PubMed Health⌕ Search

Biomedical subjects

A D Pearson

Publications and source records attributed to A D Pearson.

At least 181 records · Page 10Linked to original sources
PubMed1989

Intestinal permeability in Crohn's disease.

Crohn's disease may present insidiously, especially in childhood, and diagnosis may be delayed. In addition, the clinical assessment of the extent of disease activity may be inaccurate. Using mannitol and lactulose as probe molecules we have carried out a cross sectional study of intestinal permeability in patients with active Crohn's disease (n = 17) and control subjects (n = 31). Activity was assessed by an activity index score. The lactulose:mannitol urinary excretion ratio was significantly increased in Crohn's disease. Overall sensitivity was 82%, and 92% when activity was moderate or severe. When permeability was compared with the activity index there was a significant correlation among patients. In five patients studied longitudinally a significant correlation was also present. Measurement of intestinal permeability is non-invasive, and may be useful both as a screening test in patients with non-specific symptoms, and for the assessment of the extent of disease activity in patients with Crohn's disease.

Adolescent↗
PubMed1989

Chromosome 22 abnormalities in Ewing's sarcoma.

A child with disseminated Ewing's sarcoma underwent cytogenetic investigations which showed different structural rearrangements of chromosome 22 at diagnosis (?ring22), and at relapse [t(10;22)], but the classic translocation t(11;22) was not detectable. This case provides further evidence of the importance of chromosome 22 in this disease, while raising some questions about the central importance of the translocation between chromosomes 11 and 22.

Bone Neoplasms↗
PubMed1989

Improved method for immunoperoxidase detection of membrane antigens in frozen sections.

The visualisation of membrane antigens in frozen sections using metal-enhanced 3,3'diaminobenzidine (DAB) was investigated. Particular attention was paid to the degree of reaction enhancement, the disruptive effect on morphological detail, and the ease of the techniques. The best result was obtained using nickel-modified DAB at pH 6.0 to develop the peroxidase enzyme, with further enhancement in cobalt chloride at neutral pH. Silver methenamine enhancement is also possible but can give rise to non-specific or background staining.

3,3'-Diaminobenzidine↗
PubMed1989

Three decades of chemotherapy for childhood cancer: from cure 'at any cost' to cure 'at least cost'.

The prognosis for childhood malignancy has improved substantially over the last 30 years. This has been principally due to the use of chemotherapy, centralization of care and treatment by standard protocols. With increasing numbers of children and adolescents cured of cancer there has been an increased awareness of the late effects of therapy. The recent recognition of disease-specific prognostic factors has permitted the subclassification of tumours into good and bad risk. The aim for those malignancies associated with a good outcome is the reduction of late adverse effects, eg intellectual impairment in children with acute lymphoblastic leukemia receiving central nervous system irradiation. In those diseases which have a poor prognosis with present therapy, new innovative and intensive regimens are being investigated in randomized trials. Neuroblastoma is a chemosensitive tumour but there has been little success in translating response into improvements in long-term cure. In poor prognosis neuroblastoma conventional combination chemotherapy, high dose therapy with autologous bone marrow rescue as consolidation and more recently high dose, or high dose rapid schedule, chemotherapy as initial treatment have been sequentially evaluated. In paediatric brain tumours only now are well designed phase II studies being undertaken and problems associated with the classification and evaluation of response to therapy are being addressed. In the past 30 years much of the success with childhood cancer has been largely empirical and the hope for the future is that there will be a more scientific approach to the chemotherapy of childhood malignancy.

Antineoplastic Agents↗
PubMed1989

Expression of MHC class I and II antigens by keratinocytes and enterocytes in acute graft-versus-host disease. Newcastle Bone Marrow Transplant Group.

The expression of MHC class I and subgroups of class II antigens by keratinocytes and enterocytes has been investigated in patients receiving autologous and allogeneic bone marrow transplants. Allogeneic recipients with graft-versus-host disease (GVHD) expressed all the class II antigens HLA DR, DP and DQ more frequently than pretransplant patients, autologous or allogeneic recipients without GVHD post-BMT (p less than 0.01). Staining for DP and DQ was never detected without DR being present. Whenever there was a lymphocytic infiltrate in the epidermis or single cell necrosis in the gut, DR was expressed on the epithelium. There was no difference in class I expression in GVHD. This study further increases the immunopathological characterization of acute GVHD which may improve the understanding of its pathogenesis.

Acute Disease↗
PubMed1988

Intestinal permeability during chemotherapy for childhood tumours.

The intestinal permeability to mannitol and lactulose was measured in 29 children receiving treatment for solid tumours. At the time of study they had no gastrointestinal symptoms and appeared clinically well. However, there was a significant reduction in the absorption of mannitol when compared to normal children. This small bowel dysfunction may result in malabsorption of nutrients and drugs. There was a significant correlation between decreased mannitol absorption and low nutritional status.

Adolescent↗
PubMed1988

Multiple chromosome rearrangements in a childhood ependymoma.

Multiple karyotypically abnormal cell lines were observed in long-term cultures of an ependymoma of the fourth ventricle of a child. A previous report of a G-banded ependymoma karyotype described monosomy 8, trisomy 9, t(1;7)(p12;p13), and t(X;10)(q22-23;q24). This case also shows involvement of Xq22 and 10q24.

Cerebral Ventricle Neoplasms↗
PubMed1988

Cytogenetic abnormalities in a primitive neuroectodermal tumor.

Two distinct karyotypically abnormal cell lines were observed in cultures of a primitive neuroectodermal tumor. One involved multiple chromosome rearrangements, and the other an inversion of chromosome #7 and a t(3;10) showing an interstitial deletion of 3p; del(3)(p1?4p1?2). None of these rearrangements have been reported in previous descriptions of primitive neuroectodermal tumor karyotypes.

Child↗
PubMed1988

The extent of surface contamination of retailed chickens with Campylobacter jejuni serogroups.

Eighty-two chickens purchased at 11 retailers (supplied by 12 wholesalers) in the south of England were cultured for Campylobacter jejuni by a method involving total immersion. The organism was isolated from 22 (48%) of 46 fresh birds, 12 of 12 uneviscerated (New York dressed) birds, but only 1 of 24 frozen birds. Viable counts of up to 1.5 x 10(6)/chicken were obtained from fresh birds and 2.4 x 10(7)/chicken from uneviscerated birds. Surface swabbing of breasts, thighs, wings and vents of fresh chickens showed that contamination was generally distributed over the carcasses. Salmonellas were found in only 2 of 69 of the fresh chickens. The prevalence of several Lior and Penner C. jejuni serogroups was similar in chickens and sporadic human cases of enteritis. Penner serogroup 4 (mostly of Lior serogroup 1) was found in 26% of human isolates and 14% of chicken isolates. The rising incidence of campylobacter enteritis during the last 6 years could well be a reflection of the increasing proportion of fresh chickens consumed over that period (32% higher in 1986 than in 1981).

Animals↗
PubMed1988

Class II antigen expression by keratinocytes and enterocytes--an early feature of graft-versus-host-disease.

HLA-DR expression by keratinocytes and enterocytes was studied in 23 patients undergoing BMT (12 autologous; 11 allogeneic). Two monoclonal antibodies were used to detect the HLA-DR antigen. Only in two patients before transplant and in one following autologous BMT was HLA-DR expressed on keratinocytes. Of 11 allogeneic recipients, 7 developed clinical GVHD, and HLA-DR-positive keratinocytes were seen in 6 of these. HLA-DR was expressed by enterocytes in 5 patients with GVHD and 4 of these also showed HLA-DR expression by keratinocytes. HLA-DR expression by keratinocytes correlated well with clinical GVHD. Expression of this antigen by enterocytes was associated with characteristic histological appearances of GVHD, even in the absence of intestinal symptoms. A combination of traditional and immunocytochemical techniques offers a sensitive and accurate method of confirming GVHD before it becomes florid.

Epidermal Cells↗
PubMed1988

Clostridium difficile in an oncology unit.

In one year 21 new cases of Clostridium difficile infection occurred on a paediatric oncology unit. Eleven cases were in a two month period. This infection should be regarded as a communicable disease. Investigations to detect C difficile should be carried out in children with malignant disease who have diarrhoea.

Adolescent↗
PubMed1988

Cytogenetic investigations of solid tumours of children.

The association of non-random chromosome abnormalities with solid tumours of childhood may improve accuracy of diagnosis and prognosis and lead to a better understanding of their biology. In a pilot study in the Northern region of England fresh tumour biopsy specimens were obtained from 39 to 72 consecutive solid tumours in children who presented over a period of 21 months. Cytogenetic analysis was possible in 33 and clonal chromosomal abnormalities were detected in nine. In addition, seven of 10 tumours investigated after treatment were abnormal. Ten of these 16 abnormal karyotypes have not previously been described. This pilot study has shown that a concerted investigation of tumour cytogenetics is possible. A multicentre study is essential if our knowledge of basic tumour cytogenetics is to progress.

Biopsy↗
PubMed1988

Globe luxation in histiocytosis X.

A boy with histiocytosis X, first diagnosed at the age of 9 months, presented at the age of 5 years with left globe luxation. Under general anaesthesia the globe was reduced and a temporary paracentral tarsorrhaphy carried out. He was started on a course of oral steroids. Two years later he had normal visual acuity, full ocular movements, and healthy fundi.

Child, Preschool↗
PubMed1988

Histological features of skin and rectal biopsy specimens after autologous and allogeneic bone marrow transplantation.

The histological appearances of skin and rectal biopsy specimens were studied in 31 bone marrow transplant recipients (13 autologous, 18 allogeneic) before transplant, at 28 days, at six months, and as soon as graft versus host disease (GVHD) was clinically suspected. Grades I and II skin changes were commonly seen in patients before transplant and in the autologous group after transplant, as well as in most of the allogeneic recipients with suspected GVHD. Epidermal lymphocytic infiltration was seen only in allogeneic recipients, with clinical GVHD following transplant, but this was not a consistent finding and no other histological features were seen which would distinguish early GVHD from changes caused by cytotoxic agents. Rectal biopsy specimens, however, were normal in patients before transplant and in autologous recipients at 28 days; single cell necrosis of crypt cells was seen only in six of 13 allogeneic recipients studied after transplant with clinical skin GVHD but no gastrointestinal symptoms. Skin changes greater than I and II are required for the histological diagnosis of GVHD. Rectal changes are more specific and may be present despite a lack of intestinal symptoms.

Adolescent↗
PubMed1988

Immunocytochemical detection of tumours of neuroectodermal origin.

Immunocytochemical methods were applied to bone marrow aspirate and cerebrospinal fluid specimens to show cellular reactivity with the monoclonal antibody UJ13A, which recognises an antigen expressed by cells of neuroectodermal origin. The antigen remained stable after air drying and appropriate fixation. In five patients with various neuroectodermal tumours the diagnostic advantages of these techniques were clear; they can be performed even when only very small amounts of diagnostic material are available.

Adult↗
PubMed1987

Pharmacokinetics of oral and intramuscular methotrexate in children with acute lymphoblastic leukaemia.

Repeated methotrexate absorption studies were performed under standard conditions in 127 children receiving either oral or intramuscular methotrexate for acute lymphoblastic leukaemia. There was marked variability in peak concentration, area under the serum concentration curve and clearance both between patients and in repeated studies on the same patient. Although the intramuscular route produced higher serum concentrations and AUC than the oral route, variability within and between patients was considerable and was most marked at higher concentrations. Neither age or sex could account for variation in methotrexate absorption or clearance. Intramuscular methotrexate, although producing higher serum concentrations and AUC, does not reduce the variability observed with oral administration. Prediction of subsequent methotrexate concentrations from the knowledge of one absorption profile is not possible.

Administration, Oral↗
PubMed1987

A hospital outbreak caused by a chlorhexidine and antibiotic-resistant Proteus mirabilis.

An outbreak of urinary-tract infection involving a strain of Proteus mirabilis resistant to gentamicin and several other antibiotics affected 90 patients in Southampton between July 1980 and May 1985. The outbreak strain was also resistant to chlorhexidine and this, in combination with the antibiogram and Dienes' test, permitted differentiation from other P. mirabilis strains. The outbreak had features in common with other Enterobacteriaceae outbreaks, although certain aspects of the population involved have made it particularly difficult to control. The outbreak commenced shortly after the introduction of a catheter care policy which involved the use of chlorhexidine, and although the majority of the cases were colonized before this policy was enforced, chlorhexidine had been used extensively for other procedures within the district. Preliminary evidence suggests that there is no genetic linkage between the chlorhexidine and multiple antibiotic resistance.

Age Factors↗