Search PubMed⌕ Search

Biomedical subjects

M M Garner

Publications and source records attributed to M M Garner.

At least 37 records · Page 2Linked to original sources
PubMed2000

Clinical coccidiosis in raccoons (Procyon lotor).

Clinical coccidiosis was diagnosed in wild-caught and captive raccoons. Eimeria procyonis-like oocysts were seen in 15 of 15 captive raccoons. In 6 of 6 juvenile wild-caught raccoons examined at necropsy, endogenous coccidian stages were seen in the small intestine. Two types of schizonts (large and small) were identified. Large schizonts were up to 110 microm long, contained 10-microm-long merozoites, and were in crypt glandular epithelial cells. Smaller schizonts were 10 microm long, contained 5-microm-long merozoites, and were at the tips of the villi. Only a few gamonts and no oocysts were seen in sections. These stages were thought to be of E. procyonis.

Animals↗
PubMed1999

Encephalomyelitis associated with a Sarcocystis neurona-like organism in a sea otter.

An adult female sea otter housed for 5 years in an outdoor habitat in an aquarium developed signs of neurologic disease. Bilateral caudal paresis was evident initially and other neurologic signs consistent with CNS disease developed rapidly. Diagnostic work-up included CBC, serum biochemical analyses, determination of serum antibody titers, radiography of the vertebral column, CSF analysis, muscle biopsy, computed tomography of the brain, and assays for mercury, lead, and thiamine. A tentative diagnosis of encephalitis caused by a Sarcocystis neurona-like organism was made on the basis of detection of CSF antibodies by use of Western blot analysis. Response to treatment was not satisfactory and the sea otter was euthanatized. Immunohistochemical staining revealed S neurona-like organisms within foci of inflammation in the brain and spinal cord. This report provides evidence that, for sea otters, there may be a mode of transmission of an S neurona-like organism that does not involve opossums.

Animals↗
PubMed1999

Use of a DNA toolbox for the characterization of mutation scanning methods. I: construction of the toolbox and evaluation of heteroduplex analysis.

A systematic characterization of the effects of important physical parameters on the sensitivity and specificity of methods in searching for unknown base changes (mutations or single nucleotide polymorphisms) over a relatively long DNA segment has not been previously reported. To this end, we have constructed a set of molecules of varying G+C content (40, 50, and 60% GC) having all possible base changes at a particular location - the "DNA toolbox". Exhaustive confirmatory sequencing demonstrated that there were no other base changes in any of the clones. Using this set of clones as polymerase chain reaction (PCR) templates, amplicons of various lengths with the same base mutated to all other bases were generated. The behavior of these constructs in manual and automated heteroduplex analysis was analyzed as a function of the size and overall base content of the fragment, the nature and location of the base change. Our results show that in heteroduplex analysis, the nature of the mismatched base pair is the overriding determinant for the ability to detect the mutation, regardless of fragment length, GC content, or the location of the mutation.

DNA, Viral↗
PubMed1999

Use of DNA toolbox for the characterization of mutation scanning methods. II: evaluation of single-strand conformation polymorphism analysis.

Single-strand conformation polymorphism (SSCP) is one of the most commonly used methods for searching for unknown base changes (mutations). In order to characterize systematically the effects of important physical parameters on the sensitivity and specificity of SSCP, we used the DNA toolbox constructed as described in the companion paper [2]. Using this set of DNA molecules as polymerase chain reaction (PCR) templates, amplicons of various lengths with the same base, mutated to all other bases, were generated. The behavior of these constructs in manual and automated SSCP was analyzed as a function of the size, overall base content of the fragment, nature and location of the base change, and the temperature and pH of electrophoresis. Our results demonstrate that all of these variables interact to determine the rate of detection of single-base changes, with the GC content being the predominant determinant of detection sensitivity.

DNA↗
PubMed1999

Effect of gelation conditions on the gel structure and resolving power of agarose-based DNA sequencing gels.

The effect of gelation conditions on the structure and resolving properties of agarose-based DNA sequencing gels were studied. Gels that were formed by rapid cooling gave separation patterns with sharp, well-defined bands, and resolved base repeats that were not separated on gels which were allowed to cool slowly. Analyses by electron microscopy indicated that the rapidly cooled gels have a homogeneous pore structure with a smaller average pore size than gels that were cooled slowly. The two types of gels also differ in optical clarity, and have significant differences in their melting characteristics as measured by differential scanning calorimetry.

Bacteriophage M13↗
PubMed1999

Bacillary hemoglobinuria in a free-ranging elk calf.

A dead elk (Cervus elaphus roosevelti) calf was diagnosed with bacillary hemoglobinuria, a toxemia caused by the bacterium Clostridium haemolyticum. The mortality occurred in southwest Washington, USA (46 degrees 13'N, 123 degrees 22'W), in an area in which several previous mortalities, suspected but not conclusively diagnosed to be either bacillary hemoglobinuria, enterotoxemia, or leptospirosis, occurred. This is the first reported incidence of mortality attributable to bacillary hemoglobinuria in free-ranging elk. Similar deaths of young elk in the area suggest that mortality from this disease may be common locally.

Animals↗
PubMed1999

Xanthomatosis in geckos: five cases.

Five cases of xanthomatosis in geckos were evaluated, one in a northern green gecko (Naultinus grayi) and the remaining four in three species of leaf-tailed geckos (two Uroplatus henkeli, one U. sikorae, one U. fimbriatus). All geckos were females 3-11 yr of age, were clinically ill on presentation, and either died or were euthanized. Necropsies showed emaciation in three geckos, with white nodular foci on coelomic surfaces in two of these geckos. The other two geckos had no gross abnormalities. Histopathologic examination revealed xanthomatosis involving the coelomic surfaces of four geckos and the ventricles of the brain in all geckos. Xanthomas in the brain were associated with various degrees of hydrocephalus. The lesions were comprised of stacks of clear clefts consistent with cholesterol crystals, and these structures were surrounded by epithelioid macrophages, multinucleated giant cells, and lymphocytes. Four geckos had active folliculogenesis, and two had foci of follicular degeneration and localized yolk coelomitis. In all cases, xanthomatosis was believed to have contributed significantly to morbidity and mortality.

Animals↗
PubMed1997

Shell disease in river cooters (Pseudemys concinna) and yellow-bellied turtles (Trachemys scripta) in a Georgia (USA) lake.

A disfiguring shell disease was detected in river cooters (Pseudemys concinna) and yellow-bellied turtles (Trachemys scripta) from Lake Blackshear, Georgia (USA). The turtles used were part of a mark-recapture study conducted from September 1991 to June 1993. Histologic changes on four turtles included acute segmental necrosis of the epidermis, followed by ulceration, necrosis of the underlying dermis and dermal bone, and exaggerated remodeling of bone. Additional findings included visceral inflammatory lesions and bacterial infection, sepsis and marked trematode ova granulomatosis. The cause of the shell lesions was not determined.

Animals↗
PubMed1996

Mutagenic DNA base modifications are correlated with lesions in nonneoplastic hepatic tissue of the English sole carcinogenesis model.

Hydroxyl radical-induced mutagenic base modifications have been linked to neoplasia in a number of biological systems, including English sole from chemically contaminated urban environments. However, virtually no information exists on the relationship between the mutagenic base modifications and preneoplastic and other lesions found in tumor-free tissues prone to cancer. We studied six hepatic lesions in immature, neoplasm-free English sole exposed to an urban and reference environment and established correlations between the lesion incidence and concentrations of the mutagenic base modifications 8-hydroxyguanine and 8-hydroxyadenine. The lesions were putatively preneoplastic basophilic foci, hepatocellular karyomegaly, megalocytic hepatosis, hepatocellular vacuolar change, hyalin droplet formation, and apoptosis. With the exception of hepatocellular vacuolar change, significant positive correlations were found between the lesions and the mutagenic base modifications. The hydroxyl radical may be a common etiological factor in the formation of the base modifications and hepatic lesions.

Adenine↗
PubMed1996

Fatal cytauxzoonosis in a captive-reared white tiger (Panthera tigris).

Fatal (Panthera tigris) cytauxzoonosis was diagnosed in a 7-year-old female white tiger. The tiger presented with a 2-day history of anorexia and lethargy. She was mildly dehydrated, with a temperature of 105.2 F and a hematocrit of 26%. Over the next day, icterus developed, and her physical condition progressed to recumbency, coma, and death. Hematologic findings obtained shortly before death included icteric plasma, severe thrombocytopenia, mild anemia, hematuria, and parasites consistent with Cytauxzoon felis in circulating erythrocytes. Gross necropsy findings included generalized icterus, generalized petechiae and ecchymoses, splenomegaly, and peribronchial edema. Histologic changes included large numbers of intravascular macrophages containing developmental stages of Cytauxzoon felis that partially or completely occluded blood vessels in the lung, spleen, liver, and bone marrow. Except for an experimental infection of a bobcat, fatal cytauxzoonosis has not previously been diagnosed in felids other than domestic cats. These findings raise questions regarding the pathogenicity of this organism in felids and may impact husbandry and interstate transfer of captive large cats.

Anemia↗
PubMed1996

Staining and morphologic features of bone marrow hematopoietic cells in desert tortoises (Gopherus agassizii).

OBJECTIVES: To determine optimal site for collection of bone marrow from desert tortoises, and to characterize cytologic staining and morphologic features of bone marrow hematopoietic cells. ANIMALS: 16 desert tortoises. PROCEDURE: Bone marrow was obtained at necropsy from the pelvis, proximal portion of the humerus, femur, and thickened portions of the cranial to craniolateral and caudal to caudolateral margins of the carapace and plastron for histologic and cytologic examinations. Cytocentrifuged preparations of marrow cells were evaluated for reactivity to cytochemical stains. RESULTS: Histologic sections were adequate for evaluating acidophils, acidophil precursors, and erythrocyte precursors. It was difficult to differentiate among monocytes, lymphocytes, thrombocytes, and blast cells, and eosinophils could not be differentiated from heterophils. Basophils were in rare, small clusters of 3 to 12 cells. A few lymphoid follicles were found in the pelvis and long bones. Use of cytochemical staining accomplished differentiation between agranular heterophil precursors and granulated heterophils, and between granulated eosinophils and basophils. Monocytes, azurophils, and monoblasts had similar staining features. Staining of erythrocyte precursors with Sudan black B differentiated them from lymphocytes. Only a few small cells with periodic acid-Schiff-positive cytoplasm were identified as thrombocytes. Lymphocytes did not stain with any of the cytochemical stains. CONCLUSIONS: For histologic and cytologic evaluation of bone marrow hematopoietic cells, pelvis, proximal portion of the humerus, femur, and thickened portions of the peripheral cranial and caudal regions of the carapace and plastron are suitable sites to collect specimens. There are distinct cytochemical markers for heterophil, monocyte, and erythrocyte precursors, as well as later stage heterophils, eosinophils, basophils, monocytes, and azurophils.

Animals↗
PubMed1995

Water release associated with specific binding of gal repressor.

Water release coupled to the association of gal repressor with DNA is measured from the sensitivity of the binding constant to the solution osmotic pressure, using neutral solutes that are typically excluded from polar protein and DNA surfaces. Differences in water release for binding of repressor to different sequences are linked with differences in specificity and binding energies. With sucrose, the specific binding of repressor to operator sequences is accompanied by the release of 130 water molecules. No water release is seen for the weak, non-specific binding of repressor to poly(dI-dC).(dI-dC). A difference in the release of six water molecules is seen even for the binding of gal repressor to two different operator sequences that differ in affinity by only a factor of two.

Binding, Competitive↗
PubMed1995

Fluorescent labeling of DNA with ethidium homodimer without measurable decrease in DNA mobility: application to automated gel electrophoresis apparatus.

Mobilities of DNA, fluorescently labeled with ethidium homodimer (EtD), and normalized to the mobility of the 50-bp fragment [Rf(50)], are constant with time of electrophoresis, permitting one to conduct studies on DNA mobility in an automated electrophoresis apparatus with fluorescence detection. DNA mobility decreases with an increasing binding density of ethidium homodimer, as previously reported by others and expected since the dye decreases both the net charge and the conformational flexibility of the DNA. However, it was found that this effect of ethidium binding on electrophoretic mobility becomes undetectable at binding densities less than 1 EtD/40 bp. This implies that for the purposes of electrophoretic analysis in an apparatus with fluorescence detector, DNA with ethidium homodimer intercalated at dye-DNA ratios less than 1/40 bp behaves like unlabeled DNA and may be assumed to be in a conformation similar to that of the unliganded DNA. Necessarily, the low labeling ratio lowers the sensitivity of detection and, in particular, increases the load requirement for a full-scale band height required for the analysis of bandwidth and band shape during electrophoresis.

DNA↗
PubMed1995

Commercial automated gel electrophoresis apparatus: application to DNA, band dispersion, nonlinear Ferguson curves, and isolation.

Recently available commercial automated gel electrophoresis apparatus with intermittent scanning of fluorescently labeled gel patterns (the HPGE-1000 apparatus of LabIntelligence, Menlo Park CA) was tested with regard to (i) its applicability to DNA in its native conformation, (ii) its ability to recognize the correct number of components, (iii) its capability to evaluate the width and shape of bands detected during electrophoresis, (iv) its ability to yield nonlinear Ferguson plots in a labor-saving fashion, and (v) its preparative potential. Ethidium homodimer (EtD) DNA (bp) ratios were systematically varied and the mobility of DNA fragments labeled at each ratio was measured in order to find a ratio which provided an unaltered mobility and presumably therefore an unaltered conformation of the fragment. That ratio was found to be 1/40 EtD/DNA (bp) or less. With such weak labeling of DNA, a representative fragment of 527 bp length requires a minimum load of 200 ng and a 2 micrograms load for a full-scale peak height. Using the baseline automatically selected by the software of the apparatus, the band areas of the 17 components of a DNA digest were consistently evaluated by the software, as evidenced by the proportionality between DNA length and area. The areas of the separated bands of DNA fragments of 1857 and 121 bp length were found to be constant with time of electrophoresis. The dispersion coefficient was found to decrease with agarose concentration in electrophoresis at 1 V/cm; however, at higher field strength, the band width of the 1857 bp fragment was surprisingly found to increase with gel concentration, presumably due to stretching.(ABSTRACT TRUNCATED AT 250 WORDS)

Buffers↗
PubMed1995

Capillary electrophoresis of rat liver microsomes in polymer solutions.

Rat liver microsome components were separated by capillary zone electrophoresis in buffers containing substituted agarose, agarose crosslinked polyacrylamide, polyacrylamide, polyethylene glycol and dextran of various molecular weights. The best resolution of the components was obtained with polymers of 10-21 nm geometric mean radius. Both the crude and the purified preparations of microsomes exhibit a single major peak. In a Tris-borate-EDTA (TBE) buffer, containing polyacrylamide of 5 x 10(6) molecular weight, it has a retardation coefficient, KR, of 0.77 +/- 0.02. Translation of the KR value to geometric mean radii, R, on the basis of the standard curve applicable to polymer solutions, KR vs. R, with polystyrene carboxylate size standards in both dextran and polyacrylamide solution allows one to estimate a value of R as 13-16 nm for the major microsome component. The value is smaller than expected from electron microscopic measurements (100-250 nm), possibly due to the chemical and geometric differences between microsomes and the polystyrene particles used as size standards. The crude preparation also contains a minor component which is smaller and less charged than the major component. Another component, apparently very much larger than the major one, is seen in TBE buffer but not in a potassium-N-(2-hydroxyethyl)piperazine-2'-(2-ethanesulfonic acid) buffer and is therefore thought to be an artifact of interaction with borate. After a short incubation under conditions promoting delayed microsome fusion, i.e. in presence of GTP and Mg++ and in the absence of polyethylene glycol, the electrophoretic pattern changes dramatically: it now exhibits five unretarded, highly mobile and, therefore, presumably large components in addition to the two original retarded components of the microsome and a less highly charged species similar in KR to the smaller of the original two components.

Acrylic Resins↗
PubMed1995

Recovery of SDS-protein and DNA using commercial automated gel electrophoresis apparatus.

The HPGE-1000 apparatus (LabIntelligence, Menlo Park, CA) is a gel electrophoresis instrument with intermittent fluorescence scanning of the migration path and with preparative capability. An electroelution cup sealed with gel is placed onto the band of interest, identified and located under computer control, and the band is electroeluted into the cup at a right angle to the orientation of the resolving gel. The correct location of the eluted band and the degree of its recovery into the elution cup are then verified on the gel pattern, visualized on the computer screen. Using that procedure, SDS-conalbumin-FLUOS was electrophoresed at 5 V/cm in a discontinuous tricinate-chloride-Tris system at loads of 0.25 to 20 micrograms, using 5% agarose (MetaPhor, FMC), 0.03% SDS gel at 5 degrees C. The horizontal gel was partitioned at the sample loading slit between a gel in Tris-tricinate (prepared at the concentrations of an operative phase ZETA) and in Tris-chloride (prepared as phase BETA). The elution cup was sealed with the latter gel and overlayered with buffer of the composition of the former. This arrangement should provide for electroelution of the band as a highly concentrated stack. At electroelution times of 2, 3.5, 4-5, 12, 15 and 15 min at 15 V/cm yields were 58, 60, 54-76, 99, 99 and 84% for loads of 0.25, 0.5, 1, 4, 10 and 20 micrograms, respectively. At the most sensitive scale of detection (13), a full-scale peak was obtained at a load of 1.7 micrograms when the fluorophore (FLUOS, Boehringer-Mannheim) to protein ratio was 10:1. Similarly, homogeneous nucleosomal DNA (146 bp), electrophoresed in 0.2 x TBE buffer at a load of 5 micrograms, was near-quantitatively recovered into the same buffer by electroelution at 15 V/cm for 2.5 or 6 min.

Autoanalysis↗
PubMed1994

Molecular sieving of polystyrene carboxylate of a diameter up to 10 microns in solutions of uncrosslinked polyacrylamide of M(r) 5 x 10(6) using capillary zone electrophoresis.

Capillary zone electrophoresis of polystyrene carboxylate (PSC) up to 10 microns in diameter in 0.1 to 0.9% solutions of uncrosslinked polyacrylamide (PA) of M(r) 5 x 10(6) demonstrates effective molecular sieving in that medium. The reduced mobility, however, is not constant in Tris-borate-EDTA (1x TBE) buffer containing the polymer but increases in proportion to the load of PSC and inversely to the concentration of PA unless the TBE concentration is increased 10-fold or 50 mM 3-[(3-cholamidopropyl)dimethylammonio]propanesulfonic acid is added to the solution or in the absence of PA. Both the Ferguson plots [log(mobility) vs PA concentration] of PSC obtained at various PSC loads and the effects of the dissociating conditions, high ionic strength and detergent, signify that the variable mobilities are those of different PSC aggregation states. Thus, only the fully associated or dissociated states of PSC provide mobilities that are constant independently of PSC load. The study shows that the information inherent in Ferguson plots regarding particle and fiber properties can be exploited for particles up to 10 microns in diameter by capillary zone electrophoresis in polymer solutions even if these particles form various aggregation states. Thus, such an analysis appears feasible in application to biologically relevant and functional complexes such as subcellular-sized particles or DNA-protein complexes, providing that these particles maintain their integrity and functionality under the selected electrophoretic conditions.

Acrylic Resins↗