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Biomedical subjects

A Robinson

Publications and source records attributed to A Robinson.

At least 37 records · Page 2Linked to original sources

Cytogenetic studies of chronic myelocytic leukemia in children and adolescents.

In a 3 1/2 year cytogenetic study of 107 leukemia patients diagnosed in childhood and adloescence, 8 presented with chronic myelogenous leukemia (CML). Seven of the 8 had chromosomal abnormalities. Six had the Ph1 chromosome; 5 had the usual 9;22 translocation. Two patients had involvement with chromosome 15; one had a 9;15 translocation in Ph1 positive cells during remission while a second had a 1;15 translocation during blastic crisis. The 2 patients who did not have a Ph1 chromosome survived 13 and 30 months, respectively, considerably less time than the 4+ year survival in most of those with Ph1 positive CML.

Adolescent

Increased aneuploidy in Alzheimer disease.

The purpose of this study was to determine if cytogenetic changes are present in Alzheimer disease, one of the presenile dementias. The chromosomes of three groups of people were studied: 1) sporadic cases of Alzheimer disease (eight cases), 2) familial cases of Alzheimer disease with affected individuals in at least two generations of their families (five cases), and 3) currently unaffected siblings of the affected individuals in these families (nine cases). One hundred cells per individual were examined using GTG banding to allow chromosome identification. A statistically significant increase in aneuploidy was found in five of eight patients in group 1 (P less than 0.05) and in each of five patients in group 2 (P less than 0.001) when compared with the rate of aneuploidy in age- and sex-matched controls. In addition, two individuals in group 3 exhibited a significant increase in aneuploidy over the control group, raising the possibility that finding increased aneuploidy may allow one to anticipate the clinical expression of the disease state.

Aged

Chromosome 1 abnormalities in relapse and terminal stages in childhood leukemia.

Seven of 114 children with leukemia were shown to have abnormalities of chromosome 1. These included trisomy of parts of chromosome 1 as well as translocations of chromosome 1 to other chromosomes. The abnormalities were found during a relapse or terminal stage, after which the patient was refractory to therapy in all cases.

Adolescent

New translocations in human lymphocytes: a mutagen monitoring system.

The human lymphocyte is a premier cell for monitoring chromosome aneuploidy. The lymphocyte is easily obtained, can be studied before and after culture, and has been extensively investigated. Assays available for lymphocytes include the scoring of chromosome breaks (subjective and laborious), the analysis of chromosome abnormalities such as increase or decrease in number (versus normal background), dicentrics etc., and the micronucleus test (presumable end-state phenomena). We propose the monitoring of somatic chromosome translocations in human lymphocytes. Background data available from North America indicate that the frequency of de novo chromosome translocations in Halifax, Portland, Denver, and Atlanta is about 1.7 x 10(-3). The most common translocation arising in lymphocytes is between chromosomes 7 and 14 (with a frequency of 4 x 10(-4). All translocations occurring de novo in human lymphocytes tend to appear balanced with no evidence for loss or gain of chromosome material. Cytogenetic laboratories are processing lymphocytes daily. The resultant photographs and karyotypes are all scorable for de novo translocations. Suitable data on exposure to possible mutagenic agents could be collected in advance of these chromosome studies. This would provide a new method for monitoring chromosome changes in the population. The cost of monitoring lymphocyte chromosomes for somatic translocations would be small, since numerous laboratories study lymphocytes rountinely for clinical diagnostic purposes. There may be merit in availing ourselves of easily available data from a very available species: man.

Chromosome Aberrations

Chromosomal mosaicism in amniotic fluid cell cultures.

Over the past 6 years, using in situ processing methods, we have identified 32 cases of mosaicism in amniotic fluid cell cultures prepared from 1,100 samples. Two of these (45,X/46,XX and 46,XX/47,XX, + 21) were called true mosaics because multiple colonies demonstrated the same abnormal chromosome complement, and on subsequent evaluation of the newborn blood or fetal tissues, mosaicism was confirmed. Of the remaining cases, 29 were designated as pseudomosaics because only single or partial colonies exhibited an aberrant chromosome complement, 12 having a trisomy 2 line. In the final case, a double trisomy was demonstrated in only one of eight colonies in the first culture, but in the culture from a repeat sample an additional two colonies showed the same double trisomy. Since no abnormal cells were observed in infant blood, it was postulated that the mosaicism may only have been present in the extraembryonic tissues. It is our conviction that the use of these cloning methods should diminish the danger of misdiagnosis in genetic amniocentesis.

Amniotic Fluid

The effect of 5-hydroxytryptamine and epinephrine on newborn platelets.

Blood levels of 5-hydroxytryptamine (5-HT) and epinephrine are increased in conditions such as severe hypoxia, and hypovolemic or septic shock. The effect of these agents, which influence the blood coagulation system, were studied in vitro on platelets from newborns. 5-HT was determined in platelets from 18 newborns and 28 adults. The 5-HT content was 0.305 +/- 0.144 microgram/10(9) platelets in newborns and 0.675 +/- 0.212 microgram/10(9) platelets in the adult controls, a difference which is statistically significant (P less than 0.001). The 5-HT content of newborn platelets proved to be higher than that reported in the literature. Further studies on platelet aggregation due to 5-HT and epinephrine were then carried out. These demonstrated first-phase aggregation in 40% of cases when both 5-HT and epinephrine were applied simultaneously, while in the majority of the newborns no reaction was encountered when each of these substances was applied separately. However, in 2 cases, simultaneous application of 5-HT and epinephrine produced both first- and second-phase platelet aggregation. The reduced response of the platelets in the newborn to these aggregating agents can be considered as a protection against disseminated intravascular coagulation (DIC), particularly in high-risk situations.

Blood Platelets

Multiple leukemic clones in acute leukemia of childhood.

Two abnormal karyotypes representing clonal populations have been demonstrated in three patients in the early stage of acute leukemia. The karyotypes were apparently unrelated in one patient, while in the other two, a relationship was conjectured. Both clones were present before therapy in two patients. Although a clone resistant to therapy was associated with relapse in one case, in two cases a clone has persisted in the lymphocyte culture during drug treatment with the patients in remission.

Child

Non-leukemic dividing cells in the blood of leukemic patients.

Spontaneous mitoses in the blood of 67 patients with acute leukemia were enumerated and their identity determined by cytogenetic methods. Most patients were children with acute lymphoblastic leukemia. Simultaneous 16- to 20-hour cultures of blood leukocytes (Bu) and of bone marrow (BM) cells were performed without phytohemagglutinin (PHA). Blood leukocytes were also cultured with PHA for 72 hours (BPHA). Mitoses in Bu cultures were counted, and karyotypic analysis performed on cells from the three culture types. In 21 control subjects, Bu cultures usually yielded no mitoses. Relapse and remission patients both displayed significantly more Bu mitoses than the controls. The karyotypes of Bu, BPHA, and BM mitoses in remission patients were normal. Fifty percent of relapse patients displayed cytogenetically abnormal leukemia cell lines; the percentage of their abnormal karyotypes was significantly higher in BM cells than in Bu or BPHA cells. The majority of the mitotic cells in Bu cultures from both relapse and remission patients appear to be of a nonleukemic origin. The number of mitoses could not be correlated with type of leukemia, hematologic parameters, or prognosis.

Adult

An unusual neurological disorder of copper metabolism clinically resembling Wilson's disease but biochemically a distinct entity.

A patient with progressive neurological disease resembling Wilson's disease but in whom Kayser-Fleischer rings were absent, was given 67Cu and 64Cu, orally and intravenously, to measure the rate of absorption of copper using a convolution integral. The data show an abnormal distribution of body copper resulting in low copper concentrations in plasma, urine and liver but with an accumulation in the lower bowel probably due to a defect in mucosal transport. The importance of differentiating this condition from Wilson's disease is stressed.

Adolescent

Calcific tendinitis of the neck.

When a calcific deposit in the shoulder, hip or elbow ruptures, it results in severe pain and tenderness. Few clinicians are aware that the longus colli muscle of the neck is also subject to acute tendinitis. When it occurs, the pain and spasm mimic infectious spondylitis or meningitis. Four patients are presented with acute tendinitis of the longus colli muscle and the classic radiographic findings of soft-tissue swelling and amorphous calcium deposits in the tendon.

Adult

Limitations of fibre-optic bronchoscopy under fluoroscopy in the investigation of peripheral lung lesions.

Transbronchial lung biopsy under fluoroscopic guidance was attempted in 14 patients with discrete peripheral lesions and histological evidence of pathology was obtained in five (37.7%). The difficulties and limitations of the procedure are discussed. The radiation hazard to both patient and bronchoscope are assessed. From this study it is concluded that aspiration needle biopsy is preferred in the investigation of patients with peripheral lung lesions.

Adult