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Biomedical subjects

J C Marsh

Publications and source records attributed to J C Marsh.

At least 109 records · Page 6Linked to original sources
PubMed1987

Phase I studies with trimetrexate: clinical pharmacology, analytical methodology, and pharmacokinetics.

Twenty-two patients with advanced solid tumors were treated with a quinazoline folate antagonist, trimetrexate, to determine the toxicity spectrum, the maximal tolerated dose, and the pharmacokinetics of the drug. Negligible toxicity was seen with single doses of 10-70 mg/m2 given as a 1-h infusion. Single doses of 120 mg/m2 infused over 1 h caused moderate to grade 4 toxicity in five of nine patients treated. Two patients who had no toxicity at this level were escalated to a dose of 213 mg/m2 with mild to moderate toxicity. The primary dose-limiting toxicity was myelosuppression. Moderate transaminase elevations, rash, anorexia, nausea and vomiting, and mucositis were occasionally seen. Although there was variation in dose tolerance to this drug, with selected patients able to tolerate higher doses, we consider 120 mg/m2 every 2 weeks to be the maximal tolerated dose, and the recommended Phase II starting dose. Trimetrexate plasma concentration-time curves were best described as biphasic (N = 9) or triphasic (N = 5) in form. The half-life of the terminal elimination-phase was 16.4 h. The mean residence time was 17.8 h. The volume of distribution of the plasma compartment and the volume of distribution at steady-state were 0.17 and 0.62 liter/kg, respectively. Plasma clearance was 53 ml/min. Plasma concentrations as determined by dihydrofolate reductase enzyme inhibition assay and high-performance liquid chromatography were initially identical, but diverged at later times. Divergences were seen also in urinary recovery as determined by the two methods. Both results suggest the appearance of metabolite(s) of trimetrexate which can inhibit dihydrofolate reductase. Measurable objective solid tumor responses were not seen in this Phase I study, although three patients with colon cancer had stable disease lasting 18, 26, and 26 weeks, respectively.

Chromatography, High Pressure Liquid↗
PubMed1987

Sickle cell disease in North London.

We have examined our experience of sickle cell disease in the London Borough of Haringey over the past 20 years. There are currently (1986) 145 patients on the Haringey Sickle Cell Register and when comparison is made with other centres, admission for painful crises in Hb SS disease is more frequent than in Jamaica, but the acute chest syndrome appears to be less common in the United Kingdom than in Jamaica. Splenomegaly is less frequent in Hb SC patients in this country and there is also a lower incidence of leg ulceration in both Hb SS and Hb SC disease in the United Kingdom than in Jamaica. The incidence of alloimmunization among transfused sickle cell disease individuals in Haringey is 21%, the most frequently encountered antibodies being anti-E and anti-Kell. All pregnant patients with sickle cell disease were managed with regular blood transfusion throughout pregnancy starting at 12 weeks of gestation. There were no fetal or maternal mortalities, although three babies born were 'small for dates' despite uneventful antenatal courses and adequate Hb A levels being achieved in the mother. Examination of the effect of seasonal variation on the incidence of hospital admissions for painful crises reveals no significant clustering of cases in a particular month or season of the year.

Adolescent↗
PubMed1987

Blood volume measurement in pseudopolycythaemia--when and why?

Upper reference limits for packed cell volume (PCV) for a hospital population were established by analysis of 14,000 consecutive blood count profiles. These were 0.50 for men and 0.45 for women. In 86 patients, pseudopolycythaemia was identified by an increased PCV with red cell mass (RCM) less than 125% of predicted normal. We have proposed a modified classification of pseudopolycythaemia and identified three subsets on the basis of RCM and plasma volume (PV) values. Although all patients had raised PCV at the time of referral, by the time of blood volume study a lower PCV value was noted in a proportion of patients. Patients with a low PV (less than 80% predicted normal, Group 1) and those with a 'high normal red cell mass' (RCM 113-125% predicted normal, Group 2) had higher and more persistently elevated PCV values on repeated measurement, compared with the patients in Group 3 ('transient pseudopolycythaemia'). These latter patients have a normal RCM and PV, and although initially fulfilling the criteria for pseudopolycythaemia on the basis of a raised PCV and normal RCM, a high proportion subsequently showed fluctuation in PCV which often fell below the upper reference limit. It is important to diagnose pseudopolycythaemia because of the associated increase in morbidity and mortality, and our observations suggest that whereas a blood volume study is essential to diagnose pseudopolycythaemia reliably, this investigation need only be performed when a patient shows a persistently increased PCV on repeated measurement.

Adult↗
PubMed1987

Primary proliferative polycythaemia without splenomegaly: a diagnostic problem.

We report three cases of polycythaemia with no evidence of clinical splenomegaly and normal splenic red cell pool on isotope spleen scan. In each case, however, a diagnosis of primary proliferative polycythaemia (PPP) was suggested by in-vitro erythropoietin-independent growth of peripheral blood erythroid colonies. In one of these cases two possible causes of secondary polycythaemia were also identified. The use of investigations such as isotope spleen scanning and erythroid cell culture in helping to establish a diagnosis of PPP is discussed.

Aged↗
PubMed1987

Temperature and pH govern the self-assembly of microtubules from unfertilized sea-urchin egg extracts.

A new method for microtubule purification from unfertilized sea-urchin eggs was developed in order to obtain large quantities of calcium- and cold-labile microtubules that contained microtubule-associated components important for mitosis. By taking into consideration the pH, ionic composition of egg cytoplasm, and the physiological temperature for growth of the Pacific coast sea-urchin Strongylocentrotus purpuratus, methods were developed for the assembly of intact microtubules directly from unfertilized egg extracts. The microtubules obtained by cycles of temperature-dependent assembly and disassembly are composed of tubulin and abundant microtubule-associated proteins. These microtubules are cold- and calcium-labile and assemble at a critical protein concentration of 0.11 mg ml-1 at 24 degrees C. The yield of microtubule protein obtained by this new method is equivalent to that obtained with taxol (6-8 mg/20 ml packed eggs). Microtubules that have been fixed and prepared for electron microscopy are decorated with large, globular projections that are attached to the microtubule by thin stalks.

Actins↗
PubMed1987

Survival after antilymphocyte globulin therapy for aplastic anemia depends on disease severity.

Sixty-four patients with aplastic anemia were treated with antilymphocyte globulin (ALG Merieux) between 1980 and 1985. The actuarial survival for all patients was 53% at 6 years, with 79% survival for nonsevere aplastic anemia (NSAA) and 36% for severe aplastic anemia (SAA). The neutrophil and platelet counts before treatment with ALG were highly predictive of survival, whereas sex, age, and etiology were not. Duration of disease prior to ALG treatment was inversely related to survival, although this was not statistically significant. Survival was closely associated with response to ALG, especially for patients with SAA. The response to one course of ALG was 33%. Eighteen patients who did not respond to an initial course of ALG received a second course; of these, four (22%) responded. The overall response to one or two courses of ALG was 40%. The mean RBC volume (MCV) measured after ALG treatment was a useful early indicator of response. Both the minimum lymphocyte count during ALG therapy and the mean lymphocyte count after therapy, however, were not significantly different between responders and nonresponders. The disappointing survival of patients with SAA in this study may reflect the poor clinical condition of severely affected patients referred to us and/or the presence of longstanding aplasia. The importance of studying a large series of patients with long-term follow-up to assess ALG in the treatment of aplastic anemia is shown by this investigation.

Adolescent↗
PubMed1986

Chromosome and cell culture studies in eosinophilic leukaemia.

A cytogenetic analysis was carried out on bone marrow cells from 11 patients who presented with hypereosinophilia and the clinical features of the idiopathic hypereosinophilic syndrome. One of these patients was found to have trisomy 8 affecting the myeloid series, including eosinophils. In this patient, marrow eosinophils also showed asynchrony of nuclear-cytoplasmic maturation, and there were increased numbers of myeloid progenitor cells in the blood. Six months later, blast cell transformation occurred, and he died soon afterwards. These findings show that abnormalities in the karyotype of bone marrow cells and culture of blood progenitor cells may help to identity eosinophilic leukaemia among patients who present with features of the idiopathic hypereosinophilic syndrome.

Adolescent↗
PubMed1986

Cisplatin and 5-FU infusion chemotherapy in advanced, recurrent cancer of the head and neck: an Eastern Cooperative Oncology Group Pilot Study.

Thirty-four patients with advanced, recurrent head and neck cancer were treated with cisplatin (100 mg/m2 on Day 1) and continuous-infusion 5-FU (1.0 g/m2/24 hours on Days 1-5) every 3-4 weeks. All but one patient had failed prior radiation therapy or surgery; 27 had failed both. Two patients were not evaluable for response because of death within the first 2 weeks from unrelated heart disease. Among 30 patients with squamous cell carcinoma, five achieved complete response (CR) (17%) and 13 achieved partial response (PR) (43%). Durations of response for patients with a CR and PR were 10.4 and 3.1 months, respectively. Median time to disease progression for all patients was 4.5 months and median survival was 9.1 months. Median survival times for all responders and for complete responders and partial responders were 12.5, 14.2, and 10 months, respectively. One additional patient with an adenocarcinoma failed to respond, while a second with an adenoid cystic carcinoma achieved a PR for 3.4 months. Toxicity was moderate: seven patients experienced Eastern Cooperative Oncology Group grade 3 mucositis, and 11 patients had grade 3-4 hematologic toxicity. There was one treatment-related death due to nephrotoxicity. This study supports other studies that show a relatively high degree of activity of cisplatin and continuous-infusion 5-FU in advanced head and neck cancer.

Adult↗
PubMed1985

Correlation of hematologic toxicity of antineoplastic agents with their effects on bone marrow stem cells: interspecies studies using an in vivo assay.

The effects of 22 anticancer agents on bone marrow granulocyte-macrophage-committed colony-forming cells (CFC) have been studied using the agar diffusion chamber (ADC) assay, which allows in vivo metabolism of the injected drug by the chamber-bearing mouse. Dose-response curves at 18 h were obtained using mouse, dog, and human bone marrow in the chamber, and mouse marrow in situ. Comparisons between intrinsic sensitivities of CFC from different species were thus possible, as were also comparisons of the effect of different drugs on the same species. When possible, correlations were made with available in vivo clinical or toxicologic data, using the effect of a single intravenous dose on the blood granulocyte concentration. Dose-response curves were either exponential or formed a plateau, the latter reflecting phase specificity of the agent being studied. Species CFC sensitivities were highly variable between different drugs and the order was not predictable. Good correlation between rank order of drug efficacy in vivo and in the assay was observed for drugs in the same species. Drugs with little or no myelosuppressive effects in vivo were likewise inactive in the assay (e.g., spirogermanium). Prospective trials of new agents in the drug development process (toxicology and phase-I clinical trials) using the ADC assay are warranted.

Animals↗
PubMed1985

Stability of the in vivo P388 leukemia model in evaluation of antitumor activity of natural products.

The stability of the P388 mouse leukemia model over 15 years was examined. Eleven natural products and one synthetic compound (5-FU) tested repetitively under the same conditions of dose and schedule were associated with no significant change in their activity. The P388 model, used in conjunction with other in vivo and in vitro tumor models, continues to be of value in the anticancer drug screening process.

Animals↗
PubMed1984

Chemosensitivity of human tumor clonogenic cells simultaneously assayed in agar diffusion chambers and in a two-layer agar culture system.

We have compared plating efficiencies (PE) of 20 fresh and cryopreserved samples of human solid tumors, disaggregated and cloned simultaneously in a two-layer agar culture system (2LACS) and in agar diffusion chambers (ADC). A significant correlation (0.001 less than P less than 0.01, paired t test) was found between PE, confirming that the two methods reflect the same property of tumor cells: their clonogenic potential. The median PE in ADC was 1.4 and 3.3 times higher than that in the 2LACS for cryopreserved and fresh specimens, respectively. One- and two-drug doses, approximately clinically achievable concentrations, were assayed simultaneously in the ADC and in the 2LACS, respectively, on 15 tumor specimens. In this way we evaluated the effects of eight drugs, two to five for each tumor, in a static (2LACS) versus a dynamic (ADC) system. The comparison of percent survival in ADC versus that in the 2LACS at both concentrations tested showed no statistically significant rank correlation. If the data regarding cyclophosphamide and mitomycin, which produced significant cell kill in the ADC and almost none in the 2LACS, were excluded, the rank correlation was still not significant. We conclude that the widely used 2LACS is unsuitable to study cyclophosphamide and mitomycin, for which the ADC technique may be a valid alternative.

Agar↗
PubMed1983

Evaluation of some anthracycline antibiotics in an in vivo model for studying drug-induced human leukemia cell differentiation.

Human acute promyelocytic leukemia cells (HL-60) were induced to undergo terminal differentiation by treatment in vivo with marcellomycin. This was accomplished by cloning HL-60 cells in 0.3% agar in diffusion chambers, which were subsequently implanted in the peritoneal cavities of mice. These animals were given injections i.v. with anthracycline antibiotics, and the chambers were transferred to a second recipient 24 hr later. After an additional 8 days, the chambers were removed, the cloning efficiency was determined, and colonies were scored for the presence of differentiated cells based on their ability to reduce nitro blue tetrazolium (NBT). Marcellomycin produced dose-dependent decreases in cloning efficiency and increases in the number of differentiated cells present in chambers. At all dose levels of marcellomycin tested, three types of colonies were observed; these were colonies consisting entirely of undifferentiated cells and approximately equal numbers of colonies consisting of solely differentiated cells and those with mixtures of both differentiated and undifferentiated cells. An 8-fold increase in colonies containing differentiated cells (both pure and mixed) was observed after a single injection of marcellomycin (10 mg/kg), a dose which reduced cloning efficiency by 40%. At that dosage level, aclacinomycin A also induced differentiation, while doxorubicin was ineffective, a finding consistent with the effects of these anthracyclines on HL-60 cells in suspension culture. In addition to the functional changes accompanying differentiation, commitment was characterized by a limitation in proliferative potential. Thus, the average size of uniform NBT-positive colonies was approximately 16 cells, and few clones of NBT-positive cells greater than 32 cells in number were observed; this contrasted with NBT-negative clones which contained up to 100 cells. This finding suggests that HL-60 cells undergo an average of four and a maximum of five divisions upon commitment to granulocytic differentiation. The in vivo system described may be useful in further evaluation of differentiation-inducing agents for therapeutic potential after an initial in vitro screen to identify active compounds.

Aclarubicin↗
PubMed1983

Sensitivity of bone marrow hematopoietic colony-forming cells from mice, dogs, and humans to carminomycin, marcellomycin, aclacinomycin A, and N,N-dibenzyldaunorubicin and its relationship to clinical toxicity.

The sensitivity of bone marrow granulocyte-macrophage colony-forming cells to 4 anthracyclines, carminomycin, marcellomycin, aclacinomycin A, and N,N-dibenzyldaunorubicin, was studied using the agar diffusion chamber technique which allows exposure of target cells to drug metabolized by the chamber-bearing host after i.v. injection. Colony-forming cells from mice, dogs, and humans were all found to have exponential dose-response curves for the agents studied, with variation of the slopes between species and agents. Species sensitivities as determined by the assay related well to the available toxicological and clinical data for specific drugs. The rank order of sensitivity of human marrow colony-forming cells to five anthracyclines tested in this and a previous study related very closely to doses producing moderate leukopenia in Phase I and II clinical studies. A dose of 200 mg/sq m of N,N-dibenzyldaunorubicin would be expected to produce moderate leukopenia in future clinical trials. This assay may be useful in predicting human bone marrow toxicity of new agents before actual clinical trial because of the ability to study the survival of human colony-forming cells directly.

Aclarubicin↗
PubMed1983

In vivo drug sensitivity assay of clonogenic human melanoma cells and correlation with treatment outcome.

In vitro tests of tumor cell drug sensitivity have been suggested as a means of selecting more appropriate clinical strategies against human cancer and improving preclinical drug development. The lack of biotransformation in these in vitro assays precludes the meaningful assessment of several major chemotherapeutic agents, including dacarbazine and cyclophosphamide. In vivo drug exposure of tumor cells in agar diffusion chambers placed in mice offers a possible solution to problems of drug biotransformation and pharmacokinetics. We have prospectively used this system as an assay for sensitivity of clonogenic human melanoma cells. Tumor cells were tested fresh, cryopreserved, and/or cultured in vitro before or after clinical use of dacarbazine, semustine, and mitolactol in 41 patient-drug combinations in which a clinical correlation could be made. Tumor cell drug sensitivity in the assay using fresh or cryopreserved tumor cells was highly correlated with clinical response and resistance with clinical nonresponse. Cultured melanoma cells exhibited enhanced plating efficiency in comparison to both fresh and cryopreserved cells of the same tumor. Cultured cells also showed increased drug sensitivity which did not correlate with drug sensitivity of the same fresh or cryopreserved tumor or with clinical response. Tumor cell drug sensitivity assays carried out in vivo provide a possible basis for preclinical evaluation of drugs which are unsuitable for in vitro testing.

Animals↗