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Biomedical subjects

H N Whitfield

Publications and source records attributed to H N Whitfield.

At least 19 recordsLinked to original sources
PubMed1992

Radiation protection in percutaneous renal surgery.

Two British centres have published the radiation doses received during percutaneous nephrolithotomy (PCNL). Their results were disparate. This study was performed to establish the likely exposure of the eyes and fingers of an experienced urological surgeon who creates the track into the kidney and also performs the endoscopic operation. In addition, some radioprotective gloves were evaluated. Provided that specific precautions, including a judicious use of screening, are taken, the current dose limits are unlikely to be exceeded. However, a 30% reduction in the dose limits is probable. Wearing routine radiation badges under a lead apron is an inadequate method of monitoring exposure: urologists should press for more active assistance from radiation protection officers in the monitoring of procedures in theatre and the use of ultrasound should be encouraged.

Gloves, Surgical↗
PubMed1992

Potential use of tissue adhesive in urinary tract surgery.

The search for a tissue adhesive which obviates the need for suture materials in the apposition of wound edges is not new. The early adhesive products lacked the required safety and efficacy. Experimental use of a new fibrin adhesive has shown that it may have potential use where inflammatory reaction to the suture material is undesirable or water-tight sealing of the anastomosis is required.

Animals↗
PubMed1992

The development of synthetic polymers that resist encrustation on exposure to urine.

The consequences of long-term exposure of synthetic materials to urine have prevented the development of alloplastic replacement of diseased or damaged parts of the urinary tract. Similarly, urethral and ureteric catheters require regular replacement if the complications of encrustation and blockage are to be avoided. The mechanism of encrustation is not understood completely and thus it is unclear why certain materials appear better able to resist encrustation. This study has involved the development of a new encrustation model to provide a reproducible and quantitative assessment of the susceptibility of polymers to encrustation. This model will allow beneficial characteristics of co-polymer design to be recognised, with the aim of finding new materials that are tolerant of exposure to urine. Results of co-polymers examined show that the incorporation of fluorine-containing components confers significant resistance to the formation of encrustation. It is suggested that the physico-chemical properties of polymer surfaces may be important determinants of resistance to encrustation.

Calcium↗
PubMed1992

Prediction of response to lithotripsy--the use of scanning electron microscopy and X-ray energy dispersive spectroscopy.

A single urine sample was obtained from each of 38 patients before and immediately after treatment with a Wolf Piezolith 2300. Each sample was analysed for crystals using scanning electron microscopy and X-ray energy dispersive spectroscopy. In all cases it was possible to make a stone diagnosis prior to treatment and there was 100% correlation between the pre- and post-treatment diagnosis. All stones smaller than 90 mm2 on plain X-ray cleared with piezoelectric lithotripsy alone, regardless of composition. Larger stones composed of calcium oxalate were all successfully fragmented, but 5 of 15 mixed or phosphate stones failed to respond.

Adolescent↗
PubMed1991

Detubularisation in cystoplasty: clinical review.

Cystoplasty using a detubularised bowel segment is preferable to using a tubularised length of intestine. This has been shown experimentally to result in a reduction in the contractility of the neobladder, although contractions are not completely abolished. Incontinence, especially nocturnal, may still be a problem. Assessment of renal function has shown a marked incidence of upper tract dysfunction despite detubularisation. All patients remain at risk of upper tract obstruction following cystoplasty. Because bowel contraction waves are brought on by distension, it may be possible either to postpone or to prevent the onset of contractions by avoiding an excessive build-up of bladder volume. Clean intermittent self-catheterisation is an efficient means of emptying the bladder, although sphincter rebalancing may also be required.

Adult↗
PubMed1991

Diagnostic and surgical aspects of renal carcinoma with involvement of the inferior vena cava.

Over the past 10 years, 13 patients presented with operable renal carcinoma and tumour extension within the inferior vena cava. This was diagnosed accurately in all but 1 patient, using ultrasound. Radical nephrectomy with removal of tumour within the inferior vena cava was performed in all 13 cases, 2 requiring cardiac bypass. There were no operative deaths and 6 patients remain alive and well with a mean follow-up of 2 years. The presence and level of vena caval extension did not appear to have an adverse affect on prognosis.

Adult↗
PubMed1990

Computerisation of urothelial carcinoma records: 16 years' experience with the TNM system.

Details of 554 patients with urothelial carcinomas have been recorded on computer forms between 1973 and 1988 inclusive. Essential information from initial assessment and follow-up examinations was printed out on specially designed urothelial update sheets, copies of which were given to patients and urologists as well as being filed in the hospital notes. The survival status of all patients was established as accurately as possible in the last 2 years of the study. Multivariate analysis of 462 bladder cancer patients with adequate follow-up indicated that T category was the most important discriminating variable, followed by histological grade. After replacing T category by microscopic depth of invasion and bimanual examination, the latter was found to be the most important single variable. The omission of the findings on bimanual examination from the 1987 revision of the TNM classification therefore appears to be wrong.

Aged↗
PubMed1990

Cystoplasty: tubularisation or detubularisation?

Previous studies on substitution or augmentation cystoplasty have highlighted the profusion of surgical techniques available, but there is disagreement as to which is the best. We established an animal model to compare various types of cystoplasties, tubularised and detubularised, using ileum and caecum. Detubularisation did not abolish intrinsic bowel contractions but delayed their onset. No differences were noted in the frequency and amplitude of such contractions after detubularisation or between large and small bowel cystoplasties. Although intravenous urography did not demonstrate any abnormality in upper tract anatomy, a significant number of animals had some functional disturbance of the kidney after cystoplasty demonstrable on isotope renography, irrespective of the surgical technique. It may be possible to prevent these contractions with their associated harmful effects by preventing the bladder volume from building up excessively.

Animals↗
PubMed1985

A double-blind controlled trial of a new alpha-1 blocking drug in the treatment of bladder outflow obstruction.

Thirty-one patients with urodynamically proven bladder outflow obstruction were treated with Alfuzosin in a 3-month, double-blind, placebo-controlled study. The irritative symptoms of bladder outflow obstruction were improved significantly in the treatment group, according to both objective and subjective evaluation. There was no objective evidence of a reduction in outflow resistance or obstruction in either group.

Adult↗
PubMed1979

Obstructive nephropathy: successful evaluation with radionuclides.

A non-invasive test of nephron function, the renal parenchymal transit time (P.T.T.) index, is shown to be as accurate as antegrade pressure measurements in diagnosis of renal outflow obstruction. It is more sensitive than conventional methods of demonstrating the associated obstructive nephropathy. P.T.T. is useful in following the effects of surgery, or of temporising, in patients with confirmed or potential outflow tract obstruction. Renal radionuclide P.T.T. analysis gives the functional information essential for the management of patients in whom intravenous urography reveals a dilated renal pelvis.

Dilatation, Pathologic↗