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Biomedical subjects

A M Potter

Publications and source records attributed to A M Potter.

36 records · Page 2Linked to original sources
PubMed1985

Nonendemic Burkitt's lymphoma with complex chromosome abnormalities involving chromosomes 2 and 8.

A long surviving patient with nonendemic Burkitt's lymphoma and complex cytogenetic findings is presented. Chromosome abnormalities were seen as a minor clone in peripheral blood and were considered consistent with the t(2;8)(p12;q24) variant. The karyotype was 47,XY, -2, -8, + der2(8qter-8q24::2p12-2qter), + der8(8pter-8q23::2p12-2pter) + der8(8qter-8cen::1q21-1qter). This case illustrates the value of extensive chromosome analysis in hematologic disorders and, at the time of writing, is the first example in Britain of the t(2;8) variant in Burkitt's lymphoma.

Adult↗
PubMed1985

Value of cytogenetic studies in prediction of acute phase CML.

Twenty-five patients with Ph CML who eventually developed a blast crisis were karyotyped at regular intervals in order to correlate the evolution of abnormal clones with clinical changes. Persistent new clones appeared in the chronic phase, prior to either transition or transformation, or in the acute phase (the latter, particularly, where transformation was slow). In many patients, chromosome changes accumulated within a single abnormal clone as the disease progressed. In others, particularly where the simple Ph cell line was slow to be supplanted, new clones appeared from the remaining Ph cells at the time of transformation, perhaps reflecting the inability of certain chromosome abnormalities to coexist. We suggest that the occurrence of additional chromosome abnormalities is not reliable evidence of acute transformation, but that the nature and subsequent behavior of abnormal clones may provide more valuable indications.

Adolescent↗
PubMed1984

Propranolol-induced postoperative hypertension following coronary artery bypass grafting.

Fifteen patients receiving propranolol preoperatively and undergoing coronary artery bypass grafting had serum propranolol levels determined preoperatively and at several times early postoperatively. In addition, the patients' hemodynamic parameters and postoperative sodium nitroprusside dose requirements were monitored. All patients had significant multivessel disease and normal left ventricular function. Preoperative serum propranolol levels ranged from 16 to 243 ng/ml, with a mean level of 92 +/- 17 ng/ml; propranolol measured at the end of bypass ranged from 0 to 92 ng/ml, with a mean level of 23 +/- 7 ng/ml. Fourteen patients (93%) had hypertension postoperatively and required intravenous sodium nitroprusside to maintain mean blood pressure at or below 90 mm Hg. According to linear regression analysis, the severity of the postoperative hypertension or, specifically, the nitroprusside dose requirements, correlated significantly with the patients' serum propranolol levels postoperatively (correlation coefficient, R = 0.76, with p less than 0.001). The one normotensive patient had no detectable serum propranolol at any time postoperatively. No correlation was noted between the patient's preoperative serum propranolol levels and the need for nitroprusside therapy postoperatively. These results demonstrate that there is a significant relationship between residual propranolol and the development of hypertension postoperatively.

Adult↗
PubMed1982

Overestimation of pediatric cardiac output by thermal indicator loss.

The accurate measurement of pediatric cardiac output by thermodilution requires that the quantity of cold indicator introduced into the central circulation be known. This study defines an important source of error in the correction factor for the amount of heat gained by small volumes of cold injectate during passage through pediatric catheter systems. This error may result in significant overestimation of cardiac output (as much as 59%) when blood at body temperature is withdrawn into the injection lumen of the pediatric catheter before the injection.

Age Factors↗
PubMed1981

Significance of non-standard Philadelphia chromosomes in chronic granulocytic leukaemia.

One hundred and nineteen unselected and similarly treated patients with Ph1-positive chronic granulocytic leukaemia (CGL) had the precise nature of their chromosome rearrangements producing the Ph1 studied to determine whether this had any clinical relevance. Eighteen (15%) did not have the usual 9/22 translocation and these, by life-table analysis, had a significantly shorter benign phase of their disease than the others (P less than 0.01). It further appeared that possession of a non-standard Ph1 was related to age, in that whereas only 24 patients were over 60 at diagnosis, 9 (33%) had a non-9/22 translocation (P less than 0.01). As the duration of the benign phase seemed to be shorter in those over 60 irrespective of Ph1 type (P less than 0.01), the questions arose whether non-standard PhI chromosomes were simply occurring in older patients or whether they were affecting prognosis independently. Their independent effect was suggested by the 11 patients under 60 with a non-9/22 Ph1 who still had a significantly shorter benign phase than the 84 of similar age with a standard Ph1 (P less than 0.01). It is concluded that the myeloid karyotype can provide prognostic as well as diagnostic information in patients with CGL.

Adolescent↗
PubMed1978

Myeloid karyotype and the malignant phase of chronic granulocytic leukaemia.

During the course of a 30 month study period, 26 patients with typical chronic granulocytic leukaemia (CGL) developed karyotype abnormalities in addition to the Philadelphia (Ph1) chromosome. All cases had received at least 14 months continuous low dose busulphan, and the chromosome changes were found before clinical transformation in six patients and at the time this occurred in 20. Survival following the discovery of these additional abnormalities was short, with a median of 11 weeks for the whole group. Trisomy 8 was the commonest additional chromosome abnormality, but no one karyotype change was clearly associated with shorter survival than another. 23 of the 26 have died as a direct result of their disease, forming part of a total of 40 deaths from typical CGL encountered during the study period where karyotype analyses were performed during the terminal stages of disease. Of these 40, only two (5%) patients showed no chromosome abnormalities extra to the Ph1 prior to death. (The 17 non-study patients who died were similar in all respects to the 23 from the study group, but had no prior chromosome studies performed during the chronic phase of the disease.) It is suggested that an expanding aneuploid or pseudodiploid clone arising from the leukaemic cells during the benign phase of CGL can be used to mark the sometimes ill-defined onset of the malignant phase in all but a small proportion of cases.

Adolescent↗
PubMed1976

Non-random and random chromosomal abnormalities in transformed chronic granulocytic leukaemia.

Chromosome abnormalities, identified using a banding technique and additional to the Ph, are reported in 10 consecutive cases of transformed chronic granulocytic leukaemia. In most of the cases the abnormalities were non random. In 2 cases serial studies were performed and additional abnormalities found, antedating transformation by one week and two months respectively. In 2 others the Ph status had been established during the chronic phase of the disease. In the remaining cases the first chromosome analysis was performed at the time of transformation.

Adult↗
PubMed1976

Multiple congenital defects associated with trisomy for long arm of No. 4.

The clinical and cytogenetic findings of a male infant with multiple congenital anomalies and trisomy for the distal third of the long arm of No. 4 are described. The abnormal chromosome was inherited from the mother who had a balanced translocation, t(4;9)(q31;q34). Trisomy for the long arm of No. 4 has previously been described in only 3 patients.

Abnormalities, Multiple↗
PubMed1975

Transformation of human cells by SV40 virus.

Fibroblast cultures were prepared from skin biopsies from 29 patients and tested for their susceptibility to transformation by simian virus SV40. Cells with a normal chromosome complement showed a mean transformation frequency of 25/106 cells but for cells from a single patient with Fanconi's anaemia, the value was 152/106 cells. An increased susceptibility to transformation was observed for cells from 6 patients with Down's syndrome 3 patients with trisomy 18, a patient with trisomy 18 for 5% of cells and a patient with trisomy 13. No increased susceptibility to transformation was found for cells with a chromosome complement of XO, XXY, XX/XX + 8, XX + partial 15q or XX + 9p. The susceptiability to transformation was related to susceptibility to SV40 virus infection, as measured by the number of infected cells which contained SV40 virus induced T antigen. This latter test was technically easier to perform and could serve to detect persons of increased susceptiability to transformation, since this may indicate an increased risk of natural malignant disease.

Antigens, Neoplasm↗
PubMed1975

Karyotypic abnormalities in transformed chronic granylocytic leukaemia.

Chromosomal abnormalities in three cases of chronic granylocytic leukaemia are presented. The relative importance of 'specific' chromosomal abnormalities, additional to the Ph1 in the karyotypic evolution of chronic granylocytic leukaemia is discussed. A new abnormal metacentric chromosome is described.

Adult↗
PubMed1975

Physical and mental defect of chromosomal origin in four individuals of the same family. Trisomy for the short arm of 9.

A family with the reciprocal translocation t(9;22)(q13;q11) segregating in genetically balanced and unbalanced form is identified. The clinical features of four members with trisomy for the short arm of 9, and the proximal part of the long arm of 9, are described in detail. Features in common are summarized and compared with developmental abnormality observed in other examples of trisomy for the short arm of 9. An attempt is made to delineate further the clinical features commonly seen in trisomy for the short arm of 9.

Adult↗
PubMed1970

Comparison of transformation and T antigen induction in human cell lines.

Skin fibroblast cultures were established from eight individuals. These cell cultures, together with WI-38 cells, were examined for susceptibility to transformation by SV40 virus. Four transformation-susceptible cell lines (TS), established from patients with Down's syndrome, were found to be three to four times more susceptible to transformation than transformation-resistant cell lines (TR) from normal individuals. TR and TS cell lines were compared for their susceptibility to induction of SV40 T antigen. For dividing cells T antigen was detected in a higher percentage of TS cells than TR cells. For nondividing cells, the reverse was found; T antigen was detected in 10-fold more cells of the TR lines than in cells of the TS lines. Similar results were obtained after infection of cells with CELO virus. Titration of vaccinia virus and influenza virus A2/Scotland/49/57 indicated that TR and TS cells were equally sensitive to the former virus, but TR cells were three to five times more sensitive to influenza virus A2/Scotland/49/57 than were TS cells.

Adenoviridae↗
PubMedDate not supplied

Frequency and importance of change in blast cell karyotype in relapsing childhood lymphoblastic leukemia.

Blast cell chromosome abnormalities at presentation in childhood acute lymphoblastic leukemia (ALL) are common, and different patterns are known to be related to outcome. In contrast, the frequency and importance of further changes at the time of relapse remain unclear. Blast cell karyotype evolution was therefore studied in a group of children with recurrent disease. Of 134 consecutive children diagnosed between 1982 and 1992, 31 had a marrow relapse, and 24 had complete cytogenetic studies at both diagnosis and the time of recurrence. Fourteen (58%) of the 24 showed additional chromosomal abnormalities at relapse, 5 (21%) retained abnormalities identical to those seen at diagnosis, and 5 (21%) remained cytogenetically normal. The 14 with additional changes had shorter first remissions and showed shorter survival after relapse compared with the others. These findings indicate that emergency of cytogenetically recognizable subclones during the progression of childhood ALL could be a marker of more resistant disease.

Child↗