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Biomedical subjects

P Reizenstein

Publications and source records attributed to P Reizenstein.

At least 73 records · Page 4Linked to original sources

The quality of care of the elderly.

During this century, the number of people over 65 years of age increased 4-fold, and that of 85 year olds, 7-fold in England. In Sweden, 80% of those over 85 live alone, and those over 65 use 60% of the health care resources. One hospital bed is required for 28 nonagenarians, of whom 20% live in institutions in America and 50% in Sweden. Of institutional residents, 90% need help dressing, bathing, and/or moving, and 69% have difficulty seeing. Of octagenarians, 20% are senile, and every fourth woman over 65 has suffered fractures caused by osteopenia, the incidence of which increases by 6% per year. The Swedish staff of nurses aids employed for the care of the elderly was 95,000 in 1984 and 123,000 in 1988. An increase of between 40,000 and 70,000 is going to be needed in the future. In addition, the annual staff turnover of 25% has to be replaced, and replacements have to be found for the annual sick absenteeism of 45 days per employee. The cost for absenteeism and turnover in this category of staff alone amounts to 3% of the total Swedish health care budget. Even though the present quality of the care for the elderly is frequently considered unsatisfactory in Sweden, both in institutions and at home, the task to improve or even only to maintain this quality is monumental.

Aged↗

Accumulation of vincristine and doxorubicin in malignant lymphocytes with different immunophenotypes.

Cellular accumulation of vincristine (VCR) and doxorubicin (DOX) was studied in 15 patients with low-grade B-cell malignancies. Their leukemic lymphocytes were isolated and the effect of verapamil on drug uptake was studied. The immunophenotype was characterized using anti-IgM, -IgD, -B 1, monoclonal antibodies. The more that cells bound the IgD or B1 antibodies, the more vincristine and doxorubicin did they accumulate. The fewer the cells that bound IgM antibodies, the more drug did they accumulate.

Aged↗

[Acute myelocytic leukemia in 1989].

A number of haematologists who were mustered as a "leukemia task force" recently attempted to summarise the current situation of acute myeloid haematology. This article comprises a résumé.

Humans↗

D-verapamil and L-verapamil are equally effective in increasing vincristine accumulation in leukemic cells in vitro.

Leukemic cells isolated from peripheral blood from 6 patients with chronic lymphocytic leukemia, immunocytoma and prolymphocytic leukemia were incubated with vincristine (10 nM) with and without racemic verapamil and its L- and D-isomers (6.6 microM). Verapamil increased vincristine accumulation in all cells, the increase varying between 100 and 700%. Racemic verapamil and the L- and D-isomer increased cellular vincristine accumulation to the same extent. The verapamil effect could not be reversed by increasing the calcium concentration in the incubation medium (final concentration 2.5-5.0 mM). The results indicate that the mechanism behind the effect of verapamil on cellular accumulation of vincristine does not depend upon changes in calcium transport.

Calcium↗

Decreased blood natural killer cell activity and immunoglobulin synthesis in vitro in aplastic anemia.

Natural killer (NK) cell numbers and T lymphocyte subpopulations in peripheral blood were evaluated in six patients with aplastic anemia (AA). The immunophenotyping results were correlated to in vitro tests of NK cell cytotoxicity against K562 cells and of immunoglobulin (Ig) production after pokeweed mitogen (PWM) stimulation. A significant decrease was found both in the percentage of Leu 11 positive cells and in NK cell activity as compared to age- and sex-matched healthy controls. The decrease in NK cell activity could not be entirely compensated by an increase in effector/target cell ratios, thus suggesting not only a quantitative but also a functional defect in NK cells of the AA patients. Three of four AA patients tested showed no major increase of Ig production after PWM stimulation. All these three patients also had fewer "functional T helper" cells (Leu3+/Leu8-) and increased numbers of T suppressor/cytotoxic cells (Leu2+) when compared to controls. No significant differences in numbers of B lymphocytes (B1+) could be found. Our findings suggest a possible linkage between quantitative and qualitative abnormalities in lymphocyte subsets in aplastic anemia. However, no evidence was found to support the hypothesis of increased NK cell activation behind the hemopoietic depression in this disease.

Adolescent↗

Resistance of some leukemic blasts to lysis by lymphokine activated killer (LAK) cells.

Peripheral blood mononuclear cells (PBMC) from healthy donors and AML patients in remission were stimulated with phytohemagglutinin (PHA) and recombinant interleukin-2 (IL-2). These stimulated cells (lymphokine activated killer (LAK) cells) showed increased DNA synthesis as measured by 3H-Thymidine uptake. A synergistic effect of PHA and IL-2 was found. LAK cells' ability to kill acute myeloid leukemia (AML) blasts was investigated by the 51Cr release assay. LAK cells showed a cytotoxicity (over 10% specific 51Cr release) against 9/12 leukemic blasts, even at effector/target (E/T) ratios as low as 5:1. However, on average only 22.2% (SD 11.8) and 36.5% (SD 12.5) 51Cr release were obtained in 4- and 18-hour cytotoxicity assays, respectively, at an E/T ratio of 20:1. Leukemic blasts in 3/12 AML cases and normal PBMC were entirely resistant to lysis, even at an E/T ratio of 80:1. Susceptibility to lysis was not correlated to peanut-agglutinin receptor expression. LAK cells were more cytotoxic towards the K-562 cell line (natural killer activity) than unstimulated PBMC.

Cell Line↗

The effect of a calf thymus acid lysate on bone marrow cell growth in vitro.

Granulocyte-macrophage colony forming units (CFU-GM) were studied in cultures of bone marrow from 16 apparently healthy normal controls, 9 patients with the myelodysplastic syndrome, 5 patients with myeloproliferative disease and 2 with myeloma. Supernatants from non-stimulated 72 hr cultures of nonadherent mononuclear blood cells ("lymphocytes") stimulated the forming of an average of 38.4 colonies per 100,000 cells from normal marrow. The addition of GIBCO's commercial conditioned medium or of a medium produced by lymphocytes stimulated with different concentrations (5, 10 and 20 mcg/ml) of an acid lysate of thymus (thymomoduline), increased growth to 65.2 - 55.4 colonies (p less than 0.001 to 0.05). Similarly, a significant increase (p less than 0.05) was found in the number of clusters and colonies formed in cultures of marrow from patients with the myelodysplastic syndrome. In contrast, no growth was found when the thymus acid lysate was added directly to the bone marrow cultures, suggesting that the lysate induces the production of colony stimulating activity by lymphocytes, but does not contain it. Similarly no significant increase was found as regards the initially high number of colonies from the five patients with myeloproliferative disease, or as regards the initially low number in the two myeloma patients.

Adult↗

Increased leukotriene C4 production in chronic myelogenous leukemia.

The production of leukotrienes (LT) in peripheral blood leukocyte preparations from 9 patients with chronic myelogenous leukemia (CML) and 9 healthy controls was studied. Leukotriene generation was stimulated by the calcium ionophore A 23187 (1 mumol). Lipoxygenase products were separated and identified using a high performance liquid chromatography (HPLC) technique and computerized spectrophotometry. Leukotriene C4 (LTC4) was formed in significantly larger amounts by cells from the CML patients than cells from the controls; 14.4 +/- 4.3 pmol per 10(6) nucleated cells (mean +/- SE) and 4.0 +/- 1.2 pmol respectively (p less than 0.05). Seven of the 9 patients but none of the controls synthesized equal or higher amounts of LTC4 than LTB4. A highly significant difference in mean values of LTC4/(LTB4 + 20-OH-LTB4) ratios was observed; CML 0.69 +/- 0.08 versus controls 0.12 +/- 0.02, p less than 0.001. These findings suggest an increased LTC4 synthase activity in CML cells. In earlier studies we have found a decreased 12-lipoxygenase activity in CML bone marrow cells.

Calcimycin↗

Effect of phytohemagglutinin and interleukin-2 on malignant and nonmalignant B and T lymphocytes.

Peripheral blood mononuclear cells (PBMC) from patients with acute myeloid leukemia (AML) or non-Hodgkin lymphoma (NHL) and healthy controls were stimulated with phytohemagglutinin (PHA) and interleukin-2 (IL-2). PHA (1 microgram/ml) induced higher 3H-thymidine incorporation than 800 U/ml IL-2 in PBMC from both controls and patients with AML in complete remission. A synergistic effect between PHA and IL-2 was found. Malignant B cells from 5/12 NHL expressed IL-2 receptors and showed proliferative response to IL-2, but not to PHA. PHA induced higher cytotoxicity toward AML blasts in lymphocytes from healthy controls than did IL-2. In addition, PHA induced higher cytotoxicity in lymphocytes from healthy controls than in those from patients with AML in remission. In contrast, no difference in cytotoxicity between controls' and patients' lymphocytes was found after stimulation with IL-2. No HLA restriction could be demonstrated. Normal peripheral blood mononuclear cells and leukemic blasts from 2/12 AML were completely resistant to cytotoxic cells even at effector:target ratios four times as high as those otherwise required.

B-Lymphocytes↗