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Biomedical subjects

T E Miller

Publications and source records attributed to T E Miller.

At least 73 records · Page 4Linked to original sources
PubMed1989

Clinical applications of the etched metal retainer.

This article presents the treatment of several patients directed at the prevention of periodontal disease and restoration of an occlusion from an eating disorder. The disruption of the harmony between the anterior and posterior determinants of occlusion can lead to the loss of teeth. The lack of anterior guidance can create a molar-guided occlusion producing unfavorable occlusal interferences with destructive balancing side prematurities. Conversely, if the posterior teeth are permitted to drift into unstable occlusal relationships, the posterior dentition would develop an irregular guidance despite a suitable anterior guidance. The goal of the profession is preventing occlusal deterioration or disharmony between the anterior and posterior occlusal determinants and restore compromised occlusions when necessary. Etched metal retainers were fundamental to the treatment of specific patients while patient selection and perceptive tooth preparation were essential for success.

Acid Etching, Dental↗
PubMed1989

Chronic pyelonephritis: modulation of host defenses by cyclosporin A.

Chronic experimental pyelonephritis is characterized by a stable level of infection, which persists for many months. Administration of cyclosporin A (CsA) reactivated previously healed renal lesions and caused a marked increase in bacterial numbers in the kidney. Studies were then carried out to compare the effects of CsA, and the nonselective cytodepletive agents irradiation and cyclophosphamide, on both host defenses and the bacteriologic status of chronically infected kidneys. Two different responses were observed. In animals treated with CsA, bacterial numbers increased markedly, although circulating neutrophil numbers were relatively unaffected. This observation was in contrast to the severe ablation of leukocyte numbers and competence needed to achieve an equivalent effect when irradiation and cyclophosphamide were used. One possible explanation for the adverse effect of CsA on the host-parasite balance in chronic pyelonephritis is that CsA affects mediators that control the inflammatory response or induces a qualitative change in a critical cellular defense compartment.

Animals↗
PubMed1989

Antimicrobial agents in the management of urinary tract infection: an experimental evaluation.

Persistent and recurrent infections of the urinary tract are a formidable clinical problem, but several recently developed antibiotics have properties that suggest an increased ability to eradicate such infections. Three of the new-generation antibiotics were compared with established agents by using animal models of urinary tract infection. Of the antibiotics tested, gentamicin and ceftriaxone alone were capable of eradicating infection from acute and chronically infected kidney tissue. Chronic lower urinary tract infection was best managed by using norfloxacin or ceftriaxone. Gentamicin, aztreonam, cotrimoxazole and ampicillin were much less effective. In subacute pyelonephritis, gentamicin, aztreonam, norfloxacin and ceftriaxone successfully eliminated microorganisms from most of the infected kidneys, whereas ampicillin and cotrimoxazole had little effect on bacterial numbers. The data have provided an experimental basis for the selection of antibiotics in the management of persistent urinary tract infection.

Acute Disease↗
PubMed1989

Geriatrics, emergencies, and visible light-cured dentures.

This article will cover several aspects involved with the routine prosthodontic care of an elderly patient. One of these patients is ambulatory and the other institutionalized. The article will also cover emergency treatment rendered to a patient requiring unexpected care because of trauma.

Acrylic Resins↗
PubMed1988

Exacerbation of experimental pyelonephritis by cyclosporin A.

An athymic rat strain lacking functional T cells was used to assess the role of cell-mediated immunity (CMI) in host defence against renal infection. CMI was ruled out as a relevant host defence component, but when cyclosporin A (CsA) was administered to athymic animals, renal infection was exacerbated. CsA is thought to affect T lymphocyte function and, in the absence of a target cell, cellular defences in the athymic animal were not expected to be compromised by CsA. An effect on non-cellular defence mechanisms was therefore considered but our studies did not support this explanation--rather they indicated a depression of either cellular defences or of a specific cellular component. The present experiments have provided additional information on the relationship between CsA administration and the depression of host defence mechanisms but further studies will be necessary to identify the components affected.

Animals↗
PubMed1988

Reliable diagnosis of Trichosomoides crassicauda in the urinary bladder of the rat.

Two reliable methods are described for identifying infection of laboratory rats with the nematode Trichosomoides crassicauda. The first is a rapid method where cryostat sections of the rat urinary bladder are stained with acridine orange and viewed under a fluorescence microscope. The second involves the stabilization of the bladder surface prior to examination using scanning electron microscopy (SEM).

Animals↗
PubMed1988

Host defence mechanisms in the bladder. II. Disruption of the layer of mucus.

The urinary bladder wall is lined by a layer of mucus which is believed to provide an important barrier to bacterial invasion of the urinary tract. Abnormal function of this protective layer could therefore be a factor predisposing the host to urinary tract infection (UTI). This study investigated the contribution of the bladder mucus to host defence in both acute and chronic lower UTI, using a non-obstructive animal model of infection which reproduces many features of the disease in man. The ultrastructural appearance of the infected bladder mucosa was assessed in tissue in which both the layer of mucus and bacterial glycocalyces were stabilized prior to examination by scanning and transmission electron microscopy. The protective role of the mucus layer was determined by disrupting the layer immediately prior to bacterial challenge. Both ultrastructural and bacteriological analyses have shown that infection was increased in those animals where the mucus barrier was disrupted.

Animals↗
PubMed1988

Host defence mechanisms in the bladder. I. Role of mechanical factors.

This study evaluated the contribution of host defence mechanisms to bacterial clearance from the urinary bladder using an animal model in which rats were infected with Escherichia coli. Factors studied included the effect of hydration status, induced ultrastructural changes to the surface of the bladder mucosa, and the relevance of bacterial replication. Clearance was divided into two phases, primary (0-4 h), and secondary (4-24 h). Ninety-nine per cent of Escherichia coli 075 was cleared during the primary phase from normal, dehydrated and polyuric animals and 93% from anuric animals. Clearance was shown to be dependent on the presence of viable tissue. Bacterial numbers continued to decrease during the secondary phase in normal and dehydrated animals but increased in polyuric and anuric groups. No such rise occurred when rats were inoculated with Escherichia coli E/2/64, a non-replicating mutant. Evidence of ultrastructural changes to the bladder associated with impaired antibacterial properties was found in polyuric and anuric animals. Clearance of particulate matter (killed Candida albicans) however was unaffected by mucus disruption. The study has shown that the clearance of microorganisms from the bladder was unrelated to the voided volume, but is closely associated with the antibacterial activity of the mucosal surface.

Animals↗
PubMed1988

Peripheral blood leukocyte count as an index of defense status in the leukopenic host.

These experimental studies have investigated the reliability of the peripheral blood leukocyte count to predict whether the leukopenic host can contain or eliminate infection. Additionally, we have investigated the possibility that determination of leukocyte recruitment, supplementary to peripheral blood leukocyte counts, might allow individuals with neutropenia at risk from serious infection to be distinguished with greater certainty. Varying doses of radiation, cyclophosphamide, and methylprednisolone were used to induce distinct levels of leukopenia in rats. Leukocyte recruitment was measured by quantifying the response of neutropenic animals to evocative, subcutaneous stimuli, and the results of this assay were then compared with circulating leukocyte counts in the same individuals. Six models of experimentally induced infection were used to compare circulating and recruitable leukocytes as indicators of the susceptibility of the leukopenic host to infection. Response curves relating leukocyte numbers to host resistance were similar when circulating or recruitable leukocytes were used as an index of defense capability. These findings support the use of peripheral blood leukocyte numbers as an index of resistance to infection in individuals with leukopenia and suggest that functional analyses such as leukocyte recruitment are unlikely to provide additional information.

Animals↗
PubMed1987

Chromosomal location of genes coding for endosperm proteins of Hordeum chilense, determined by two-dimensional electrophoresis of wheat-H. chilense chromosome addition lines.

The proteins of Hordeum chilense grain were resolved into 25 major components by two-dimensional electrophoresis. Their solubilities in aqueous alcohol solutions were determined to distinguish prolamin storage proteins from metabolic and structural proteins. The prolamins were divided into two groups, based on the presence or absence of intermolecular disulfide bonds determined by gel-filtration chromatography. Using an incomplete set of Chinese Spring wheat-H. chilense disomic addition lines, the structural genes of 21 of the 26 most dominant seed proteins were assigned to chromosomes. The great majority of the prolamin genes, including those coding for a high molecular weight (HMW) prolamin subunit, was present on chromosome 1 Hch. However, a small number of prolamin genes also occurred on chromosomes 5 Hch and 7 Hch. A minor protein, probably belonging to the nonstorage group of proteins, is coded by genes on 5 Hch. Various ditelosomic addition lines and ditelosomic and disomic substitution lines for chromosome 7 Hch were also analyzed by electrophoresis. This technique revealed that the genes for three major prolamins occur on the beta arm of chromosome 7 Hch and that a gene for a minor protein, also thought to be a prolamin, occurs on the alpha arm. These results are discussed in relation to the evolution of prolamin genes in the Triticeae.

Chromosome Mapping↗
PubMed1987

Inhibition of neutrophil myeloperoxidase activity by selected tissues.

Myeloperoxidase, a polymorphonuclear leukocyte-specific enzyme, has been used previously to quantify the number of polymorphonuclear leukocytes in tissue. When this method was employed in an attempt to measure polymorphonuclear leukocyte numbers in infected kidneys, it was found that myeloperoxidase could not be demonstrated, although significant numbers of neutrophils were present in the pyelonephritic lesions. Further studies were carried out to determine the effect of other tissues on free and cell-bound exogenous myeloperoxidase. We have shown that while skin had little effect on enzyme levels, liver and spleen totally destroyed myeloperoxidase activity within 30 sec. Cardiac and striated muscle had an intermediate effect. When intact neutrophils were added to fresh cardiac tissue 72.5% myeloperoxidase activity was destroyed during the enzyme solubilization procedure. These findings indicate that the technique can only be used for the quantification of polymorphonuclear leukocytes in selected tissues and that appropriate controls are essential. Previous studies in which myeloperoxidase levels have been used to estimate polymorphonuclear leukocyte numbers in cardiac tissue will need reevaluation.

Animals↗
PubMed1987

Cellular basis of host defence in pyelonephritis. III. Deletion of individual components.

Hosts were depleted of individual cellular components to determine the effects of these manipulations on cellular defence mechanisms in acute and chronic pyelonephritis. T-lymphocytes were found to have little or no involvement in host protection but cyclosporin A administration had a dramatic effect on the gross pathology and bacteriological status of experimentally induced pyelonephritis. This change represented a major depression of host defence status. Cyclosporin A also activated resolved lesions in chronic pyelonephritis, associated with an increase in bacterial numbers. Administration of antineutrophil serum also led to a 1000-fold increase in bacterial numbers in the acute phase but had little effect on the host-parasite balance in chronic pyelonephritis. Macrophage blockade, on the other hand, did not affect the course of either acute or chronic infection. These studies have provided additional information on the immunobiology of experimental pyelonephritis and have focussed attention on the role of neutrophils, and an unidentified mechanism, affected by cyclosporin A, in host defence to renal infection.

Animals↗