Biomedical subjects

M M Garner

Publications and source records attributed to M M Garner.

61 records · Page 4Linked to original sources

PubMedDate not supplied

Advances in DNA electrophoresis in polymer solutions.

DNA electrophoresis in gels and solutions of agarose and polyacrylamide was objectively evaluated with regard to separation efficiency at optimal polymer concentrations. In application to DNA fragments, polyacrylamide gels were superior for separating fragments of less than 7800 bp, and agarose gels are the best choice for larger fragments. Agarose solutions are nearly as good as polyacrylamide gels for small DNA (< 300 bp). Agarose solutions have a higher efficiency than polyacrylamide solutions for DNA of less than 1200 bp. Separation efficiency sharply decreases with increasing length of DNA. Retardation in polyacrylamide solutions was found to depend on polymer length in a biphasic fashion. The choice of resolving polymer concentrations depends on the progressive stretching of DNA in proportion to polymer concentration. The rate of that stretching appears higher in polyacrylmide solution than in gels or in liquid or gelled agarose. Application of polymer solutions to capillary electrophoresis raises further problems concerning agarose plugs, DNA interactions with the polymers, operation at low field strength and long durations as well as detection sensitivity.

Acrylic Resins↗

PubMedDate not supplied

Capillary zone electrophoresis of large DNA.

Capillary zone electrophoresis (CZE) of DNA 23.1 to 48.5 kb in length in polyacrylamide solutions of several concentrations provides evidence for polymer concentration and DNA length-dependent stretching and orientation of these species and suggests an effective separation at a polymer concentration of about 0.6%. Applying a 0.1% polyacrylamide concentration to the lambda-phage DNA ladder, at least 5 components are separated; separation improves with lowering of the field strength to 2 V/cm and, correspondingly, extended duration of CZE. Saccharomyces pombe chromosomal DNA separates into 3 major components on CZE at high field strength (270 V/cm) in 0.9% polyacrylamide solution, confirming a previous finding made on electrophoresis in a 1.1 mm ID tube at low field strength. However, the finding is limited to one source of the DNA plug, and the chromosomal identity of the components remains unknown. Methodological problems in the CZE of large DNA relate to the need for extended duration of pressure injection if absorbance detection is applied, the need to define the starting zone after extended pressure injection, the need to melt and digest agarose plugs prior to loading, and related needs for thermostating of the sample chamber and for software compatible with low voltage operation.

Acrylic Resins↗

PubMedDate not supplied

Transverse pore gradient gel electrophoresis, using the PhastSystem.

The application of pore gradient gels prefabricated for the PhastSystem (Pharmacia) to transverse pore gradient gel electrophoresis is demonstrated. It has the twofold advantage of (i) horizontal positioning, avoiding gel stretching during the preparation of these gels and resulting pore size irreproducibility experienced with vertically applied pore gradient gels, which necessitate an orthogonal transfer of spacers, and (ii) miniaturized gel dimensions, which allow a small sample load and a short duration of electrophoresis and staining.

Base Composition↗

PubMedDate not supplied

Detection of a single base mismatch in double-stranded DNA by electrophoresis on uncrosslinked polyacrylamide gel.

Uncrosslinked polyacrylamide forms gels in the concentration range of 15-40% acrylamide. Electrophoresis in these gels of a commercially available 350 bp heteroduplex DNA preparation separates it from the homoduplex DNA of the same size. The separation is qualitatively equivalent to that previously achieved in a commercial proprietary gel ("Mutation Detection Gel" of AT-Biochem), or in an equivalent 14% T, 0.15% C (N,N'-methylenebisacrylamide) gel, but the mechanical stability of mutation detection electrophoresis (MDE) gels or 0.15% C gels is better than that of uncrosslinked polyacrylamide gels. The separation in any of these three gel media can be carried out in short gel tubes within a few hours of electrophoresis time. In both uncrosslinked polyacrylamide and MDE gel media, the Ferguson plots [log(mobility) vs. gel concentration] and the plots of effective molecular radius vs. gel concentration ("T-plots") of both the heteroduplex and homoduplex DNA indicate an augmented size but similar flexibility upon passage through the gel than exhibited by the components of a DNA standard ladder. Homoduplex and heteroduplex DNA correspondingly exhibit a parallelism of their Ferguson curves in transverse MDE pore gradient gel electrophoresis, suggesting a surface net charge difference, possibly due to a conformational reorientation too subtle to be detected by a shift in the slope of the Ferguson plot, as has been observed once previously with a "kinked" DNA species. The gel fiber radius or length per unit volume of uncrosslinked polyacrylamide and MDE gels do not differ significantly within confidence limits, which are wide compared to unconventionally crosslinked gels, presumably because of their greater swelling.

Acrylic Resins↗

PubMedDate not supplied

Antioxidant status in a squirrel monkey (Saimiri sciureus) with chronic pancreatitis and degenerative myopathy.

A squirrel monkey (Saimiri sciureus) presented with wasting, vomiting and diarrhoea. Haematology revealed elevation of creatinine phosphokinase, lactic dehydrogenase, alanine aminotransferase, amylase and lipase, together with azotaemia and hypoalbuminaemia. Prominent findings were chronic pancreatitis with acinar and ductal plugs, granulomatous and necrotizing peripancreatic steatitis, degenerative myopathy, testicular atrophy, candidiasis and bacterial necrotizing glossitis. Antioxidant analyses revealed low concentrations of serum vitamin E (and apparently A), hepatic selenium and hair zinc. Pancreatitis may have caused malabsorption and maldigestion, associated with deficiency of multiple antioxidants.

Animals↗

PubMedDate not supplied

Spontaneous tumours in captive African hedgehogs (Atelerix albiventris): a retrospective study.

Forty tumours were diagnosed in 35 (53%) of 66 captive African hedgehogs documented at Northwest ZooPath (NZP) between 1994 and 1999. Three hedgehogs had more than one type of tumour and the remaining 32 had a single type. Of the 35 hedgehogs with tumours, 14 were female, 11 were male, and 10 were of unknown gender; 21 were from zoological parks and 14 were privately owned. Twenty of the hedgehogs with tumours were adult (>1 year old) with a median age of 3.5 years (range 2-5.5 years); 15, of unreported age, were classified as adult. Thirty-four (85%) of the 40 tumours were classified as malignant and six (15%) as benign. The integumentary, haemolymphatic, digestive and endocrine systems were common sites for tumours. The most common tumours were mammary gland adenocarcinoma, lympho-sarcoma and oral squamous cell carcinoma.

Animals↗

PubMedDate not supplied

Outbreak of salmonellosis in a zoologic collection of lorikeets and lories (Trichoglossus, Lorius, and Eos spp.).

During August 2001, a syndrome characterized by acute lethargy and dyspnea was observed in a population of 45 lorikeets and lories in an open-air zoologic exhibit. The first death occurred on August 10, and within the next 12 days, nine more birds died (22% mortality rate). Hepatomegaly, reddening and congestion of the lungs, and injection of the serosal surface of the intestines were the common gross findings. Histologic changes, including fibrinonecrotic hepatitis and splenitis, bacterial emboli (liver, spleen, lung, kidney, proventriculus), pulmonary congestion and hemorrhage, and enteritis, were indicative of an acute, overwhelming bacterial septicemia. Salmonella typhimurium, with the same antibiogram, was isolated from four birds. Several birds had attacked and killed a snake on July 24, and Salmonella serogroup B (untypeable) was isolated from intestine and kidney samples of a garter snake caught in the open-air exhibit on August 28. Salmonella was also isolated from environmental samples of the exhibit but not from food preparation areas. After antimicrobial therapy, Salmonella spp. was not isolated from the surviving birds. The source of Salmonella in this outbreak remains unknown, but infection either directly or indirectly from snakes in the exhibit is possible. Contact between captive psittacine populations and reptiles should be avoided to prevent the risk of salmonellosis.

Animals↗