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Biomedical subjects

G Wilson

Publications and source records attributed to G Wilson.

At least 253 records · Page 14Linked to original sources
PubMed1986

The decline in congenital rubella syndrome in Western Australia: an impact of the school girl vaccination program?

Rubella vaccination became available in 1970 in Australia. In Western Australia (WA), a school girl vaccination program was well established by 1971. Mothers under 26 years of age in 1983 would have been eligible for this program and they constitute 40 per cent of WA births. Data on Congenital Rubella Syndrome (CRS) cases were obtained for years of birth 1968-83 inclusive to ascertain if there had been an impact of the program on the CRS rate. Epidemics of rubella occurred in 1970-71, 1974, and 1979-80. The CRS rate has fallen steadily; it did not rise during the 1979-80 epidemic and was less than one in each year after 1977. All CRS cases born since 1974 were to mothers too old to have been eligible for the program. The data suggest that the vaccination program is effective, but this cannot be proven until data become available on pregnancy terminations.

Adolescent↗
PubMed1986

Magnetic resonance imaging of the facial nerve. Normal anatomy and pathology.

Magnetic resonance imaging with surface coils permits visualization of the facial nerve from within the brainstem and continuing through a major portion of the parotid gland. Diagnostic capabilities have been expanded to include white matter disease that affects the tracts of the facial nerve within the brainstem and tumors of the parotid gland that involve the facial nerve trunks after the nerve exists from the stylomastoid foramen.

Facial Nerve↗
PubMed1985

[Flow cytometric measurements of in vivo incorporated bromodeoxy- uridine into the DNA of experimental and human tumors].

A new cell kinetic method was used in vivo in an experimental mouse tumour and in human tumours of the oral cavity for the first time. The incorporation of BUdR into cells in the S-phase that are actively synthesizing DNA enables the determination of the rate of DNA synthesis from the amount of BUdR-related fluorescence using monoclonal antibody and the proportion of S-phase cells which are actively engaged in synthesis. The application of BUdR to the patients and the preparation of the tumour is reported.

Adenocarcinoma↗
PubMed1985

The removal of carbohydrates from ricin with endoglycosidases H, F and D and alpha-mannosidase.

Recently, several investigators have explored the possibility of targeting ricin to designated cell types in animals by its linkage to specific antibodies. There is evidence, however, that the mannose-containing oligosaccharide chains on ricin are recognised by reticuloendothelial cells in the liver and spleen and so cause the immunotoxins to be removed rapidly from the blood stream. In the present study we analysed the carbohydrate composition of ricin and examined enzymic methods for removing the carbohydrate. The carbohydrate analysis ricin A-chain revealed the presence of one residue of xylose and one of fucose in addition to mannose and N-acetylglucosamine which had been detected previously. The B-chain contained only mannose and N-acetylglycosamine. Ricin A-chain is heterogeneous containing two components of molecular weight 30 000 and 32 000. Strong evidence was found that the heavier form of the A-chain contains an extra carbohydrate unit which is heterogeneous with respect to concanavalin A binding and sensitivity to endoglycosidase H. The lower molecular weight form of A-chain did not bind concanavalin A and was insusceptible to endoglycosidases. Only one of the two high mannose oligosaccharide units on the isolated B-chain could be removed by endoglycosidases H or F, whereas both were removable after denaturation of the polypeptide by SDS. Both the isolated A- and B-chains were sensitive to alpha-mannosidase. Intact ricin was resistant to endoglycosidase treatment and was only slightly sensitive to alpha-mannosidase. The addition of SDS allowed endoglycosidase H to remove both of the B-chain oligosaccharides from intact ricin and increased the toxin's sensitivity to alpha-mannosidase. In conclusion, extensive enzymic deglycosylation of ricin may only be possible if the A- and B-chains are first separated, treated with enzymes and then recombined to form the toxin.

Carbohydrates↗
PubMed1985

Modification of the carbohydrate in ricin with metaperiodate-cyanoborohydride mixtures. Effects on toxicity and in vivo distribution.

Attempts to target antibody-ricin conjugates (immunotoxins) to designated cell types in vivo may be thwarted by their rapid clearance by hepatic reticuloendothelial cells which have receptors that recognise oligosaccharide side chains on the toxin. The B-chain of ricin contains high mannose type oligosaccharides and the A-chain contains a complex unit (GlcNAc)2-Fuc-Xyl-(Man)4-6, all of which potentially could be recognised by the reticuloendothelial system. Treatment of ricin with a mixture of sodium metaperiodate and sodium cyanoborohydride at pH 3.5 resulted in oxidative cleavage of the carbohydrates and reduction of the aldehyde groups thus formed to primary alcohols. By conducting the modification procedure at acidic pH, both the possibility of Schiff's base formation between the aldehyde groups and amino groups in the protein and the possibility of non-specific oxidation of amino acids were minimised. The extent of the carbohydrate modification depended on the duration of treatment, resulting maximally in the destruction of 13 of the 18 mannose residues and of all xylose and fucose. The toxicity of the modified toxin to cells in culture declined by up to 90% as the carbohydrate was destroyed. This was not due to a reduced ability of the B-chain to bind to cells or of the A-chain to inactivate ribosomes. In contrast to the in vitro results, the toxicity of the modified toxin to mice and rats was elevated by up to fourfold. The modification greatly reduced the clearance of the toxin by non-parenchymal cells in the liver and prevented the damage to hepatic Kupffer and sinusoidal cells and to the red pulp of the spleen that is inflicted by the native toxin. The elevated toxicity to animals appears to be because the modified toxin evades the reticuloendothelial system and persists in the bloodstream for longer periods, thus resulting in lethal damage to vital tissues in the animal at lower dosage. The results suggest that immunotoxins prepared from modified ricin would not be readily cleared by the reticuloendothelial system and so be more effective at killing their target cells.

Amino Acids↗
PubMed1985

In vivo and in vitro models of demyelinating diseases. XII. Persistence and expression of corona JHM virus functions in RN2-2 Schwannoma cells during latency.

The coronavirus JHMV persistently infects rat Schwannoma cells RN2-2 at 32.5 degrees C and enters a host-imposed reversible, latent state at 39.5 degrees C. JHMV can remain up to 20 days in the latent state and about 14 days before the cultures lose the capacity to resume virus production upon return to 32.5 degrees C. Although persistently and latently infected RN2-2 cells display resistance to superinfection by a heterologous agent VSV, these cells do not release detectable soluble mediators (e.g., interferon) of the antiviral state. Nevertheless, RN2-2 cells are competent to synthesize and release interferon when treated with the appropriate inducers. These observations suggest that interferon does not play any role or may not be the major factor in the control of latency in the Schwannoma cell. Hybridization with virus-specific cDNAs shows that all viral mRNAs are present during latency and that viral mRNAs are present in the polysomes of infected cells at 39.5 degrees C. Western immunoblotting with hybridoma antibodies demonstrates that viral specific proteins are produced at the restrictive temperature. These results suggest that despite the absence of production of infectious virus at 39.5 degrees C, there is active transcription and translation into virus-specified products.

Animals↗
PubMed1985

Acute chromium poisoning in a 2 year old child.

Sodium dichromate ingestion in children is uncommon and potentially lethal. The most appropriate management is uncertain because of the lack of sound data contained in the few reports of successfully treated patients. Immediate treatment should include urgent induction of emesis, administration of ascorbic acid as an antidote, followed by supportive treatment.

Antidotes↗
PubMed1985

Janet Lindsay Greig: a pioneer.

Janet Lindsay Greig was the first women Anaesthetist in Australia; she was also the first Resident Medical Officer who later became an anaesthetist to be trained by E.H. Embley at the Royal Melbourne Hospital. Janet Greig played a pioneering role among medical women in Australia. She was a founder of the Queen Victoria Hospital, Melbourne. A brief resume is given of the history of the entry of women into the Faculty of Medicine at the University of Melbourne; of the first appointments of women as Resident Medical Officers, and of the foundation of the Queen Victoria Hospital.

Anesthesiology↗
PubMed1985

Essential ions for maintenance of the corneal epithelial surface.

It is generally believed that tears are required to furnish only oxygen to the corneal epithelium. However, as tears are a very complicated solution, it is likely that other factors are essential to the cells of the corneal surface. The amount of light scattered from the epithelial surface of the excised rabbit cornea was examined with the in vitro specular microscope while the epithelium was bathed in different solutions. It was shown that the epithelial surface was maintained best with a buffered solution containing potassium, calcium, magnesium, phosphate and bicarbonate, in addition to sodium chloride. The solution was named Basic Tear Solution (BTS). The effect was not due to osmolarity. Potassium was particularly important, as corneas bathed with sodium chloride and potassium chloride were maintained better than corneas bathed with sodium chloride only. The appearance of the epithelial surface was different in these bathing solutions. In sodium chloride the surface scattered more light and more cells were sloughed. Least light was scattered in BTS, and cell-sloughing was at a minimum. Thus, the rate at which cells were sloughed from the epithelial surface and the quality of the surface were dependent on the bathing solution.

Animals↗
PubMed1984

Immune deficiency due to adenosine deaminase and purine nucleoside phosphorylase deficiency: a simple diagnostic test.

A simple method is described for diagnosing adenosine deaminase and purine nucleoside phosphorylase deficiency using urine. Cellulose thin layer chromatography of 1 microliter of urine from affected children was performed and deoxyadenosine and deoxyguanosine were easily detected by phosphorescence at the temperature of liquid nitrogen. This test is not expensive and can be done in any laboratory. It should be suitable for diagnostic screening in patients with immune deficiency.

Adenosine Deaminase↗
PubMed1984

Differential swelling in compartments of the corneal stroma.

When a hypotonic solution is applied to the corneal surface the stroma swells. This well-known osmotic response masks a surprising hydration change in the posterior stroma. This was studied by measuring thickness changes in the anterior, middle, and posterior stroma of the rabbit cornea. Measurements were made continuously for 1 hour following osmotic perturbation of the epithelial surface. The data revealed that following a hypotonic shift on the epithelial surface, the posterior stroma thinned briefly. This unexpected effect is predicted satisfactorily by Klyce and Russell's mathematical model. The method of measuring fluid flow between stromal compartments will allow further development of the model in describing the dynamics of stromal hydration.

Animals↗
PubMed1984

Effect of prostaglandin E1 on blood flow in normal and ischemic canine hindlimbs.

Prostaglandin E1 (PGE1) is a potent vasodilator that will increase peripheral blood flow. After infusion of PGE1, little is known about the distribution of flow between skin and muscle or the effect of PGE1 on an ischemic leg. We infused intra-arterially PGE1 (5 ng/kg/min) into normal and ischemic canine hindlimbs. Radioactive microspheres were used to measure nutrient flow to skin and muscle and flow shunted through arteriovenous connections. Intra-arterial PGE1 caused significant increases in skin blood flow in both normal and ischemic hindlimbs. Shunted flow did not increase. Muscle flow increased in normal canine hindlimbs, but this increase was prevented by femoral artery ligation. We conclude that PGE1 increases absolute nutrient flow rather than opening arteriovenous shunts in the canine hindlimb. Skin flow is most sensitive to prostaglandin infusion. Muscle flow is increased in normal but not ischemic limbs. PGE1 may be useful in situations where vasospasm is a prominent feature. The role of PGE1 in atherosclerotic ischemic disease remains unclear.

Alprostadil↗
PubMed1984

Serous fluid leakage: a complication following the modified Blalock-Taussig shunt.

Polytetrafluoroethylene tubular grafts are useful in performing a systemic-to-pulmonary artery shunt (modified Blalock-Taussig). They allow a controlled-volume shunt, avoid kinking of the pulmonary artery, and preserve distal flow in the subclavian artery. Unfortunately, occasionally excessive serous fluid will drain through the interstices of the fabric. This results in excessive and prolonged chest tube drainage and/or localized seroma formation around the graft. This complication occurred in 26 children, an incidence of 18.8% of the 138 modified Blalock-Taussig operations. Repeat thoracotomy was required in four of these children--for evacuation of seroma mass in three and for relief of cardiac tamponade in one. Four other children required reinsertion of pleural or pericardial chest drains for excessive serous drainage persisting as long as 6 weeks after operation. Wrapping of the graft with silicone sheeting to facilitate subsequent takedown of the shunt led to seroma formation in five of nine children. We believe this practice should be abandoned. Excessive drainage of serous fluid through the interstices of PTFE grafts in almost 20% of our patients has compromised an otherwise satisfactory result of the modified Blalock-Taussig operation.

Blood Vessel Prosthesis↗