Biomedical subjects

J M Hawkins

Publications and source records attributed to J M Hawkins.

8 recordsLinked to original sources

PubMed1992

Karyotype and T-cell receptor expression in T-lineage acute lymphoblastic leukemia.

The relationship between karyotype and expression of the T-cell receptor (TCR) proteins was examined in 19 patients with T-lineage acute lymphoblastic leukemia (T-ALL). All patients expressed CD3 molecules in the cytoplasm or on the cell membrane. Patients were classified according to TCR expression thus: no TCR expression (TCR-), six cases; cytoplasmic expression of TCR beta chain (cTCRB) only, six cases; membrane expression of TCR alpha and beta chains (mTCRAB), five cases; membrane expression of TCR gamma and delta (mTCRGD), two cases. A chromosomally abnormal clone was detected in 15 cases. The most common site of chromosomal change was at 14q11 (seven cases), the chromosomal band to which TCRA and TCRD have been mapped; as a deletion (two cases); or as a translocation with reciprocal breakpoints in bands containing the TCRG (7p15); TCRB (7q35); or putative oncogenes HOXII (10q24), RBTN2 (11p13) or MYC (8q24) genes. Breakpoints were also seen in 6q (three cases), 9p (two cases), or 11q23 (two cases). The following observations were made: All four chromosomally normal cases lacked TCR expression (TCR-). Breakpoints at 14q11 were found in one of six TCR- cases, four of six cTCRB cases, and two of five mTCRAB cases. Abnormalities of 6q and of 9p were seen only in cases with full TCR expression (mTCRAB or mTCRGD).

Antigens, Differentiation, T-Lymphocyte↗

PubMed1992

Isochromosome 1q in acute monocytic leukemia: a new nonrandom association.

We report a case of de novo acute monocytic leukemia in a 25-year-old man in whom the sole clonal cytogenetic abnormality was an additional isochromosome 1q. Cytogenetic polymorphisms indicate that, in addition to the formation of the isochromosome, a duplication of the remaining normal chromosome 1 had taken place. Other reported cases suggest an association between acute monocytic leukemia and i(1q).

Adult↗

PubMed1991

Evaluation of cytogenetic samples and pertinent technical variables in adult acute lymphocytic leukemia.

Data on 200 bone marrow and peripheral blood samples received from 190 adults with acute lymphoblastic leukemia (ALL) were analyzed with respect to sample type (bone marrow or peripheral blood), sample cell count (concentration and total count), time in transit (days), and year of analysis. Each sample was assessed for 1) number and quality of metaphases, and 2) presence or absence of a clone. Sample type, concentration of cells, time in transit, and year of analysis all significantly affected the number and quality of metaphases and the detection of a clone. The chance of obtaining 10 or more cells for cytogenetic analysis in adult ALL was shown to be as low as 10% with a suboptimal sample (peripheral blood, low cell concentration) and as high as 70% with an optimal sample (bone marrow, adequate cell concentration, 1 day or less in transit). The likelihood of detecting a clone was smallest (0%) for the group (bone marrow, adequate cell concentration, 2 or more days in transit) and greatest (68%) in the optimal group (bone marrow, adequate cell concentration, 1 day or less in transit).

Bone Marrow Examination↗

PubMed1991

Ewing's sarcoma t(11;22) in a case of acute nonlymphocytic leukemia.

Chromosome analysis of bone marrow cells from a patient with acute nonlymphocytic leukemia M2 revealed the translocation t(11;22)(q24;q12) usually associated with Ewing's sarcoma. Molecular investigations ruled out the possibility that this was a variant Philadelphia translocation with breakpoints in the major breakpoint cluster region. Although cytogenetic analysis was not available at diagnosis, this abnormality was found both pre- and postallogeneic bone marrow transplant.

Adolescent↗

PubMed1991

Molecular investigation of 19p13 in standard and variant translocations: the E12 probe recognizes the 19p13 breakpoint in cases with t(1;19) and acute leukemia other than pre-B immunophenotype.

The gene E2A has recently been cloned, mapped to 19p13 and shown to be rearranged in cases of pre-B acute lymphoblastic leukemia (ALL) with t(1;19) (q23;p13). Nine cases with a 19p13 breakpoint, four having a phenotype other than pre-B, have been investigated with the E12 probe to the E2A gene. Five cases had t(1;19) (q23;p13) and C-ALL with pre-B phenotype in four out of four cases tested. Two cases had t(1;19) (q21;p13), one with Null cell phenotype, t(4;11), and 'jumping translocations' and the other with acute non-lymphocytic leukemia M5 following bone marrow transplantation for C-ALL. Variant translocations in patients with ALL were t(15;19) (q15;p13) and t(17;19) (q21;p13). Southern blotting with E12 showed rearrangement in the cases with t(1;19) (q23;p13) and t(1;19) (q21;p13), but not in other cases with variant 19p13 breakpoints. Thus rearrangement of the E2A gene is not restricted to cases with pre-B ALL but may also occur in acute leukemias with other immunological phenotypes. Failure to detect rearrangement in 19p13 variants may be due to an E2A breakpoint outside the E12 recognition region. Alternatively, there may be further genes in this location with relevance to leukemogenesis.

Adolescent↗

PubMed1991

Philadelphia positive acute lymphoblastic leukemia in adults: age distribution, BCR breakpoint and prognostic significance.

Clonal karyotype, clinical and blast cell features were established in 113 adults, aged 15-68 (mean 31.2) years with acute lymphoblastic leukemia (ALL). The karyotypes were: Philadelphia positive (Ph+), 23 cases; t(4;11), six cases; other chromosome findings (group II), 84 cases. Ph+ patients were older (mean 39.7 years) at presentation than the group II patients (mean 28.3 years) (p less than 0.0001). Ph+ was less frequent than expected in teenagers (15-20 years) (10.3%) and patients aged 21-50 years (21.8%), and more frequent in patients over 50 years old (43.8%) (p less than 0.01). Follow-up (between 0.5 and 4.5 years) was obtained for 108 patients. Age and karyotype (Ph+ versus group II) were prognostically significant for event-free (EFS) and overall survival (S) (p less than 0.001 in each instance). Ph+ patients fared worse than group II cases in all age groups, but karyotype added prognostic significance to age only when Ph+ and t(4;11) cases were combined (group I) (group I versus group II: EFS, p = 0.054; S, p = 0.043). The Ph breakpoint location M-bcr+ (nine cases) and M-bcr- (14 cases) was irrelevant to age (mean 37.7 and 41.3, respectively) and to prognosis. The findings indicate a fundamental difference between the genetics of ALL in most older and the majority of younger patients which may partly explain the increasingly poor prognosis with age.

Adolescent↗

PubMed1990

First intron and M-bcr breakpoints are restricted to the lymphoid lineage in Philadelphia positive acute lymphoblastic leukemia.

Knowledge of the level of commitment of the target cell in hematological malignancies may have important therapeutic and prognostic implications. Cell lineage involvement was investigated in two cases presenting with acute lymphoblastic leukemia diagnosed on clinical and immunological findings and having the Philadelphia translocation t(9;22)(q34;q11). DNA from cells separated into mononuclear (lymphoid) and granulocytic fractions was hybridized with Philadelphia breakpoint-specific probes. This revealed that the breakpoint giving rise to the Philadelphia chromosome in case 1 was within the major breakpoint cluster region and in case 2 was in the first intron of the BCR gene. Rearrangement was found in the lymphoid but not the granulocyte fraction in each case. It is therefore concluded that the target cell for chromosomal change in these cases was a lymphoid committed progenitor cell, irrespective of breakpoint location.

Adult↗

PubMed1978

Clinical placements by computer program.

A computer allocation and recording system was developed and implemented to permit an integrated, sequesntial and, to some extent, individually tailored clinical experience for occupational therapy students. Necessary technical information is described for those who may wish to adapt the program to their needs. A difficult administrative task was solved by a machine well known for its speed and accuracy, extensive memory, and copy-typing capabilities.

Clinical Competence↗