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Biomedical subjects

K R Allen

Publications and source records attributed to K R Allen.

At least 19 recordsLinked to original sources
PubMed2002

Evaluation of whole blood serotonin and plasma and urine 5-hydroxyindole acetic acid in diagnosis of carcinoid disease.

BACKGROUND: Carcinoid disease is an uncommon disorder resulting from tumours of the enterochromaffin cells. Current biochemical investigation usually involves the measurement of 5-hydroxyindole-3-acetic acid (5-HIAA) in 24-h urine collections. Because of the problems associated with urine collections (i.e. inconvenience, accuracy of collection and requirement for preservatives) two alternative markers, fasting plasma 5-HIAA and whole blood serotonin (5-hydroxytryptamine), have been studied. METHODS AND RESULTS: Whole blood serotonin concentration and plasma and urine 5-HIAA concentrations were measured by high-performance liquid chromatography in 31 patients suspected of having carcinoid and 26 known carcinoid patients. Receiver operator characteristic curve analysis of the data showed no statistical difference between the three markers (P>0.01) with regard to their discriminating function. However, fasting plasma 5-HIAA assay showed greater stability than whole blood serotonin assay and is more convenient for the patient than a 24-h urine collection. At a cut-off value of 118 nmol/L plasma 5-HIAA assay showed a sensitivity of 89%, a specificity of 97% and a test efficiency of 93%. Whole blood serotonin assay was further limited by its saturation in platelets at 40 nmol/10(9) platelets which made it less suitable for monitoring the treatment of carcinoid disease. CONCLUSION: Fasting plasma 5-HIAA concentration provides a more convenient screening test for carcinoid and overcomes the problems associated with 24-h urine collections, without any loss of diagnostic precision.

Adolescent↗
PubMed2000

Effects of a multicomponent intervention on functional outcomes and process of care in hospitalized older patients: a randomized controlled trial of Acute Care for Elders (ACE) in a community hospital.

BACKGROUND: Older persons frequently experience a decline in function following an acute medical illness and hospitalization. OBJECTIVE: To test the hypothesis that a multicomponent intervention, called Acute Care for Elders (ACE), will improve functional outcomes and the process of care in hospitalized older patients. DESIGN: Randomized controlled trial. SETTING: Community teaching hospital. PATIENTS: A total of 1,531 community-dwelling patients, aged 70 or older, admitted for an acute medical illness between November 1994 and May 1997. INTERVENTION: ACE includes a specially designed environment (with, for example, carpeting and uncluttered hallways); patient-centered care, including nursing care plans for prevention of disability and rehabilitation; planning for patient discharge to home; and review of medical care to prevent iatrogenic illness. MEASUREMENTS: The main outcome was change in the number of independent activities of daily living (ADL) from 2 weeks before admission (baseline) to discharge. Secondary outcomes included resource use, implementation of orders to promote function, and patient and provider satisfaction. RESULTS: Self-reported measures of function did not differ at discharge between the intervention and usual care groups by intention-to-treat analysis. The composite outcome of ADL decline from baseline or nursing home placement was less frequent in the intervention group at discharge (34% vs 40%; P = .027) and during the year following hospitalization (P = .022). There were no significant group differences in hospital length of stay and costs, home healthcare visits, or readmissions. Nursing care plans to promote independent function were more often implemented in the intervention group (79% vs 50%; P = .001), physical therapy consults were obtained more frequently (42% vs 36%; P = .027), and restraints were applied to fewer patients (2% vs 6%; P = .001). Satisfaction with care was higher for the intervention group than the usual care group among patients, caregivers, physicians, and nurses (P < .05). CONCLUSIONS: ACE in a community hospital improved the process of care and patient and provider satisfaction without increasing hospital length of stay or costs. A lower frequency of the composite outcome ADL decline or nursing home placement may indicate potentially beneficial effects on patient outcomes.

Activities of Daily Living↗
PubMed1999

Measurement of phenylalanine and tyrosine in plasma by high-performance liquid chromatography using the inherent fluorescence of aromatic amino acids.

An isocratic high-performance liquid chromatography (HPLC) method is described using the natural fluorescence of phenylalanine and tyrosine compared with that of an internal standard N-methyl phenylalanine. Plasma precipitated with 6% perchloric acid was separated isocratically using a base-deactivated C18 column with 5% acetonitrile in water as the mobile phase. Fluorescent measurements at an excitation wavelength of 215 nm and emission 283 nm showed only three peaks for tyrosine, phenylalanine and the internal standard eluting within 9 min. Inter-batch coefficients of variation for phenylalanine were 2.9% and 1.8% at levels of 70 and 567 mumol/L, respectively, and 2.9% at a level of 63 mumol/L for tyrosine. The results for phenylalanine for this method showed a small mean positive bias (11 mumol/L) when compared with the target all-method means for UK National External Quality Assessment Scheme samples (n = 31). The results for tyrosine showed a small positive mean bias (10 mumol/L) when compared with an ion-exchange chromatographic method (n = 40). This method provides a quick and simple alternative to those using HPLC with pre- or post-column derivatization for monitoring patients with phenylketonuria. It is also less subject to interferences than HPLC methods using ultraviolet detection, particularly for the early eluting tyrosine peak.

Chromatography, High Pressure Liquid↗
PubMed1999

Older women, their children, and grandchildren: a feminist perspective on family relationships.

Using gerontological and feminist frameworks, we explored the relationships older women have with their children and grandchildren. In-depth, qualitative interviews were conducted with 34 women, ranging in age from 55 to 88. From our analyses of the women's perceptions of their family relationships, two themes were prevalent: the centrality of children and the peripherality of grandchildren in their everyday lives. The women had varying degrees of involvement with their children and grandchildren, and these relationships contributed to their sense of self and family. Their relationships were not stagnant, but were continually reshaped as both the women and their family members proceeded through the life course.

Adolescent↗
PubMed1998

The ratio of erythrocyte zinc-protoporphyrin to protoporphyrin IX in disease and its significance in the mechanism of lead toxicity on haem synthesis.

Protoporphyrin and zinc-protoporphyrin were measured in the erythrocytes of normal subjects, workers exposed to lead and patients with iron deficiency and erythropoietic protoporphyria (EPP). Results showed significantly higher levels of zinc-protoporphyrin in the lead-exposed workers (P < 0.0001), patients with iron deficiency (P < 0.0001) and EPP patients (P < 0.001) compared with normal subjects. The lead-exposed workers showed the highest levels of zinc-protoporphyrin, which were significantly greater than both the iron-deficient and EPP patients (P < 0.0001). They also showed a higher ratio of zinc-protoporphyrin to free protoporphyrin compared with normal subjects (P < 0.0001) but no significant difference in this ratio was found when compared with iron-deficient patients (P = 0.1). These results are discussed in light of the controversy concerning the mechanism of formation of zinc-protoporphyrin in lead exposure.

Adult↗
PubMed1996

No-react detoxification process: a superior anticalcification method for bioprostheses.

BACKGROUND: Glutaraldehyde pretreatment of bioprosthetic heart valves is the major pathogenic factor in their calcific degeneration. This comparative study investigates the merit of the No-React aldehyde detoxification process as an alternative modifier of xenograft tissues. METHODS: Glutaraldehyde- and No-React-pretreated porcine aortic valve cusps were implanted subcutaneously in 6-week-old rats (n = 20). At 3, 6, and 14 weeks, randomly selected animals were sacrificed and the explants underwent mineral and morphologic analyses. Glutaraldehyde- and No-React-treated bovine pericardium and porcine aortic valve cusp were incubated in fibroblast cell culture plates. Cell viability was observed under reversed microscope at 6, 24, 48, and 96 hours. Erythrosin B dye exclusion test was used to validate percent cell death. RESULTS: Pretreatment with No-React significantly inhibited calcification of aortic cusp subcutaneous implants throughout the 14-week period (mean tissue Ca2+ content = 1.3 +/- 0.7 micrograms/mg at 14 weeks.) Glutaraldehyde-treated cusps underwent protracted calcification (Ca2+ content = 190.6 +/- 89.5 micrograms/mg; p < 0.01). Morphologic findings correlated with mineral analyses. One-hundred percent of fibroblast cells survived in the presence of No-React-treated tissue, with a growth pattern indistinguishable from control cell culture (ie, in the presence of no tissue). The cells incubated with glutaraldehyde-treated tissue showed signs of nonviability by 6 hours, with 100% cell death by 48 hours. Dye exclusion tests validated these findings. CONCLUSIONS: The No-React detoxification process completely abolishes the cytotoxicity of the xenograft tissue and inhibits calcific degeneration.

Animals↗
PubMed1992

Measure of satisfaction of general practitioners with the chemical pathology services in Leeds Western Health District.

The satisfaction of general practitioners with the District Chemical Pathology Services in Leeds Western Health District was assessed by means of a postal questionnaire. The areas of interest covered included communication, test turn-round times, format of reports, advice about tests undertaken in the practice and chemical pathology information services. Communication with the laboratory was the major area of dissatisfaction (21% GPs), followed by test turn-round times (14%) and format of reports (10%). More than half the respondents were interested in an offer of help in selecting equipment for their surgeries and subsequent quality control. Customer satisfaction will become an important issue as a result of the NHS reforms and laboratories may find this exercise useful.

England↗
PubMed1992

Prevalence of haemoglobin variants in a diabetic population and their effect on glycated haemoglobin measurement.

The measurement of glycated haemoglobin (glycated Hb) by automated high pressure liquid chromatography enabled the prevalence of haemoglobin variants (Hb variant) to be determined in a large diabetic population within Leeds, UK. There were 16 patients showing a Hb variant amongst a total of 5300 diabetics, the majority of the variants being HbA/S traits. There were also 13 patients showing a slightly raised HbF in the range of 2% to 5%. A multi-centre study was carried out by distributing blood specimens from some of the patients with Hb traits. Significant differences in the percentage of glycated Hb were observed relating to the methodology used. However, glycated Hb is used to monitor glycaemic control and laboratories must be aware of Hb variant interferences on their methods. Also, screening for Hb variants should be considered for the at risk groups of diabetic patients.

Diabetes Mellitus↗
PubMed1991

Relationships between caregiving daughters and their elderly mothers.

In this qualitative study of 29 pairs of widowed mothers and their caregiving daughters, we employ social exchange theory to identify three relationship types: intrinsic (45%), ambivalent (34%), and conflicted (21%). These types differ in the extent to which the women receive rewards from interacting with their partner, experience costs in their interaction, handle conflicts that arise in their relationship, and express feelings of concern for each other. They also differ in that daughters in intrinsic pairs have fewer children and shorter caregiving histories than daughters in ambivalent or conflicted pairs.

Aged↗
PubMed1991

Leisure and the older black woman.

Older black women's leisure experiences have not been studied in the past. Their unique point of view comes from diverse social and cultural experiences punctuated by a lifetime of inequities. Their experiences were described in routine terms; they talked about making it through the day. Their losses led to a feeling of loneliness. They found refuge in affiliating with others at the church and senior centers. Church activities and the personal experience of worship provided a context for remaining independent as they aged.

Black or African American↗
PubMed1990

A lifetime of work: the context and meanings of leisure for aging black women.

Qualitative in-depth interviews with 30 African-American women were conducted to examine the contemporary meanings of leisure within the context of lifelong work histories. Respondents followed a pattern of unpaid agricultural work in childhood, paid work in mostly domestic and service jobs as adults, and volunteer work in church and senior centers as retirees. The women continued their history of self-reliance by incorporating their lifetime of hard work into their leisure experiences and service to self and others in old age.

Black or African American↗
PubMed1989

The introduction of a quality assessment scheme for extra-laboratory blood glucose analysis.

An external quality assessment scheme is described for on-ward testing of blood glucose by nursing staff using the Glucometer II/Glucostix system. This involved the distribution of two concentrations of glucose solutions to the wards at 2-week intervals. Initially, results were examined prior to the introduction of a formal training programme for use of the blood glucose meters when the hospital CV was 25% (low glucose) and 19% (high glucose). Some improvement was shown after 6 months, with CVs of 13 and 8%, and a greater improvement after 12 months with CVs of 6 and 8%, respectively. A ward report was designed to allow easy interpretation of performance by the participants in the scheme. The introduction of this report was well received and generated enthusiasm among the ward staff.

Blood Glucose↗
PubMed1985

Clinical value of a sensitive immunoradiometric assay for TSH.

We have investigated a sensitive immunoradiometric assay for serum thyroid-stimulating hormone (TSH) in 45 thyrotoxic patients not on treatment, 464 euthyroid patients and 111 hypothyroid patients on replacement therapy. Forty-three thyrotoxic and seven euthyroid patients were found to have an undetectable TSH (less than 0.2 mIU/L). Previous work has shown a very clear separation of thyrotoxic and euthyroid patients using sensitive TSH assays. However, our extended study here has revealed that a significant number of euthyroid patients with undetectable TSH (1.5% in our study) are likely to be found if TSH becomes the initial test for thyroid function. Thirty of the hypothyroid patients on thyroxine were found to have undetectable TSH, but only one showed clinical signs of thyrotoxicosis. Most of the patients, although having raised serum free T4, had serum free T3 levels within the euthyroid range or just slightly elevated.

Adolescent↗
PubMed1985

Use of a diode array detector in investigation of neonatal organic aciduria.

We investigated the use of a diode array detector in conjunction with isocratic cation-exchange liquid chromatography for detection of organic acids in urine. The spectra and retention times of abnormal peaks found on chromatography of urine from patients with methylmalonic aciduria, maple syrup urine disease, and lactic aciduria were recorded and compared with those obtained for group of pure organic acids. Our results show that diode array detection helps considerably in tentatively identifying peaks appearing on an abnormal chromatogram while awaiting confirmation by mass spectrometry.

Amino Acid Metabolism, Inborn Errors↗