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Biomedical subjects

J Laszlo

Publications and source records attributed to J Laszlo.

At least 73 records · Page 4Linked to original sources
PubMed1982

Treatment of anemia in myeloproliferative disorders: a randomized study of fluoxymesterone v transfusions only.

Previously untreated patients who had anemia (hemoglobin level, less than or equal to 10 g/dL) caused by myelofibrosis (MF) (16 patients) or other myeloproliferative disorders (13 patients) were given the opportunity to participate in a prospective randomized study-to be treated either with 30 mg/day of oral fluoxymesterone and necessary transfusions or by transfusions alone. Of the 24 patients whose data could be evaluated, four (29%) of 14 responded well to fluoxymesterone therapy (hemoglobin level rise, of greater than 2 to greater than 10 g/dL and relief of symptoms of anemia), whereas, in the transfusion arm, there were no good "responders"; one of ten patients was a partial "remitter" (responder), with a rise in the hemoglobin level of 1 to 2 g/dL. All responders to fluoxymesterone therapy showed a 50% or more maximum uptake of injected ferrous citrate Fe 59 into RBC hemoglobin, whereas no nonresponder met this criterion. All responders had MF (marrow more than one third replaced by collagen). There was no significant difference in survival of patients in the two arms of the study.

Aged↗
PubMed1982

Metabolic inhibition by a new antifolate, 2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methyl-pyrido[2,3-d]pyrimidine (BW3O1U), an effective inhibitor of human lymphoid and dihydrofolate reductase-overproducing mouse cell lines.

The human lymphoblastoid cell line, WIL-2, and a mouse cell line, 3T6R400, that overproduces a mutant dihydrofolate reductase (DHFR) having greater than 100-fold increased resistance to methotrexate (MTX) inhibition, were used to compare the inhibitory properties of a novel lipid-soluble antifolate, 2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methyl-pyrido[2,3-d]pyrimidine (BW301U), with the 2,4-arylpyrimidine, 2,4-diamino-5-(3,4'-dichlorophenyl)-6-methylpyrimidine (DDMP) and with MTX. These studies demonstrated that, like DDMP, BW301U rapidly entered cells and inhibited the incorporation of dUrd into DNA. Drug association with cells was temperature-independent and apparently did not require active transport. BW301U inhibited cell growth by 50% at 0.025 microM, whereas MTX caused equivalent inhibition at 0.045 microM. Inhibition of DNA synthesis produced by 90 min of exposure to BW301U was completely reversed within 2 hr after washing cells and suspending them in drug-free medium. In contrast, inhibition of DNA synthesis in MTX-treated cells was not reversed by simply removing the antifolate, but required the addition of calcium leukovorin or thymidine to the drug-free medium in order to facilitate complete reversal of DNA synthesis. Finally, like DDMP, BW301U was approximately 1000 times more effective than MTX in inhibiting dUrd incorporation into the DNA of a DHFR gene-amplified cell line of mouse 3T6 cells.

Animals↗
PubMed1981

Increased incidence of acute leukemia in polycythemia vera associated with chlorambucil therapy.

In studies to determine the optimal treatment for polycythemia vera, 431 previously untreated patients whose disease met established diagnostic criteria were entered into a prospective, randomized controlled trial between 1967 and 1974. Three treatment regimens were used: phlebotomy alone, chlorambucil supplemented by phlebotomy, or radioactive phosphorus supplemented by phlebotomy. Despite minor differences in age and sex, the three groups were comparable in initial hematocrit, white-cell and platelet counts, and disease-related symptoms. The median duration of follow-up is now more than 6 1/2 years. As of February 15, 1980, there were no statistically significant differences in survival among the groups. However, the risk of acute leukemia in patients given chlorambucil was 2.3 times that in patients given radioactive phosphorus and 13 times that in patients treated with phlebotomy alone. The increased incidence of leukemia during chlorambucil treatment is statistically significant (P less than or equal to 0.002); accordingly, the Polycythemia Vera Study Group has discontinued the use of chlorambucil in the treatment of polycythemia vera.

Acute Disease↗
PubMed1981

Medusa cells: cytostructure and cytochemistry of amoeboid eosinophils with pseudopod-like processes.

Eosinophils having one or more pseudopod-like processes of various lengths are observed in bone marrow, peripheral blood, sputum, nasal smears, and in other exfoliative cytology and tissue specimens after fixation and staining for histochemical study; they are called medusa cells. Although the conformations and lengths of the processes vary, they resemble protozoal pseudopodia. The form which first called our attention to these cells is a conical determinate projection that tapers to a fine tip, much like a protozoal axopod. A basal specialization in the form of a vesicle or thickening may be frequently observed where the process protrudes from, or appears attached to, the cell body. The processes of these eosinophil variants appear morphologically specialized to interact with other cellular elements of the blood and are occasionally seen in contact with, or engulfing, erythrocytes, platelets or other leukocytes. Two hydroperoxidases have been elucidated in eosinophils and medusa cells by virtue of different substrate specificities, subcellular localizations and inhibitor sensitivities. One of these hydroperoxidases is shown by 3,3'-diaminobenzidine, is cyanide resistant, and is never observed in granules or rods in the medusa cell processes; it is frequently polarized to the sites of contact of medusa cells with other cellular elements of the blood. The other hydroperoxidase is revealed by p-phenylenediamine-pyrocatechol, is sensitive to cyanide and is frequently observed in granules and rods in medusa cell processes as well as in a population of larger granules in the cell bodies; the granules in the processes appear to be precursors to the rods, which may be related to Charcot-Leyden crystals. The extrusion of medusa cell processes is facilitated by the divalent cations calcium and magnesium and is inhibited by anions which sequester them such as phosphate, EDTA, citrate and oxalate. Medusa cells have been observed in samples from both rodents and humans and can be very prominent when eosinophilia accompanies allergy, parasitosis and malignancy.

Asthma↗
PubMed1981

Treatment of small cell carcinoma of the lung with methotrexate, doxorubicin, cyclophosphamide, and lomustine: a community-based study.

Forty-four patients with undifferentiated small cell carcinoma of the lung (SCCL) were diagnosed and treated at community hospitals. Patients with limited disease were treated with surgical resection or primary radiation therapy (RT) followed by chemotherapy; those with extensive disease received chemotherapy followed by RT if there was not a complete primary response. The chemotherapy used was a combination of methotrexate, doxorubicin, cyclophosphamide, and lomustine. Median survival for patients with both limited and extensive disease was 12 months, with a six-month survival of 89%. Half of the patients had recurrence in the lung. The toxicity was moderate and tolerable. We conclude that this combination chemotherapy plus radiation therapy carries acceptable toxicity and can be used in a community hospital to achieve response rates and survival of SCCL equivalent to that obtained in large cancer centers.

Adult↗
PubMed1981

Human plasma and amino acids as moderators of uptake and metabolic consequences of antifolates in WIL-2 and human leukemia cells.

Plasma and medium composition significantly affect cellular association of the lipid-soluble antifolate 2,4-diamino-5-(3',4'-dichlorophenyl)-6-methylpyrimidine (DDMP). This was demonstrated by measuring association of labeled drug with cells and by assaying the antimetabolic effect of DDMP on incorporation of deoxyuridine into DNA. Uptake of both aqueous and lipid-soluble antifolates was substantially reduced in the human lymphoblastoid cell line WIL-2 when Eagle's minimum essential medium (EMEM) was substituted for a basal salts solution containing glucose [DDMP approximatley 50%, methotrexate (MTX) approximately 30%]. Uptake of DDMP, however, was inhibited by the amino acid fraction of EMEM or glutamine alone, whereas MTX uptake was unaffected by amino acids. Further studies with human leukemia cells showed that DDMP was only about 25% as effective an inhibitor of deoxyuridine incorporation in autologous human plasma when compared to its inhibitory effect in RPMI-1640 medium MTX inhibition of deoxyuridine incorporation in these cells was essentially unaffected by substitution of autologous human plasma for RPMI-1640 medium. Replacing EMEM with pooled human plasma resulted in a 60-70% decrease in DDMP uptake but had only a marginal effect upon MTX uptake. Thus the choice of medium is important in studies of lipid-soluble antifolates such as DDMP that have a high affinity for cellular and medium lipoprotein components.

Amino Acids↗
PubMed1981

U.S. centralized cancer patient data system for uniform communication among cancer centers.

The evolution of the Centralized Cancer Patient Data System, a cooperative venture of the 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that ae 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that ae 21 comprehensive cancer centers in the United States, and its structure at the end of 3 years of data collection are described. Functions of the data system are detailed in terms of input and output. It is concluded that the short-run objective of establishing a data system to provide high-quality patient data that are comparable among cancer centers has been largely accomplished. Moreover, the very process of setting up the national data system has benefited the participating centers by upgrading their individual cancer registries. For the future, the goal is to realize the research potential of this new cooperative data collection mechanism, as well as the accumulating data themselves. Progress toward the long-term goal is just beginning.

Cancer Care Facilities↗
PubMed1980

delta 9-Tetrahydrocannabinol for refractory vomiting induced by cancer chemotherapy.

Fifty-three patients receiving antineoplastic chemotherapy who had experienced severe nausea and vomiting refractory to standard antiemetic agents were treated with delta 9-tetrahydrocannabinol (THC). These patients were given THC 8 to 12 hours before, during, and for 24 hours after chemotherapy. Ten patients (19%) had no further nausea and vomiting; 28 (53%) had at least a 50% reduction of nausea and vomiting compared to previous courses with the same agents. No appreciable reduction of nausea and vomiting was seen in 15 patients (28%). Toxic reactions were generally mild, with only four patients experiencing reactions that necessitated stopping THC therapy. We suggest that, since THC is a useful antimetic agent in patients having refractory chemotherapy-induced vomiting, existing restrictions prohibiting its therapeutic use should promptly be eased.

Adult↗
PubMed1980

Some electrophysiological and pharmacological properties of the cortical, noradrenergic projection of the locus coeruleus in the rat.

The effect of repetitive stimulation of the locus coeruleus (LC) on the discharge rate of spontaneously active neurons of the visual, rostral and cingulate cortex was investigated in untreated and catecholamine-depleted rats under chloral hydrate anesthesia. In untreated animals, the inhibitory transsynaptic effects predominated over the excitatory ones. In catecholamine-depleted rats, the percentage of inhibited cells was significantly reducted in all areas. The vast majority of spontaneously active neurons in all cortical regions was depressed by microiontophoretically applied noradrenaline (NA). A few cells were resistant to NA; no excitatory effects were noticed on any cell. The transsynaptically mediated depression of the discharge rate of cells in all three cortical areas was reversibly antagonized by the iontophoretically administered beta-receptor blocking drug practolol. On the contrary the a-receptor blocking drugs piperoxane and WB4101 were ineffective in this respect. Thus, we tentatively conclude from these data that the NA-elicited depression of cells in the cortex is mediated by a receptor of the beta-type. Repetitive stimulation of the reticular formation elicited a desynchronizing effect on the EEG of chloral hydrate anaesthetized rats. LC stimulation, in contrast, hardly produced any modification of the EEG as judged by visual examination of the recordings.

Adrenergic alpha-Antagonists↗
PubMed1979

Prognostic factors in metastatic and hormonally unresponsive carcinoma of the prostate.

Eighty-eight patients with hormone-resistant Stage IV prostate cancer were treated with a five-drug chemotherapy program. Patient demographic data, prior therapy, symptoms, extent of disease, and laboratory studies were analyzed statistically to evaluate the association of these parameters with survival from the onset of chemotherapy. Factors associated with short survival included age greater than 65, severe bone pain, poor performance status, presence of soft tissue metastases, anemia, elevation of serum LDH, SGOT, alkaline and acid phosphatases, and prolactin, and hypoalbuminemia. Race, stage at initial diagnosis, prior radiation therapy, prior orchiectomy, and elevation of CEA had no prognostic association. We suggest that clinical trials of new therapies of hormone-resistant prostate cancer take into account the presence of these prognostic factors in the analysis of the results of therapeutic programs.

Aged↗