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Biomedical subjects

M Hoare

Publications and source records attributed to M Hoare.

47 records · Page 3Linked to original sources

Blunt abdominal aortic trauma.

Due to its well protected position within the abdomen, blunt injuries to the abdominal aorta are uncommon. A review of previous reports in the literature, together with four new cases, are presented here. Motor car accidents are the most common cause of this injury, especially if seat belts are worn. Associated gastrointestinal injuries did not lead to any increased mortality; however, delay in the diagnosis was a significant factor in the deaths of several patients. Prompt recognition and early surgical management are essential in the treatment of this problem.

Accidents, Traffic↗

Biochemical engineering challenges of purifying useful proteins.

Some of the biochemical engineering issues that arise when the purification of proteins is scaled up are examined. The first question addressed is the quantity of various proteins likely to be required. Consideration is given to the order in which isolation procedures may be applied and to the selective removal on a large scale of non-proteinaceous materials. Some general problems such as the effect of mechanical forces on proteins and their complexes and aggregates are examined, together with ways of enhancing the properties of these aggregates and the methods of recovering them. The manner in which on-line process optimization can be achieved during pilot plant trials is discussed and the paper concludes with a summary of new scientific developments to which the biochemical engineer will need to respond.

Biotechnology↗

Intermittent sequential pneumatic compression of the legs and thromboembolism-deterrent stockings in the prevention of postoperative deep venous thrombosis.

One hundred fifty patients over the age of 30 who had undergone major abdominal operations were stratified according to the risk of deep venous thrombosis and randomized into three groups to receive different prophylactic regimens: group A, electrical calf stimulation; group B, low-dose subcutaneous heparin; group C, intermittent sequential compression and thromboembolism-deterrent (TED) stockings. All the patients were scanned with the 125I-fibrinogen test for the whole stay in hospital. The incidence of 125I-fibrinogen detected deep venous thrombi was 18% in group A, 9% in group B, and 4% in group C. The results indicate that the regimen of intermittent sequential compression and TED stockings is as effective as low-dose subcutaneous heparin. Electrical calf stimulation is less effective.

Abdomen↗

The effect of local cooling on digital systolic pressure in patients with Raynaud's syndrome.

The effect of local controlled cooling on the digital systolic blood pressure in the hand was studied in 25 healthy volunteers and 25 patients with Raynaud's syndrome. Arterial systolic pressure was indirectly measured using a digital cuff over the proximal phalanx and a photoplethysmographic probe over the digital pulp to detect pulsation. Pressures were measured after occlusion of the circulation (cuff at 180 mmHg) for 5 minutes with water circulating initially at 30 degrees C and then at 10 degrees C. An air filled cuff was used simultaneously on a control finger. The digital systolic pressure at 10 degrees C in the patients was significantly lower (P less than 0.001 Mann-Whitney U test) than in the normal volunteers whilst calculation of the percentage change in pressure induced by cooling the digit to 10 degrees C allowed complete separation between both groups. The range in the controls was +2 per cent to -26 per cent and in the patients, -33 per cent to -100 per cent. The test gives reproducible results (coefficient of variation 5-11 per cent) and offers an objective method of identifying patients with excessive vasospasm due to a cold stimulus. It may prove useful in studying natural history and the effect of drug therapy.

Adult↗

Selective flocculation and precipitation for the improvement of virus-like particle recovery from yeast homogenate.

The purification of an intracellular product from a complex mixture of contaminants after cell disruption is a common problem in processes downstream of fermentation systems. This is particularly challenging for the recovery of particulate (80 nm in diameter) multimeric protein products, named virus-like particles (VLPs), from cell debris and other intracellular components. Selective flocculation for debris removal followed by selective precipitation of the target protein can be used as a preclarification step to aid purification. In this paper, selective borax flocculation of cell debris in yeast homogenate, followed by selective poly(ethylene glycol) precipitation of VLPs are defined with a view to demonstrating their potential in aiding the initial clarification stages of the purification sequence. The translation from laboratory scale to pilot scale operation is addressed, demonstrating the challenge of scale-up of solid-liquid separation stages for biological particle processing.

Borates↗

Use of at-line spectrophotometry for the rapid definition of pilot-scale flocculation processes.

Traditionally most downstream bioprocesses have been operated without real-time knowledge of product and key contaminants, yielding little confidence in their operation and the impact on subsequent operations. A rapid UV-vis spectral prediction technique has been successfully demonstrated for the at-line characterization of a large scale continuous flocculation process in terms of RNA, key protein contaminants, and cell debris. A comparison was made between the spectral predictions and retrospective wet chemical assays, and a highly linear correlation was obtained. The spectral analysis technique allowed for real-time system information, which was applied to control the flocculation process to maintain satisfactory process performance, even when subjected to given possible process disturbances.

Alcohol Dehydrogenase↗