Biomedical subjects

R A Lord

Publications and source records attributed to R A Lord.

13 recordsLinked to original sources

PubMed2003

Metal contamination of active stream sediments in upper Weardale, northern Pennine Orefield, UK.

In the Upper Weardale area the headwaters of the River Wear bisect the Northern Pennine Orefield, where Pb-Zn-F-Ba vein-type mineralisation has been exploited since the Roman Conquest. The area contains evidence of open pit, underground and hydraulic mining of base metal ores, associated mineral processing and smelting, exploitation of ironstones during the industrial revolution, recent extraction of fluorite and active quarrying. The aim of this study was to determine the extent of modern sediment contamination arising from these past activities. Samples of active stream sediments were collected from all major drainage channels at 1 km intervals. The sediments were analysed for Pb, Zn, Ba, Mn, Fe, Co, Ni, Cu, Cr, As, Sb, Ag and compared to data from earlier regional geochemical surveys of low order drainage samples using ArcView software. The significance of contamination levels was assessed using the Ontario aquatic sediment quality guidelines. Our results indicate widespread contamination of some major drainages by Pb, Mn, Zn and As at concentration levels anticipated to significantly affect use of the sediments by benthic organisms. Furthermore, Pb contamination shows persistence in stream sediments downstream towards agricultural areas of the floodplain and drinking water abstraction points, above which interaction with colliery mine water discharges may occur.

Agriculture↗

PubMed1992

Effect of aprotinin on neutrophil function after major vascular surgery.

High-dose aprotinin reduces blood loss and blood transfusion requirements during liver transplantation and cardiac and vascular surgery. The mechanism of the haemostatic effect of aprotinin is unclear. A general effect on the anti-inflammatory response may be involved. Because leucocyte activation is part of this process, white cell function was measured in patients undergoing aortic surgery who received high-dose aprotinin therapy (n = 10) and was compared with the results from controls who did not (n = 10). The test group received an intravenous bolus (2 x 10(6) kallikrein inhibitor units) of aprotinin after induction of anaesthesia followed by continuous infusion (0.5 x 10(6) kallikrein inhibitor units/h) until the end of the operation. Blood samples were obtained before operation, immediately after surgery, and 1 and 7 days after operation. Aprotinin maintained significantly better postoperative white cell function as measured by bipolar shape formation (P less than 0.001), unstimulated nitroblue tetrazolium (NBT) reduction (P less than 0.001) and chemotaxis (P less than 0.001). Endotoxin-stimulated NBT reduction was similar in both groups, indicating that neutrophils from treated individuals retained the capacity to respond to oxidative stimuli. Aortic surgery activates neutrophils in vivo, as reflected by impaired chemotaxis and increased superoxide production. Aprotinin protects the cells against this potentially deleterious effect without affecting their ability to respond when provoked. Whether this affects leucocyte interaction with coagulation pathways and contributes to the reduction in blood loss remains to be determined.

Aged↗

PubMed1992

Platelet counting using plasma platelet concentrate samples.

Platelet counting using samples of plasma from platelet concentrates prepared for transfusion was assessed. The methods employed included a manual phase-contrast method, and counting with Coulter S Plus and Sysmex E-2500 counters. All methods were reproducible (mean CV of 4.9, 2.2 and 1.4%, respectively). However, neat samples of platelet concentrates analysed by Coulter counter were inaccurate (mean count of 863.8 x 10(9)/l compared to 1018.9 x 10(9)/l counted manually). Moreover, the Coulter platelet counts were non-linear above 900 x 10(9)/l, whereas the E-2500 platelet counts were linear to 2700 x 10(9)/l. A one-in-three pre-dilution was required to obtain accurate, linear counts with the Coulter counter, whereas the E-2500 was accurate without pre-dilution (mean count of 1030.2 x 10(9)/l compared to 1018.9 x 10(9)/l counted manually). In conclusion, the method of platelet counting may affect true platelet yields.

Automation↗

PubMed1990

Evaluation and comparison of neutrophil bipolar shape formation with a migration assay.

The neutrophil shape change response to a chemotactic formylpeptide was assessed. Neutrophil bipolar shape formation (BSF) was also simultaneously assessed with a Boyden chamber-based neutrophil migration assay. Both assays were precise and relatively reproducible; the average coefficient of variation for the BSF assay was 9.6% and 9.2% for the migration assay. In a blind study the BSF assay showed 100% sensitivity at detecting subjects with known abnormal neutrophil migration. Unlike the migration assay, the BSF assay does not require isolated neutrophils, reducing possible cell activation and monitoring the cell response under more physiological conditions. Small blood samples--1 ml or less compared with 20-40 ml for the migration assay--are used, and the method is technically simple. Results are available within 40 minutes, and routine (EDTA) blood samples are used. It is concluded that the BSF assay is a suitable motility screening test for both the clinical and pharmacological examination of the movement of polymorphonuclear leucocytes.

Cell Movement↗

PubMed1986

Combined cold- and heat-induced cholinergic urticaria.

A 36-year-old white woman with a 20-year history of cutaneous, respiratory, and cardiovascular symptoms triggered by physical activity and by exposure to either heat or cold was evaluated. A routine evaluation for the cause of her condition was positive only for certain physical factors. Cutaneous testing for dermatographism, ice-cube challenge, and exposure to ultraviolet A and ultraviolet B light were negative. A methacholine skin test was positive. Sitting in a cold room (4 degrees C) induced micropapular wheals on exposed areas similar to those classically associated with cholinergic urticaria. Placing both feet in warm water (44 degrees C) induced similar but more intense cutaneous lesions at sites not exposed to heat, light headedness, and severe asthma. Exercise for 10 minutes caused confluent and punctate urticarial lesions. Simultaneous measurement of plasma histamine during cold and heat challenges revealed increases paralleling the course of symptoms. Repeat challenge with cold, heat, and exercise after beginning treatment with both H1 and H2 histamine antagonists resulted in marked reduction in symptoms; however, significant rises in plasma histamines were still noted.

Adult↗

PubMed1985

Familial exercise-induced anaphylaxis.

An 18-year-old hispanic male, his two brothers, father, two paternal uncles, and paternal grandfather experienced cutaneous and cardiorespiratory symptoms during vigorous exercise beginning at about 10 years of age. The propositus was challenged by running to exhaustion and by immersion in hot water. In neither case were allergic signs or symptoms noted; however, plasma histamine rose from undetectable levels to 1.0 and 3.7 ng/ml, respectively. Furthermore, C2 and C5 were significantly reduced and fell during exercise.

Adolescent↗

PubMed1979

Effect of specific antibodies on chronic echovirus type 5 encephalitis in a patient with hypogammaglobulinemia.

The effects of specific antibodies in chronic echovirus type 5 (echo 5) encephalitis were investigated in a patient with x-linked hypogammaglobulinemia. Virus was detected in cerebrospinal fluid (CSF) and blood despite treatment with commercial human gammaglobulin that contained low titers of antibodies to echo 5 (0.6 x 10(4) units per injection). Virus disappeared from blood and CSF when plasma containing high concentrations of antibodies (total dose, 1--4 x 10(4) units/kg) was administered intravenously. Maximal inhibition of virus was achieved in culture and in the patient's CSF when the titer of antibody to echo 5 in CSF was greater than or equal to 16 units/ml. Although the patient died, hyperimmune plasma improved the neurologic status and eliminated detectable virus from the blood and CSF.

Agammaglobulinemia↗

PubMed1975