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Biomedical subjects

P Keeling

Publications and source records attributed to P Keeling.

At least 19 recordsLinked to original sources
PubMed2001

Severe juvenile chronic constipation.

Constipation in the paediatric population is common and encompasses a spectrum of organic and functional pathology which differ from that of the adult population. Recently an expert group published a comprehensive system of classification of childhood functional gastrointestinal disorders that may have useful clinical application. We present the case of an adolescent schoolgirl with severe constipation with extreme anorectal, urological and neurological sequelae who displayed inappropriate behavioral response to her condition. The patient appeared inappropriately unmotivated and undisturbed by the severity of her constipation. This abnormal psychological habituation and adaptation to an abnormal bowel habit perpetuated the constipation. In addition, we examined the role of recent advances in anorectal investigation techniques and treatment in the context of the recent guidelines issued by the American Gastroenterological Association

Adolescent↗
PubMed1999

Collaborative care: a professional practice model.

Healthcare economics has caused dramatic changes in resource assessment, utilization, and reorganization in hospitals. To address the mismatch between demand and resources and to ensure quality at the bedside, staff members at a 354-bed acute care facility designed and implemented the Collaborative Care Model (CCM). The authors describe this theory-based, collaborative, multidisciplinary professional practice model.

Consultants↗
PubMed1997

Comparing the properties of Escherichia coli branching enzyme and maize branching enzyme.

Escherichia coli glycogen branching enzyme (GBE) and maize starch branching enzymes I (SBEI) and II (SBEII) were expressed in E. coli and purified. E. coli GBE branched amylose at a higher rate than did SBEII, but branched amylose at a lower rate than did SBEI. Similar to SBEI, GBE branched amylopectin at a lower rate than did SBEII. High-performance anion-exchange chromatography analysis of the branched products produced by BE revealed the minimum chain length (cl) required for branching. While GBE and SBEII showed the same minimum cl [degree of polymerization (dp) 12] required for branching, SBEI had a slightly higher minimum cl (dp 16) requirement for branching. The major differences between GBE and SBE are their specificities in terms of the size of chains transferred. In comparison with SBE, GBE had a much narrower size range of chains transferred and transferred mainly shorter chains. While SBEI and SBEII produced a large number of chains ranging from dp 6 to over dp 30, GBE predominantly transferred chains ranging from dp 5 to 16 and produced only a very small number of long chains with dp greater than 20. Although it has been reported that SBEI and SBEII preferentially transfer longer and shorter chains, respectively (1), this study further defines the differences between SBEI and SBEII in the size of chains transferred. SBEI predominantly transfers longer chains with dp greater than 10, while producing few shorter chains with dp 3 to 5. In contrast, SBEII preferentially transfers smaller chains with dp 3 to 9, with the most abundant chains being dp 6 and 7. The significance of minimum chain-length requirement by SBE is discussed in setting the invariant size of amylopectin cluster size (9 nm).

1,4-alpha-Glucan Branching Enzyme↗
PubMed1996

The major form of ADP-glucose pyrophosphorylase in maize endosperm is extra-plastidial.

Preparations enriched in plastids were used to investigate the location of ADP-glucose pyrophosphorylase (AGPase) in the developing endosperm of maize (Zea mays L.). These preparations contained more than 25% of the total activity of the plastid marker enzymes alkaline pyrophosphatase and soluble starch synthase, less than 2% of the cytosolic marker enzymes alcohol dehydrogenase and pyrophosphate, fructose 6-phosphate 1-phosphotransferase, and approximately 3% of the AGPase activity. Comparison with the marker enzyme distribution suggests that more than 95% of the activity of AGPase in maize endosperm is extra-plastidial. Two proteins were recognized by antibodies to the small subunit of AGPase from maize endosperm Brittle-2 (Bt2). The larger of the two proteins was the major small subunit in homogenates of maize endosperm, and the smaller, less abundant of the two proteins was enriched in preparations containing plastids. These results suggest that there are distinct plastidial and cytosolic forms of AGPase, which are composed of different subunits. Consistent with this was the finding that the bt2 mutation specifically eliminated the extraplastidial AGPase activity and the larger of the two proteins recognized by the antibody to the Bt2 subunit.

Alcohol Dehydrogenase↗
PubMed1995

Comparison of two immunoassay procedures for detecting enterovirus IgM.

Enteroviruses cause significant illness in man but viral diagnosis is problematic. Enterovirus-specific IgM tests have been developed but due to the difficulties of obtaining reliable control sera the interpretation of assay data remains mainly arbitrary and empirical. The present study was undertaken to assess the reliability of such assays by comparing two tests performed independently in two different laboratories: a mu-capture radioimmunoassay (MACRIA) which utilizes 35S-labelled Coxsackie virus antigens and an enzyme immunoassay (EIA). A feature of the MACRIA was that sera were tested in one large batch whereas the EIA was in routine use in a reference laboratory. The MACRIA was easy to perform but more suitable for research investigations than routine diagnostic use. Similar results were detected in the majority of sera tested in the two assays with 85% concordance achieved on testing 120 sera. Of the 18 discrepant results, 11 were positive by EIA only and 7 by MACRIA only. 89-95% concordance was obtained on testing sera against individual Coxsackie B1-5 serotypes, moreover 52% of the sera positive in MACRIA were reactive against only one viral antigen and the results on certain of the more strongly reactive sera suggested the existence of a measure of type specificity in the MACRIA test. Qualitative differences between the two tests highlighted problems of interpretation in the absence of a gold standard and cautioned against sole reliance on serology for diagnosis of enteroviral infections.

Animals↗
PubMed1994

Association of cytomegalovirus infection with post-transplantation cardiac rejection as studied using the polymerase chain reaction.

The relationship between cytomegalovirus (CMV) infection and cardiac allograft rejection is controversial, some authors reporting a significant association, others not, on the basis of the results of conventional virological diagnosis by culture or serology. This problem was reinvestigated in 88 patients using a semi-quantitative nest polymerase chain reaction (PCR) procedure for detecting CMV DNA in endomyocardial biopsy specimens. Significantly more positive biopsies were obtained from patients with moderate (grade 2; P = 0.02) or severe (grade 3a-4; P = 0.03) rejection than with no or mild (grade 0-1b) rejection, whereas there was no significant association between rejection and CMV as diagnosed by virus isolation from urine, throat or blood, or by the detection of CMV-IgM. PCR-positive biopsies originated most frequently from CMV-antibody positive recipients (R+) of hearts from seropositive donors (D+), in association with moderate or severe rejection rather than with mild or no rejection The detection of CMV in the heart thus seemed to be related more to R+D+ serological status than to severity of rejection, that is, to circumstances that favoured co-infection with strains of CMV from both donor and recipient. Studies on sequential biopsy specimens from selected patients also provided evidence that CMV infection and rejection were not always related events. The PCR was able to differentiate latent from active CMV infection; moreover, some seronegative individuals gave repeatedly positive biopsies, thereby supporting the work of others that some patients undergo CMV infection without mounting a detectable antibody response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Influence of filtering techniques on the time-domain analysis, diagnosis, and clinical use of signal-averaged electrocardiogram.

In order to investigate the effect of different filtering techniques on the time-domain analysis of signal-averaged electrocardiogram (SAECG), recordings of 1,192 subjects were analyzed using Butterworth and Del Mar filters, both set at 40-250 Hz high and low pass frequencies. The recordings were taken from six clinically defined groups: (a) survivors of acute myocardial infarction (n = 553); (b) patients with sustained symptomatic postinfarction ventricular tachycardia (n = 89); (c) patients with hyperthropic cardiomyopathy (n = 219); (d) patients with dilated cardiomyopathy (n = 76); (e) direct relatives of patients with dilated cardiomyopathy (n = 170); and (f) normal healthy volunteers (n = 85). The study investigated differences between the SAECG results reported with both filters in three individual aspects: (1) numerical values of individual time-domain SAECG variables; (2) differences in SAECG findings of patients with postinfarction ventricular tachycardia and pair matched patients with uncomplicated follow-up after acute infarction; and (3) the power of SAECG findings to predict high risk of arrhythmic complication (sudden death and/or sustained ventricular tachycardia) among survivors of acute myocardial infarction. Compared with the Butterworth filter, the Del Mar filter led to a systematic difference of +8% in total QRS duration, was equally powerful in distinguishing between the pair matched patients with and without postinfarction ventricular tachycardia, and was statistically significantly more powerful in identifying those survivors of acute infarction who were at high risk of arrhythmic complications. The study concludes that the use of different filters may produce discordant results of SAECG analysis. Normal and abnormal values for various types of SAECG recording and analysis have to be established individually for different equipment and different software settings. These optimal cut-offs of SAECG variables should also take into account the clinical characteristics of patient groups.

Cardiomyopathy, Dilated↗
PubMed1992

Transhiatal oesophagectomy in the management of advanced oesophageal carcinoma.

Thirty-seven patients have undergone transhiatal oesophagectomy for tumours in the upper (n = 3), middle (n = 12) and lower (n = 22) thirds of the oesophagus. Four tumours arose in association with Barrett's oesophagus. Dysphagia for solids was the presenting symptom in 95% of cases. Orringer's technique was used and all cervical anastomoses were hand-sewn. The median duration of surgery was 2.9 (range 1.5-4.0) h and the 30-day hospital mortality rate was 16% (six patients). Respiratory complications were considerable (48%) and accounted for three deaths. Median postoperative stay was 21 (range 13-53 days) while median stay in the intensive care unit was 8.5 days. The majority (97%) of patients had stage III disease and 14 (38%) had lymph node involvement. The actuarial survival was 56% at 1 year and 31% at 2 years. Of the operative survivors, 90% resumed normal swallowing although 17 (55%) required outpatient dilatation. Transhiatal oesophagectomy provides safe and efficient palliation while mortality and 1-year survival rates compare with the transthoracic approach.

Aged↗
PubMed1991

Chylothorax after oesophagectomy.

Chylothorax is an uncommon complication of oesophagectomy. In a review of 537 oesophageal resections there were 11 cases of chylothorax, an incidence of 2.0 per cent. There was no correlation with site, size, penetration, lymph node status, length or type of tumour but there was a significant correlation between chylothorax and the type of operative procedure carried out. The incidence in 95 transhiatal resections was 10.5 per cent. The incidence following 442 transthoracic procedures was 0.2 per cent (P less than 0.001) with one chylous fistula occurring after a three-stage oesophagectomy. Initial management was conservative with chest drainage and total parenteral nutrition. Thoracotomy and duct ligation was subsequently carried out in three patients and was successful in two. The third patient died. Conservative management alone was successful in four out of eight patients, with closure of the fistula at a median of 35 days (range 14-42 days). Four patients treated conservatively died. Transhiatal oesophagectomy greatly increases the risk of chylothorax, a condition that carries a high mortality rate (46 per cent in this series) whether managed conservatively or by surgical intervention.

Chylothorax↗
PubMed1991

A preventable cause of tracheal injury at oesophagectomy.

Advocates of transhiatal oesophagectomy warn of the danger of tracheal injury resulting from the blind dissection of tumours of the upper and middle thirds of the oesophagus when the tumour has invaded the membranous part of the trachea. We report an unusual cause of tracheal injury at transhiatal oesophagectomy due to dissection at the level of the inflated endotracheal cuff in a patient with a tumour at the gastro-oesophageal junction.

Aged↗
PubMed1990

Carboxyhaemoglobin concentrations, pulse oximetry and arterial blood-gas tensions during jet ventilation for Nd-YAG laser bronchoscopy.

Oxygen saturation measured with pulse oximetry (SpO2) is overestimated in the presence of carboxyhaemoglobin (COHb). Smoke produced during laser resection of tracheobronchial malignancies may increase concentrations of COHb. We have measured COHb concentrations in 14 patients undergoing laser resection and compared SpO2 with functional oxygen saturation (SaO2) to ascertain if pulse oximetry is an accurate monitor of oxygen saturation. During the procedure frequent changes occur in ventilatory mechanics. Arterial blood-gas tensions were measured to see if gas exchange was satisfactory. Mean preoperative COHb was 1.4%. There was no significant change in COHb in any patient at any stage during treatment. The highest value was 2.05%. The mean difference between SaO2 and SpO2 was 1.13% (95% confidence interval 0.70-1.56%). Oxygen saturation may therefore safely be monitored by pulse oximetry in patients managed by our technique. Empirical setting of a jet ventilator provided acceptable blood-gas tensions, although sometimes it was necessary to increase the FlO2 to greater than 0.3 to maintain oxygenation.

Adult↗
PubMed1990

Transhiatal oesophagectomy--its role for tumours of the middle third of the intrathoracic oesophagus.

All patients presenting to a regional unit with oesophageal carcinoma over a twelve month period are reviewed and the role of transhiatal oesophagectomy for tumours of the middle third of the intrathoracic oesophagus is evaluated. Of the 28 cases of oesophageal carcinoma, 22 (78%) were resected by blunt transhiatal oesophagectomy, the remaining six (22%) has various forms of palliative treatment. In the resected group post-operative morbidity was compared in patients with tumours of the middle third to those with lower and upper third tumours combined. There was one post-operative death in each group giving an overall operative mortality of 9%. Resection for carcinoma of the middle third (N = 7) resulted in a complication rate of 50% and a mean ICU stay of 19.5 days as opposed to a complication rate of 35% and a mean ICU stay of ten days (P = 0.050) for tumours of upper and lower third combined (N = 15). On the basis of these figures we question whether transhiatal oesophagectomy, despite its many advantages, can be applied safely to tumours of the middle third of the intrathoracic oesophagus.

Aged↗
PubMed1989

A prospective randomized trial of angelchik prosthesis versus Nissen fundoplication.

A total of 61 patients with gastro-oesophageal reflux; resistant to medical therapy, were entered into a prospective randomized trial comparing the Angelchik antireflux prosthesis with Nissen's fundoplication. Both groups had a similar age and sex distribution and their reflux profiles were comparable. An Angelchik prosthesis was inserted in 30 patients and 31 underwent fundoplication. The mean duration of postoperative follow-up was 38 months. At clinical assessment 23 (77 per cent) of the Angelchik group were graded Visick grade I or II, compared with 29 (94 per cent) of the Nissen group. Assessment by 24 h pH monitoring and manometry between 3 and 6 months after operation showed that both procedures were equally effective in reducing reflux and increasing lower oesophageal sphincter pressure. However, long-term endoscopic follow-up revealed grade III oesophagitis in seven patients in the Angelchik group. No patient in the fundoplication group had grade III oesophagitis. Three of eight patients with strictures in the Angelchik group reported persistent dysphagia. All seven patients with strictures in the Nissen group were relieved of their dysphagia. Migration or erosion of the prosthesis did not occur. Three prostheses (10 per cent) were removed, two for dysphagia and one because of sepsis.

Clinical Trials as Topic↗
PubMed1988

Experimental columnar metaplasia in the canine oesophagus.

Regeneration of canine oesophageal mucosa was studied under basal conditions and in the presence of gastro-oesophageal reflux. In normal circumstances mucosal defects in the oesophagus regenerate by squamous epithelium. In the presence of gastro-oesophageal reflux of either acid or a combination of acid and bile, regeneration was frequently by columnar epithelium (Barrett's oesophagus). This columnar regeneration was not seen with bile reflux alone. By the use of squamous barriers to proximal migration of columnar epithelium in the stomach, it was demonstrated that columnar re-epithelialization may occur from cells intrinsic to the oesophagus and is not dependent on proximal migration of cardiac columnar epithelium. The cell of origin of this epithelium may be located in oesophageal gland ducts and is likely to be a multipotential stem cell since the regenerated columnar epithelium may contain goblet and parietal cells not normally found in the oesophagus. This epithelium is morphologically distinct on mucin histochemistry from cardiac columnar epithelium. These findings support the concept that Barrett's epithelium is metaplastic.

Animals↗