. The exclusive expression in activated T-lymphocytes is of high interest since the receptors for chemokines which have been shown so far to attract lymphocytes, e.g., MCP-1, MCP-2, MCP-3, MIP-1 alpha, MIP-1 beta, and RANTES, are also found in monocytes and granulocytes. The present observations suggest that the IP10/Mig receptor is involved in the selective recruitment of effector T cells.
Amino Acid Sequence↗
Different functions for the interleukin 8 receptors (IL-8R) of human neutrophil leukocytes: NADPH oxidase and phospholipase D are activated through IL-8R1 but not IL-8R2.
Two monoclonal antibodies, anti-IL8R1 and anti-IL8R2, raised against both interleukin 8 receptors (IL-8R) of human neutrophils, IL-8R1 and IL-8R2, were used to study individual receptor functions after stimulation with IL-8, GRO alpha, or NAP-2. Efficacy and selectivity of the antibodies were tested in Jurkat cells transfected with cDNA coding for one or the other receptor. The binding of 125 I labeled IL-8 and IL-8-induced changes of the cytosolic free Ca2+ concentration were inhibited by anti-IL8RI in cells expressing IL-8R1 and by anti-IL8R2 in cells expressing IL-8R2. In human neutrophils, release of elastase was observed after stimulation with IL-8 or GRO alpha. The response to IL-8 was inhibited slightly by anti-IL8R1 and more substantially when both monoclonal antibodies were present, while the response to GRO alpha was inhibited by anti-IL8R2 but was not affected by anti-IL8R1. These results indicate that both IL-8 receptors can signal independently for granule enzyme release. Superoxide production, a measure of the respiratory burst, was obtained with increasing concentrations of IL-8 with maximum effects at 25 to 50 nM, but no response was observed upon challenge with GRO alpha or NAP-2 up to 1000 nM. The superoxide production induced by IL-8 was inhibited by anti-IL8R1, but was not affected by anti-IL8R2. Stimulation of neutrophils with IL-8, in contrast to GRO alpha or NAP-2, also elicited phospholipase D activity. The effect of IL-8 was again inhibited by anti-IL-8R1 but not by anti-IL8R2, indicating that this response, like the respiratory burst, was mediated by IL-8R1. Taken together, our results show that IL-8R1 and IL-8R2 are functionally different. Responses, such as cytosolic free Ca2+ changes and the release of granule enzymes, are mediated through both receptors, whereas the respiratory burst and the activation of phospholipase D depend exclusively on stimulation through IL-8R1.
Antigens, CD↗
Expression of high- and low-affinity receptors for C3a on the human mast cell line, HMC-1.
The proteolytic cleavage product of complement component 3, (C3a), is like C4a and C5a, is a potent anaphylatoxin and induces the production of inflammatory mediators in phagocytes. Notably, mast cells respond to C3a with the release of vasoactive substances, including histamine. We have examined the function and receptor binding of C3a in a human leukemic mast cell line, HMC-1. Similar to chemoattractant agonists in leukocytes, C3a induced rapid cytosolic free calcium concentration increases in HMC-1 cells. EGTA did not diminish this response, indicating that mobilizable Ca2+ was from intracellular stores. Receptors of C3a in HMC-1 cells couple in part to Bordetella pertussis toxin-sensitive G-proteins and, therefore, appear to belong to the family of serpentine receptors that require G-proteins for signal transduction. HMC-1 cells express two types of C3a receptors, C3aR1 and C3aR2, that were shown to bind 125I-C3a with high-(Kd1 = 2.1-4.8 nM) or low-affinity (Kd2 = 30-150 nM), and both receptors are expressed at high level: 3 x 10(5)-6 x 10(5) C3aR1/cell and 5 x 10(5)-2.3 x 10(6) C3aR2/cell. Results from cross-linking experiments with 125I-C3a fully agree with the presence of two different classes of C3a receptors in HMC-1 cells. Two membrane proteins with apparent molecular masses of 54-61 kDa (p57) and 86-107 kDa (p97) could be covalently modified with 125I-C3a, and this cross-linking was inhibited with an excess of unlabeled C3a. Many of the known agonists for leukocytes including 13 chemokines (IL-8, NAP-2, GRO alpha, ENA-78, IP10, PF4, MCP-1, 2 and 3, RANTES, MIP-1 alpha, MIP-1 beta and I309), three neuropeptides (neuropeptide Y, somatostatin and calcitonin), as well as C5a, did not activate HMC-1 cells, indicating that C3a is one of a few protein ligands for which this cell line expresses specific receptors. The apparent selectivity for C3a and the abundant expression of C3a receptors make the HMC-1 cell line an excellent choice for the cloning of the receptor genes.
Anaphylatoxins↗
Effects of donor age and brain-derived neurotrophic factor on the survival of dopaminergic neurons and axonal growth in postnatal rat nigrostriatal cocultures.
Early postnatal rat brain tissue can be grown for several weeks as organotypic slice cultures by the roller-tube method. We have here used this method to study the effects of donor age and brain-derived neurotrophic factor (BDNF) on the survival and growth of tyrosine hydroxylase immunoreactive (TH-i), dopaminergic (DA) neurons during the postnatal period when their nerve fibers normally innervate the striatal target. Tissue slices of ventral mesencephalon (VM) and striatum were prepared from newborn and 7-day-old rats and cocultured for 3--3 1/2 weeks with different combinations of the two donor ages. After immunocytochemical staining the number of TH-i, ventral mesencephalic neurons were counted, and the growth of TH-i fibers into the striatal part of the cocultures was evaluated. Co-cultures, with both VM and striatal slices prepared from newborn rats, contained a significantly higher number of TH-i neurons and displayed a significantly increased innervation of the striatal slices compared with other combinations of donor ages. Addition of BDNF resulted in both an increased survival of TH-i neurons and an increased growth of TH-i fibers into the cocultured striatal slices. Significant neurotrophic effect of BDNF did, however, require young donor age of both VM and striatal slices. It is suggested that BDNF induces more cells, possibly progenitor cells, to express TH immunoreactivity. Alternatively BDNF may suppress apoptotic cell death documented by others to occur in the postnatal rat substantia nigra pars compacta. Irrespective of the mechanisms, survival of more TH-i neurons was related to an increased innervation of the striatal slices by TH-i nerve fibers. The observed effects of BDNF on both survival and fiber growth of TH-i neurons indicate a potential role of BDNF for treatment of Parkinson's disease or grafts of immature DA neurons transplanted to patients with Parkinson's disease. A significant trophic effect of BDNF did, however, seem to depend on young developmental age of both striatum and VM. Parallel treatment with striatal neurotrophic factors may therefore be a necessary prerequisite to a trophic effect of BDNF under clinical conditions.
Age Factors↗
The influence of acoustic impedance mismatch on post-stenotic pulsed-Doppler ultrasound measurements in a coronary artery model.
Acoustic impedance mismatch at the fluid-wall interface was shown to affect the spectra from an intravascular Doppler device in an in vitro model with a diameter typical of human coronary arteries. Measurements were obtained first under Poiseuille flow conditions with impedance mismatches of 0%, 7% and 12%, and then under stenosed conditions for the 0% and 7% mismatch cases. For the zero mismatch case, the Doppler spectra could be readily interpreted in terms of fluid mechanical phenomena. When mismatch was present, the spectra from Poiseuille flow exhibited multiple peaks which could not be directly related to the velocity profile. Also, the spectra from stenosed flow with a mismatch of 7% were similar to those from the zero mismatch case but did not exhibit the specific flow-related features as clearly. These results indicate that the impedance mismatch alters the acoustic environment inside the model and that this causes artifact in the Doppler spectra.
Blood Flow Velocity↗
An unusual (and somewhat piercing) cause of paraphimosis.
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Adult↗
Pustular vasculitis and sclerosing cholangitis.
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Adult↗
Expression of phagocyte NADPH oxidase components in human endothelial cells.
Low-level generation of reactive oxygen species (ROS) by endothelial cells in response to a variety of stimuli has been observed; however, the enzyme system responsible is unknown. Using a variety of techniques, we examined for components of the phagocyte superoxide-generating NADPH oxidase to elucidate whether this enzyme could be a source of endothelial-derived ROS. Superoxide generation on addition of 100 microM NAD(P)H to human umbilical vein endothelial cell (HUVEC) sonicates (using lucigenin-enhanced chemiluminescence) was partially inhibited on addition of the flavoenzyme inhibitor diphenyliodonium (IDP). Reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated expression of gp91phox, p22phox, p67phox, and p47phox in four independent HUVEC isolates. Expression of p22phox was also confirmed by Northern blotting. RT-PCR for tumor necrosis factor-alpha was negative, indicating an absence of mononuclear cell contamination (a potential source of NADPH oxidase). Immunoperoxidase staining, using anti-p47phox (JW-1)- and anti-p67phox (JW-2)-specific antibodies, showed protein expression of these cytosolic components. However, heme spectroscopy failed to indicate the presence of the low-potential cytochrome b558. These data indicate that cultured human endothelial cells express both mRNA and protein for cytosolic components of the phagocyte superoxide-generating NADPH oxidase. However, because the cytochrome b558 heme could not be conclusively demonstrated, a contribution of the phagocyte NADPH oxidase to endothelial oxidant generation may be unlikely.
Cells, Cultured↗
Rebound increase in fetal breathing movements after 24-h prostaglandin E2 infusion in fetal sheep.
We investigated the hypothesis that the precipitous decrease in prostaglandin E2 (PGE2), a potent inhibitor of fetal breathing, from high plasma concentrations during labor causes a rebound stimulation of breathing without newborn concentrations falling below prelabor fetal values. Fetal plasma PGE2 concentration was gradually increased from 384 +/- 82 (SE) pg/ml in 2-h steps [0 (baseline), 1.5, 3, and 6 micrograms/min] to labor levels (1,230 +/- 381 pg/ml at 6 micrograms/min) and then was maintained for 24 h (n = 9). PGE2 at 1.5 micrograms/min significantly decreased breathing incidence [from 42 +/- 4 (baseline) to 14 +/- 4%] and breath amplitude (from 2.1 +/- 0.5 to 1.5 +/- 0.2 arbitrary units) and increased breath-to-breath interval (from 1.16 +/- 0.07 to 1.56 +/- 0.06 s). No further dose-related changes were observed. During the first 2 h after PGE2 infusion was stopped, PGE2 concentration returned to basal (352 +/- 64 pg/ml) but breathing incidence and amplitude were significantly higher (74 +/- 8% and 2.4 +/- 0.3 arbitrary units, respectively) and breath-to-breath interval was significantly lower (0.95 +/- 0.10 s) than were basal levels. Changes arose within approximately 15 min and were maintained for at least 4 h. Breathing did not change significantly in the saline-treated group (n = 7). Results suggest that the rapid decrease in plasma PGE2 concentration at birth promotes the onset of breathing.
Adrenocorticotropic Hormone↗
Intradialytic parenteral nutrition after small bowel resection.
Malnutrition is frequently observed in the hemodialysis patient population. It may be associated with increased morbidity and mortality as well as affect overall quality of life, which may already be compromised from dialytic physical and psychological demands. In the past, intradialytic parenteral nutrition (IDPN) has been available to hemodialysis patients as an adjunct to their dietary intake. In this time of cost containment and the increasing need to scientifically justify the benefit of such therapies to have them paid for by third party reimbursers, IDPN is coming under much scrutiny. This report describes a case of inadequate enteral nutrient absorption in a malnourished hemodialysis patient. This is a case in which IDPN was beneficial and without which other alternatives would have proven more costly physically, emotionally, and economically to the patient.
Aged↗
Conversion of pemphigoid gestationis to bullous pemphigoid--two refractory cases highlighting this association.
Pemphigoid gestationis and bullous pemphigoid are autoimmune diseases characterized by subepidermal blisters and antibodies against the hemidesmosomal antigens: BPAG1 and BPAG2. Clinical histological and immunological similarities between pemphigoid gestationis and bullous pemphigoid suggest that they may have common pathogenetic determinants. We report two patients who presented initially with clinico-pathological features characteristic of pemphigoid gestationis but who subsequently evolved into bullous pemphigoid.
Adult↗
The influence of target and non-target brain regions on the development of mid-brain dopaminergic neurons in organotypic slice culture.
The development and regeneration of rat dopaminergic neurons of the ventral mesencephalon was studied in organotypic slice cultures. Single ventral mesencephalon cultures and co-cultures of ventral mesencephalon with striatum (a target region) or cerebellum (a non-target region) were prepared from postnatal day 1 Wistar rats. Cultures were processed for tyrosine hydroxylase and glial fibrillary acidic protein immunoreactivity, at two day intervals, for an overall incubation period of 20 days. Analysis of these cultures revealed that the striatal target tissue, exerted neither a trophic nor a tropic influence on the tyrosine hydroxylase immunoreactive neurons. In both single and co-cultures, tyrosine hydroxylase immunoreactive neurites projected radially from the ventral mesencephalon slice. However, in striatal co-cultures, tyrosine hydroxylase immunoreactive neurites were seen penetrating the striatal slice, whereas in cerebellar co-cultures no tyrosine hydroxylase immunoreactive neurites entered the cerebellar tissue. Glial fibrillary acidic protein positive cells actively migrated from the tissue sections, however tyrosine hydroxylase immunoreactive neurite outgrowth was not guided by these glial cells. Tyrosine hydroxylase immunoreactive neurites terminated once they had penetrated the striatal slice. This retardation of neurite growth by a target region could be important in establishing and reinforcing synaptic connections in the developing nigro-striatal pathway.
Animals↗