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Biomedical subjects

J Drago

Publications and source records attributed to J Drago.

At least 73 records · Page 4Linked to original sources
PubMed1991

The American Cancer Society National Prostate Cancer Detection Project. Findings on the detection of early prostate cancer in 2425 men.

The American Cancer Society National Prostate Cancer Detection Project (ACS-NPCDP) is a multidisciplinary, multicenter effort to assess the feasibility of early prostate cancer detection by digital rectal examination (DRE), transrectal ultrasound (TRUS), and prostate specific antigen (PSA) assay. By June 1990, 2425 men not previously suspected of having prostate cancer had been examined in ten participating clinical centers according to the project protocol. Three hundred ninety-six men (16.3%) were recommended for biopsy on the basis of TRUS or DRE. An analysis of the results of 330 completed biopsies showed 52 cancers detected by DRE and/or TRUS. Forty-four (84.6%) of the men with cancer had positive TRUS examination results compared with 33 (63.5%) with positive DRE. Five additional cancers were discovered as a result of elevated PSA levels. The overall detection rate was 2.4% and this rate varied by age. The detection rate in men 55 to 60 years of age was 1.3% and this rose to 3.3% in men older than 65 years of age. The estimated sensitivity was significantly greater for TRUS compared with DRE (77.2% versus 57.9%; P less than 0.05). The estimated specificity of DRE was greater than that of TRUS (96.3% versus 89.4%; P less than 0.01). The positive predictive value (PPV) for the tests varied as a function of patient and disease characteristics. The overall PPV was 28.0% for DRE and 15.2% for TRUS. The occurrence of elevated PSA levels significantly increased the PPV of both TRUS and DRE. The majority of cancers detected were at early stages. These preliminary data suggest the feasibility of using these techniques to promote cancer control, but additional data and follow-up are needed to assess the significance of the results.

Age Factors↗
PubMed1991

Fibroblast growth factor-mediated proliferation of central nervous system precursors depends on endogenous production of insulin-like growth factor I.

Fibroblast growth factor stimulates proliferation and subsequent differentiation of precursor cells isolated from the neuroepithelium of embryonic day 10 mice in vitro. Here we show that fibroblast growth factor-induced proliferation is dependent on the presence of insulin-like growth factors (IGFs) and that IGF-I is endogenously produced by the neuroepithelial cells. Blocking of endogenous IGF-I activity with anti-IGF-I antibodies results in complete inhibition of fibroblast growth factor-mediated proliferation and in cell death. IGF-I alone acts as a survival agent. These observations correlate with the detection of transcripts for IGF-I and basic fibroblast growth factor in freshly isolated neuroepithelium and are consistent with an autocrine action of these factors in early brain development in vivo.

Animals↗
PubMed1991

Laminin through its long arm E8 fragment promotes the proliferation and differentiation of murine neuroepithelial cells in vitro.

The epigenetic factors involved in regulating the proliferation and differentiation of cells of the developing mammalian central nervous system are largely unknown. In this study, laminin, a molecule which is present in the basal lamina from the earliest stage of neural tube formation, has been examined in vitro for its possible regulatory role in mammalian neural development. Purified populations of murine neuroepithelial (NEP) cells isolated from the 10-day embryonic telencephalon and mesencephalon respond in vitro to laminin by undergoing aggregation, proliferation, and extensive neurite elaboration. The proliferation and differentiation of NEP cells induced by the interaction with laminin were dependent upon an early cell aggregation, since precoating of wells with poly-L-ornithine, a procedure which prevented such aggregation, completely blocked these responses. The previously reported proliferative effect of acidic fibroblast growth factor (FGF) on NEP cells was found to be synergistic with that of laminin. This observation is consistent with the idea that laminin may regulate cell responses in several ways: by direct stimulation via laminin receptors; by optimal presentation of FGF molecules to neural cells; and finally by upregulation of FGF receptor numbers on responsive cells. The in vitro response of laminin is mimicked by its long arm elastase digestion fragment, E8, whereas the cross arm fragment of laminin, E1-4, had no effect. In addition, antibodies specific for epitopes on the long arm blocked the effect seen with the whole laminin molecule. Binding studies of 125I-labeled laminin and its fragment performed on freshly isolated NEP cells confirmed the specificity of the in vitro observations: whole laminin and the E8 fragment bound to the NEP cell surface whereas the E1-4 fragment did not. These studies demonstrate mechanisms by which laminin, specifically through its long arm fragment, may assert a regulatory function during development of the mammalian central nervous system.

Animals↗
PubMed1991

Basic fibroblast growth factor upregulates steady-state levels of laminin B1 and B2 chain mRNA in cultured neuroepithelial cells.

The growth of purified populations of murine neuroepithelial cells isolated from 10 day embryonic (E10) telencephalon and mesencephalon can be specifically enhanced by supplementing growth culture media with basic fibroblast growth factor (bFGF). One effect of bFGF on cultured neuroepithelial cells was to enhance the amount of laminin expressed at the protein level as detected by immunofluorescence. This was correlated with significant upregulation of steady-state levels of laminin B1 and B2 chain expression as analyzed at the mRNA level. When E12 neuroepithelial cells were split into precursor neuronal or glial subpopulations on the basis of differential expression of major histocompatibility class-1 antigens, only the glial progenitor fraction was found to be capable of detectable laminin synthesis. It is thus possible that a primary action of FGF is to increase the synthesis and release of extracellular matrix molecules from neural cells which act back in a paracrine manner to stimulate differentiation.

Animals↗
PubMed1991

A method for the isolation of purified murine neuroepithelial cells from the developing mouse brain.

The adult mammalian central nervous system develops from the pseudostratified neuroepithelium of the neural tube. In order to study, in vitro, the differentiation of the neuroepithelial cells in detail and to identify factors that may influence this process, an uncontaminated, viable population of neuroepithelial cells, that still retains full developmental potential, is required. In this paper we describe a highly efficient method, involving differential trypsinization and micro-dissection, to cleanly separate the neuroepithelium from surrounding mesenchyme and ectoderm. The purity of isolated neuroepithelium has been assessed by monitoring for the presence of endothelial cells using an anti-endothelial antibody, MTS-12, and found to contain no significant level of contamination. Neuroepithelial cells prepared by this method have been demonstrated to divide and differentiate in tissue culture, to act as target cells for immortalization by proto-oncogenes and to differentiate into neurons in neural transplantation studies.

Animals↗
PubMed1990

Fibroblast growth factor stimulates the proliferation and differentiation of neural precursor cells in vitro.

We have developed an in vitro culture system to study the regulation of proliferation and differentiation of neural precursor cells contained within the neuroepithelium of embryonic day 10 mice. A number of soluble growth factors have been tested for their ability to regulate these early events and, of these factors, we have found that the fibroblast growth factors [FGFs] can directly stimulate the proliferation and survival of the neuroepithelial cells. At least 50% of the neuroepithelial cells divide in the presence of FGF whereas in the absence of FGF all of the cells die within 6 days of culture. At higher concentrations of FGF, the cells change from being nonadherent round cells in tight clusters into a more flattened cell type which adheres to the substratum. This morphological change is accompanied by the expression of both neurofilament and GFAP, which are definitive markers of the two major cell types in the central nervous system: neurons and glia. In addition a neuroepithelial cell line, which does not rely on FGF for survival or proliferation, expresses both of these markers in response to FGF. These results indicate that FGF is stimulating the differentiation of the neuroepithelial cells into mature neurons and glia.

Animals↗
PubMed1990

Phase II trial of interferon-beta-serine in metastatic renal cell carcinoma.

Interferon-beta-serine (IFN-beta-ser) is a muteine, recombinant IFN that is tolerated at a dose fivefold to 10-fold higher than IFN-alfa and interacts with the same cell membrane receptor as IFN-alfa. We hypothesized that at high doses IFN-beta-ser might induce a higher response rate than IFN-alfa in metastatic renal cell carcinoma. We undertook a phase II trial of IFN-beta-ser in patients with metastatic renal cell carcinoma. Patients were treated three times each week by a 2-hour intravenous infusion. Doses were escalated weekly (.25 to 5.5 mg, 1 mg = 180,000,000 U) until the maximum-tolerated treatment dose (MTTD) was determined. The MTTD is defined as one dose level less than that which caused grade 3 toxicity and was subsequently administered three times weekly for at least 4 weeks. Twenty-nine patients were entered, and 25 were assessable for response and toxicity. The performance status was 0-1 in all patients and only one patient received previous chemotherapy. The MTTD dose was 2.5 mg (range, 0.5 to 5.5 mg per treatment), although in 10 patients, doses were later deescalated because of cumulative toxicity. Initial dose-limiting toxicity and cumulative toxicity were fatigue, malaise, and fever in most patients. Hepatic transaminitis, neutropenia, and elevation of serum creatinine were also observed but were not dose-limiting. There was one complete response (CR) and four partial responses (PRs). All responses but one occurred in pulmonary metastases. The median time to response was 26 days (range, 17 to 102 days). These data demonstrate that IFN-beta-ser given in high doses exhibits significant antitumor activity in renal cell carcinoma; however, the objective response rate is 20%. This is no higher than previous IFN studies; therefore, we reject the hypothesis than IFN-beta-ser at high doses may induce a greater response rate than IFN-alfa. However, we did observe more responses than were seen in a similar trial undertaken with lower dose IFN-beta serine in renal cell carcinoma.

Adult↗
PubMed1989

Induction of the ganglioside marker A2B5 on cultured cerebellar neural cells by growth factors.

The surface ganglioside marker A2B5 was originally detected on neurons, but has subsequently been shown to be expressed on a wide range of macroglial and non-neural cells. This marker has been used in vitro to categorize subpopulations of neural cells within the central nervous system, as well as defining developmental pathways of macroglia. These categorizations are based on the assumption that this marker cannot easily be modulated. In this study of cerebellar cultures we demonstrate that A2B5 can be induced on approximately 16% of A2B5 non-expressing cells by the growth factors: basic fibroblast growth factor (b-FGF); acidic fibroblast growth factor (a-FGF); and, to a lesser degree, epidermal growth factor (EGF).

Animals↗
PubMed1989

Formation of a cryogel during processing of cell-free plasma.

Automated plasmapheresis devices are being integrated into many modern plasma procurement programs. Owing to the use of a different concentration and type of anticoagulant, the recovered plasma differs in pH and citrate levels from that obtained by manual plasmapheresis or whole blood donation. Recently, fractionators noted the recovery of a sticky, gelatinous fraction (cryogel) during thawing of cell-free (CF) plasma, along with reduced recovery of factor VIII:C (FVIII:C) in the cryoprecipitate fraction. Following their manufacturing procedures, it was established that the cryogel fraction of CF plasma is enriched in FVIII:C, fibrinogen, and fibronectin, as compared to cryoprecipitate from CPDA-1 plasma. Cryogel formation was not significantly affected by pH or citrate adjustment of the recovered plasma, by the use of polycarbonate or nylon filter membranes, or by the filter wetting agent polyvinylpyrrolidone (PVP). Furthermore, passage of CPDA-1 plasma through the polycarbonate filter did not alter cryoprecipitate quality. However, cryogel formation from CF plasma was reduced significantly by 1) slow thawing at 4 degrees C rather than quick thawing at 20 and 0 or 20 and 4 degrees C, 2) the use of 1:16.6 sodium citrate rather than 1:12.5 ACD-A, or 3) the addition of intact platelets, platelet lysate, membranes, or cytosol to CF plasma before freezing. The data suggest an important and, indeed, essential role of platelet constituents in the formation of both cryoprecipitate and cryogel during the low-temperature purification of plasma proteins.

Blood Platelets↗
PubMed1987

Androgen depletion and repletion as a means of potentiating the effect of cytotoxic chemotherapy in advanced prostate cancer.

Seventy-five patients with stage D-2 prostate cancer refractory to orchiectomy have been entered in a controlled trial to test whether androgen priming enhances the efficacy of chemotherapy. All patients are treated with aminoglutethimide and hydrocortisone as a means of achieving medical adrenalectomy and are given cyclic i.v. chemotherapy with cytoxan, adriamycin and 5-fluorouracil. Patients in the stimulation arm (N = 39) receive, in addition, fluoxymesterone (5 mg p.o. b.i.d.) for 3 days before and on the day of chemotherapy. A similar response rate was observed in the stimulation and control arm (83% vs 74% respectively) when the analysis was restricted to evaluable patients. When all patients were included, a significantly higher response rate was observed in the control arm (64% vs 49%, P less than 0.05) as a result of the larger fraction of unevaluable patients in the stimulation arm (41% vs 14%). Median duration of response is 9 months in the stimulation and 10 months in the control arm. Median overall survival in the stimulation and control group is 12 months and 16 months respectively. Significant toxicity consisting of exacerbation of bone pain and, in two patients, development of reversible spinal cord compression was observed following androgen priming. Our results suggest that combined medical adrenalectomy and chemotherapy are highly effective in the treatment of advanced prostate cancer. Thus far, no additional benefit has been observed with androgen priming.

Aminoglutethimide↗
PubMed1986

The fibrinolytic system in experimental prostate tumor.

Hypofibrinogenemia and disseminated intravascular coagulation are common events in patients with metastatic prostate carcinoma. This study tests the hypothesis that prostate tumor growth and metastasis is associated with sustained activation of fibrinolysis secondary to increased release of plasminogen activator. We implanted an androgen-insensitive prostate tumor into an inbred strain of rats and serially measured plasminogen, plasminogen activator, plasmin and fibrinogen. Control groups included animals without tumor and a group implanted with transitional cell bladder carcinoma, a locally infiltrating tumor not usually associated with hemostatic complications. Our results showed a significant and steady rise in plasma plasminogen activator, plasmin and fibrinogen levels in animals implanted with prostate cancer. This, however, is not specific for prostate tumor. Similar, perhaps more profound changes were noted in animals implanted with the transitional cell carcinoma.

Animals↗
PubMed1986

Androgen priming and response to chemotherapy in advanced prostatic cancer.

A total of 67 patients with progressive stage D2 prostatic cancer refractory to orchiectomy was entered in a controlled clinical trial to test whether androgen priming enhances the efficacy of cytotoxic drugs. All patients were treated continuously with aminoglutethimide and hydrocortisone to lower adrenal androgen secretion and were given cyclic intravenous chemotherapy. In addition, the 34 patients randomized to the stimulation arm received fluoxymesterone for 3 days before and on the day of chemotherapy. There was 33 controls. The median duration of followup was 24 months. A modestly higher response rate (objective remission plus disease stabilization) was observed in the stimulation arm (85 versus 72 per cent, p less than 0.05) when the analysis was restricted to the evaluable patients. However, a larger fraction of unevaluable patients was present in the stimulation group (41 versus 16 per cent), mostly as a result of toxicity from fluoxymesterone, which prompted early discontinuation of treatment. Thus, when data analysis included all patients the response rate actually was slightly higher in the control than in the stimulation arm (60 versus 50 per cent, p not significant). No difference was observed in median duration of response (9 months in both groups) or over-all survival. Our data suggest that at least in those patients with advanced disease androgen priming does not seem to enhance significantly the antitumor effect of the combination of amino-glutethimide and chemotherapy, and is associated with significant toxicity. These largely negative results may be explained by the large number of hormone-resistant cells present in tumors that have become refractory to orchiectomy.

Aged↗
PubMed1985

Stabilization of red blood cells by the plasticizer, diethylhexylphthalate.

The red blood cells of blood stored in containers made of polyvinylchloride (PVC) film are osmotically more stable and lose on average about 1/3 less hemoglobin than when blood is stored in another plastic [poly-(ethylene-co-ethyl acrylate); EEA]. The stability of uniform volumes of stored red blood cells varies directly with PVC surface area, whereas changes in EEA surface area have comparatively little or no effect. PVC contains high concentrations of the plasticizer, diethylhexylphthalate (DEHP), known to migrate into blood and to have a high potential for toxicity. To determine if DEHP could be the red cell stabilizing agent in PVC, whole blood was stored in containers made from EEA into which was incorporated varying amounts of DEHP. Incorporation of DEHP into EEA significantly reduced erythrocyte osmotic fragility (p = 0.01). The degree of reduced fragility correlated with the level of DEHP in the cell phase implicating DEHP in PVC containers as the stabilizing agent for red cells.

Acrylic Resins↗
PubMed1983

Effect of very high dose D-leucine6-gonadotropin-releasing hormone proethylamide on the hypothalamic-pituitary testicular axis in patients with prostatic cancer.

Potent synthetic analogs of gonadotropin-releasing hormone produce parodoxical antireproductive effects when administered chronically. These compounds are minimally toxic and may exhibit no plateau of the dose-response curve even at very high doses. These considerations served as the basis for our systematic evaluation of [D-leucine6-desarginine-glycine-NH2(10)]gonadotropin-releasing hormone (GnRH-A) proethylamide in the very high dose range (i.e., 10-fold larger amounts than previously used). In rats given the analog for 12 wk, prostate, testis, and seminal vesicle weights were suppressed to a greater extent with 200 micrograms q.d. than with 40 micrograms q.d. (P less than 0.01 prostate, less than 0.01 testis, less than 0.01 seminal vesicles), indicating dose-response effects in the very high dose range. 200 micrograms of [D-Leu6-des-Gly-NH2(10]-GnRH-A consistently suppressed leutinizing hormone (LH) values at 6 and 12 wk (basal 71 +/- 9.5; 6 wk 34 +/- 3.8; 12 wk 28 +/- 5 ng/ml) whereas 40 micrograms suppressed LH variably (basal 33 +/- 3.8; 6 wk 17 +/- 3.9; 12 wk 32 +/- 5.2). Testosterone fell to 15 +/- 2.4 and 19 +/- 2.0 ng/100 ml in response to 200 micrograms q.d. and to 27 +/- 6.4 and 22 +/- 7.4 ng/100 ml with the 40-micrograms dose. These findings in the rodent prompted treatment of stage D prostate cancer patients with similarly high doses of [D-Leu6-des-Gly-NH2(10)]-GnRH-A. After treatment for 11 wk with 1,000 or 10,000 micrograms/d of the analog, testosterone and dihydrotestosterone levels transiently rose and then fell into the surgically castrate range (testosterone 19 +/- 4.4 ng/100 ml [D-Leu6-des-Gly-NH2(10)]-GnRH-A vs. surgically castrate 11 +/- 0.9 ng/100 ml, P = NS; dihydrotestosterone 15 +/- 1.7 ng/100 ml GnRH-A vs. surgically castrate 15 +/- 4.1 ng/100 ml. P = NS). However, unlike the chronic stimulatory effect on the pituitary at lower doses, very high dose therapy resulted in profound suppression of plasma and urine LH. Plasma levels fell to the limit of assay detectability, whereas the more sensitive urinary assay detected prepubertal levels of excretion (i.e., 64 +/- 8.4 mlU/h). The highly sensitive rat interstitial cell testosterone bioassay for LH also demonstrated a marked decline in LH to undetectable levels in 17/19 subjects. Clinical results with [D-Leu6-des-Gly-NH2(10)]-GnRH-A simulate those achieved by surgical castration in men with prostatic cancer as suggested by available preliminary data.

Adenocarcinoma↗
PubMed1979

Comparative patterns of serum immunoglobulin levels in specific-pathogen-free congenitally athymic (nude), hereditarily asplenic (Dh/+), congenitally athymic-asplenic (lasat) and splenectomized athymic mice.

Serial determinations of serum immunoglobulin levels were assessed in congenitally athymic (nude), hereditarily asplenic (Dh/+) and congenitally athymic-asplenic (lasat) mice and the results compared to normal intact littermate controls (nu/+), neonatally splenectomized nu/+ and neonatally splenectomized nude mice. Quantification of Ig levels was accomplished by radial immunodiffusion, for IgM, IgG1, IgG2a, IgG2b and IgA antibody isotypes. Intact spleen and/or thymus function was shown to have marked effects on the age-dependent development of serum IgM, IgG2b and IgA production. Furthermore, because of higher levels of IgA in congenitally athymic-asplenic mice and neonatally splenectomized nude mice v. sham splenectomized nude mice, it is suggested that an IgA-specific suppressor population resides in the spleen. Finally, because of frequent problems in the literature in interpretation of immunoglobulin values, the criteria for the statistical evaluation of such data in establishing normal serum Ig values and ascertaining real differences between treatment groups are emphasized.

Aging↗
PubMed1977

Clinical and radiographic findings of focally infected polycystic kidneys.

Three patients with localized polycystic kidney infections are presented with the pertinent clinical, laboratory, and radiographic findings. Gallium-67 citrate and angiography play an important role in evaluation of these patients. Angiography in particular is valuable in the diagnosis and the exact localization of the inflammatory disease. Localization is extremely important in planning surgical treatment should conservative therapy fail.

Adult↗