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P T Rowley

Publications and source records attributed to P T Rowley.

At least 19 recordsLinked to original sources
PubMed1992

Single K562 human leukemia cells express and are inducible for both erythroid and megakaryocytic antigens.

In a previous study we explored the inducibility of erythroid, granulocytic, monocytic and megakaryocytic antigens in the human multipotent leukemia cell line K562. In this study we examine the relationship between induction into the two lineages for which inducibility is most marked: erythroid and megakaryocytic types. Specifically, does any cell manifest markers of both lineages? We show that 1) cultured without inducer, a minority of single cells expresses both erythroid and megakaryocytic antigens, i.e., glycophorin A and Plt-1 antigen, 2) thymidine-hypoxanthine and phorbol dibutyrate each induce each antigen, 3) the percentage of individual cells carrying both antigens increases under each of these inducing conditions, 4) the induction of each is not only relative in terms of percentage of total cells that are positive, but also absolute in terms of mean antigen per cell and (taking into account cell multiplication) total antigen per ml of culture, and 5) the inducibility of individual cells bearing both erythroid and megakaryocytic markers is confirmed by using a different inducer (butyric acid) and antibodies for different inducer (butyric acid) and antibodies for different erythroid and megakaryocytic antigens (VIE-G4 and AP-3, respectively).

Antigens, Differentiation↗
PubMed1992

Induction of the fms proto-oncogene product in HL-60 cells by vitamin D: a flow cytometric analysis.

Agents which induce monocytic characteristics in HL-60 human acute promyelocytic leukemia cells induce mRNA for the fms proto-oncogene, which encodes the receptor for M-CSF. Previous studies of fms expression in HL-60 cells have characterized chiefly induction by phorbol esters of fms mRNA. Our studies of fms expression in HI-60 cells have characterized induction by vitamin D3 of the fms protein. We have used flow cytometry to correlate fms antigen with a monocyte-specific differentiation antigen recognized by antibody MO2 (CD14), with DNA content, and with the nuclear antigen Ki-67, a marker of cell cycling. HL-60 cells were cultured with or without 1 microM vitamin D for 7 days. fms antigen was found on 42 +/- 5.8% of the cells cultured without vitamin D, but on 63 +/- 4.3% of the cells cultured with vitamin D. MO2 binding was detected on only 2 +/- 0.5% of the cells without vitamin D, but on 59 +/- 9% with vitamin D. Cells cultured with vitamin D that were fms-positive were also predominantly (83%) MO2-positive. Analysis of DNA content, measured by propidium iodide staining, showed that 57 +/- 1.5% of cells cultured without vitamin D, but 93 +/- 0.5% of cells cultured with vitamin D, were in the G0/G1 cell cycle phase. Analysis of nuclear antigen Ki-67 revealed that, of the vitamin D-treated cells that were fms-positive, a significant proportion (37%) were still cycling. We conclude that (1) fms is demonstrable on some uninduced HL-60 cells, (2) when HL-60 cells are induced to develop monocytic characteristics by vitamin D, fms induction is part of the program for monocytic differentiation that includes MO2 expression, yet (3) some induced cells expressing fms are still cycling.

Antigens, Differentiation↗
PubMed1991

Induction of HL60 cell differentiation by tiazofurin and its analogues: characterization and efficacy.

Among inducers of myeloid differentiation for leukemic cells, tiazofurin is of special interest because its mechanism of action is known; it inhibits inosine monophosphate dehydrogenase and thus decreases the guanine nucleotide pool. Reported here are three aspects of tiazofurin induction of myeloid differentiation in HL60 human acute promyelocytic leukemia cells. First, inductive efficacy was evaluated for analogues ara-tiazofurin, xylo-tiazofurin, and selenazofurin, for dinucleotide anabolites thiazole-4-carboxamide adenine dinucleotide (TAD) and selenazole-4-carboxamide adenine dinucleotide (SAD), and for a phosphodiesterase-resistant TAD analogue, beta-methylene TAD. The results showed that the parent compounds are more effective inducers than the dinucleotide derivatives and that the selenazole analogues are more effective inducers than the thiazole compounds. Second, HL60 cell induction by tiazofurin was shown to be synergistic with that produced by the antiviral agent ribavirin. Finally, tiazofurin was found to induce expression of a phosphatidylinositol-specific phospholipase C-sensitive Fc gamma-receptor III (FcRIII) on HL60 cells, a feature consistent with neutrophilic, but not monocytic, differentiation.

Cell Differentiation↗
PubMed1991

The neurofibroma in von Recklinghausen neurofibromatosis has a unicellular origin.

von Recklinghausen neurofibromatosis (NF1) is the most common hereditary syndrome predisposing to neoplasia. NF1 is an autosomal dominant disease caused by a single gene which maps to chromosome 17q11.2. The most common symptomatic manifestation of NF1 is the benign neurofibroma. Our previous studies of tumors in NF1, studies which detected a loss of heterozygosity for DNA markers from the NF1 region of chromosome 17 in malignant tumors, did not detect a loss in neurofibromas. We report here that a more extensive study, including the analysis of neurofibromas from 19 unrelated NF1 patients by using seven probes, failed to detect a single instance of loss of heterozygosity. This finding suggests that neurofibromas are either polyclonal or monoclonal in origin but arise by a mechanism different from that of NF1 malignancies. In order to investigate the first possibility, we analyzed neurofibromas from female NF1 patients by using an X chromosome-specific probe, from the phosphoglycerokinase (PGK) gene, which detects an RFLP. The detected alleles carry additional recognition sites for the methylation-sensitive enzyme HpaII, so that the allele derived from the active X chromosome is digested by HpaII while the one from the hypermethylated, inactive X chromosome is not. We analyzed neurofibromas from 30 unrelated females with NF1. Eight patients were heterozygous for the PGK RFLP. By this assay, neurofibromas from all eight appeared monoclonal in origin. These results suggest that benign neurofibromas in NF1 arise by a mechanism that is different from that of malignant tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Southern↗
PubMed1991

Prenatal hemoglobinopathy screening. IV. Follow-up of women at risk for a child with a clinically significant hemoglobinopathy.

To determine the benefits and burdens of prenatal hemoglobinopathy carrier identification and genetic counseling and its impact on subsequent reproductive behavior, we recontacted women whom we had previously identified as at risk for having a child with a clinically significant hemoglobinopathy, regardless of whether they had accepted the offer of prenatal diagnosis. Of the 46 such women, 31 were available for interview. These 31 women had received offers of prenatal diagnosis in 47 pregnancies. Seventeen had been accepted, and 30 had been declined. The proportion of patients accepting the offer of prenatal diagnosis was higher for the index pregnancy (50%) than for subsequent pregnancies (22%). The mean interval between the initial counseling of the patient and the follow-up interview was 43 mo (standard error +/- 2.7 mo). Ninety-four percent of those interviewed recalled having received information from the screening program; 74% recalled the name of their condition; 90% knew that trait did not affect their health; 84% recalled the name of the condition for which their fetus had been at risk; and 77% could state at least one symptom of the disease. Of the 29 women asked whether they intended to use prenatal diagnosis in future pregnancies, 13 said yes and 16 said no. Of the 26 patients asked about satisfaction with their previous decision about prenatal diagnosis, all were satisfied with their decision. Eighteen said they would make the same decision in their next pregnancy, but seven patients said they would not, and one was undecided.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Prenatal screening for hemoglobinopathies. I. A prospective regional trial.

Prenatal hemoglobinopathy screening was chosen as a model system for the study of patient receptivity to unsolicited genetic information. Providers of prenatal care in Rochester, NY, were offered free testing of all their prenatal patients and genetic counseling of women found positive. The 18,907 prenatal samples tested in a 5-year period represented 35.1% of the pregnancies in the Rochester metropolitan region. A hemoglobinopathy was found in 810 pregnancies (4.3%). Of the 21 different types of hemoglobinopathies detected, the most common were sickle cell trait (59%), hemoglobin C trait (19%), beta-thalassemia trait (11%), and hemoglobin E trait (5%). At the time of phlebotomy, 75% of the pregnancies were of less than 18 wk duration. Sixty-six percent of the pregnancies occurred in patients unaware of their diagnosis, and 80% occurred in patients unaware that they might be at risk for a child with a serious blood disorder. Of the 810 positive pregnancies, 551 (68%) occurred in patients who came for counseling. Of 453 women counseled during their first screened pregnancy, 390 (86%) said they wanted their partners tested and 254 (55%) had their partner tested. In the 77 pregnancies thus found to be at risk, the couple was too late for prenatal diagnosis in 12 cases, and the condition for which the fetus was at risk was too mild in 12 cases. Prenatal diagnosis was offered in the remaining 53 pregnancies and was accepted by 25 couples (47%). These results indicate that unselected patients in the primary care setting in this region, even though pregnant, are receptive to and utilize genetic information.

Adult↗
PubMed1991

Prenatal screening for hemoglobinopathies. II. Evaluation of counseling.

Learning during genetic counseling is often below expectations, especially in the context of genetic screening. In this report we describe learning as a result of genetic counseling of 298 pregnant women identified as hemoglobinopathy carriers, 234 with sickle cell trait and 64 with beta-thalassemia trait. Counseling was designed to provide the information needed in a simple, clear, and nondirective manner. A special videotape produced for this purpose provided dramatization and a role model illustrating an appropriate response. After viewing the videotape the counselee had an opportunity to question the counselor and to have any misconceptions corrected. Questionnaires revealed significantly increased knowledge as a result of counseling in each of the three hemoglobinopathy subject areas tested-namely, clinical manifestations, genetics, and prenatal diagnosis. Five factors correlated with higher knowledge scores after counseling-namely, a younger patient age, more years of education, knowledge of having trait before this identification, knowledge of the baby's father having trait before counseling, and having no prior children.

Female↗
PubMed1991

Prenatal screening for hemoglobinopathies. III. Applicability of the health belief model.

A comprehensive prenatal hemoglobinopathy screening program in Rochester, NY, has been described in a preceding paper in this issue of the Journal. A woman identified as a carrier may face three decisions. The first is whether to accept the offer of counseling. The second is whether to have her partner tested. If her partner also tests positive, then the third decision is whether to accept the offer of prenatal diagnosis. This report analyzes factors affecting her decision, with special attention being given to factors invoked by the Health Belief Model. Factors predicting that a patient who we identified as a carrier would come for counseling included the following: patient had no prior knowledge that she is a carrier (P less than .001), a gestational age less than 18 wk (P less than .01), and Caucasian race (P less than .05). For sickle cell trait counselees and beta-thalassamia trait counselees, factors found to predict patient's intent to have partner tested were the following: a greater postcounseling knowledge of the disease (P less than .009), a lesser perceived burden of intervention (P less than .011), and belief that the partner is also a carrier (P less than .008). Also for sickle cell trait counselees and beta-thalassemia trait counselees, factors predicting that the partner actually will be tested were the following: living with the partner (P less than .001), gestational age at identification less than or equal to 18 wk (P less than .001), a lesser perceived burden of intervention (P less than .002), and a greater perceived seriousness of the disease (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude to Health↗
PubMed1990

Tetrahydrocannabinol inhibits adenyl cyclase in human leukemia cells.

Delta 9-tetrahydrocannabinol has been shown to induce incomplete maturation in ML2 human leukemia cell lines. We extend the observation of its induction of morphologic maturation to HL60 cells and of its induction of growth restriction to HL60 and K562 cells. We show that tetrahydrocannabinol reduces the cyclic AMP content of ML2 cells. Finally we demonstrate that this agent inhibits adenyl cyclase activity in ML2 cell membrane-enriched fractions. This finding in myeloid cells is compatible with one hypothesis of cannabinoid action in neuronal cells.

Adenylyl Cyclase Inhibitors↗
PubMed1989

Molecular genetic analysis of tumors in von Recklinghausen neurofibromatosis: loss of heterozygosity for chromosome 17.

The most common inherited syndrome in man predisposing to neoplasia is neurofibromatosis-1 (von Recklinghausen disease) (NF1). We investigated the hypothesis that affected individuals carry a single inactive allele at the NF1 locus in the germline and that a tumor arises from a cell in a susceptible tissue in which the remaining normal allele has been lost or inactivated. DNA from tumor and nontumor tissue from 27 NF1 patients was analyzed with three markers closely linked to the NF1 locus and two additional markers from chromosome 17. No loss of heterozygosity was observed in neurofibromas, plexiform or not. For other tumor types analyzed, seven of 14 showed a loss. A loss of heterozygosity was observed in six of 11 of the malignant peripheral nerve tumors analyzed. Of the seven malignancies demonstrating a loss, five involved a neurofibrosarcoma. These findings suggest that the pathogenesis of neurofibrosarcoma in NF1 involves a deficiency of the NF1 gene product. In any given patient, loss of heterozygosity was detected at some marker loci but not others. Thus the mutations demonstrated in these tumors comprise a set of overlapping mutations, which may facilitate more precise localization of the NF1 gene.

Alleles↗
PubMed1989

Prenatal diagnosis for sickle cell disease. A survey of the United States and Canada.

Prenatal diagnoses for sickle cell disease in the United States and Canada numbered at least 1065 through the end of 1987. The 272 prenatal diagnoses in the United States in 1987 constituted only about 4.1% of the estimated pregnancies at risk. The termination rate for diagnosed fetuses was 39% for sickle cell anemia and 23% for hemoglobin SC disease. Prenatal hemoglobinopathy screening programs should not be judged solely on the number of terminations for affected fetuses. Other benefits are reassurance for couples shown to have an unaffected fetus and, for couples shown to have an affected fetus, preparation for the birth of a child requiring special care and information relevant to future childbearing.

Anemia, Sickle Cell↗
PubMed1989

Do pregnant women benefit from hemoglobinopathy carrier detection?

A 45% sample of all pregnancies in Rochester, N.Y. over a five-year period showed that 4.2% of pregnant women had a hemoglobinopathy. Sixty-six percent of these women did not know they had such an abnormality, and 80% did not understand its reproductive significance. Sixty-eight percent of women informed they were positive came for counseling. Fifty-seven percent of counseled women had the baby's father tested. Forty-seven percent of couples at risk offered amniocentesis wanted it. (table; see text) A woman was more likely to want her partner tested if she had a more thorough knowledge of the disease or viewed having an affected child as more burdensome. The partner was more likely to come for testing if the couple were living together than if living apart. Prenatal hemoglobinopathy screening is accepted by providers and pregnant women, at least when expert services are provided at no charge to either. Women and couples use the information provided to pursue their reproductive goals.

Female↗
PubMed1987

Induction of hemoglobin synthesis in K562 cells by carbon dioxide deficiency.

Proliferation and differentiation are inversely related in many cell culture systems. The study of inducible systems is facilitated by optimal growth conditions in order that whatever differentiation is observed may be attributed to a specific effect of the inducer, rather than to a nonspecific effect of adverse growth conditions. To investigate the role of CO2 supply in an inducible system, the K562 human leukemia cell line inducible for hemoglobin synthesis was studied at 10%, 5% and 1.5% CO2 concentrations. The lower the CO2 concentration, the higher the percentage of benzidine-positive cells but the slower the growth rate. This increase in benzidine positivity reflected hemoglobin synthesis as indicated by incorporation of 3H-leucine into globin chains. If, in addition to reducing CO2 concentration, the complete medium was replaced by a bicarbonate-free medium, the percentage of benzidine-positive cells was further increased and growth further slowed. However, if endogenously produced CO2 was retained by sealing the culture vessel, these effects were mitigated. Since addition of ribosides blocked these effects, the mechanism for these effects appears to be inhibition of riboside biosynthesis due to the depletion of CO2 as a substrate. The implication of this work is that, for reproducibility in studies of inducible systems in which reduction of proliferation may itself increase the probability of differentiation, the CO2 tension, the bicarbonate concentration in the medium and the rate of egress of endogenously produced CO2 must be kept constant.

Carbon Dioxide↗
PubMed1987

Regulation of the activity of heme degradative enzymes in K562 erythroleukemic cells: induction by thymidine.

Heme oxygenase is rate-limiting in the heme degradative pathway, and its activity is induced by a host of chemicals. In K562 human erythroleukemic cells, heme oxygenase activity was not increased by exposure to potent inducers, such as cobalt chloride, bromobenzene, and heme. Indeed heme treatment severely suppressed the enzyme activity, and at 18 h the activity measured less than 5% of the control. Heme and cobalt chloride did not inhibit activities of NADPH-cytochrome c (P-450) reductase and biliverdin reductase to a marked degree. In contrast, treatment of cells with thymidine/hypoxanthine alone, or in combination with cobalt chloride, caused an increase in the activity of three enzymes of heme degradation. It is suggested that with thymidine, which is a committing inducer of hemoglobin synthesis, the induction of activity of the three enzymes of the heme degradation pathway is coupled with cell differentiation. On the other hand, in the case of heme, a noncommitting inducer of hemoglobin synthesis, induction of hemoglobin synthesis and increase in heme degradation activity may be independent.

Bromobenzenes↗