Jessie L. Watt

Chromosome damage and sister chromatid exchanges in lymphocyte cultures from patients with two primary cancers

Sister chromatid exchanges (SCEs) and chromosome damage were scored in lymphocyte cultures from 11 patients with two or more primary cancers and were compared with normal controls. None of the patients had a constitutional chromosome anomaly, but six showed evidence of chromosome instability, which could not be accounted for by treatment, expressed either as elevated SCE frequency or increased nonspecific chromosome damage and chromosome loss. Chromosome damage included major rearrangements as well as deletions and gaps. The possibility of common mechanisms in chromosome instability leading to susceptibility to a heterogeneous group of primary cancers is discussed.

Problems of detecting mosaicism in skin. A case of trisomy 8 mosaicism illustrating the advantages of in situ tissue culture

A case of mosaic trisomy 8 is described and the accuracy of flask culture and in situ culture techniques in detecting chromosomal mosaicism in tissues discussed. The advantages of the in situ method are illustrated and the importance of mixed colonies in defining mosaicism highlighted. The implications for prenatal diagnosis of mosaicism are pointed out.

Triploidy, partial mole and dispermy. An investigation of 12 cases

Twelve triploid abortuses were investigated to determine the origin of the additional haploid set and were retrospectively examined for the development of partial hydatidiform mole. Eight out of ten suitable triploids were diagnosed as partial mole. Dispermy was indicated as the cause of triploidy in 6 informative cases of which 3 were also partial moles. However, one diandric triploid had no features of partial mole. The problem of maternal cell contamination in triploids and the difficulty of diagnosing partial moles on pathological grounds alone are discussed.

Preliminary Evidence for the Common Origin of a Lympho-Myeloid Complex in Man

In 2 patients with chronic myeloid leukemia, the Philadelphia chromosome was demonstrated in peripheral blood lymphocytes. This finding points to the common origin of lymphocytes and other blood cells in man.

Variation in the Philadelphia chromosome

SummaryCytogenetic study of 17 cases of chronic myeloid leukaemia has shown that the Philadelphia chromosome is a variable entity, differing in size and banding pattern between individuals.

Reciprocal translocation and the Philadelphia chromosome.

SummaryWe examined metaphases from three patients with chronic myeloid leukaemia and a typical Philadelphia chromosome with one chromosome 9 as the recipient to determine whether the 9q+ 22q- translocation is reciprocal. Good quality G-banded photographs of the chromosomes concerned were subjected to light absorption density analysis. This provided enlarged tracings corresponding to the relevant chromosome regions and so facilitated accurate measurement. This technique has unambiguously shown that the typical Philadelphia chromosome results from a reciprocal translocation and that probably no material is gained or lost in the exchange. Furthermore, in a total of six patients for whom sequential G and C banding was performed, the chromosome 9 with the largest block of centromeric heterochromatin received the translocated material. We offer tentative explanations for this curious observation.

Variation of SCE frequency in lymphocyte cultures from patients with Hodgkin's disease before, during, and after treatment

Seven patients with newly-diagnosed Hodgkins disease, having standard mustine-vinblastine-prednisolone-procarbazine therapy, had a large and regular pattern of rise in SCE frequency in their peripheral lymphocytes, which apparently started to fall before the end of the course (32 wk). In contrast, SCE frequency fell below normal in the lymphocytes of nine patients having mantle radiotherapy. Twenty-eight patients studied 2-13 yr after initial chemotherapy or radiotherapy for Hodgkins disease had normal or near normal SCE frequencies.

Cytogenetic study of 10 cases of infectious mononucleosis

Cytogenetic analysis of 10 cases of infectious mononucleosis has revealed increased damage in the form of chromosome breakage and aberrations typical of viral infection, but in addition a few cells were consistently found to harbour a deleted number 22, similar to the Philadelphia chromosome. The presence of a plasma inhibitor of lymphocyte response to the mitogen phytohaemagglutinin is suggested. This inhibitor appears to have a reversible action on the patients own lymphocytes but no inhibitory effect on control lymphocytes.

Clonal Evolution of Marker Chromosomes in a Case of Myelofibrosis with Myeloid Metaplasia and Myeloblastic Transformation

The diverse spectrum of acquired chromosome abnormalities in a female patient with myelofibrosis and myeloid metaplasia is described. A sequence of karyotypic evolution involving a ring chromosome is postulated. The terminal clinical picture was unusual in that there was obstructive renal failure from extramedullary myeloblastic transformation and infiltration of the bladder, and this was also present in other sites. Initially neutrophils showed low alkaline phosphatases activity but latterly two distinct populations in which cells had either high activity or none.

An unusual karyotype in preleukemia.

A case of a myeloproliferative disorder classified as preleukemia is described in which the patient developed a single, complicated, abnormal karyotype in 100% of the bone marrow cells (45, XY, -2, -5, -7, -8, -11, -12, -13, -14, + t(2;5), +t(11;12), +t(16;17), +17, plus three or four dicentric markers). The possible significance of these unusual, if not unique, chromosome changes is discussed in relation to hematologic and clinical findings and with particular reference to the existing nonrandom patterns of chromosome changes in myeloproliferative disorders and acute nonlymphoblastic leukemias.