Sebekiosis in captive alligator hatchlings.
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Alligators and Crocodiles↗
Biomedical subjects
M King
Publications and source records attributed to M King.
[Mechanical fatigue of an arterial prosthesis].
This case study reports the analysis of a knitted polyester arterial prosthesis that was implanted in an 18-year old patient for five years following a bicycle accident which injured the left external iliac artery. In spite of the prosthesis, the patient continued to participate in competitive cycling. The graft became dilated and stretched by tension from the hypertrophic psoas muscle, and because the patient presented with pain and claudication, a second surgical operation was performed. The central region of the prosthesis was badly kinked. A segment was resected and analyzed in terms of pathological, textile and chemical properties. The analysis showed a poorly healed graft that had suffered from mechanical and chemical degradation. The findings point to the wisdom of implanting woven rather than knitted grafts in young patients and also suggest that in this particular case, where mechanical deterioration was accompanied by chemical degradation, it would have been preferable to remove the whole prosthesis.
Adolescent↗
Iron transport across brush-border membranes from normal and iron-deficient mouse upper small intestine.
We have studied Fe(III)-citrate and Fe(II)-ascorbate uptake by purified intestinal brush-border membrane vesicles from normal (iron-replete) and iron-deficient mice. In iron-replete mice using a final Fe(III) concentration of 1.43 microM, 25-30 pmol of Fe(III)/mg of protein were bound to the membranes versus 65-70 pmol in iron-deficient mice. Fe(II) uptake in normal mice using a final Fe(II) concentration of 1.79 microM was 1600-1800 pmol/mg of protein versus 3600-4000 pmol in iron-deficient mice. Evidence that Fe(II) was transported into the vesicles by a membrane carrier-mediated process was obtained by observing saturation kinetics under conditions of isotope exchange at equilibrium in mice rendered iron-deficient, but not in iron-replete mice. Eighty per cent of the transported Fe(II) could be removed by strong chelating agents. The remainder was exchangeable with Fe(II) in the medium when measured under equilibrium conditions. We can explain these results by the following model; iron uptake appears to be a 2-fold process. The first step is the transport of Fe(II) across the membrane by a carrier-mediated process which is biologically regulated. The second step is the subsequent binding of iron on the inside of the membrane. The number of binding sites is also regulated by the iron status of the mouse. The membrane binding affinity for Fe(II) appears to be weaker than that for dithiothreitol but stronger than for ascorbate.
Animals↗
Cytocompatibility of albuminated polyester fabrics.
An alternative to the usual technique of preclotting porous textile vascular prostheses prior to surgical implantation is to render them impermeable to blood by impregnation with a cross-linked albumin filler matrix. This material subsequently becomes the foundation for cellular development. The compatibility of such impregnated fabrics with newly formed endothelial cells has been evaluated by an in vitro organotypic culture method. This technique enables the characterization and numeration of cells that develop on blood contact surfaces and enables determination of their rate of development. Woven, knitted, and velour fabrics were evaluated following coating with albumin and either storage in Tyrode solution or 40% ethanol or desiccation by critical point drying. Preclotted cardiovascular repair fabrics prepared according to conventional surgical protocol served as controls. The identification of the newly formed cells was confirmed histologically. The most extensive and rapid cellular development was observed on the woven fabric and is believed may have resulted from the smoother surface topography of this substrate. Good cellular development was noted particularly on fabrics which had been stored in Tyrode solution. Ethanol had a deleterious effect on the apparent compatibility.
Albumins↗
Anaphylactic reaction to cytarabine: in vitro evidence that the response is immunoglobulin E mediated.
A 48-year-old female developed significant bronchospasm on two occasions after being treated with cytarabine (Ara-C) by the intraperitoneal route. In this report we present the first in vitro evidence that such a reaction to cytarabine can be associated with the release of histamine and therefore might be immunoglobulin E (IgE) mediated. In addition, this report emphasizes the fact that, while uncommon, severe allergic reactions to this useful chemotherapeutic agent do occur and must be considered in the differential diagnosis of anaphylaxis and related symptoms in patients receiving this drug.
Anaphylaxis↗
Infantile type 2 sialidosis in a Pakistani family--a clinical and biochemical study.
Two siblings of consanguineous parents presented in infancy with failure to thrive, mild coarsening of facies, visceromegaly and corneal opacities. One showed reduced hepatic beta-galactosidase activity suggesting a GM1-gangliosidosis variant. Both patients developed progressive coarsening of facies, slow neurological deterioration, macular cherry-red spots and punctate cataracts over the first decade. Urine screening with thin layer chromatography revealed abnormal excretion of two slow-moving oligosaccharide bands and leukocyte and fibroblast neuraminidase activity was grossly reduced. The mother, phenotypically normal, showed levels of neuraminidase compatible with heterozygosity. These patients have primary neuraminidase deficiency. The clinical and biochemical variables are reviewed.
Adolescent↗
Albumin coating of a knitted polyester arterial prosthesis: an alternative to preclotting.
Coating a knitted polyester arterial prosthesis with cross-linked albumin fills the interstices of the graft and relieves the surgeon of the necessity to preclot . This is of particular value in patients whose blood clotting properties are hypercoagulable, or hypocoagulable . In addition, such prostheses require less handling, which can lower the risk of bacteremic colonization and shorten the operative time. The in vivo behavior of the implanted albuminated prosthesis in the thoracic aorta of dogs is similar to that of preclotted grafts, although the sequences of early healing are different. The preclotted graft develops a continuous, thick thrombotic matrix on its luminal surface during the first 4 hours of implantation. Following the initiation of the fibrinolytic mechanism 24 to 48 hours postoperatively, this thrombotic deposit quickly recedes , leaving blood cells and platelets adhering here and there to the prosthetic surface. In comparison, the albuminated coating is not associated with major early thrombotic deposits. The albumin remains visible between the filaments during the first 2 weeks of implantation. Both treated and control grafts contain numerous thrombi on their inner surface after 1 to 2 weeks. After 1, 3, and 6 months, both implants are well encapsulated and present a glistening and continuous luminal surface. This excellent healing, however, can be compromised should the graft adhere too closely to the animal's lungs.+2
Albumins↗
Direct evidence for specific binding of the replicative origin of the Escherichia coli chromosome to the membrane.
The origin of replication of the Escherichia coli chromosomal DNA binds with high affinity to outer membrane preparations. This specific binding requires a 463-base-pair region of origin DNA between positions -45 and +417 of the oriC map. We show that binding does not require the presence of adjacent regions. From further analysis, we conclude that more than one binding site resides within the 325-base-pair fragment between positions +38 (BamHI) and +417 (XhoI). When this fragment is cut, two pieces bind with high affinity and one binds with lesser affinity. The binding ability of one of the high affinity sites is abolished by cutting it at position +92 with BamHI.
Binding Sites↗
Tracheal mucus clearance in high-frequency oscillation. II: Chest wall versus mouth oscillation.
We compared the tracheal mucus clearance rate (TMCR) in anesthetized dogs during spontaneous breathing (SB), ventilation by high-frequency oscillation at the airway opening (HFO/AO), and ventilation by high-frequency oscillation of the chest wall (HFO/CW). The HFO/AO was carried out by using a piston pump with a high impedance transverse flow at the proximal end of the endotracheal tube; HFO/CW was effected by creating rapid pressure oscillations in an air-filled cuff wrapped around the lower thorax of the animal, causing small tidal volumes at the mouth. The TMCR was measured by observing the rate of displacement of a charcoal marker in the lower trachea; a fiberoptic bronchoscope was used to deposit the marker before each experiment and to relocate it after a 5-min run. In 7 dogs, mean TMCR during control (SB) was 8.9 +/- 3.5 mm/min. At 13 Hz with an oscillatory tidal volume (VTO) of 1.5 ml/kg, mean TMCR was 240% of control with HFO/CW (p less than 0.001) and 76% of control with HFO/AO (NS). During HFO/AO at 20 Hz and a VTO of 3 ml/kg, mean TMCR was 97% of control. We conclude that high-frequency ventilation by rapid chest wall compression enhances tracheal mucus clearance when compared with spontaneous breathing, whereas high-frequency oscillation at the mouth does not.
Animals↗
[The Sparks-Mandril arterial prosthesis. An ingenious concept, a total failure. What can we learn from it?].
In spite of its ingenuity, the Sparks-mandril concept has failed to generate a satisfactory arterial substitute. Pathological analysis of prostheses retrieved from humans and explanted from dogs as part of a controlled laboratory study has demonstrated that the tissue laid down during the autogenous generation stage contains neither elastin fibers nor smooth muscle cells capable of providing the required dimensional stability of a blood vessel. The supporting polyester mesh tube has been found to stretch in vivo, resulting in dilation and lengthening of the prosthesis and the formation of aneurysm and thrombosis. It is recommended that the use of devices relying on the Sparks-mandril concept not to be reintroduced until such time as the mechanism of growth promoting factors for angiogenesis are fully understood.
Adult↗
Parenteral acyclovir therapy for cytomegalovirus infection after renal transplantation.
Three patients who had received cadaveric renal transplants developed fevers within three months of transplantation. Concurrent cytomegalovirus infection was confirmed by virological studies. In all three patients there was both a clinical and virological response to a five day course of intravenous acyclovir. In one patient the dose required to produce this response was 5 mg/kg/day; however two patients required 10 mg/kg/day. All three patients remain well after 8-12 months follow-up.
Acyclovir↗
Textile Teflon arterial prostheses: how successful are they?
Today the woven and knitted Teflon vascular prostheses developed over 25 years ago by Edwards are of only minor clinical interest. The literature contains a chronology of postoperative complications critical of textile Teflon as a prosthetic material, and this led to its discontinuance as a commercial product. Recent evidence from pathologic and material analyses of three grafts removed from patients after implantation for 11, 19 and 19 years, respectively, suggests that the previously reported complications were more likely to have been related to the use of silk sutures, the fraying and ravelling of the woven and weft-knitted constructions and local or systemic reactions than to degradation of the Teflon. Experimental studies of grafts implanted in the thoracic and abdominal aortas of dogs for periods of up to 6 months support these findings. Because of the apparent long-term stability of textile Teflon as an implantable material, the authors see merit in its reintroduction as a warp-knitted vascular prosthesis.
Aged↗
[First contact between blood and the arterial prosthesis. Study of the retention of the blood elements].
In order to characterize the nature of the interaction between arterial prostheses and their initial contact with blood, we propose the use of an in vitro test using labelled platelets and fibrinogen to measure the amount of the thrombotic matrix that is entrapped by the wall of the graft. The results have been confirmed by scanning electron microscopy. Polyester prostheses, whose healing process depends on the reorganisation of the thrombotic matrix, retains considerably more blood cells than the polytetrafluoroethylene microporous prostheses or the treated biological devices, whose fate, following implantation, maintains almost complete passivity.
Biocompatible Materials↗
Brugia pahangi: serum-dependent cell-mediated reactions to sheathed and exsheathed microfilariae.
The immune mechanisms operating on the sheath and the cuticle of the Brugia pahangi microfilariae have been studied in vitro. The intact and exsheathed parasites were used for this purpose with serum from albino rats immunized with sonicated homogenates of the parasites as the source of antibodies. The IgG component of the serum was found to promote adherence of rat leucocytes and death of the sheathed and exsheathed parasites in presence of fresh normal serum. EDTA and EGTA abolished the adherence activity suggesting the involvement of complement components via the classical pathway. Both macrophages and neutrophils participate in this reaction. Eosinophils exhibit marginal activity only on exsheathed parasites. The intensity of adherence and killing by neutrophils in the presence of immune serum was greater with the exsheathed microfilariae than with the sheathed ones.
Animals↗
Absorption, distribution, and excretion of 8-methoxypsoralen in HRA/Skh mice.
The tissue distribution and excretion of [3H]8-methoxypsoralen (8-MOP), a well-accepted therapeutic agent for the treatment of psoriasis, was studied in hairless HRA/Skh female mice. Mice were given single oral doses of 6 mg of [3H]8-MOP or 5-[14C]8-MOP/kg in corn oil. Radiochemical analyses of tissues and excreta were accomplished by liquid scintillation counting. The 8-MOP appeared to be rapidly absorbed through the gastrointestinal tract, where the tritium levels were highest, followed by skin, blood, and liver; levels were lowest in fat (adipose tissue). In female HRA/Skh mice which had not been irradiated with UVA (320-400 nm), 84% of the carbon-14 and 58% of the tritium were recovered in the urine and feces within 24 hours of oral administration of 5-[14C]8-MOP or [3H]8-MOP, respectively. Animals that were exposed to UVA and received [3H]8-MOP excreted approximately 12% less tritium in the urine and feces compared with the animals which received no UVA.
Absorption↗
Polymerization of visible light cured composites with a fiberoptic handpiece.
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Composite Resins↗
Nurses in society. Do Poms care?
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Female↗