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Biomedical subjects

P W Thompson

Publications and source records attributed to P W Thompson.

At least 37 records · Page 2Linked to original sources
PubMed1996

A cytogenetic deletion, del(17)(q11.22q21.1), in a patient with sporadic neurofibromatosis type 1 (NF1) associated with dysmorphism and developmental delay.

We report the first visible cytogenetic deletion involving the NF1 gene in a patient with sporadic neurofibromatosis, dysmorphic features, and marked developmental delay. The combined evidence of molecular and cytogenetic techniques based on dosage reduction, hemizygosity for microsatellite markers, high resolution G banding, and FISH analysis, predicts this deletion to be approximately 7 Mb in size. Our findings highlight the importance of conducting a detailed cytogenetic and FISH analysis in patients with NF1 who have additional dysmorphic features or particularly severe learning difficulties.

Cells, Cultured↗
PubMed1995

The effect of regular intramuscular corticosteroid therapy on bone mineral density in rheumatoid patients.

To evaluate the effect of long term regular bolus doses of intramuscular corticosteroid on bone mineral density in rheumatoid patients we undertook a retrospective cross-sectional study of 68 rheumatoid patients. Patients were divided into three groups; those who had received maintenance doses of intramuscular corticosteroid (steroid), those who had been taking regular doses of oral steroid and those who had never received steroid by either route. Bone mineral density (BMD) was measured at the hip and lumbar spine by dual photon X-ray absorptiometry (DEXA). Z scores were calculated for each patient at both sites. There is a statistical difference in Z scores at the hip in both steroid treated groups compared with the no steroid group (p < 0.001). Total steroid was less in the IM treated group compared to the oral steroid group. These results suggest that maintenance therapy with IM steroids produces significant losses of bone mineral density at the hip in rheumatoid patients and that this effect appears to be independent of the total dose.

Adrenal Cortex Hormones↗
PubMed1995

RAS and FMS mutations following cytotoxic therapy for childhood acute lymphoblastic leukaemia.

Patients who have received cytotoxic therapy for primary neoplastic disease are at an increased risk of developing secondary (therapy-related) acute myeloid leukaemia (AML) or myelodysplasia (MDS). RAS and FMS mutations have been observed in patients with AML and MDS. It has been suggested that the mutational status within these genes may be predictive of early secondary leukaemic disease. In this study we have screened 50 haematologically normal patients in complete remission from childhood acute lymphoblastic leukaemia (ALL) for activating point mutations in the RAS and FMS proto-oncogenes. Such patients may be considered at risk of therapy-related disease. Codons 12, 13 and 61 were screened in RAS and codon 969 in FMS using the polymerase chain reaction (PCR) followed by oligonucleotide hybridization (ONH). Three of the 50 patients (6%) were found to harbour N12 RAS mutations. One of these three patients (2%) had both a N12 RAS and FMS 969 mutation. Upon sequencing the RAS mutations, substitutions of serine, cysteine and aspartic acid for glycine were identified. The FMS 969 mutation was also confirmed, by sequencing, as a histidine substitution. RAS mutations were not detected in presentation samples indicating that these lesions have been somatically acquired presumably subsequent to cytotoxic therapy for the primary disease. Continued follow-up of these patients may indicate a role for these mutations in the development of secondary malignancies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Towards a measure of patient-perceived handicap in rheumatoid arthritis.

The impact of chronic disease on an individual depends not only on the severity of the disease, but on his/her life role i.e. his/her needs, expectations etc. The World Health Organization expresses the impact of chronic disease in terms of impairment, disability and handicap, where handicap is the social disadvantage resulting from disease. This article argues that the assessment of patient-perceived handicap is essential to the clinical management of chronic disease because it provides the physician with clinically relevant information about the meaning of disease for each patient, enabling treatment and intervention to be tailored to meet individuals' needs. The development of a method for assessing patient-perceived handicap using patient profiles with the object of supplying the physician with a simple clinical tool is described.

Adult↗
PubMed1994

Red cell dimorphism in a young man with a constitutional chromosomal translocation t(11;22)(p15.5;q11.21).

A constitutional, balanced chromosomal translocation t(11;22)(p15.5;q11.21) was discovered in a tall young man during investigation of a red cell dimorphism. The red cells are predominantly normochromic and normocytic with a small population of hypochromic, microcytic cells. Contained within the regions involved in the translocation are determinants of height (IGF2:11p15.5), red cell haemoglobinization (non-alpha globin gene complex: 11p15.5) and oncogenesis (cHa-Ras-1, Beckwith-Wiedemann syndrome: 11p15.5; BCR, Burkitts lymphoma, Ewings sarcoma: 22q11.21). To map these regions in the patient, somatic cell hybrids were generated and cell lines that segregated the chromosomes 11, 22 and 22q- were obtained. All 11p15.5 sequences investigated, in particular the whole of the non-alpha globin gene complex including its 5' and 3' regulatory sequences, were found to be translocated to 22q-. All chromosome 22 sequences studied were missing from the 22q- cell lines, including the proximal anonymous marker D22S24, and therefore assumed to be translocated to 11p+. These results suggest that the non-alpha globin gene complex has been moved close to the centromeric region of chromosome 22q-. It is postulated that such a positioning subjects the complex to a variegated position-effect bringing about a clonal exclusion of the complex and thus producing a beta-thalassaemia trait mosaic.

Adolescent↗
PubMed1994

Non-dysplastic myelodysplasia?

Patients successfully treated for a malignancy with cytotoxic therapy have an increased risk of developing secondary myelodysplasia (MDS) and acute myeloid leukemia (AML). We report a patient in remission from Hodgkin's disease (HD) who remains hematologically normal 4 years after combination chemotherapy, but who has biological and genetic abnormalities characteristic of myelodysplasia. X-inactivation analysis using a 5' phosphoglycerate kinase (PGK) probe demonstrates polyclonal hematopoiesis, but cytogenetic analysis reveals a clonal population with a minority of metaphases having a 7q-deletion. NRAS mutations are not detectable 1 year after treatment, but are present in two separate clones (at codons 12 and 15) analyzed by single-stranded conformational polymorphism (SSCP), followed by cloning and sequencing 4 years after treatment. The presence of an activated NRAS with the same codon 12 mutation was independently confirmed by the nude mouse tumorigenicity assay. In vitro peripheral blood granulocyte-macrophage colony-forming units (CFU-GM) have changed from normal to undetectable levels while erythroid burst forming units (BFU-E) were significantly reduced on two occasions during the period of observation. These abnormalities are characteristic of MDS. Continued clinical follow-up will determine whether these evolving genetic and biological abnormalities pre-date the onset of clinical and morphological features of MDS.

Adult↗
PubMed1993

Increased levels of urinary collagen crosslinks in females with rheumatoid arthritis.

Bone loss is a feature of RA, but the exact mechanisms involved are not clear. The collagen crosslinks deoxypyridinoline (DPYR) and pyridinoline (PYR) are specific indices of 'mature' collagen breakdown and reflect increased bone turnover. The aims of the study were to examine crosslink levels in RA and their association with disease activity and the effect of steroids. Urinary crosslinks corrected for creatinine were measured on morning fasting samples by HPLC in 70 postmenopausal women with rheumatoid arthritis (RA) aged 45-65 and compared with 169 postmenopausal healthy age-matched controls from the population. Mean levels of PYR were significantly higher in RA cases than in controls (52.4 versus 37.5 nmols/mmolCr) although mean levels of DPYR did not differ significantly. A weak correlation was found with ESR and PYR (r = 0.35) but not with other markers of disease activity. Thirteen of the RA cases were current steroid users and their levels of DPYR and PYR even with low doses, were significantly elevated above those of non-users, ex-users and controls. The finding of raised urinary PYR but not the bone specific DPYR in nonsteroid using RA cases suggests that the increased collagen breakdown does not primarily come from bone but from other sources such as cartilage and synovium. The large increases in collagen excretion in low dose steroid users, may reflect the higher risk of osteoporosis in this group.

Aged↗
PubMed1993

C-anaphase in a case of acute nonlymphocytic leukemia.

C-anaphase was seen in approximately 50% of bone marrow cells from a patient with acute nonlymphocytic leukemia (ANLL). The abnormality acting as a marker for the disease, being present at diagnosis, disappearing during remission and returning at relapse.

Aged↗
PubMed1993

Trisomy 4 with double minute chromosomes in acute nonlymphocytic leukemia.

We report on three further cases of trisomy 4 in acute nonlymphocytic leukemia. In one case the trisomy 4 was accompanied by double minute (dmin) chromosomes. Of the 34 reports of trisomy 4, dmin were also found in five cases, showing a clear nonrandom association between the two cytogenetic abnormalities.

Adult↗
PubMed1993

Biochemical changes in the collagen of human osteoporotic bone matrix.

Although it is known that collagen imparts mechanical strength to bone no detailed biochemical analysis has been made of osteoporotic bone collagen. We report for the first time significant changes in the properties of the collagen. Analysis of collagen types revealed little change in the proportion of Type III collagen, but in some cases there was a significant loss of the Type VI. However, the major differences were observed in the post-translational modifications, namely, in the stabilizing cross-links and the hydroxylation of the collagen. These changes indicated a higher turnover in the head region compared to the neck region of the femoral head and are consistent with the susceptibility of the neck region to fracture. Clearly, the collagen is altered in osteoporosis and these changes may play a role in the pathogenesis of the disease.

Aged↗
PubMed1992

Post-translational modifications in the collagen of human osteoporotic femoral head.

No detailed biochemical analysis has been made of the possible compositional changes in the collagen relating to the fragility of osteoporotic bone. We report for the first time significant changes in the compositional properties of the collagen. The major differences were observed in the post-translational modifications, namely, in the hydroxylation of lysine residues and the nature of the stabilizing cross-links of the collagen fibre. The increase in hydroxylation was greater in the head region compared to the neck region of the femoral head, whilst the decrease in the intermediate cross-links was greater in the neck region. Clearly, the collagen is altered in osteoporosis and it is important that these changes are recognised in studies of bone metabolism in osteoporosis since they may play a role in the pathogenesis of the disease.

Adult↗
PubMed1992

Urinary collagen crosslinks reflect the radiographic severity of knee osteoarthritis.

The collagen crosslinks deoxypyridinoline and pyridinoline are indices of mature collagen breakdown and reflect increased bone turnover. Urinary levels were found to be significantly raised in a group of 59 women with knee OA compared to 110 female controls from the general population. Levels of the crosslinks correlated significantly with X-ray grade of all subjects including women from the general population with mild, often asymptomatic, disease. These correlations were not diminished after adjustment for age and weight.

Aged↗
PubMed1992

Juvenile chronic arthritis and Wegener's granulomatosis.

We present a case of Wegener's granulomatosis in a teenage boy with systemic onset juvenile chronic arthritis. We discuss the implication of these two uncommon conditions coexisting in one patient. The recent characterization of the antineutrophil cytoplasmic antibody (ANCA) as a marker of small vessel vasculitis has helped in the differential diagnosis of pulmonary renal syndromes.

Adolescent↗
PubMed1992

Morphological evidence that activated polymorphs circulate in the peripheral blood of patients with rheumatoid arthritis.

Purified peripheral blood polymorphonuclear leucocytes (PMNs) from patients with rheumatoid arthritis (RA) have been found to differ from purified PMNs from normal subjects in ways that are consistent with their prior activation. However, it is currently contentious whether activated PMNs really circulate in patients with RA, or whether they are produced as an in vitro artefact of purification. Recently developed rapid leucocyte fixation and preparation technique showed that the proportion of polarised (activated) PMNs (36.9 (24.7)%, mean (SD); n = 31) was increased relative to that in control subjects (8.1 (5.6)%; n = 12). Serum cytidine deaminase levels, a biochemical marker of PMN lysis, were also increased in patients with RA (11.59 (7.26) U/ml) compared with those in controls (6.82 (3.78) U/ml), but the proportion of polarised PMNs and the levels of cytidine deaminase activity were unrelated to clinical assessments of inflammatory disease activity. Twelve patients who were not receiving drugs or who were receiving only non-steroidal anti-inflammatory drugs (NSAIDs) had more polarised PMNs than 19 patients receiving second line treatment in addition to NSAIDs (patients receiving NSAIDs, 49.6 (25.9)%; patients receiving second line treatment, 27.5 (21.1)%). Fluorescence activated cytometric analysis of CR1 and CR3 expression on PMNs from a randomly selected subgroup of patients with RA showed that the serum level of cytidine deaminase activity was correlated positively with the expression of CR1 (the C3b receptor) on the cell surface and that the proportion of polarised PMNs was positively correlated with the expression of CR3 (or CD11b/CD18), the iC3b receptor that is upregulated on activation. It is suggested that the polarised PMNs which circulate in blood samples from patients with RA represent cells which have been activated but not yet marginated, or activated cells which have marginated but subsequently returned to the circulating pool.

Adult↗