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Biomedical subjects

J Pritchard

Publications and source records attributed to J Pritchard.

At least 163 records · Page 9Linked to original sources
PubMed1990

How curable is relapsed Wilms' tumour? The United Kingdom Children's Cancer Study Group.

Three hundred and eighty one children with Wilms' tumour were treated on the United Kingdom Children's Cancer Study Group WT1 Study (1980/6). Seventy one patients relapsed during or after treatment, which included surgery and chemotherapy, with irradiation depending on stage and histology. Despite treatment with various combinations of chemotherapy, surgery, and radiotherapy there were only 17 survivors. For unfavourable histology, any stage, only two of 20 survive. We conclude that, after relapse, even for patients who have had localised disease and favourable histology, the 'salvage' rate is little more than 50% and for all others the likelihood of cure is very small. Three of 41 children who relapsed less than 12 months from diagnosis survive, compared with 14 of 30 who relapsed later. It is essential that even with this 'good prognosis' tumour initial treatment is optimal and given by centres experienced in management of children's cancer. Furthermore, there is a clear need for additional effective chemotherapeutic agents for relapsed patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Ovine mesangiocapillary glomerulonephritis type I and crescent formation.

Morphologic examination of four Finnish Landrace mixed-breed lambs, 27 to 35 days of age, affected with mesangiocapillary glomerulonephritis type 1, demonstrated a progressive glomerulonephritis. By 27 days of age, three lambs had crescents in 58 to 93% of glomeruli. These three lambs were also uremic. The accelerated rate of crescent formation was attributed to infiltrating polymorphonuclear leukocytes and monocytes, the result of discontinuities (gaps) in the glomerular basement membrane, and to the loss of the integrity of Bowman's capsule. In the three lambs, platelets were identified adjacent to the endothelium or denuded glomerular basement membrane. Two distinctly different types of crescents were noted, apparently dependent on the integrity of Bowman's capsule. One type resulted from the influx of inflammatory cells and dissociation of parietal epithelial cells from Bowman's capsule. The other type was more extensive and contained collagen and was associated with damage to Bowman's capsule resulting in cellular infiltration from the interstitium and sclerosis. Based on morphologic similarities, ovine mesangiocapillary glomerulonephritis is a suitable model for studying the pathogenesis and treatment of mesangiocapillary glomerulonephritis type 1 in human beings.

Animals↗
PubMed1990

Primary thyroid lymphoma in childhood: treatment with chemotherapy alone.

A 7-year-old boy developed primary non-Hodgkin's lymphoma (NHL) localized to the thyroid gland and was treated with combination chemotherapy alone. He has been continuously disease-free for 5 years since diagnosis, and is probably cured, without evidence of hypothyroidism or other unwanted late sequelae of external beam irradiation. Chemotherapy, alone, should be considered for the treatment of most, if not all, cases of localized NHL in childhood.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Preferential loss of maternal alleles in sporadic Wilms' tumour.

Loss of heterozygosity at loci on the short arm of chromosome 11 has been reported in 31% (11/38) of Wilms' tumours in our series. Lymphoblastoid cell lines were prepared from the parents of 10/11 of the patients showing allele loss in their tumours. In 9 of the cases, where the parental origin of the alleles could be followed, it was the paternal alleles which were retained in the tumour. This preferential loss of the maternal alleles implies a role for genomic imprinting in the pathogenesis of Wilms' tumour.

Alleles↗
PubMed1990

Loss of heterozygosity in Wilms' tumour involves two distinct regions of chromosome 11.

Pairs of tumour and normal DNA samples from 38 Wilms' tumour patients have been investigated for loss of heterozygosity using 12 probes from chromosome 11. Allele loss was detected in only 11 cases (31%). Densitometric analysis showed that allele loss was not due to non-disjunction or hemizygous deletion, but rather to mitotic recombination or non-disjunction plus reduplication. Although the development of homozygosity sometimes involved the whole of the short arm of chromosome 11, in a few tumours allele loss was restricted to band 11p15 or 11p13 and distal sequences. This suggests mutations in two distinct regions play an important role in Wilms' tumorigenesis. There was no apparent correlation between loss of heterozygosity and tumour stage, age of presentation, or prior exposure to chemotherapy.

Alleles↗
PubMed1990

Skeletal assessment in neuroblastoma--the pitfalls of iodine-123-MIBG scans.

This study was carried out to compare iodine-123 metaiodobenzylguanidine ([I123I]MIBG) and technetium-99m-methylene diphosphonate bone scans (99mTc-MDP) in the detection of skeletal involvement by neuroblastoma. Forty-four children with neuroblastoma underwent both [123I] MIBG and 99mTc-MDP scans within a 4-wk period; bone marrow examination also was performed; all these investigations were done both at diagnosis and at follow-up. At diagnosis, four children with Stage 4 disease had normal [123I]MIBG scans but abnormal 99mTc-MDP scans, while at follow-up there were four children with negative [123I]MIBG studies who later died from disseminated neuroblastoma. All eight scans are considered false-negative. In 24 children, the [123I]MIBG revealed more extensive disease with 161 positive sites while the 99mTc-MDP scan showed only 100 positive sites; 34 of these sites were common to both studies. This study shows that underassessment of skeletal involvement by neuroblastoma occurred using [123I]MIBG scans and that one cannot therefore substitute [123I]MIBG for 99mTc-MDP bone scans in the staging of neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1989

The frequency and natural history of diabetes insipidus in children with Langerhans-cell histiocytosis.

Diabetes insipidus is a well-recognized complication of Langerhans-cell histiocytosis (histiocytosis X), but its frequency and natural history are not well defined. Of 52 children with histiocytosis whom we studied, 12 (23 percent) had diabetes insipidus. Only two children had diabetes insipidus at presentation with histiocytosis, but the cumulative risk that it would develop during the first four years after the presentation and diagnosis of histiocytosis was found to be 42 percent. Diabetes insipidus occurred most often among children with multisystem disease and those with proptosis. To determine the natural history of diabetes insipidus in children with histiocytosis, we measured the response of urinary arginine vasopressin to water deprivation every six months in 21 children who did not have diabetes insipidus and who had had histiocytosis for less than four years. Five of the 21 children (24 percent) had subnormal responses during the initial test. One subsequently had spontaneous improvement in the functioning of the posterior pituitary, and diabetes insipidus subsequently developed in two, as it did in one of the children who initially had normal function of the posterior pituitary. Two of the children received irradiation to the pituitary within two to four weeks after diabetes insipidus developed, but they had no improvement in pituitary function. However, diabetes insipidus improved transiently during prednisolone therapy in one of these children and improved permanently after etoposide therapy in another child. We conclude that prospective study with the use of a simple water-deprivation test will allow partial defects of posterior-pituitary function to be detected in patients with histiocytosis and will permit a more appropriate evaluation of the effects of therapeutic intervention.

Adolescent↗
PubMed1989

Etoposide (VP16) in the treatment of multisystem Langerhans cell histiocytosis (histiocytosis X).

Ten children with Langerhans cell histiocytosis (histiocytosis X) either resistant to or intolerant of corticosteroids received etoposide (VP16). Nine responded. In one instance, partial diabetes insipidus was temporarily reversed. There was no major toxicity. Etoposide should be seriously considered as therapy for patients with LCH in whom the toxicity/benefit ratio of steroid therapy is unacceptably high.

Adolescent↗
PubMed1989

Monoclonal antibodies as targeting agents for cytotoxic compounds in vivo: a current assessment.

Monoclonal antibodies have proved useful in the in vitro diagnosis of tumour type. Radiolabelled antibodies have also been investigated as targeting agents for the in vivo diagnosis of tumour metastasis. These studies have revealed the potential of using 'targeting agents' to identify tumours, but in addition have exposed some of the problems associated with the technique. This review describes our experiences using radiolabelled antibodies for the identification and treatment of tumours arising from the neuro-ectoderm. Based on a small number of 4 patients studies, we conclude that there are limitations on the use of radiolabelled antibodies for targeting isotopes to primary tumour masses. In addition, we outline a possible important role for antibodies in targeting therapeutic agents to minimal residual disease and diffuse tumours presenting as micro-metastasis.

Animals↗
PubMed1989

Fibrous tissue tumours.

Thirty-three patients, ranging in age from newborn to 12 years, with fibrous tissue tumours, were treated at the Hospital for Sick Children, Great Ormond Street, London, from 1970 to 1984. Seven infants presented with tumours at birth. In 42% of cases, the tumour was noted during the 1st year of life. The anatomical distribution of the lesions was: upper extremity 6, lower extremity 5, head and neck 10, trunk 6, thoracic cavity 2 (heart 1), abdominal cavity 4 (pelvis, bladder, small bowel mesentery, and canal). Three patients had multiple tumours. Seven of the tumours were classified as sarcomas. Complete excision was possible in 28 patients, following initial biopsy in six patients of whom three were treated preoperatively with radiotherapy and/or chemotherapy. There were two deaths, one in an infant with a huge resectable pelvic tumour and the other in a child with cardiac fibroma. Recurrences occurred in 14 patients (48%), in nine of whom the recurrences were multiple. The mean time interval to recurrence was 13.8 months.

Adolescent↗
PubMed1989

A phase II study of ifosfamide in paediatric solid tumours.

A total of 20 children with recurrent or unresponsive tumours (10 Wilms' tumours, 3 rhabdomyosarcomas, 4 Ewing's sarcomas, 1 osteosarcoma, 1 hepatoblastoma, 1 hepatoma) were given ifosfamide as a 24-h infusion (5 g/m2), with mesna as a uroprotector. The number of courses ranged from 1 to 13 (median, 3), and the interval between them was 2-3 weeks. In all, 16 of these patients had previously received cyclophosphamide. Complete clinical responses (CRs) were seen in 3 cases (2 Wilms' tumours and 1 Ewing's sarcoma) and lasted 5, 7, and 9 months. Partial responses (PRs) were seen in 3 instances; mixed response or stable disease, in 4; and progressive disease, in 10. Treatment was well tolerated in most patients, with no cystitis or severe myelosuppression, but two children developed transient neurological symptoms and one became hypertensive. Nausea and vomiting were controlled by high-dose dexamethasone in most children.

Adolescent↗