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Biomedical subjects

K Hyde

Publications and source records attributed to K Hyde.

At least 19 recordsLinked to original sources
PubMed1999

Chloride-bicarbonate exchangers in the human fetal pancreas.

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that encodes a small conductance cAMP-activated chloride ion channel. In the CF pancreatic duct, mutations in CFTR cause a reduction in bicarbonate secretion. This is thought to result from CFTR operating in parallel with a chloride-bicarbonate (Cl(-)/HCO(-)(3)) exchanger, located in the apical membrane of pancreatic duct cells. The molecular basis of this Cl(-)/HCO(-)(3) exchanger has not been identified. A combination of screening cDNA libraries, RNase protection, and 5' RACE analysis was used to identify Cl(-)/HCO(-)(3) exchangers in human fetal pancreas. An AE2 Cl(-)/HCO(-)(3) exchanger was shown to be expressed in human fetal pancreas from the midtrimester of gestation, at a time when CF-associated pathology commences. In addition, an AE1 Cl(-)/HCO(3) was identified in fetal pancreas but was absent from the adult pancreas and cultured ductal epithelial cells from fetal and adult pancreas.

Adult↗
PubMed1998

An evaluation of the Bio-Rad Variant Haemoglobin Testing System for the detection of haemoglobinopathies.

The Bio-Rad Variant Haemoglobin Testing System is an automated analyser which uses the principle of cation exchange high performance liquid chromatography. This evaluation was undertaken to examine the effectiveness of the instrument as a screening mechanism to assist in the diagnosis of haemoglobinopathies. The ability to quantify haemoglobins A2 and F and to 'flag' other haemoglobin variants was tested. Within-batch precision was excellent and between-batch precision was good. Linearity and sensitivity compared favourably with the manufacturer's published ranges. The level of carry-over for haemoglobins F, S and A was less than 0.25%. The mean carry-over for haemoglobin A2 was 2.08%. This higher figure reflected the smaller absolute difference between the high and low samples for this parameter. The instrument never failed to indicate the presence of an abnormal haemoglobin in 271 selected samples. The instrument was reliable throughout the evaluation and at no time was a run aborted.

Cations↗
PubMed1998

Ethnicity study and non-selective screening for haemoglobinopathies in the antenatal population of central Manchester.

The objective of this study was to determine the frequency of ethnic groups within the antenatal population in central Manchester and thereby ensure that the haemoglobinopathy service was targeting the correct population and their needs. Ethnic data collection records of 6718 patients were analysed over a 7 month period. Of these 62.3% stated that they were White, 13.2% Asian, 7.9% Black, 3.8% Chinese or 'other ethnic groups' and 12.7% gave no information about their ethnic background. A subset of 1144 patients were screened for haemoglobinopathies over a 1 month period. The incidence of haemoglobinopathies within the screened population was 2.62%, and comprised 0.69% beta thalassaemia trait, 1.22% sickle cell trait, 0.43% haemoglobin C trait and 0.26% haemoglobin D trait. The total incidence of haemoglobinopathies was highest within the Black population (18.2%), followed by the no information group (5.6%), Asian (3.35%) and white (0.26%). The high proportion of ethnic minorities and the significant carrier frequency in the no information group, support our view that non-selective screening should be offered to the antenatal population of central Manchester.

England↗
PubMed1998

Outcomes in abdominal hysterectomy patients with benign disease. Use of physician-developed clinical protocols.

OBJECTIVE: To develop a clinical protocol for standardizing preoperative and postoperative care in abdominal hysterectomy patients with benign disease while maintaining quality and increasing efficiency. STUDY DESIGN: Protocol and nonprotocol groups of patients were compared with respect to key quality and efficiency outcomes in a non-randomized study. Patient group outcomes were compared using descriptive, Student's t, chi 2 and log-rank statistics. Statistical tests were performed at a .05 level of significance. RESULTS: Results from two separate protocol study periods conducted in 1996 and 1997 are reported. In both study periods statistical analyses and graphic presentations illustrate that protocol implementation improved quality of care by increasing the percentage of patients receiving appropriate antibiotic prophylaxis; maintained quality as monitored through 30-day readmission rates and a postdischarge patient survey; and improved efficiency, as evidenced by shorter times to incision and length of hospital stay. CONCLUSION: At Toledo Hospital, the clinical practice protocol directed at abdominal hysterectomy patients has been an effective tool in efforts to improve quality and efficiency in patient care.

Clinical Protocols↗
PubMed1997

The cystic fibrosis transmembrane conductance regulator as a marker of human pancreatic duct development.

BACKGROUND & AIMS: The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a small conductance adenosine 3',5'-cyclic monophosphate (cAMP)-activated chloride ion channel found in the apical membranes of epithelia within the pancreas, airway, intestine, bile duct, sweat gland, and male genital ducts. Pancreatic insufficiency is a feature of about 85% of patients with cystic fibrosis and is believed to be caused by pancreatic autolysis after pancreatic duct obstruction. The aim of this study was to investigate the expression of CFTR in the pancreas from early development to postnatal life to establish whether the CFTR plays a key role in development of the pancreatic duct epithelium. METHODS: Expression of CFTR from the start of the mid-trimester of human development through term to adult life by messenger RNA (mRNA) in situ hybridization was examined. RESULTS: CFTR mRNA is detected throughout the pancreatic duct epithelium and its pattern of expression follows the differentiation of the duct system. CONCLUSIONS: CFTR is a valuable marker of human pancreatic duct cell development and differentiation.

Aging↗
PubMed1997

The in vitro effect of pegylated recombinant human megakaryocyte growth and development factor (PEG rHuMGDF) on megakaryopoiesis in normal subjects and patients with myelodysplasia and acute myeloid leukaemia.

Mpl ligand is a recently cloned haemopoietic growth factor that stimulates megakaryopoiesis in vitro and in vivo. We describe the in vitro effect of a truncated form of Mpl ligand, recombinant human megakaryocyte growth and development factor (rHuMGDF), on megakaryopoiesis in bone marrow from normal subjects and patients with myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). We used both semi-solid and suspension culture techniques to assess the effect of pegylated (PEG) rHuMGDF on megakaryocyte colony growth (CFU-Mk) and on the production of CD61+ cells in 7d suspension cultures. PEG rHuMGDF increased CFU-Mk growth and CD61+ cell production in a dose-dependent fashion in all normal marrows tested. Normal CFU-Mk growth was increased threefold with the addition of 10 ng/ml PEG rHuMGDF to cultures and CD61+ cells were increased 8-10-fold by the same dose. Although increased CFU-Mk growth was only seen in 1/10 AML and 6/16 MDS marrows, CD61+ cell numbers in suspension culture were increased in 9/13 AML and 12/15 MDS samples, responses ranged from very limited to normal magnitude. There was no correlation between platelet count and CFU-Mk number, CD61+ cell number or response to PEG rHuMGDF. We did not find any increased CFU-GM colony or cluster growth in response to PEG rHuMGDF and the CD61+ cells produced in suspension culture had features of megakaryocytic differentiation. These data suggest that PEG rHuMGDF can enhance megakaryocyte proliferation in some patients with MDS and AML, and may have a role in the treatment of thrombocytopenia in these patients.

Bone Marrow Cells↗
PubMed1997

Cystic fibrosis of the pancreas: involvement of MUC6 mucin in obstruction of pancreatic ducts.

BACKGROUND: Cystic fibrosis (CF) is characterized by pancreatic destruction following the gradual obstruction of small pancreatic ducts, from the mid-trimester of gestation onwards. To date, the material causing the obstruction has not been identified. The MUC6 mucin cDNA was isolated from human stomach and has been shown to be expressed in a number of other tissues in the gastrointestinal tract, including the gall bladder and parts of the ileum and colon. MATERIALS AND METHODS: We have examined the expression of MUC6 mucin in the human pancreas, both during development and postnatally, by mRNA in situ hybridization and immunocytochemistry. RESULTS: In this report we establish that MUC6 transcripts are abundant in pancreatic epithelial cells and show a very similar pattern of expression in the epithelium lining small ducts and centroacinar cells to that shown by the cystic fibrosis transmembrane conductance regulator gene (CFTR). In addition, material obstructing the pancreatic ducts of CF pancreas was shown to contain MUC6 mucin. CONCLUSION: We have identified MUC6 mucin as a significant constituent of the material obstructing the small pancreatic ducts in CF.

Adolescent↗
PubMed1995

Immunostaining of whole agar cultures by APAAP.

We have adapted the alkaline phosphatase-anti alkaline phosphatase (APAAP) technique to demonstrate cell antigen distributions in intact agar culture. The method facilitates batch processing and is no less convenient to perform than standard APAAP procedures. Myeloid and lymphoid antigens generally demonstrated strong staining intensity. However, staining at day 0 consistently produced no antigen expression for two monoclonals (CD11c and CD34) in contrast to positivity in parallel cytospins. CD11c showed rapidly increasing antigen expression over subsequent days of culture whereas the expression of CD34 could not be shown in conventional agar culture at any time from day 0 to day 14. Positivity was only restored in CD34-positive leukaemic cells using a modified culture technique in which cells were cultured as pre-formed small aggregates. Assessment of these aggregates extended to cell cycle analysis using anti-bromodeoxyuridine. CD71 positivity in normal culture samples correlated with colony configuration (whether clones were 'spread' or 'tight' in appearance). CD38 staining of normal bone marrow culture at day 7 showed asymmetrical staining of cells in a small number of micro-groups. The clonal detection of aberrant antigens (CD7, CD2) for assessment of minimal residual disease in AML was a disappointment due to the relative frequency of positive clones in normal culture.

Agar↗
PubMed1994

Influence of azathioprine on the ferrokinetics of patients with renal failure before and after treatment with erythropoietin.

In 16 patients (9 on azathioprine, 7 not) the ineffective iron turnover (IIT) was much higher in the azathioprine group (62.7 +/- 6.7 vs. 23.5 +/- 3.5 mumol/l blood/day, p < 0.0001, 2-tailed t test), though the red cell iron turnover (RCIT) was similar (42.8 +/- 2.9 vs. 41 +/- 4.8). Erythropoietin improved the anaemia in all patients and raised the RCIT (4 still on azathioprine to 72.2 +/- 9.8, p < 0.003; 7 non-azathioprine patients to 62.7 +/- 5.3, p < 0.01); the IIT remained higher in the azathioprine-treated (85.5 +/- 19.3 vs. 37.1 +/- 5.4; p < 0.013). In 2 patients who discontinued azathioprine, the IIT declined markedly to normal. In summary, azathioprine exacerbates the anaemia of renal failure by augmenting ineffective erythropoiesis, while erythropoietin benefits those on azathioprine as much as other renal patients by stimulating both effective and ineffective erythropoiesis.

Anemia↗
PubMed1993

Effects of azathioprine on response of renal anaemia to subcutaneous recombinant human erythropoietin.

AIMS: To determine the effect of concomitant azathioprine treatment on the response of patients with renal failure to treatment with subcutaneous recombinant human erythropoietin (r-HuEPO). METHODS: Two groups of patients with renal failure not receiving haemodialysis were studied. One comprised seven patients receiving erythropoietin alone, the second consisted of nine patients who were also treated with azathioprine. The haematological changes were monitored, and the functional erythropoietic response was studied by two different ferrokinetic models. One analysed the initial, the other the extended plasma iron clearance. Studies were performed before r-HuEPO treatment on all 16 patients, and repeated on 11 of these when the target haemoglobin (10-11 g/dl) was achieved and stabilised. Total erythropoiesis was determined using both techniques. Analysis of the extended plasma iron clearance also permitted calculation of both effective and ineffective erythroid activity. RESULTS: The haematological response to r-HuEPO was the same for both patient groups. Measurement of total erythropoiesis by both ferrokinetic methods showed good correlation. For those receiving long term azathioprine, the percentage ineffective erythropoiesis was high compared with that of the other patients, and remained so for as long as they continued with azathioprine. For those uncomplicated by azathioprine treatment, r-HuEPO increased levels of both effective and ineffective erythropoiesis by the same degree. A substantial reduction in ineffective erythropoiesis was shown only by those patients who either discontinued or reduced their azathioprine once they started r-HuEPO treatment. CONCLUSIONS: Azathioprine increases ineffective erythropoiesis. In this study, the r-HuEPO dose was sufficient to overcome this effect and promoted effective erythropoiesis so that the anaemia lessened. Measurement of total erythropoiesis provided limited information on the functional changes involved, differentiation of effective from ineffective erythropoiesis being necessary to define the changes after azathioprine reduction or withdrawal.

Anemia↗
PubMed1993

Monitoring of iron requirements in renal patients on erythropoietin.

We studied 38 patients (9 haemodialysis, 18 peritoneal dialysis, 11 advanced renal failure) over the first 12 weeks of erythropoietin therapy. In 14 iron-overloaded patients (ferritin > 500 micrograms/l the haemoglobin (+/- SEM) increased from 6.74 +/- 0.27 to 9.85 +/- 0.36 g/dl (P < 0.0001) entirely by mobilizing iron reserves (reduced from 1,220 +/- 73 to 739 +/- 111 mg, P < 0.0001). In the 24 non-overloaded patients (ferritin < 500 micrograms/l) the haemoglobin rose similarly from 7.04 +/- 0.18 to 10.70 +/- 0.36 g/dl (P < 0.0001), partly from iron reserves (depleted from 200 +/- 74 to -44 +/- 77 mg, P = 0.016) and partly from oral iron supplements (305 +/- 110 mg). In the overloaded patients the ferritin declined from 1057 micrograms/l (geometric mean, range 504-3699) to 317 micrograms/l (42-1505, P < 0.0001). In the non-overloaded patients it declined from 82 micrograms/l (8-461) to 45 micrograms/l (5-379, P = 0.016). The transferrin saturation (TS) in the overloaded patients appeared to decline from 38.3 +/- 7.2% to 24.0 +/- 3.7% but this was not statistically significant. In the non-overloaded the TS was unchanged (23.3 +/- 2.4 before and 28.1 +/- 3.6% after treatment). Considering all 38 patients together, the haemoglobin correlated negatively with the ferritin (r = 0.3731, P < 0.001) but not with the TS. The TS correlated with the serum ferritin initially (r = 0.75, P < 0.001) but not after the first 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Influence of blood volume on the blood pressure of predialysis and peritoneal dialysis patients treated with erythropoietin.

Twenty-seven patients with renal failure (16 on CAPD and 11 predialysis) were treated with erythropoietin. At 12 weeks, the mean haemoglobin concentration (+/- SEM) in the CAPD patients had increased from 7.07 +/- 0.20 to 10.88 +/- 0.45 g/dl (two-tailed paired t test, P < 0.0001) and in the predialysis patients from 6.90 +/- 0.35 to 10.05 +/- 0.47 g/dl (P < 0.0001). Predialysis patients were taking more antihypertensive medication at baseline. No increase was required in either group after erythropoietin; there was no change in blood pressure in the CAPD patients, though in the predialysis patients the systolic blood pressure rose slightly from 132 to 146 mmHg (P = 0.029) and the mean blood pressure from 95 to 103 mmHg (P = 0.028). In 12 patients (6 on CAPD and 6 predialysis) the red cell volume, plasma volume, and total blood volume were measured before and after treatment. In the CAPD patients there was a marked expansion of the red cell volume from 912 +/- 127 to 1471 +/- 222 ml (P = 0.004) and a concomitant contraction of the plasma volume from 3932 +/- 250 to 3178 +/- 326 ml (P = 0.005), leaving the blood volume unchanged from 4843 +/- 352 to 4649 +/- 503 ml. Predialysis patients had a similar expansion of the red cell volume from 733 +/- 59 to 1304 +/- 161 ml (P = 0.017) but no contraction of the plasma volume (from 3417 +/- 354 to 3314 +/- 260 ml), so that the blood volume tended to expand from 4149 +/- 347 to 4618 +/- 414 ml (P = 0.053).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1993

Polymerase chain reaction analysis of allele frequency and loss at the Harvey ras locus in myeloid malignancies.

The hypothesis that 'rare' variable number tandem repeat (VNTR) alleles of the Harvey ras (Ha-ras) locus are an inherited predisposing factor in myeloid malignancies has been evaluated. We describe an application of the polymerase chain reaction (PCR) which amplifies the VNTR region at the Ha-ras locus and offers a number of advantages over conventional Southern analysis. Ha-ras VNTR genotypes were assigned to 57 normal subjects, 46 patients with acute myeloid leukaemia (AML), 26 with myelodysplastic syndrome (MDS) and 49 with chronic granulocytic leukaemia (CGL). By comparison with previous reports we found significantly higher frequencies of rare alleles (20.2%) in our normal subjects of whom more than 35% had at least one 'rare' allele. The frequencies of rare alleles in the patient groups was not significantly different from the normal group (chi 2 = 0.54, p = 0.91). In studies of constitutional and leukaemic DNA from patients with AML, we found that allelic loss at the Ha-ras locus was not a common phenomenon. The improved resolution achievable with PCR compared with Southern analysis was demonstrated by the inability of Southern analysis to resolve six out of 34 PCR heterozygotes. We therefore suggest that previous studies showing linkage between rare Ha-ras alleles and susceptibility to malignancy should be reevaluated using our sensitive PCR technique.

Acute Disease↗
PubMed1992

Two-colour immunoenzymatic technique using sequential staining by APAAP to evaluate two cell antigens.

AIMS: To extend the alkaline phosphatase-antialkaline phosphatase (APAAP) immunoenzyme single stain method to a more generally applicable double stain technique. This will allow two primary antibodies of the same isotype of IgG and specifically the nuclear antigen bromodeoxyuridine (BRdU) to be evaluated with a cell surface antigen identifier. METHOD: Sequential applications of the APAAP method showed two antigen sites by different dye couplings to a common alkaline phosphatase substrate, producing blue and red reaction products on the same slide. Antigens on different cell populations as well as those in different compartments of the same cell were analysed. The method allowed a surface antigen monoclonal to be revealed first, using an optimal fixative, before alcohol/gluteraldehyde fixation was used to start the second (BRdU) staining sequence. RESULTS: An analysis of double staining of T lymphocyte subsets (CD4 and CD8) showed no significant difference in the order of application of the primaries (n = 10) and no significant difference from their corresponding single stain results (n = 50), confirming the validity of the technique where antigens are exclusively distributed. Other examples, including antigens distributed in different compartments of the same cell, displayed discrete staining which implied validity. CONCLUSION: Double staining by APAAP with this technique seems to be applicable to those cases where antigens are exclusively distributed and includes cases where different compartments of the same cell are stained. It is especially useful in revealing antigens that require different fixation and preparation--that is DNA incorporated BRdU with a surface antigen. But it does seem to have a limited ability to produce a dual colour at a common site.

Antibodies, Monoclonal↗
PubMed1992

A computerized database for haemophilia patient records.

A microcomputer database system for the storage, retrieval, and statistical analysis of data associated with the treatment of haemophilia and other defects of haemostasis is described. The hardware requirements are an IBM compatible PC with both hard and floppy disc drives and a suitable printer. The system was written using Smartware II, a powerful integrated software package which incorporates database, word processor, spreadsheet and communications functions. The programs were written with flexibility in mind and can be readily adapted to accommodate the work patterns of any haemophilia centre. This system has now been operational in the Regional Haemophilia Centre at the Manchester Royal Infirmary since January 1990. Its introduction has led to a marked improvement in the efficiency of patient data handling with significant savings in staff time.

England↗
PubMed1991

Continuous assessment of performance in External Quality Assessment Schemes.

A simple, standardised procedure was used for processing data from External Quality Assessment Schemes and for producing performance charts. A graphic presentation of cumulative performance is generated for each test, using an integrated software package to display results in a standardised format. This permits interpretation of satisfactory and poor performances and facilitates identification of "outlying" results. Although most results are recorded as Deviation Indices, the system is flexible and can be used to present other performance variables, such as Percentage Deviations and relevant textual information relating to interpretative assessments. It is therefore readily adaptable for use by other pathology disciplines.

Data Interpretation, Statistical↗