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Biomedical subjects

B Preston

Publications and source records attributed to B Preston.

At least 19 recordsLinked to original sources
PubMed1993

Effect of pH and denaturants on the folding and stability of murine interleukin-6.

The conformation and stability of a recombinant mouse interleukin-6 (mIL-6) has been investigated by analytical ultracentrifugation, fluorescence spectroscopy, urea-gradient gel electrophoresis, and near- and far-ultraviolet circular dichroism. On decreasing the pH from 8.0 to 4.0, the tryptophan fluorescence of mIL-6 was quenched 40%, the midpoint of the transition occurring at pH 6.9. The change in fluorescence quantum yield was not due to unfolding of the molecule because the conformation of mIL-6, as judged by both urea-gradient gel electrophoresis and CD spectroscopy, was stable over the pH range 2.0-10.0. Sedimentation equilibrium experiments indicated that mIL-6 was monomeric, with a molecular mass of 22,500 Da over the pH range used in these physicochemical studies. Quenching of tryptophan fluorescence (20%) also occurred in the presence of 6 M guanidine hydrochloride upon going from pH 7.4 to 4.0 suggesting that an amino acid residue vicinal in the primary structure to one or both of the two tryptophan residues, Trp-36 and Trp-160, may be partially involved in the quenching of endogenous fluorescence. In this regard, similar results were obtained for a 17-residue synthetic peptide, peptide H1, which corresponds to an N-terminal region of mIL-6 (residues Val-27-Lys-43). The pH-dependent acid quenching of endogenous tryptophan fluorescence of peptide H1 was 30% in the random coil conformation and 60% in the presence of alpha-helix-promoting solvents. Replacement of His-33 with Ala-33 in peptide H1 alleviated a significant portion of the pH-dependent quenching of fluorescence suggesting that the interaction of the imidazole ring of His-33 with the indole ring of Trp-36 is a major determinant responsible for the quenching of the endogenous protein fluorescence of mIL-6.

Amino Acid Sequence↗
PubMed1993

Radiographic progression of hospital referred osteoarthritis of the hip.

Various factors have been considered important in the rate of progression of osteoarthritis of the hip, though few data are available from large longitudinal studies. One hundred and thirty six patients referred to hospital (85 women, 51 men; mean age 65 years, range 29-86 years) with osteoarthritis of the hip (192 affected hips) were followed up for a median of 27 (range 3-72) months. One hundred and six patients (144 affected hips) were reviewed for a minimum of one year (median 28, range 12-72 months). Fifty three per cent of all osteoarthritic hips required an operation at a median of 14 (range 3-48) months from entry. All radiographs before and after entry were examined (median four films for each patient over a median of three years, range 0.5-19 years). Hips showing rapid radiographic progression on prospective films more often had superior migration, or an atrophic bone response; those with no progression more often had an indeterminate, medial, or axial migration pattern, protrusio or mild osteoarthritis at presentation. A higher occurrence of rapid progression was seen in women, in those of older age at symptom onset, and in hips with a higher Kellgren grade at entry; men more often showed no progression. Age at presentation, body mass index, symptom duration, or presence of chondrocalcinosis, hand osteoarthritis/nodes, or Forestier's disease did not influence progression. This study supports the contention that, at the time of hospital referral, certain patient characteristics and radiographic features at the hip may help to identify those at high risk of rapidly progressive hip osteoarthritis.

Adult↗
PubMed1992

Radiographic patterns and associations of osteoarthritis of the hip.

A number of patterns of osteoarthritis of the hip are described, though studies are conflicting with respect to the frequency of such patterns and their associations. Two hundred and eleven patients (133 women, 78 men; mean age 66 years, range 29-86) referred to hospital with osteoarthritis of the hip were studied. Involvement was unilateral in 108 (51%) and bilateral in 89 (42%); 14 (7%) had undergone arthroplasty and were presenting with osteoarthritis hips). Sixty one per cent of hips had severe, 28% moderate, and 11% mild changes (Kellgren grade). Superior pole migration occurred in 82% (46% superolateral, 25% intermediate, 11% superomedial), medial/axial migration occurred in only 8%, and in 10% the pattern was indeterminate. In bilateral osteoarthritis of the hip the pattern was generally symmetrical. Superomedial and medial/axial patterns were proportionately more common in women, whereas superlateral osteoarthritis predominated in men. No association was found between multiple clinical nodes, radiographic polyarticular interphalangeal or first carpometacarpal osteoarthritis and any migration pattern. Any interphalangeal osteoarthritis was negatively associated with medial migration. Only 40% of hips could be categorised as hypertrophic or atrophic; chondrocalcinosis at any site was associated with atrophic osteoarthritis; no associations were seen with Forestier's disease. This large survey confirms the association between chondrocalcinosis and atrophic osteoarthritis of the hip. Importantly it suggests that gender, rather than associated osteoarthritis at other sites, is a major determinant of the pattern of osteoarthritis of the hip.

Adult↗
PubMed1990

Hospital cost accounting: who's doing what and why.

The movement away from cost-based reimbursement by Medicare and other third party payers has prompted an increasing number of hospitals to implement more advanced costing techniques in their operations. Findings from a recent survey of hospital executives regarding cost accounting methods shed light on the extent of this trend.

Accounting↗
PubMed1990

Use of care levels in the postanesthesia care setting.

Most hospitals no longer charge a flat postanesthesia care rate, although many have only one charge code based on unit of time to cover all patients regardless of the level or intensity of their care. The author reports a mechanism developed to charge patients for PACU care based on both length of time and level or intensity of care required. Objectives of the project included a more accurate determination of cost of care provided to each patient, and provision of accurate data for productivity measurement and reporting on an ongoing basis. The installed system, based on four levels of care, provided the following results: more accurate cost of PACU care data reflecting both length and intensity of care; more accurate PACU workload units provided to hospital-wide productivity reporting system; patients charged based on both level and intensity of nursing care in the PACU; nurses feeling that their care efforts are recognized and appreciated; and estimation of overall workload for the next day along with when workload should peak.

Accounting↗
PubMed1989

Child pedestrian casualties with special reference to casualties on the journey to or from school in Manchester and Salford, England.

There are two separate facets of the casualty rates for child pedestrians in Great Britain that require explanation. (1) The casualty rate for child pedestrians aged 11-14 years is higher than the rate for those aged 5-10 years. In Manchester and Salford the casualty rate for the older age group is higher for children on the journey to or from school but at nonschool times the casualty rate is lower for those aged 11-14 years than for those aged 5-10 years. It is suggested that the high casualty rate for older children is connected with the school journey, which is longer to secondary than to primary schools. (2) The casualty rate for the older age group has increased in recent years. Comparing the casualty rates at school and nonschool times in Manchester and Salford in 1969 and 1987 suggests that this increase is due to an increase in accidents on the school journey.

Accidents, Traffic↗
PubMed1989

Primary osteoarthritis of the elbow.

Sixteen patients (14 male, two female; mean age 61, range 49-75 years) with elbow osteoarthritis (OA) unassociated with nodal or crystal related OA were studied. None had received obvious trauma. The dominant elbow was affected in 14, the other in 12 (mean symptom onset in these 26 elbows 53 years (range 31-63), mean symptom duration 7 year (range 1-20]. Joint fluids (six patients) were non-inflammatory: biopsy (two) showed non-specific synovitis. Radiographic changes occurred in humeroulnar (25/26, 96%), humeroradial (100%), and radioulnar (22/26, 85%) compartments: uniform narrowing with hypertrophic change predominated and osseous bodies were common (18/26, 69%). Thirteen had OA elsewhere, notably 2nd/3rd metacarpophalangeal joints (10/16, 62%), knees (6/16, 38%), and hips (5/16, 31%). A good clinical outcome was observed in 22/26 elbows. In our experience symptomatic 'primary' OA of the elbow particularly affects middle aged men, commonly associate with metacarpophalangeal OA ('Missouri metacarpal syndrome'), and has a favourable outcome. Contrary to previous reports a major role for trauma is difficult to substantiate.

Aged↗
PubMed1980

Peripheral blood flow in the neonate; 1. Changes in total, skin, and muscle blood flow with gestational and postnatal age.

Total peripheral blood flow and blood flow through the skin and muscle were measured in the calf with an electrocapacitance plethysmograph with counter pressure in a group of 62 "well" newborn infants (birth weight, less than 3500 g). Blood pressure in the contralateral leg was measured with an Arteriosonde 1010, and peripheral vascular resistance was calculated as mean blood pressure (mm Hg) divided by blood flow (ml per 100 ml tissue per min). The results show that total peripheral blood flow and blood flow through he skin and muscle correlated inversely with increasing birth weight and gestational age. Postnatally, total blood flow and blood flow through the skin and muscle decreased gradually during the first 7 days of life and in the rest of the neonatal period. Peripheral vascular resistance and resistance in the skin and muscle correlated directly with increasing birth weight and gestational age. Postnatally, peripheral vascular resistance and resistance in the skin and muscle increased during the first 7 days of life and the neonatal period.

Aging↗
PubMed1979

Bone scanning: its lack of value in the follow-up of patients with breast cancer.

Three hundred and fifty-four women with primary operable breast cancer had a bone scan performed within 6 weeks of a simple mastectomy. Eight (2.3 per cent) were positive, but 7 of these patients had radiological evidence of bony metastases. Follow-up bone scans 1 year postoperatively on 278 patients showed only 12 (4.3 per cent) positive, and of these, 9 had other radiological evidence of metastatic disease. At 2 years postoperatively there were 13 (9.2 per cent) positive bone scans amongst 141 patients. Only 2 of these 13 had no other evidence of metastases. Although a bone scan is a useful investigation in patients with bone pain, there is no place for routine bone scanning in either the staging or follow-up of women with operable breast cancer.

Adult↗
PubMed1977

Multiple forms of thymidine kinase during human development.

The developmental progression of thymidine kinase from the electrophoretically slow-migrating 'fetal' forms to the fast-migrating 'adult' form was examined in human serum and fetal liver. In fetal liver, only the fetal forms of the enzyme were present at 17 weeks' gestation. A transitional period followed in that both enzyme forms were identified and by 24 weeks only the adult form was detected in fetal liver. This same enzyme changeover pattern--fetal to transitional to adult--occurred at a later time in human serum as it took place between 30 and 40 weeks' gestation.

Adult↗