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Biomedical subjects

R A Streuli

Publications and source records attributed to R A Streuli.

At least 37 records · Page 2Linked to original sources
PubMed1985

Central nervous system involvement in hairy cell leukemia.

A patient with central nervous system involvement by hairy cell leukemia is reported. Hairy cells were identified in the cerebrospinal fluid by electron microscopy and by tartrate-resistant acid phosphatase positive staining. Intrathecal treatment with methotrexate resulted in neurologic improvement, but was complicated by Cryptococcus neoformans meningitis. The leukemic phase of the disease was later successfully controlled by treatment with alpha interferon. Surface marker studies indicated a B- and T-cell phenotype of the hairy cells.

Brain Neoplasms↗
PubMed1985

Megakaryocytopoiesis in different forms of thrombocytosis and thrombocytopenia: identification of megakaryocyte precursors by immunostaining of intracytoplasmic factor-VIII-related antigen.

Megakaryocytopoiesis was investigated with a polyclonal (26 cases) and a monoclonal (20 cases) antibody to factor-VIII-related antigen (factor VIII RAg) with the indirect peroxidase-antiperoxidase (PAP) method on air-dried bone marrow aspirates (BM). Numerous megakaryocyte precursors were identified in 5 patients with essential thrombocythemia (ET) and the 2 patients with acute myelogeneous leukaemia (AML) after recovery from therapeutic aplasia. Small megakaryocyte precursors were rare in controls (C), patients with reactive thrombocytosis (RT) and immune thrombocytopenia (IT). In 2 patients with severe alcoholism the number of mature megakaryocytes increased after 5 and 7 days of abstinence, respectively.

Antibodies, Monoclonal↗
PubMed1984

Influence of oxygenated sterol compounds on phase transitions in model membranes. A study by differential scanning calorimetry.

A marked influence of oxygenated sterol compounds (OSC: 7 alpha-, 7 beta-, and 25-hydroxycholesterol and 7-ketocholestanol) on the reversible gel to liquid-crystalline phase transition behavior of cholesterol-free and cholesterol-containing model membranes is evidenced by high-sensitivity differential scanning calorimetry. Liposomes of dipalmitoylphosphatidylcholine (DPPC) were chosen as model membranes. Each of the investigated OSC exerts an individual influence on the phase transition of DPPC liposomes, which expresses itself in the temperature range, the corresponding enthalpy, and the peak shape of calorimetric curves. The onset temperature of the phase transition is lowered in the following range of effectiveness: 7 beta-hydroxycholesterol greater than 7 alpha-hydroxycholesterol greater than 7-ketocholestanol greater than cholesterol. The mutual presence of cholesterol and of OSC leads to the following order: 7 alpha-hydroxycholesterol approximately equal to 7 beta-hydroxycholesterol greater than 7-ketocholestanol greater than cholesterol (without OSC) greater than 25-hydroxycholesterol. The enthalpy of the phase transition is decreased with increasing content of cholesterol, 7 alpha- or 7 beta-hydroxycholesterol, or 7-ketocholestanol. At a concentration of about 10 mol % of the latter three OSC, the corresponding enthalpy value of the transition is lowered from 9.1 kcal/mol for pure DPPC to about 7.5 kcal/mol, whereas 10 mol % cholesterol lowers the enthalpy value to 7.0 kcal/mol.(ABSTRACT TRUNCATED AT 250 WORDS)

Calorimetry, Differential Scanning↗
PubMed1981

[The current state of curability of Hodgkin's disease].

The introduction of the chemotherapy regimen MOPP in 1964 led to a breakthrough in the treatment of disseminated Hodgkin's disease. 80% of previously untreated patients achieve complete remission which in the majority of cases is durable. However, in view of prolonged survival in an increasing number of patients, more secondary malignancies (acute myelogenous leukemia and non-Hodgkin's lymphoma) are observed. The problem of how to treat patients who fail to respond to MOPP is still unsolved. Alternating use of two chemotherapy regimens and additional radiotherapy may further diminish the incidence of relapses in patients who have achieved complete remission. Stage II Hodgkin's disease probably should be divided into two substages requiring different treatment.

Chromosome Aberrations↗
PubMed1981

Serum lipoproteins modulate oxygenated sterol insertion into human red cell membranes.

The insertion of oxygenated sterol compounds into human red blood cell membranes as well as the consequent transformation of the red cells to an echinocyte shape and the expansion of the membranes are impeded by the presence of serum lipoproteins in the incubation medium. All density classes of human serum lipoproteins bind oxygenated sterol compounds, and lipoproteins can act as acceptors of oxygenated sterols previously inserted into red cells. Since oxygenated sterols have been reported to be atherogenic, the modulating and possibly protective effects of serum lipoproteins on oxygenated sterol-induced derangement of cell membrane structure and function may provide a useful model for further study.

Cholesterol↗
PubMed1981

Lymphoblastic lymphoma in adults.

Clinical and cytogenetic studied were done on 12 patients with lymphoblastic lymphoma. The ages of the patients ranged from 17 to 58 years (median, 24.5 years). Males predominated by a ration of 5:1. Ten of the 12 patients had a mediastinal mass at diagnosis; two thirds of the patients had involvement of the bone marrow (3 of 12 patients initially were in a leukemic phase), and 5 of 12 patients had involvement of the central nervous system (CNS) with lymphoma. In all patients, the malignant cells were characterized by nuclear convolutions. Cytogenetic studies done on four patients showed clonal chromosome abnormalities in two cases. Six of the 12 patients were treated with the combination chemotherapy regimen COPA and received CNS prophylaxis; their survival was slightly longer than that of the other patients, who were treated with a variety of treatment regimens. Two of the 12 patients achieved a complete remission. The median survival of all patients was 11.5 months but was shorter in patients with initial CNS involvement or leukemia. The poor results achieved thus far in the treatment of this disease demand a new therapeutic approach.

Adolescent↗
PubMed1981

Diminished osmotic fragility of human erythrocytes following the membrane insertion of oxygenated sterol compounds.

Oxygenated sterol compounds (OSC), when incubated for 1 hr with human erythrocytes in lipoprotein-depleted medium at concentrations of 0.625-5 X 10(-5) M, are inserted into the cell membrane and remain there despite subsequent washing of the cells. The insertion results in expansion of the surface area of the red cell ghost membrane, an increase in critical hemolytic volume, and as a consequence, in diminished osmotic fragility of the erythrocytes. This effect is seen with echinocyte-forming as well as with non-echinocyte-forming OSC. Erythrocytes treated with OSC do not differ from control cells with respect to their mean cell volume (MCV) in isotonic solution, water content, ion fluxes, and filterability through polycarbonate filters. The shift of the osmotic fragility curve toward lower NaCl concentrations is proportional to the amount of OSC inserted into the red cell membrane. 7 beta-Hydroxycholesterol, 22-ketocholesterol, and 20 alpha-hydroxycholesterol are the most potent inhibitors of osmotic lysis. The effect of OSC on osmotic fragility is diminished if the erythrocytes are incubated in a lipoprotein-containing medium; free cholesterol, however, does not change this effect. Various progesterones also protect red cell from osmotic lysis, but only if the erythrocytes are directly exposed to the compounds present in the hypotonic NaCl solutions used for measurement of their osmotic fragility. Progesterones do not remain in the membrane after the cells have been washed. The OSC are also capable of correcting the osmotic fragility curve of red cells from patients with hereditary spherocytosis. These experiments may suggest an approach to the pharmacologic treatment of hereditary spherocytosis.

Cell Membrane↗