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Biomedical subjects

D Hartley

Publications and source records attributed to D Hartley.

14 recordsLinked to original sources
PubMed1992

Use of community-based mental health programs by HMOs: evidence from a Medicaid demonstration.

BACKGROUND: Proposals to enroll Medicaid beneficiaries in health maintenance organizations (HMOs) have raised concerns that community-based mental health treatment programs would be adversely affected. METHODS: In Hennepin County (Minnesota) 35% of Medicaid beneficiaries were randomly assigned to prepaid plans. Random samples of individuals with severe mental illness with selected from the prepaid enrollees and from beneficiaries remaining with traditional Medicaid. The two groups were compared with respect to their use of community treatment programs and the write-off (the proportion of patient charges for which payment was not received) experienced by those programs for members of the study sample. RESULTS: There was no strong evidence that Medicaid beneficiaries with severe mental illness who were randomly assigned to prepaid plans used community-based mental health treatment programs differently than did other Medicaid beneficiaries. However, write-offs were consistently higher for enrollees in prepaid plans. CONCLUSIONS: In the short run, the use of community-based mental health treatment programs need not be affected by enrollment of Medicaid beneficiaries in prepaid plans, providing that Medicaid program administrators take steps to minimize the disruption of ongoing treatment, offer beneficiaries a choice among prepaid plans, and encourage community treatment programs to contract with plans to serve beneficiaries.

Adult↗
PubMed1991

Prevalence and correlates of cutting behavior: risk for HIV transmission.

The prevalence of cutting behavior among a population of 76 psychiatrically hospitalized adolescents was found to be 61.2%. The frequency ranged from a single occasion to over 50 instances, with a mean of 9.9 occasions. Increased self-mutilation was not found to be associated with gender, age, ethnicity, or primary psychiatric diagnosis. A significant association was identified between adolescents who report forced sex and those who report cutting behavior. Approximately 26.7% of those reporting this behavior also report sharing cutting implements with other adolescents. This article raises concern about this behavior as it relates to the transmission of human immunodeficiency virus and makes recommendations for clinicians treating this population.

Adolescent↗
PubMed1990

Effect of time-limited psychotherapy on patient dropout rates.

The authors conducted an archival study of 149 new clinic patients at a large community mental health center. The dropout rate for patients in brief psychotherapy in which the length of therapy was specified at the outset of treatment (time-limited psychotherapy) (32%) was about one-half the dropout rate for patients in brief (67%) and long-term (61%) individual psychotherapy. The difference in dropout rates could not be explained by patient demographic or diagnostic variables or by therapist characteristics measured in the study. The results suggest that setting a specific time limit on individual psychotherapy at the outset of treatment can reduce the patient dropout rate in a public mental health clinic.

Ambulatory Care↗
PubMed1989

Persistence of the irradiated host component in thymocyte populations from bone marrow radiation chimeras infected with lymphocytic choriomeningitis virus.

The thymus of chimeras made using T cell-depleted donor bone marrow from Thy1.1+ mice and 950 rad Thy 1.2+ recipients is dominated initially by cells expressing the Thy 1.2+ phenotype of the irradiated host. The thymocyte population recovered at 2 weeks after reconstitution comprises 80% Thy 1.2+ cells (host), the remainder being Thy 1.1+ (donor). This situation is normally reversed within a further week, with the host Ty 1.2+ (donor). This situation is normally reversed within a further week, with the host Thy 1.2+ thymocytes being present at a frequency of less than 5% from Week 4. Infection with lymphocytic choriomeningitis virus (LCMV) at 1 week after reconstitution with bone marrow causes a profound and persistent drop in the total number of thymocytes. The decline is equivalent for all categories of donor-derived thymocytes defined by two-color flow microfluorometric analysis for CD4 and CD8. However, there is a partial compensation by the retention of cells originating from the Thy 1.2+ host, which constitute 30-40% of the total thymocyte pool as late as 8 weeks after administration of bone marrow in the LCMV-infected chimeras. These radiation-resistant precursors give rise to CD4-8-, CD4-8+, CD4+8-, and CD4+8+ thymocytes, with the latter category being present at increased frequency. The potential skewing of the mature T cell repertoire as a consequence of persistent virus infection is discussed.

Animals↗
PubMed1989

Consequences of exposure to ionizing radiation for effector T cell function in vivo.

The adoptive transfer of actuely primed and memory virus-immune CD8+ T cells causes enhanced meningitis in both cyclophosphamide (Cy) suppressed, and unsuppressed, recipients infected with lymphocytic choriomeningitis virus (LCMV). The severity of meningitis is assessed by counting cells in cerebrospinal fluid (CSF) obtained from the cisterna magna, which allows measurement of significant inflammatory process ranging from 3 to more than 300 times the background number of cells found in mice injected with virus alone. Exposure of the donor immune population to ionizing radiation prior to transfer has shown that activated T cells from mice primed 7 or 8 days previously with virus may still promote a low level of meningitis in unsuppressed recipients following as much as 800 rads, while this effect is lost totally in Cy-suppressed mice at 600 rads. Memory T cells are more susceptible and show no evidence of in vivo effector function in either recipient population subsequent to 400 rads, a dose level which also greatly reduces the efficacy of acutely-primed T cells. The results are interpreted as indicating that heavily irradiated cells that are already fully functional show evidence of primary localization to the CNS and a limited capacity to cause pathology. Secondary localization, and events that require further proliferation of the T cells in vivo, are greatly inhibited by irradiation.

Animals↗
PubMed1988

Effects of ethanol and pantothenic acid on brain acetylcholine synthesis.

1. Measurements of brain acetylcholine (ACh) synthesis from precursor [14C]-pyruvate, pantothenic acid (PA) concentration in the brain, and blood ethanol (EtOH) concentration were made in rats treated with either ethanol (5-6 g kg-1 body wt daily) alone or ethanol with PA supplementation (100-200 mg kg-1 body wt daily). EtOH with or without PA was administered orally by either Lieber-Decarli liquid diet for 4 weeks and 4 months or by oral intubation for 1 and 4 days. Matched controls were given either ethanol-free liquid diet or saline. 2. ACh synthesis in the brain of rats treated with ethanol alone for 4 months was significantly (P less than 0.01) inhibited. PA concentration of the brain was diminished to 7.0% of the control value. 3. PA concentration in the brain of rats treated with ethanol plus PA for 4 months was three times that of rats treated with ethanol alone. ACh synthesis in rats with ethanol and PA supplementation was also significantly (P less than 0.01) higher. 4. There was no difference in blood EtOH concentration between rats treated with ethanol with or without PA supplement. 5. The EtOH effect on ACh synthesis and PA concentration in the brain was observed in the chronic treatments but not in the acute treatments. 6. Data suggest that chronic ethanol exposure may decrease ACh synthesis by depleting PA, a precursor for the synthesis of acetyl CoA. Acetyl CoA is an essential substrate for ACh synthesis.

Acetylcholine↗
PubMed1987

Manpower.

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Persons with Disabilities↗
PubMed1986

Spontaneous deletion formation at the aprt locus of hamster cells: the presence of short sequence homologies and dyad symmetries at deletion termini.

To examine the factors governing the generation of DNA sequence rearrangements in mammalian somatic cells, we have cloned and sequenced novel junctions produced by six spontaneous deletion mutations at the aprt locus of Chinese hamster ovary cells. Our analyses indicate that these rearrangements were produced by non-homologous recombinational events occurring between short (2-7 bp) sequence repeats at the two termini of the deletion which leave one copy of the repeat in the mutant gene. Certain tri- and tetranucleotides recur at the deletion termini, suggesting that these may possibly be a recognition sequence for an enzyme involved in the event. No other gene structural alterations were found at the novel junctions or in neighbouring sequences. The deletions are not randomly distributed over the aprt gene; four termini clustered in a 40-bp sequence. This region of aprt is unusual as it contains both significant stretches of dyad symmetry which could potentially form stable DNA secondary structures and short direct repeats. Regions of dyad symmetry were also found at at least one terminus of all the deletions. In view of the similar properties of this set of deletions, possible mechanisms for the formation of this type of gene rearrangement are considered.

Adenine Phosphoribosyltransferase↗
PubMed1985

Increased dihydrofolate reductase activity in methotrexate-resistant human promyelocytic-leukaemia (HL-60) cells. Lack of correlation between increased activity and overproduction.

Methotrexate(MTX)-resistant human promyelocytic-leukaemia cells (HL-60) derived from MTX-sensitive cells have a 20-fold increase in dihydrofolate reductase (DHFR) activity as compared with the sensitive cells. This increase is not associated with a concomitant increase in DHFR protein as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by immunological methods using mouse anti-DHFR antibody. The rate of DHFR synthesis is similar in both cell lines. Furthermore, both the sensitive and resistant cells have similar amounts of RNA hybridizing to a DHFR complementary-DNA probe, correlating well with the lack of increase in DHFR protein. DHFR-gene dosages were similar in both types of cells. We conclude that the 20-fold increase in DHFR activity present in these MTX-resistant cells is not due to the overproduction of DHFR but due to the expression of a more active form of the enzyme.

Cell Line↗
PubMed1985

Heterogeneity in the specific activity and methotrexate sensitivity of dihydrofolate reductase from blast cells of acute myelogenous leukemia patients.

Dihydrofolate reductase activity was found to be highly heterogeneous in terms of its specific activity and methotrexate sensitivity in the blast cells of patients with acute myelogenous leukemia. None of the patients had previously been treated with methotrexate (MTX). The blast cells of four of 12 patients studied contained methotrexate-insensitive forms of dihydrofolate reductase, and the blast cells of three (distinct from the four mentioned previously) of the 12 had significantly higher dihydrofolate reductase activities than the rest. The presence of MTX-insensitive dihydrofolate reductases and high levels of enzyme activity represent intrinsic mechanisms of resistance and may explain the apparent clinical resistance of acute myelogenous leukemia to methotrexate.

Cells, Cultured↗