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Biomedical subjects

S Sykes

Publications and source records attributed to S Sykes.

11 recordsLinked to original sources

Reducing nosocomial pressure ulcers in an acute care facility.

In 1996, a nursing committee at an acute care facility organized the first pressure ulcer point prevalence survey for that hospital. In 1996, hospital-acquired pressure ulcers were 90 percent of the predicted prevalence rate; in 1997, the rate dropped to 59 percent of the predicted prevalence and in 1998, to 53 percent of the predicted prevalence. The severity index decreased markedly from 291 (1996) to 98 (1997) then to 62 (1998). These improvements are attributed to the purposeful addition of multidimensional interventions, including best practices and research-based protocols, to prevent and treat nosocomial pressure ulcers.

Benchmarking↗

Aural rehabilitation and graduate audiology programs.

The quantity and quality of aural rehabilitation training that audiology graduate students receive versus the current services available to those students regarding work with the hearing impaired, cochlear implant recipients, patients with vestibular disorders, patients with central auditory processing disorders, and patients suffering from tinnitus were examined. Forty ASHA-accredited colleges and universities were contacted by telephone and audiology faculty members were surveyed. The results of the survey may provide valuable information for identifying and addressing shortfalls in aural rehabilitation programs.

American Speech-Language-Hearing Association↗

Stabilization of von Willebrand factor in banked blood by leucocyte depletion.

The von Willebrand factor (vWf) activity, as measured by the ristocetin co-factor (vWf:RCo) and collagen binding (vWf:CBA) assays, declined progressively in standard blood units stored at 4 degrees C after a 2-day storage period. This loss of activity was accompanied by a loss and degradation of high molecular weight (HMW) vWf multimers. In studies using a paired design, filtration of blood with a high efficiency leucocyte-removal filter, prior to storage at 4 degrees C, led to significantly improved maintenance of vWf:RCo and vWf:CBA compared with unfiltered units (P < 0.01 after 8 days). Loss and degradation of HMW vWf decreased when blood was filtered prior to 4 degrees C storage. Filtration had no effect on vWf-associated activities when blood was stored at 22 degrees C for 10 days. These results indicate that part of the storage lesion of vWf in banked blood is due to leucocyte-mediated removal and degradation of HMW vWf. This has implications when specifying plasma for the production of vWF concentrates and may also play a role in the haemostatic lesion associated with massive transfusion of stored blood.

Blood Banks↗

von Willebrand factor characterization of a severe dry-heat treated factor VIII concentrate, AHF (high purity).

Eight batches of a severe dry-heat treated (80 degrees C for 72 hours) Factor VIII concentrate manufactured by the Commonwealth Serum Laboratories (CSL Ltd.) were analysed for the following von Willebrand factor-related (vWf) activities: ristocetin cofactor activity (vWf:RCof), collagen binding activity (CBA), vWf antigen levels (vWf:Ag), vWf multimeric analysis and 2-stage FVIII clotting activity (VIII:C). The average potency per vial of vWf:Ag was 440 +/- 80 units, vWf:RCof 500 +/- 60 units, CBA 350 +/- 50 units and VIII:C 242 +/- 36 International Units. Multimeric analysis indicated the presence of high molecular weight multimers and a triplet structure slightly different to normal plasma. Viral inactivation studies using a marker virus, Sindbis, demonstrated that the terminal severe dry- heating step reduced the viral load in the product by greater than 6 log10TCID50/ml. This CSL Ltd. FVIII concentrate may thus provide a safer, purer and more convenient source of vWf than cryoprecipitate. Clinical studies to establish product efficacy in patients with von Willebrand's disease are underway.

Blood Protein Electrophoresis↗

Multimeric analysis of von Willebrand factor by molecular sieving electrophoresis in sodium dodecyl sulphate agarose gel.

We report the development and optimisation of an agarose gel electrophoretic method for the separation and detection of von Willebrand Factor (vWF) multimers. The method has been specifically developed for use in the clinical evaluation and classification of patients with von Willebrand's Disease (vWD) and clearly shows structural multimer abnormalities associated with the bleeding diathesis of this inherited bleeding disorder.

Biopolymers↗

More severe impairment of oral than intravenous glucose tolerance in rats after eating a high fat diet.

Glucose and insulin responses to oral and intravenous glucose (1 g/kg body weight) were measured after consumption of a high fat (HF) or low fat (LF) diet for 3 wk in conscious rats with implanted intravenous and intra-arterial catheters. The HF diet resulted in impaired glucose tolerance and insulin resistance after both oral and intravenous glucose; the effect was more pronounced after oral glucose. In an attempt to understand the basis of the impairment of glucose tolerance after consuming the HF diet, the activity of hepatic glucokinase and the rate of intestinal glucose uptake were also measured. The more severe impairment of glucose tolerance by oral rather than intravenous administration was not explained by an increased rate of intestinal glucose uptake. Indeed, there was a small but significant reduction in the rate of jejunal glucose uptake in the HF rats. However, the greatly reduced activity of hepatic glucokinase in the HF rats was consistent with a reduced capacity for hepatic glucose uptake, which may have contributed significantly to the impaired glucose tolerance. The effects of the HF diet on the insulin response to glucose were much more pronounced after oral rather than intravenous glucose administration. This indicated that the HF diet may have stimulated the enteroinsular axis. However, it is also possible that the particularly high circulating insulin levels, resulting from oral glucose in the HF rats, were a direct response to hyperglycemia, secondary to reduced glucose removal.

Administration, Oral↗

Evidence for preferential stimulation of gastric inhibitory polypeptide secretion in the rat by actively transported carbohydrates and their analogues.

A rat intestinal perfusion technique has been used to assess the ability of a number of monosaccharides, monosaccharide analogues and disaccharides to stimulate intestinal release of immunoreactive gastric inhibitory polypeptide (GIP). Perfusates containing glucose, sucrose, galactose, maltose, 3-O-methylglucose or alpha- or beta- methylglucoside at concentrations of 100 mmol/l in Krebs-Ringer phosphate buffer (KRP) produced significant stimulation of GIP release compared with the control perfusions with KRP alone (P less than 0.02). Mannose, 6-deoxygalactose, 2-deoxyglucose, myoinositol, fructose or lactose (100 mmol/l of each) did not stimulate GIP release compared with controls. There was no significant difference in the ability of sucrose, maltose or beta-methylglucoside (100 mmol/l of ach) to release GIP compared with 100 mmol glucose/l, but galactose, 3-O-methylglucose and alpha-methylglucoside (100 mmol/l of each) produced significantly lower GIP responses than did glucose (P less than 0.02). Addition of 5 mmol phloridzin/l to a perfusate containing 50 mmol glucose/l prevented intestinal absorption of glucose and abolished the GIP response. The molecular configuration of monosaccharides which have the ability to stimulate GIP release agreed well with the structural requirements for active transport by the sodium-dependent hexose pathway.

Animals↗

Problems encountered in the immunoassay of alpha-foetoprotein in patients with hepatoma.

Immunoradiometric assays suffer from the phenomenon of paradoxical increase in count rate with increasing dilution of highly concentrated samples--the "hook-effect". This is particularly important for alpha-foetoprotein where in hepatoma may be thousands of times the upper limit of the range of immunoradiometric assays. Using a commercial kit method we have encountered some degree of hook effect in many patients with hepatoma. Significant hooking occurred after 1,000 to 2,000 micrograms/1 but the extent of the effect was sample dependent. Of the samples tested so far, only one patient produced a hook which extended into the standard curve counts range. This resulted in a measured values of 20 micrograms/1 (value on dilution: 100,000 micrograms/1). We recommend that this method should be used routinely in conjunction with a screening method e.g., counterimmunoelectrophoresis and that quantitation of very high values should be by radial immunodiffusion or a method with similar sensitivity.

Carcinoma, Hepatocellular↗

Electroradioimmunoassay: a sensitive method for the quantitation of alpha-fetoprotein.

A sensitive technique, electroradioimmunoassay has been adapted for the estimation of alpha1-fetoprotein in normal adult human plasma and serum. Commercially available antisera were used and a 10-fold increase in sensitivity was obtained in comparison with two conventional radioimmunoassays. Plasma alpha 1-fetoprotein levels of 2.6 +/- 1.2 microgram/1 (mean and standard deviation) were found in a normal population as compared with levels of 4.1 +/- 2.6 microgram/l in a group of 49 patients with alcoholic liver disease.

Alcoholism↗

Video nation.

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Attitude to Health↗