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Biomedical subjects

P Harrison

Publications and source records attributed to P Harrison.

At least 199 records · Page 11Linked to original sources
PubMed1987

Chromatography of vWf on dextran sulphate sepharose.

A relatively simple and reproducible chromatographic separation using Dextran Sulphate (DS) Agarose is described for the purification of vWf:Ag from cryoprecipitate or plasma source material. The elution profiles suggest high affinity of vWf for the matrix permitting resolution from Fibrinogen, IgG and the unbound Albumin. The major contaminant fibronectin can be removed prior to the chromatography step by Gelatin-Sepharose adsorption. Chromatography of 125I-vWf, added to cryoprecipitate as a marker, gives two distinct peaks one of which elutes with the column wash through fractions and expresses negligible biological activity. The re-eluted bound material expresses normal vWf:RCo activity with full multimer integrity as assessed by SDS Agarose electrophoresis. DS sepharose chromatography offers an excellent method for the purification of 125I-vWf since all the viable label is resolved from excess free radiolabel and denatured protein. Low recoveries of VIII:C were demonstrated at both R.T. or 4 degrees C possibly due to the presence of Tri-Sodium citrate and the absence of sufficient free CaCl 2 in the buffers.

Chromatography, Affinity↗
PubMed1987

Changes in minor transcripts from the alpha 1 and beta maj globin and glutathione peroxidase genes during erythropoiesis.

We have analysed the transcriptional regulation of the murine alpha 1 and beta maj globin genes and the glutathione peroxidase (GSHPx) gene, which are all highly expressed during erythropoiesis. The levels of minor RNAs compared to the major message were monitored throughout differentiation within the erythroid lineage. For each gene, upstream transcripts arise from distinct clusters of sites which are regulated differently during differentiation: some occur only during early erythropoiesis, some occur early and persist to the terminal stages, while others accumulate later and roughly in parallel with the main RNA transcript. In addition, opposite strand transcripts from the GSHPx gene were found in increasing amounts during later stages of erythropoiesis. The initiation sites for specific subsets of these minor transcripts lie close to sequences known to be involved in globin gene regulation (i.e. the TATA, CAAT and the CACCCT boxes) or other conserved sequences; others lie close to developmentally regulated DNase I hypersensitive sites around the globin and GSHPx genes.

Animals↗
PubMed1987

Evaluation of the efficacy and acceptability to patients of a physiotherapist working in a health centre.

The records of the first 805 patients who had been referred by general practitioners at this health centre to the attached physiotherapist were examined in November 1985, three years after the physiotherapy department was opened. Seventy per cent (549) of the patients had been treated within one week, treatment having started on the same day for 8.5% (67) of the patients. This compares with a mean of six weeks for direct access to a district general hospital that is eight miles away and between six and 13 months for the three nearest orthopaedic consultants who are 13 miles away. The most common conditions treated were knee injuries (16.5%), followed by cervical (15.5%) and shoulder (13.8%) injuries. Surprisingly, only 9% were back injuries. The non-attendance rate was 2.2% and only 7% of patients failed to complete treatment. Nearly all the patients were able to attend the clinic, only 4% requiring home treatment. By March 1986, 90 treatments a week were being carried out at a cost of 6.11 pounds per patient. Compared with official hospital figures, this represents a savings of 21,500 pounds a year for a practice of 12,000 patients.

Adolescent↗
PubMed1987

Amaurosis fugax under the age of 40 years.

Sixteen patients who presented under the age of 40 years with amaurosis fugax have been studied. Follow up from the time of presentation was one to 13 years with a median of 3 years. One patient whose attacks of uniocular visual loss were associated with headache developed a permanent uniocular field defect. None of the other patients has suffered permanent visual loss, or had symptoms of cerebral or myocardial ischaemia. All angiograms were normal and it is suggested that carotid angiography is unnecessary in this age group. Four out of ten patients studied demonstrated evidence of platelet hyperaggregability to low concentrations of arachidonic acid and adenosine diphosphate with spontaneous aggregation. However, in six patients treated with aspirin, including three with previous platelet hyperaggregability, there was no change in the frequency of their attacks implying that the observed platelet abnormalities were not the cause of the amaurosis fugax.

Adenosine Diphosphate↗
PubMed1987

Chronic muscle contraction headache: the importance of depression and anxiety.

Seventy consecutive patients presenting with a clinical diagnosis of chronic muscle contraction headache over a two-year period were evaluated for depression and anxiety scores, along with other possible aetiological factors in this form of headache. Fifty-five of these patients (33 from a hospital neurology clinic and 22 from a local general practice) completed a double-blind study to evaluate flupenthixol 0.5 mg twice daily, diazepam 5 mg twice daily and placebo as prophylactic agents. Patients evaluated in the hospital neurology clinic had more frequent headaches of longer duration, higher analgesic consumption and higher depression, but no higher anxiety scores than those in general practice. Flupenthixol and diazepam were both significantly superior to placebo in reducing headaches and analgesic consumption. The trend was for flupenthixol to be superior to diazepam without reaching statistical significance. Flupenthixol was significantly better than diazepam and placebo in the reduction of Hamilton depression scores. This effect was independent of the effect on headache and analgesic reduction.

Adolescent↗
PubMed1986

The Goodpasture antigen in Alport's syndrome: studies with a monoclonal antibody.

A mouse monoclonal antibody (MCA-P1), which recognizes an antigenic determinant in human glomerular basement membrane against which autoantibodies are directed in Goodpasture's syndrome, was used in indirect immunofluorescence studies to investigate glomerular basement membrane structure in Alport's syndrome. We found reduced or absent binding of MCA-P1 to glomerular and distal tubular basement membranes in renal biopsy tissue from ten patients with Alport's syndrome. Antiglomerular basement membrane antibody eluted from the kidneys of a patient who had died from Goodpasture's syndrome was used to confirm these findings. In contrast, there was bright linear fluorescence of MCA-P1 on glomerular and tubular basement membranes of normal renal material and renal biopsy tissue obtained from patients with a variety of glomerulonephritides. These results suggest an abnormality or a variable quantity of the immunoreactive autoantigen in the glomerular basement membrane of patients with Alport's syndrome. Furthermore, MCA-P1 may be of value in the diagnostic interpretation of renal biopsies from patients with familial nephritis.

Anti-Glomerular Basement Membrane Disease↗
PubMed1985

Evaluating RECONSIDER. A computer program for diagnostic prompting.

RECONSIDER, a computer program designed to perform as a diagnostic prompting aid, was evaluated for its ability to include the correct diagnosis in an ordered computed list of candidate diseases. The study was performed using 100 consecutive first admissions to the medical service of a university hospital, where the individuals entering the data into the program were blind to all but a limited set of findings known at time of admission. Each person entering the data created one or more lists of diagnostic possibilities (versions) using the program. The program suggested the correct diagnosis within the first 40 on its list 61% (498/797) of the time; the correct diagnosis was present with the first 40 in at least one version 93% (98/105) of the time. Performance was found to be best with cases having a single diagnosis and when more terms were entered into the program.

Computers↗
PubMed1985

The cell specificity and biosynthesis of mouse glycophorins studied with monoclonal antibodies.

Murine erythropoiesis represents a favourable system in which to investigate the coordinate regulation of gene expression due to the availability of erythroid precursor cells at various stages of differentiation. In this report, we investigate the biosynthesis and cell specificity of two characteristic murine RBC membrane glycoproteins that resemble the human RBC glycophorins: a major component of apparent molecular mass 31 kD (glycophorin MA) and a minor 46 kD component (glycophorin MB). Both glycophorins bind to wheat germ lectin and share a common protein antigenic determinant recognised by a monoclonal antibody (GP 29.4), but they differ significantly in their carbohydrate components: whilst both glycophorins contain mainly O-linked sugars, glycophorin MA contains in addition at least one N-linked carbohydrate residue and terminal sialic acid residues. Pulse-chase in vivo labelling experiments combined with in vitro translations of glycophorin mRNAs show that the initial precursor to glycophorin MA is a 24.5 kD polypeptide which is subsequently processed and glycosylated to give the mature 31 kD molecule via a 21.5 kD polypeptide intermediate. Both glycophorins MA and MB are synthesized most actively in early to mid erythroblasts (e.g., Friend cells induced for 3 days with DMSO) but their synthesis is considerably reduced by the reticulocyte stage. However, of the other cell types tested (neuroblastoma, myeloma, fibroblasts, epithelial cells and T-lymphoma cells), none synthesizes glycophorin with the possible exception of a low level in thymus tissue. Thus murine glycophorins, in contrast to the RBC cytoskeletal proteins (spectrin, ankyrin, band 4.1) seem to be restricted to the erythroid cell lineage like human glycophorin.

Animals↗
PubMed1983

Long acting beta-blockers in the twenty fourth hour.

Fifteen mild to moderate hypertensives were submitted to exercise testing using a bicycle ergometer with a fixed load. Heart rate, blood pressure and ECG were recorded throughout 5 min exercise and 10 min recovery. Oxygen uptake was measured during the final minute of exercise and blood glucose estimation and serum drug levels assessed 5 min after recovery. The above measurements were made after exactly 24 h following seven days administration of 160 mg of long acting (L.A.) propranolol, 200 mg of sustained action (S.A.) metoprolol and two matched placebos. Propranolol L.A. was superior to Metoprolol S.A. in the reduction of exercise induced tachycardia and both drugs were significantly superior to placebos. Both drugs were effective agents for the lowering of resting blood pressure after 24 h but propranolol L.A. was more effective in the lowering of systolic peaks observed during exercise. There was no significant effect upon oxygen uptake and blood glucose. The incidence of side effects was low and showed no significant difference from placebo.

Blood Glucose↗
PubMed1983

A monoclonal antibody against erythrocyte spectrin reacts with both alpha- and beta-subunits and detects spectrin-like molecules in non-erythroid cells.

A panel of nine monoclonal antibodies against the characteristic erythrocyte membrane protein spectrin has been isolated. One antibody reacts with both the 240 000 and 220 000 D alpha- and beta-subunits of spectrin after denaturation. The same antibody reacts with a 240 000 D protein present in various hemopoietic and other cell lines, as well as some smaller polypeptides, as established by western blotting and immunoautoradiography. These results indicate that the alpha- and beta-subunits of spectrin, a polypeptide of 240 000, and some smaller polypeptides present in non-erythroid cell types possess a considerable region of sequence homology, but it is not yet clear just how extensively the spectrin-like molecules and other polypeptides are related.

Amino Acid Sequence↗