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Biomedical subjects

M L Workman

Publications and source records attributed to M L Workman.

25 records · Page 2Linked to original sources
PubMed1985

Biologic characteristics of four Ewing's sarcomas.

Four Ewing's sarcomas were examined for chromosomal characteristics, growth in cell culture, tumorigenicity in nude mice, and presence of beta-adrenergic receptors. Three tumors were from untreated patients (one obtained directly from the patient and two after growth in nude mice) and one was a metastatic lesion obtained after treatment. All four tumors were diploid or near-diploid, with one or more structural rearrangements. In the metastatic lesion, 21 abnormalities were seen. No specific chromosome aberration was found to be common to all four tumors, although a t(1,16) was observed in two and a t(11;22) in two. Abnormalities involving chromosomes #1, #3, #11, #13, #16, and #22 were each found in two of four tumors. All four tumors were tumorigenic in nude mice; two grew well in cell culture, one of which became an established line, and all four expressed high concentrations of beta-adrenergic receptors.

Adolescent↗
PubMed1985

Cardiovascular and endocrine effects of potassium in spontaneously hypertensive rats.

Although potassium is known to lower blood pressure in a number of forms of experimental and human hypertension, the mechanism for this effect remains unclear. We studied several possible mechanisms for this effect in the spontaneously hypertensive rat (SHR). Fourteen-week-old SHR were given 0.5% KCl in the drinking water. This potassium supplement resulted in a 16-mmHg fall in mean arterial pressure and a 22% decrease in peripheral vascular resistance. Plasma potassium increased 0.4 meq/l, while muscle potassium was unchanged. Potassium supplementation resulted in no change in plasma renin activity, plasma aldosterone, or plasma norepinephrine. Urinary excretion of prostaglandin (PG) E2 and 6-keto-PGF1 alpha was also not altered by potassium supplementation. Potassium-supplemented SHR were found to have no difference in sodium excretion compared with control SHR, and plasma volume was similar in both groups. The pressor response to angiotensin II and norepinephrine was not substantially affected by potassium supplementation. Furthermore, baroreflex control of heart rate was not altered by potassium supplementation. Finally, potassium supplementation resulted in no change in mesenteric artery angiotensin II receptor number or receptor affinity. Therefore, although potassium lowers blood pressure in the SHR by decreasing peripheral vascular resistance, the mechanism of this effect on vascular resistance remains unknown.

Angiotensin II↗
PubMed1984

Chromosome features of two retinoblastomas.

Giemsa-banded chromosomal analysis of two unilateral retinoblastoma tumors from unrelated patients with normal constitutional chromosomes revealed near-diploid karyotypes with multiple structural rearrangements. The two tumors shared aberrations of trisomy 1q, monosomy 16 and 17, and 21p+. Other aberrations were unique to each tumor. One tumor expressed a del(13) and trisomy 6p.

Adult↗
PubMed1983

Double minute chromatin bodies and other chromosome alterations in human myeloid HL-60 leukemia cells susceptible or resistant to induction of differentiation by phorbol-12-myristate-13-acetate.

An analysis of the chromosomal karyotype of the human promyelocytic HL-60 leukemia cell line and of a number of its sublines that exhibit varying degrees of resistance to induction of differentiation by phorbol-12-myristate-13-acetate was conducted. The HL-60 cell line and the derived sublines contained two consistent marker chromosomes [9p- and t(10;13)], which suggested that they have a common and possibly clonal origin. HL-60 cells that are susceptible to phorbol-12-myristate-13-acetate-induced cell differentiation contained double minute chromatin bodies. The sublines with different degrees of resistance showed a corresponding sequential reduction of double minute chromatin bodies in metaphase cells. This loss of double minute chromatin bodies was not associated with an appearance of homogeneously staining chromosomal regions. Resistant and susceptible HL-60 cells differed also in a number of other chromosomal alterations, including gains or losses involving chromosomes 5, 8, 11, 13, 16, and 17. Thus, it is suggested that acquisition of resistance to phorbol-12-myristate-13-acetate-induced cell differentiation in the HL-60 cells may involve one or more of the above chromosomal changes.

Cell Differentiation↗
PubMedDate not supplied

Loss of alleles at loci on human chromosome 11 during genesis of Wilms' tumour.

Evidence that recessive cellular alleles at specific chromosomal loci are involved in tumorigenesis has been recently shown by work on tissues from patients with retinoblastoma, a neoplasm of embryonic retina whose predisposition is inherited as an autosomal dominant trait. A comparison of germ-line and tumour genotypes at loci on human chromosome 13, defined by restriction fragment length polymorphisms, showed that loss of the chromosome bearing the wild-type allele at the Rb-1 locus occurred frequently in the development of retinoblastoma. We report here results of similar studies of another embryonal neoplasm, Wilms' tumour of the kidney. Examination of germ-line and tumour genotypes from seven patients showed that five cases were consistent with the presence on human chromosome 11 of a locus in which recessive mutational events are expressed after abnormal chromosomal segregation events during mitosis.

Alleles↗
PubMedDate not supplied

Virtual reality as a distraction intervention for older children receiving chemotherapy.

The purpose of this pilot study was to describe the perceived effectiveness and feasibility of using virtual reality (VR) as a distraction intervention for children, aged 10-17, receiving outpatient chemotherapy. Treatments for cancer are intensive and difficult to endure. Distraction interventions are effective because the individual concentrates on pleasant or interesting stimuli instead of focusing on unpleasant symptoms. VR is a computer-simulated technique allowing an individual to hear and feel stimuli that correspond with a visual image. Evaluation of the VR intervention demonstrated positive outcomes. Eighty-two percent of the children (n = 11) indicated the chemotherapy treatment with the VR was better than previous chemotherapy treatments. All subjects responded positively when asked if they would like to use the VR again. The intervention was easy to implement, did not require practice to be effective, and required minimal nursing time. Results from this pilot study suggest that VR as a distraction intervention has the potential to enhance positive clinical outcomes. This intervention warrants further investigation with both pediatric and adult populations.

Adolescent↗