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P Vowden

Publications and source records attributed to P Vowden.

18 recordsLinked to original sources
PubMed1990

Non-invasive estimation of peripheral resistance using Pulse Generated Runoff before femorodistal bypass.

The measurement of peripheral resistance (PR) is a useful technique for predicting the outcome of femorodistal bypass. In an attempt, noninvasively, to predict PR, Pulse Generated Runoff (PGR) was used to assess 35 consecutive patients undergoing femorodistal non-reversed vein bypass for critical ischaemia. The PGR subscores (anterior tibial, posterior tibial, peroneal, pedal arch status were correlated against the measured PR. Using multiple linear regression three resistance values were derived for runoff at different levels: (1) a single calf vessel (R1); (2) distal popliteal artery (R3); (3) irrespective of the level (R0). There was good agreement between the predicted resistances R0, R1 and R3 and the measured PR. In the single calf vessel group (R1) the limits of agreement (-0.41 to +0.39) and 95 per cent confidence interval (-0.16 to +0.14) with the measured PR were better than in the R0 and R3 groups. These levels of agreement are small enough to replace the measured PR with the predicted PR method. Using the appropriate resistance equation in a further prospective series of 14 cases, there was agreement between the predicted and measured PR (limits of agreement -0.67 to +0.41; 95 per cent confidence interval -0.26 to +0.15). These results confirm the value of PGR in the assessment of critically ischaemic limbs particularly with a single calf vessel. Calf vessel continuity with the pedal arch appears to be a major determinant of PR, particularly in the isolated calf vessel group. A non-invasive resistance value can be derived which will predict the intraoperative peripheral resistance and should help predict subsequent graft outcome.

Aged↗
PubMed1989

Plasma eicosanoids, platelet function and cold sensitivity.

As abnormal eicosanoid (prostaglandin) metabolism has been suggested as a factor in the aetiology of vasospastic diseases we have measured levels of stable eicosanoid metabolites using a radioimmunoassay in 30 normal subjects and 31 patients with Raynaud's phenomenon. There were 13 patients with primary Raynaud's, ten with Raynaud's secondary to scleroderma and eight men with vibration white finger (VWF) disease. We have also measured platelet aggregation to adenosine diphosphate (ADP), collagen and adrenaline in 19 normal subjects, 22 patients with primary Raynaud's, 12 with Raynaud's secondary to scleroderma and 14 men with VWF. When compared with our normal subjects, patients with VWF have an elevated thromboxane B2 level, with a normal 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) level. Their platelets are less sensitive to ADP and collagen. Patients with primary and secondary Raynaud's have elevated thromboxane B2 levels but this is much more marked in the secondary group. Patients with primary Raynaud's have a normal 6-keto-PGF1 alpha level but in patients with secondary Raynaud's the 6-keto-PGF1 alpha level is markedly raised. The platelets from both groups are more sensitive to ADP and collagen and this is more marked in the secondary group. Whether these phenomena are a cause or an effect of vasospasm remains unknown.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Inappropriate use of metronidazole in gastrointestinal surgery.

Pharmacokinetic data suggest that current treatment regimens of metronidazole in abdominal surgery are not always appropriate. We have examined antibiotic concentrations during emergency and elective surgery using a specific and sensitive high pressure liquid chromatography assay. Serum and tissue concentrations were measured after intravenous infusion during intra-abdominal surgery and after suppositories given before appendicectomy. After intravenous dosage, bactericidal concentrations were reached in serum (13.6 +/- 7.8 micrograms/ml), bowel (9.0 +/- 6.6 micrograms/g), tumour (9.9 +/- 7.1 micrograms/g) and subcutaneous fat (4.9 +/- 3.2 micrograms/g). After suppositories the concentrations were: serum 4.6 +/- 2.7 micrograms/ml, appendix 1.1 +/- 0.6 micrograms/g, fat 1.5 +/- 0.9 micrograms/g and peritoneal fluid 4.7 +/- 4.3 micrograms/g. These values were obtained at a mean interval of 86.9 +/- 27.5 min following administration of the drug. Serum concentrations were measured during post-surgical infusion of 500 mg i.v. 8 or 12 hourly. Mean concentrations after 8 hourly doses were 16.3 +/- 4.85 micrograms/ml pre-dose and 28.7 +/- 6.76 micrograms/ml post-dose, with evidence of drug accumulation by detection of metabolites. Twelve hourly infusions gave pre-dose levels of 7.4 +/- 3.86 micrograms/ml and post-dose levels of 17.1 +/- 3.69 micrograms/ml. Metronidazole (500 mg) intravenously at induction of anaesthetic gives effective prophylactic concentrations in all tissues including tumour, but a metronidazole 1 g suppository before appendicectomy does not provide reliable tissue concentrations. Metronidazole (500 mg) i.v. 12 hourly gives effective bactericidal concentrations of the drug and is more economical.

Aged↗
PubMed1989

Forearm blood flow measurements using technetium-99m human serum albumin following brachial arteriotomy.

A simple, low cost method for measuring forearm blood flow during reactive hyperemia has been developed. Subjects are seated with hands and forearms over a large field-of-view gamma camera. Blood pressure cuffs inflated above the elbows isolate the blood in the forearms and hands and induce a hyperemic response. The remaining blood pool is labeled with technetium. The rate of increase of activity following release of the cuffs is measured from the gradient of time-activity curves and is calibrated for flow by counting a venous blood sample. The technique has been applied to a group of normal controls and to symptomatic and asymptomatic patients following right brachial arteriotomy. Forearm blood flow in normal subjects was 32.9 +/- 6.4 ml/100 ml/min and for subjects with occlusion of the brachial artery was 6.4 +/- 2.1 ml/100 ml/min. The method is simple, widely available, and reproducible. The good signal to noise ratio allows it to be used in cases of very low flow either as an aid to diagnosis or to measure treatment response.

Adult↗
PubMed1987

Use of a gamma camera for measuring limb blood flow in peripheral vascular disease.

A method for measuring limb blood flow during reactive hyperaemia is described. Pneumatic cuffs inflated to 300 mmHg are used to isolate the blood in the limbs from the rest of the circulation. The remaining blood is labelled with technetium. The increase in radioactivity in the limb following release of the cuffs is measured using a gamma camera. The mean rate of flow of blood to the limb (in ml (100 ml)-1 tissue min-1) is derived from the graph of radioactivity versus time and from the radioactivity in a sample of venous blood. The results of measurements carried out in patients with peripheral vascular disease (30 limbs) and normal controls (24 limbs) are presented. Repeated studies in 10 subjects (20 limbs) showed the method to be highly reproducible at high and low flow rates (r = 0.99). Case studies illustrating the use of the method as a screening test for peripheral vascular disease and to monitor the effects of treatment are presented.

Aged↗
PubMed1987

A reliable and readily available method of measuring limb blood flow in intermittent claudication.

To evaluate isotope limb blood flow measurement in intermittent claudication we have assessed 58 non-diabetic patients comparing our new method with treadmill testing and Doppler assessment. Limb blood flow was applicable to all 58 patients; 25 patients were unable to walk on a treadmill and of the 33 who could 12 failed to walk for one minute, making a standard one minute exercise test inappropriate. In those patients who could perform exercise tests there was a significant correlation between maximum walking distance and limb blood flow (r = 0.35, P = 0.02). Resting, post-exercise and post-hyperaemic ankle-brachial systolic pressure indices bore no relationship to the maximum walking distance. Isotope limb blood flow measurement is reproducible (r = 0.97), can be applied to those patients who cannot walk on a treadmill and provides information about both legs. It correlated significantly with all the other tests and can be recommended for the minimally invasive assessment of intermittent claudication.

Adult↗
PubMed1986

Thyroid blood group isoantigen expression: a parallel with ABH isoantigen expression in the distal colon.

An interesting and not previously reported parallel has been observed between the known pattern of ABO (H) blood group isoantigen expression in normal and neoplastic colonic epithelium and that in the thyroid. Epithelial expression of blood group isoantigens was not observed in 16 specimens of normal or non-neoplastic thyroid tissue. This contrasts with the progressive re-expression of these antigens in neoplastic thyroid tissue. Blood group isoantigens were detected in two of eight papillary adenomas and 13 of 17 papillary carcinomas. Antigen expression was in part related to differentiation, and stained cells were less readily detected in follicular tumours, only one of five adenomas and two of seven carcinomas displaying blood group antigens while three medullary and two anaplastic carcinomas were antigen-deficient.

ABO Blood-Group System↗
PubMed1986

Are blood group isoantigens lost from malignant prostatic epithelium? Immunohistochemical support for the preservation of the H isoantigen.

Previous studies while demonstrating the presence of blood group isoantigens on normal prostatic epithelium have failed to identify such antigens on malignant prostatic tissue. Using a series of blood group specific monoclonal antibodies directed towards the A, B, H and Y antigens we have reinvestigated blood group isoantigen expression in both benign prostatic hypertrophy and prostatic adenocarcinoma. Results obtained from areas of benign prostatic hypertrophy are in broad agreement with those published however though we were unable to detect either A or B blood group isoantigens Type 2H and Y isoantigens were identified in 10 of the 12 tumours. These findings, while differing from previously reported results, lend support to the suggested connection between ontogenesis, oncogenesis and blood group isoantigen expression and also support the proposed link between Type 2 structures and malignant transformation.

ABO Blood-Group System↗
PubMed1986

The expression of ABH and Y blood group antigens in benign and malignant breast tissue: the preservation of the H and Y antigens in malignant epithelium.

The ABO(H) and Y antigen status of epithelial cells from 45 breast carcinomas, 14 benign breast lesions and 7 normal breasts have been assessed using an indirect immunoperoxidase histochemical assay and a series of blood group specific monoclonal antibodies. All 20 A, AB and B group tumours had lost the A and B isoantigens, 13 of these tumours were however found to express H and Y antigens. Of 25 group O tumours 17 expressed the expected H and Y antigens. These findings were not dependent on the histological nature or the invasive characteristics of the tumour. Similar results were obtained when 28 metastases from breast carcinomas were examined, the H and Y antigens being identified in the tumour elements in 24 lymph nodes while we failed to identify either the A or B antigens. The development of breast malignancy appeared therefore to correlate best with the deletion of A and B glycosyl transferases. Normal breast tissue consistently expressed the expected blood group isoantigens. Areas of benign breast disease showed a more varied pattern of antigen expression. Seven of 14 lesions lacked ABH antigens, the loss of blood group structures could not however be correlated with any specific histological features and was not limited to the loss of A and B substances.

ABO Blood-Group System↗
PubMed1986

The concentration of latamoxef achieved in the bile and gallbladder wall of patients with cholecystitis.

This study reports the clinical and pharmacokinetic results following an injection of latamoxef (moxalactam disodium) in patients undergoing cholecystectomy for symptomatic cholelithiasis. Two groups were involved in the study. Group A consisted of 22 patients who received 1 g of intramuscular latamoxef at the time of premedication prior to surgery, and group B consisted of 12 patients each of whom received an intravenous dose of 0.5 g of latamoxef at the time of anaesthetic induction. Latamoxef levels were then measured in peripheral blood, gall bladder bile, common bile duct (CBD) bile and gall bladder wall. Despite a significant difference in the sampling times, inhibitory levels were obtained in the majority of samples in both groups, singularly high levels being assayed in CBD bile. We conclude that an intravenous dosage of latamoxef (0.5 g) given with anaesthetic induction is as effective as 1 g intramuscular dosage given with the pre-medication.

Adolescent↗
PubMed1986

Delorme's operation: the first choice in complete rectal prolapse?

The Delorme operation has been used to treat 27 consecutive patients with complete rectal prolapse. The mean age in this group was 74 years and the average length of the prolapse was 12 cms. There was no postoperative mortality or morbidity. The follow-up ranges from 11 months to 64 months (mean 35 months) and so far there have been two recurrences. One of these has been successfully treated by a second Delorme operation. The second patient has declined further surgery. This low recurrence rate combined with the minor nature of the procedure suggests that the Delorme operation should be considered in all patients presenting with complete rectal prolapse.

Adult↗
PubMedDate not supplied

A comparison of three imaging techniques in the assessment of an abdominal aortic aneurysm.

Twenty-five patients undergoing elective surgery for large abdominal aortic aneurysms (AAAs) were investigated by preoperative ultrasonography (US), computed tomography (CT) or intravenous digital subtraction angiography (IV-DSA). The accuracy of each modality in assessing the upper and lower extent of aneurysmal disease was then compared. IV-DSA proved 100% accurate in assessing the relationship of the renal arteries to the aneurysm sac. Both CT and US overestimated the incidence of juxta or suprarenal AAAs and only had a predictive value for suprarenal disease of 13% and 14% respectively. If, however, US or CT stated the aneurysm to be infrarenal this was likely to be true though both investigations classified one suprarenal aneurysm as infrarenal. The distal extent of aneurysmal disease was again most accurately predicted by IV-DSA (predictive value 88%). Bowel gas frequently prevented US from visualizing the iliac arteries (19 of 25 cases). IV-DSA is a safe and accurate method for defining the relationship of an aneurysm to the renal arteries and should be adopted as a routine preoperative investigation of abdominal aneurysmal disease.

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