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Biomedical subjects

S A White

Publications and source records attributed to S A White.

At least 19 recordsLinked to original sources
PubMed1999

Detailed active site configuration of a new crystal form of methanol dehydrogenase from Methylophilus W3A1 at 1.9 A resolution.

The three-dimensional structure of a new crystal form of methanol dehydrogenase from Methylophilus W3A1 has been obtained in the presence of substrate using data recorded at a synchrotron. The structure of this approximately 140 kDa heterotetramer, refined at 1. 9 A resolution, reveals the detailed configuration of its redox cofactor, pyrroloquinoline quinone (PQQ). C4, one of the oxygen-bearing atoms of this orthoquinone is in a planar configuration while C5, which bears the other quinone oxygen, is tetrahedral, suggesting that the PQQ is in the semiquinone redox state. The substrate binding site has been identified close to PQQ and to the side chain of Asp297, the putative active site base. The proximity of the hydroxyl of methanol to C5 of PQQ compared to the greater separation of the substrate methyl group from C5 supports the addition-elimination reaction mechanism involving a hemiketal intermediate.

Alcohol Oxidoreductases↗
PubMed1999

A novel intubation technique for tracheoesophageal fistula in adults.

PURPOSE: To describe a novel technique of tracheal intubation and ventilation in an adult patient with a large tracheoesophageal fistula at the level of the carina. CLINICAL FEATURES: A 59 yr old woman with squamous cell carcinoma of the esophagus developed a large (2 cm diameter) tracheoesophageal fistula after radiotherapy. The level of her fistula precluded traditional use of a double-lumen endobronchial tube. Intubation and ventilation were managed with two endobronchial tubes. The ability to ventilate or collapse each lung individually was preserved and anesthesia and surgery proceeded uneventfully. CONCLUSION: Double endobronchial intubation is described to manage anesthesia in an adult patient with a tracheoesophageal fistula at the level of the carina.

Female↗
PubMed1999

An investigation into the distribution of different collagen types within adult and juvenile porcine pancreata.

One of the difficulties of porcine islet isolation is their fragility during collagenase digestion. The object of this study was to determine the distribution of 4 different collagen types within adult and juvenile porcine pancreata. Five different areas from each pancreas were analysed by light microscopy. The distribution of collagen types I, IV, V and VI were measured within the interlobar, intralobular (acinar), peri-insular and intra-islet regions. Their was an abundance of collagen type VI compared to I, IV and V in both the interlobar and intralobular septa in both juveniles (P<0.001) and adults (P<0.001). The periinsular collagen content also showed diversity. This was mainly attributable to the distribution of collagen type I (weak) and type VI (intense) in both adults and juveniles. In general, the peri-insular capsule was fragmentary and contained less than 50% of the total islet circumference. The latter finding taken together with the distributions of different collagen types can partly explain some of the variability of porcine islet isolation.

Animals↗
PubMed1999

Pancreatic islet autotransplantation combined with total pancreatectomy for the treatment of chronic pancreatitis--the Leicester experience.

Islet autotransplantation offers the potential for preventing the surgically induced diabetes that is an inevitable consequence of total pancreatectomy. This paper describes the first islet autotransplant programme in the United Kingdom and the first series in the world to use the spleen as a site for the islet graft. Over an 11 month period, 7 patients underwent total pancreatectomy for chronic pancreatitis combined with a simultaneous islet autotransplant. All 7 patients had normal glucose-tolerance levels and normal C-peptide levels pre-operatively. In 6 patients, islets were embolized into the liver via the portal vein (median transplanted volume=8.5 ml). In addition, 3 patients received islets into the splenic sinusoids via a short gastric vein (median transplanted volume=4 ml). One patient received islets into the spleen alone. One patient died of a stroke 4 weeks post transplantation. Two patients have achieved insulin independence, with a further two patients achieving "transient" insulin independence (<1 month). The remaining 2 patients, although requiring reduced insulin doses, have not achieved insulin-independence. However, all patients have C-peptide levels within the normal range. In trying to explain these findings, split proinsulin levels were measured and found to be elevated. High levels of split proinsulin cross react with the C-peptide assay and this would explain the falsely elevated C-peptide levels. Indeed insulin levels in these patients were all below the normal range. These findings would suggest that the use of C-peptide levels as the "gold standard" for monitoring islet autograft function, may require reappraisal.

C-Peptide↗
PubMed1999

Physiological values and procedures in the 24 h before ICU admission from the ward.

Physiological values and interventions in the 24 h before entry to intensive care were collected for admissions from hospital wards. In a 13-month period, there were 79 admissions in 76 patients who had been in hospital for at least 24 h and had not undergone surgery within 24 h of admission to intensive care. Thirty-four per cent of patients underwent cardiopulmonary resuscitation before intensive care admission. Using Acute Physiology and Chronic Health Evaluation II scoring to quantify abnormal physiology in the group as a whole, a significant deterioration in respiratory function before admission was found. During the 6-h period immediately before intensive care admission, 75% of patients received oxygen, 37% underwent arterial blood gas sampling, and oxygen saturation was measured in 61% of patients, 63% of whom had an oxygen saturation of less than 90%. Overall hospital mortality in the study group was 58%. Information collected on the wards identified seriously ill patients who may have benefited from earlier expert treatment.

APACHE↗
PubMed1999

Vascularized pancreas allotransplantation--clinical indications and outcome.

AIMS: This review examines the status of vascularized pancreas transplantation as a treatment for Type 1 diabetes mellitus (DM). METHODS: The world literature, with a particular emphasis on data from the International Pancreas Transplant Registry (IPTR), is reviewed and interpreted particularly for clinical indications and outcome. RESULTS: Over 9000 cases of vascularized pancreas transplant (VPT) have been registered, with insulin dependence approaching 82% at 1 year with 94% patient survival. The majority of transplants are simultaneous pancreas and kidney (SPK) transplants, with far fewer pancreas after kidney (PAK) or pancreas transplants alone (PTA). The success rates differ between the procedures but are generally improving as technical advances, improvements in immunosupression and greater experience are gained. The most obvious advantage is an improved quality of life (QoL) but there are risks associated with the procedure and with the immunosuppression. There is some evidence coming to light of a very slow beneficial effect on microvascular complications. CONCLUSIONS: VPT is an attractive option to offer Type 1 DM patients who need or already have a renal allograft. Patients have to decide between the increased surgical risk and the risks of long-term immunosuppression and the benefits of improved QoL. In the absense of end-stage renal failure (ESRF) there is no justification for PTA, except where the diabetes itself poses a greater risk to life than the transplantation procedure.

Diabetes Mellitus, Type 1↗
PubMed1999

Open water scuba diving accidents at Leicester: five years' experience.

OBJECTIVES: The aim of this study was to determine the incidence, type, outcome, and possible risk factors of diving accidents in each year of a five year period presenting from one dive centre to a large teaching hospital accident and emergency (A&E) department. METHODS: All patients included in this study presented to the A&E department at a local teaching hospital in close proximity to the largest inland diving centre in the UK. Our main outcome measures were: presenting symptoms, administration of recompression treatment, mortality, and postmortem examination report where applicable. RESULTS: Overall, 25 patients experienced a serious open water diving accident at the centre between 1992 and 1996 inclusive. The percentage of survivors (n = 18) with symptoms of decompression sickness receiving recompression treatment was 52%. All surviving patients received medical treatment for at least 24 hours before discharge. The median depth of diving accidents was 24 metres (m) (range 7-36 m). During the study period, 1992-96, the number of accidents increased from one to 10 and the incidence of diving accidents increased from four per 100,000 to 15.4 per 100,000. Over the same time period the number of deaths increased threefold. CONCLUSIONS: The aetiology of the increase in the incidence of accidents is multifactorial. Important risk factors were thought to be: rapid ascent (in 48% of patients), cold water, poor visibility, the number of dives per diver, and the experience of the diver. It is concluded that there needs to be an increased awareness of the management of diving injuries in an A&E department in close proximity to an inland diving centre.

Accidents↗
PubMed1999

Diagnosing anaemia in pregnancy in rural clinics: assessing the potential of the Haemoglobin Colour Scale.

Anaemia in pregnancy is a common and severe problem in many developing countries. Because of lack of resources and staff motivation, screening for anaemia is often solely by clinical examination of the conjunctiva or is not carried out at all. A new colour scale for the estimation of haemoglobin concentration has been developed by WHO. The present study compares the results obtained using the new colour scale on 729 women visiting rural antenatal clinics in Malawi with those obtained by HemoCue haemoglobinometer and electronic Coulter Counter and with the assessment of anaemia by clinical examination of the conjunctiva. Sensitivity using the colour scale was consistently better than for conjunctival inspection alone and interobserver agreement and agreement with Coulter Counter measurements was good. The Haemoglobin Colour Scale is simple to use, well accepted, cheap and gives immediate results. It shows considerable potential for use in screening for anaemia in antenatal clinics in settings where resources are limited.

Anemia↗
PubMed1999

The determination of lysergide (LSD) in urine by high-performance liquid chromatography-isotope dilution mass spectrometry (IDMS).

The use of isotope dilution mass spectrometry (IDMS) has been investigated for the forensic confirmation of lysergic acid diethylamide (LSD) in urine by LC-MS. The advantages of using a deuterated analog of LSD as an internal standard over methysergide are discussed. This study includes a comparison of the electrospray mass spectra of LSD, LSD-d3 and methysergide, and discusses the choice of suitable ions for use in selected ion monitoring (SIM) mode. An IDMS method is presented for the LC-MS confirmation of LSD in urine, with a limit of quantification (LOQ) of 0.5 ng/mL, reflecting the forensic requirement at this laboratory. Under some circumstances the LOQ can be improved to 0.1 ng/mL. This method is linear in the range tested (up to 10 ng/mL LSD in urine) and has been validated in terms of accuracy and precision.

Chromatography, High Pressure Liquid↗
PubMed1999

A prospective controlled trial of the efficacy of isopropyl alcohol wipes before venesection in surgical patients.

It has previously been suggested that skin preparation before venesection with antiseptic agents is unnecessary. However thousands of doctors and medical students continue to use isopropyl alcohol (IPA) swabs for venesection, at an estimated cost of 10,000 P per annum in a 500 bed hospital. An audit of IPA swab use among junior doctors and medical students at our institution was undertaken; 76% of doctors and 100% of medical students routinely prepared the skin with alcohol before venesection and only one used the swabs correctly. A randomised single-blind controlled trial was conducted of IPA versus no IPA skin preparation before venesection. There were 194 patients in the study, 93 in the IPA group and 101 controls. There was no statistical difference with respect to complications at the venepuncture site between the two groups.

2-Propanol↗