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Biomedical subjects

R Wilkinson

Publications and source records attributed to R Wilkinson.

At least 199 records · Page 11Linked to original sources
PubMed1989

Utility of the indium 111-labeled human immunoglobulin G scan for the detection of focal vascular graft infection.

The ability to diagnose and localize vascular graft infections has been a major challenge. Recent studies in animal models and humans with focal bacterial infection have shown that radiolabeled, polyclonal, human immunoglobulin G accumulates at the site of inflammation and can serve as the basis for an imaging technique. This study investigated this new technique for the diagnosis and localization of vascular graft infections. Twenty-five patients with suspected vascular infections involving grafts (22), atherosclerotic aneurysms (2), and subclavian vein thrombophlebitis (1) were studied. Gamma camera images of the suspected area were obtained between 5 and 48 hours after intravenous administration of 1.5 to 2.0 mCi (56 to 74 mBq) of indium 111-labeled, human, polyclonal immunoglobulin G. Scan results were interpreted without clinical information about the patient and were subsequently correlated with surgical findings, other imaging modalities, and/or clinical follow-up. In 10 of 10 patients found to have positive scan results, localized infections were confirmed at the involved sites. In 14 of 15 patients whose scan results were interpreted as negative, no vascular infections were identified at follow-up. The patient with false-negative results and recurrent bacteremia from an aortoduodenal fistula was found to have a negative scan outcome at a time when his disease was quiescent. These data suggest that nonspecific, human, indium 111-labeled immunoglobulin G scanning can be a useful noninvasive means of localizing vascular infections.

Adult↗
PubMed1988

Escherichia coli-specific T lymphocytes in experimental pyelonephritis.

We have assessed the phenotype and specificity of infiltrating mononuclear cells in a model of unilateral ascending acute pyelonephritis induced in rats with nephritogenic Escherichia coli or Pseudomonas aeruginosa. Histologic examination showed a predominance of mononuclear cells in the interstitium at all periods examined (4, 8, 15, 21, and 25 days), although at 4 and 8 days neutrophils were also abundant. Most of the mononuclear cells had the morphologic appearance of large lymphocytes. Immunoperoxidase studies with mAb showed that most of the mononuclear cells were W3/25+; many were W3/13+ and a small proportion were OX8+. Many of the mononuclear cells were Ia+. T cells were propagated in IL-2-containing media from small fragments of renal tissue with pyelonephritic lesions. Most of the propagated cells were W3/25+; fewer than (10%) were OX8+ or Ia+. T cells propagated from kidneys infected with E. coli responded, in proliferation assays, to the infecting strain or other E. coli strains, but not to P. aeruginosa or enterococci. The response to non-p-pilus-bearing E. coli was as great or greater than to E. coli with adhesins. T cells derived from lesions induced by P. aeruginosa responded to the infecting organisms, but not to E. coli. The response to the infecting organism (E. coli or P. aeruginosa) was MHC restricted, as indicated by the requirement for syngeneic APC. The results show that large numbers of T lymphocytes, especially with the "helper/inducer" phenotype, accumulate in the lesions of acute pyelonephritis in rats. Among the infiltrating T lymphocytes are activated cells and cells with specific reactivity to the infecting bacteria (or related strains). The findings indicate that T lymphocytes play a role within the kidney in response to the invading bacteria.

Animals↗
PubMed1988

Hypertension and hyperinsulinaemia: a relation in diabetes but not essential hypertension.

To investigate the hypothesis that insulin resistance is concerned in the pathogenesis of essential hypertension fasting glucose/insulin and fasting insulin/C-peptide ratios were measured in non-obese normotensive and hypertensive diabetic and non-diabetic subjects. Patients with essential hypertension had normal fasting serum insulin values and normal fasting glucose/insulin ratios; by contrast, the hypertensive non-insulin-dependent diabetic subjects had higher fasting serum insulin and lower glucose/insulin ratios than either normotensive diabetic or non-diabetic patients. Both hypertensive and normotensive diabetic subjects had higher fasting C-peptide values than those without diabetes. Hypertensive diabetic patients had the highest insulin/C-peptide ratios, indicating low hepatic insulin extraction rates. These findings suggest that hyperinsulinaemia is not causally related to essential hypertension but that it may contribute to the hypertension of non-insulin-dependent diabetes in association with low hepatic insulin clearance.

Analysis of Variance↗
PubMed1988

Increased in vitro bone resorption by monocytes in the hyper-immunoglobulin E syndrome.

Children with the hyper-immunoglobulinemia E syndrome are prone to bone fractures. We determined bone density in six patients with hyper-IgE syndrome using photon absorptiometry. All six patients had significantly reduced bone density compared with age- and sex-matched controls. The capacity of peripheral blood monocytes to degrade 45Ca-labeled bone in vitro was studied. The mean percent 45Ca release in four hyper-IgE patients (40.8 +/- 8.6) was significantly higher (p less than 0.01) than in ten age-matched healthy control subjects (7.1 +/- 2.6), seven age-matched patients with recurrent infections (7.9 +/- 1.6), or nine patients with severe atopic dermatitis and elevated serum IgE levels (5.8 +/- 1.3). Monocytes from four of four patients studied spontaneously released abnormally high levels of prostaglandin E2. Bone degradation by these monocytes was significantly reduced in the presence of 10(-6) M indomethacin in vitro. Administration of aspirin in vivo to two hyper-IgE patients reduced boned degradation by their monocytes to normal levels. These results suggest that monocytes from patients with hyper-IgE syndrome are activated to resorb bone via products of the prostaglandin synthase (cyclooxygenase) pathway. The activation of cells in the monocyte/macrophage family to resorb bone may contribute to the osteopenia observed in hyper-IgE syndrome.

Aspirin↗
PubMed1988

Sodium-lithium countertransport activity and its sensitivity to inhibitors with erythrocyte ageing in man.

Sodium-lithium countertransport is believed to depend on a specific protein and since such proteins usually decline with erythrocyte age it would be expected to be reduced in older cells. In fact, sodium-lithium countertransport increased with ageing, whereas the rate constant of the sodium pump decreased. The increase in sodium-lithium countertransport with erythrocyte ageing was due to a phloretin insensitive component that was not present in young erythrocytes. Raised sodium-lithium countertransport in patients with essential hypertension was due mainly to an increased phloretin sensitive component but the phloretin insensitive component was also higher in middle aged erythrocytes. Amiloride had no effect upon sodium-lithium countertransport or unidirectional sodium influx in cells of any age. This suggests that sodium-lithium countertransport is not a mode of action of the sodium-proton exchanger in the erythrocyte.

Aging↗
PubMed1988

Jacalin: its binding reactivity with immunoglobulin A from various mammalian species.

Jacalin, a recently described lectin, has been demonstrated to have unique binding properties for some forms of human immunoglobulin A (IgA). The lectin has now become commercially available, immobilized to a beaded agarose support. This laboratory undertook a short study to determine whether this immobilized jacalin demonstrated any binding capacity for IgA from various mammalian species, with a view to utilizing this new form of affinity chromatography to simplify the purification of IgA from these species. Utilizing the chromatographic conditions recommended by the manufacturer, the bound jacalin demonstrated no IgA reactivity from pig, goat, horse, cow or dog.

Animals↗
PubMed1988

Humoral and cell-mediated immune responses in non-pregnant heifers following infection and vaccination with Brucella abortus.

Humoral and cell-mediated-immune responses to Brucella abortus were observed in non-pregnant heifers following infection alone; infection followed by vaccination; vaccination followed by infection; and vaccination alone. The humoral responses, as measured by the Rose Bengal test (RBT), complement fixation test (CFT), indirect haemolysis test (IHLT) and the enzyme-linked immunosorbent assay (ELISA) tended to be immediate and transient following infection alone, infection following vaccination and vaccination alone. However, when vaccination was superimposed on infection, reactions were maintained for at least 2 years. The cell-mediated-immune (CMI) responses were assessed by the lymphocyte stimulation test. The responses occurred after the humoral responses had peaked and were present for periods of 6-22 weeks. However, the level of stimulation was greater following infection than following vaccination, and the response when vaccination was superimposed on infection was present for less than 6 months.

Animals↗
PubMed1988

Detection of acute inflammation with 111In-labeled nonspecific polyclonal IgG.

The detection of focal sites of inflammation is an integral part of the clinical evaluation of the febrile patient. When anatomically distinct abscesses are present, lesion detection can be accomplished by standard radiographic techniques, particularly in patients with normal anatomy. At the phlegmon stage, however, and in patients who have undergone surgery, these techniques are considerably less effective. While radionuclide methods, such as Gallium-67 (67Ga)-citrate and Indium-111 (111In)-labeled WBCs have been relatively successful for the detection of early inflammation, neither approach is ideal. In the course of studies addressing the use of specific organism-directed antibodies for imaging experimental infections in animals, we observed that nonspecific polyclonal immunoglobulin G (IgG) localized as well as specific antibodies. Preliminary experiments suggested that the Fc portion of IgG is necessary for effective inflammation localization. Since polyclonal IgG in gram quantities has been safely used for therapy in patients with immune deficiency states, we decided to test whether milligram quantities of radiolabeled IgG could image focal sites of inflammation in humans. Thus far, we have studied a series of 84 patients with suspected lesions in the abdomen, pelvis, vascular grafts, lungs, or bones/joints. In 48 of 52 patients with focal lesions detected by surgery, computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound (US), the IgG scan correctly localized the site, while 31 patients without focal inflammation had no abnormal focal localization of the radiopharmaceutical. Four patients had false negative scans and one patient had a false positive scan. For this small series, the overall sensitivity and specificity were 92% and 95%, respectively. In this report, we review our experience with this exciting new agent.

Acute Disease↗
PubMed1988

Critical analysis of the use of skeletal surveys in patients with chronic renal failure.

Skeletal radiology and bone histopathology were compared in 82 patients with renal failure. The performance of radiology in detecting lesions was assessed using interobserver studies which showed disappointing levels of agreement probably reflecting the subjective nature of the radiological signs. Radiology was very insensitive in detecting and grading hyperparathyroidism even when histology and serum biochemistry were floridly abnormal. The most useful radiographs for monitoring subperiosteal erosions and vascular and soft tissue calcification are identified.

Adolescent↗
PubMed1988

Catecholamine concentrations during exposure of resting man to the heat of a standard sweat test.

1. Normal subjects were heated for 45 min with a heat cradle under the conditions used to investigate sweating clinically. 2. Skin temperatures on the chest and in the external auditory meatus rose but concentrations of noradrenaline and adrenaline decreased during heating. 3. There was no change in adrenoceptor affinity or number as a result of the heat exposure. 4. There was little change in blood pressure and heart rate and no dysrhythmias were observed with an electrocardiogram. 5. It is concluded that heating with a heat cradle is generally not stressful and that there is a reduction in sympathetic nervous activity involving noradrenergic or adrenergic transmission during the procedure.

Adult↗
PubMed1988

Urinary enzyme excretion after donor nephrectomy.

A number of recent studies of long-term kidney donors have reviewed glomerular function and blood pressure. Little attention has been paid to the potentially damaging effects of compensatory hyperfiltration on renal tubular cells after donor nephrectomy. The urinary excretion of high-molecular-weight enzymes is a sensitive indicator of renal tubular cell damage. This study compares the urinary excretion of four enzymes (alanine aminopeptidase, alkaline phosphatase, N-acetyl-beta-D-glucosaminidase, and lactate dehydrogenase) in a group of 77 subjects who had undergone unilateral nephrectomy up to 21 years previously with 52 healthy non-nephrectomized controls. The urinary excretion for all four enzymes by the remaining kidney after contralateral nephrectomy in the kidney donors was significantly greater than the enzyme excretion per single kidney in the control group (p less than 0.001). No correlation was found between the degree of enzymuria and either glomerular filtration rate or time since nephrectomy. The elevated activity of urinary enzymes in kidney donors may be related to increased metabolism by the renal tubular cells after contralateral nephrectomy. This study suggests that long-term compensatory hyperfiltration does not damage tubular cells, at least over this time scale.

Acetylglucosaminidase↗