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Biomedical subjects

M Blake

Publications and source records attributed to M Blake.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of acute myelogenous leukemia blast proliferation by interleukin-1 (IL-1) receptor antagonist and soluble IL-1 receptors.

Interleukin-1 (IL-1) has recently been reported to play an important role in acute myelogenous leukemia (AML) blast proliferation. We therefore investigated the effect of soluble IL-1 receptors (sIL-1R) and IL-1 receptor antagonist (IL-1RA) on the growth of AML bone marrow blast progenitors from 25 patients. In the AML blast colony culture assay, sIL-1R and IL-1RA inhibited blast colony-forming cell replication in a dose-dependent fashion, at concentrations ranging from 10 to 500 ng/mL (sIL-1R) and 10 to 1,000 ng/mL (IL-1RA), and their inhibitory effect was partially reversed by IL-1 beta. A similar inhibitory effect was also noted with the use of anti-IL-1 beta neutralizing antibodies. When AML blast progenitors were grown either in the presence of fetal calf serum (FCS) alone or with one of the following: phytohemagglutinin leukocyte-conditioned medium (PHA-LCM), granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, interleukin-3 (IL-3), or stem cell factor (SCF), addition of 100 ng/mL sIL-1R or IL-1RA inhibited blast colony formation by 3% to 96% and 2% to 97%, respectively. In sharp contrast, neither of these IL-1-inhibitory molecules significantly inhibited proliferation of normal marrow hematopoietic progenitors. Lysates of 2 x 10(7) low-density AML marrow cells were tested for intrinsic IL-1 beta content using an enzyme-linked immunoadsorbant assay (ELISA). Samples from five of six patients showed high concentrations (ranging from 501 to 2,041 pg), whereas 2 x 10(7) cells from two normal marrow aspirates yielded 54.6 pg of IL-1 beta. AML blast colony-forming cells from all six patients were inhibited by sIL-1R, IL-1RA, or both. Incubation of nine samples of AML low-density cells with either sIL-1R or IL-1RA reduced GM-CSF concentrations in cell lysates, and supernatants from nine (P less than .01) and six samples (P less than .037), respectively, and G-CSF concentration in lysates from six of nine samples (P less than .03), and in supernatants from five of six samples (P less than .06) when studied by ELISAs. Our data implicate IL-1 in AML blast proliferation and suggest the potential benefits of using IL-1-inhibitory molecules in future therapies for AML.

Adult↗
PubMed1991

Suppression of chronic myelogenous leukemia colony growth by interleukin-1 (IL-1) receptor antagonist and soluble IL-1 receptors: a novel application for inhibitors of IL-1 activity.

In this study, we investigated the role of interleukin-1 beta (IL-1 beta) in the malignant evolution of chronic myelogenous leukemia (CML) and the functional activity of IL-1 inhibitors. Bone marrow (BM) and peripheral blood (PB) low-density cells from 38 CML patients were studied in the colony-forming unit-granulocyte, erythrocyte, monocyte, megakaryocyte colony culture assay. Samples from patients with early stage, interferon-alpha (IFN)-sensitive disease formed hematopoietic colonies in the presence of fetal calf serum (FCS), erythropoietin (Epo), and one of the following: granulocyte-macrophage colony-stimulating factor (10 ng/mL), IL-3 (15 ng/mL), both, or phytohemagglutinin-conditioned medium. The addition of IL-1 beta augmented IFN-sensitive CML colony growth in a dose-dependent manner at concentrations of 10 to 100 U/mL. In sharp contrast, addition of the above growth factors did not augment the colony growth-promoting effect of FCS and Epo in samples from IFN-resistant patients; further, adherent cell fractionation or T-lymphocyte depletion attenuated the "autonomous" colony growth. Lysates of 2.5 x 10(7) low-density cells from each of six IFN-resistant and six IFN-sensitive CML patients and three normal volunteers were tested for intrinsic IL-1 beta content in an enzyme-linked immunosorbent assay and yielded a mean of 610 pg, 54.6 pg, and 49.4 pg of IL-1 beta, respectively (P less than .045). Interestingly, both soluble IL-1 receptors (sIL-1R) and IL-1 receptor antagonist (IL-1RA) at concentrations of 5 to 100 ng/mL (sIL-1R) and 10 to 500 ng/mL (IL-1RA) inhibited CML colony growth in a dose-dependent fashion, with maximal inhibition of 64% and 65%, respectively. A similar effect was noted with the use of anti-IL-1 beta neutralizing antibodies. These data implicate IL-1 beta in CML disease progression and suggest that the inhibitory effects of molecules such as sIL-1R and IL-1RA could conceivably be the basis of a novel therapeutic strategy against this disorder.

Adolescent↗
PubMed1991

Granulocyte-macrophage colony-stimulating factor and interleukin-3 in combination: a potent and consistent myelodysplastic syndrome bone marrow stimulant in vitro.

In an effort to overcome bone marrow failure in myelodysplastic syndrome (MDS), we have investigated recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) in phase I-II clinical trials. Although these agents partially increased peripheral blood granulocyte counts, their effect on other hematopoietic lineages was generally sporadic. Since in vitro analysis and in vivo studies in primates indicate that GM-CSF and IL-3 synergistically enhance hematopoietic stem cell proliferation, we evaluated their combined effect on marrow progenitors obtained from ten MDS patients. When used singly, each growth factor stimulated replication of granulocyte-macrophage (CFU-GM) and erythroid (BFU-E) colony-forming cells in a dose-dependent fashion. When colony-stimulating activity was compared at concentrations that maximally amplified individual MDS patients' colony numbers, IL-3 was a more potent stimulant in some patients and GM-CSF in others. When used in combination, IL-3 plus GM-CSF was more effective than each growth factor by itself in five of six patients. Our data indicate that the MDS hematopoietic progenitor stimulatory effect of these growth factors varies from patient to patient. However, the combination of GM-CSF and IL-3 appears to be more potent than the individual molecules in the majority of patients.

Bone Marrow↗
PubMed1991

Effects of protein I of Neisseria gonorrhoeae on neutrophil activation: generation of diacylglycerol from phosphatidylcholine via a specific phospholipase C is associated with exocytosis.

Upon engagement of chemoattractant receptors, neutrophils generate inositol trisphosphate and diacylglycerol (DG) by means of a phosphatidylinositol-specific phospholipase C (PI-PLC) which is regulated by a GTP-binding protein(s). We have previously reported (Reibman, J., H. M. Korchak, L. B. Vosshall, K. A. Haines, A. M. Rich, and G. Weissmann. 1988. J. Biol. Chem. 263:6322-6328) a biphasic rise in DG after exposure of neutrophils to the chemoattractant FMLP: a rapid (less than or equal to 15 s) phase ("triggering") and a slow (greater than or equal to 30 s) phase ("activation"). These derive from distinct intracellular lipid pools. To study the source of rapid and slow DG, we have used a unique probe, protein I, a porin that is the major outer membrane protein of Neisseria gonorrhoeae. Treatment of neutrophils with protein I inhibits exocytosis and homotypic cell adhesion provoked by FMLP without inhibiting assembly of the NADPH oxidase responsible for O2-. generation. DG turnover in PMN labeled with [3H]arachidonate and [14C]glycerol was profoundly altered by protein I. Whereas the rapid peak of DG was only modestly diminished (FMLP vs. FMLP plus protein I = DG labeled with [3H]arachidonic acid (3H-a.a.-DG): 142 +/- 14% SEM vs. 125 +/- 22%; DG labeled with the glycerol backbone with [14C]glycerol (D-14C-G): 125 +/- 10% SEM vs. 107 +/- 8.5% SEM), the slow rise in both 3H-a.a.-DG and D-14C-G was essentially abolished. Moreover, treatment of neutrophils with 4-4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), which, like protein I, inhibits exocytosis without affecting O2-. generation also inhibited slow DG. However, protein phosphorylation and dephosphorylation (47phox, 66phox) were unaffected in the absence of slow DG. To determine the source of the slow DG, we have analyzed radiolabeled phospholipid (PL) turnover after FMLP +/- protein I (P.I.). Treatment of PMN with FMLP (0.1 microM) resulted in breakdown of phosphatidylcholine (PC), beginning at 30 s, and reaching a nadir at 60 s (3H-PC = 59 +/- 10.2% SEM of resting, 14C-PC = 57 +/- 6.4%). Protein I (0.25 microM) significantly inhibited PC turnover after FMLP ([3H]PC = 95 +/- 5.6% and [14C]PC = 86 +/- 8.4% of resting at 60 s), but failed to alter the metabolism of 3H- or 14C-phosphatidylinositol after FMLP (91 +/- 19.6 and 88 +/- 16.5% vs. 92 +/- 9.2 and 91 +/- 16% at 60 s).(ABSTRACT TRUNCATED AT 400 WORDS)

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1991

Pilin expression and processing in pilus mutants of Neisseria gonorrhoeae: critical role of Gly-1 in assembly.

Spontaneous mutants of Neisseria gonorrheae failing to express pili or having diminished levels of piliation were studied with regard to pilin expression. All mutants displayed altered pilin processing detectable as the release of soluble, truncated pilin molecules (S-pilin). Of particular interest was the finding, in one mutant, that substitution of serine for glycine at position -1 of propilin, a highly conserved residue among N-metPhe and related pilins, abolished pilus expression but not S-pilin release. The degree of S-pilin processing and the levels of membrane-associated pilin varied among the different classes of mutants, suggesting that each was blocked at a distinct step of pilus biogenesis. The data support a model in which increased S-pilin processing is a result of a decreased rate of pilus polymerization.

Amino Acid Sequence↗
PubMed1991

Assessment of nutrient intake in association with weight loss after gastric restrictive procedures for morbid obesity.

Postoperative nutrient intakes were examined in patients who were losing weight in an early period following gastric restrictive surgery for morbid obesity (3 to 6 months post-surgery), and patients whose reduced weight was relatively stable at 1 to 2 years post-surgery. In association with weight loss, patients showed increased physical activity and reduced energy intakes which were frequently less than the Recommended Daily Intakes (RDI), particularly in the early period. Protein intake was also below recommended levels in the two post-operative phases. The intakes of iron, folate and calcium were below the recommended levels in the early postoperative phase. The intakes of iron and folate were also below recommended levels in the late postoperative phase. The study indicates the potential for deficiencies of iron, folate and calcium after gastric restrictive surgery and supports the importance of careful and prolonged follow-up of these patients, with particular attention to nutritional status.

Adult↗
PubMed1991

Role of E2F transcription factor in E1A-mediated trans activation of cellular genes.

Adenovirus E1A-dependent trans activation of the adenovirus E2 gene involves the activation of the cellular transcription factor E2F. E2F binding sites have also been identified in the 5'-flanking region of a number of cellular genes, raising the possibility that such genes are targets for E1A trans activation. We now demonstrate that two genes that possess E2F recognition sites, N-myc and DHFR, are stimulated by E1A, dependent on the E2F sites. We also find that although there are multiple E2F sites in these promoters, a single intact E2F binding site is sufficient for E1A-mediated induction, although not to the full wild-type level. These results thus demonstrate that a variety of cellular genes that possess E2F binding sites are subject to E1A trans activation. Moreover, since the products of most of these genes are likely critical for cellular proliferation, there are obvious consequences of this trans activation for cellular phenotype.

Adenovirus Early Proteins↗
PubMed1991

Management of odontogenic sinusitis with persistent oro-antral fistula.

Sixteen patients were treated for odontogenic sinusitis secondary to persistent oro-antral fistula. Males outnumbered females 12 to 4. Frequency of presentation increased directly with age. Chronic signs and symptoms included facial pain, swelling, tenderness and nasal and oral discharge. The clinical diagnosis of chronic sinusitis was confirmed in all cases by radiographic findings. An opacified maxillary sinus with or without ethmoid involvement was observed in all 16 patients. Surgical pathology revealed chronic mucosal thickening and/or antral polyps in 69% of the cases. Surgical treatment of the sinusitis consisted of antrostomy alone or in combination with Caldwell-Luc procedure. The oro-antral fistula was repaired with mucosal flaps from the buccal and/or palatal region. No postoperative recurrences have been noted during a follow-up period of six months to seven years. Bacterial cultures grew out pure aerobes (44%) or mixed aerobic-anaerobic bacteria (44%). None yielded pure anaerobes. The bacteriologic spectrum was notably lacking in S. pneumoniae and H. influenzae and differed from organisms commonly found in sinusitis of rhinogenous origin.

Adolescent↗
PubMed1991

Synergistic antiproliferative effect of interferon alpha and azidothymidine in chronic myelogenous leukemia.

The possible synergistic interaction between azidothymidine (AZT) and interferon alpha (rIFN-alpha 2a) in the treatment of chronic myelogenous leukemia (CML) was studied in vitro using marrow or peripheral blood hematopoietic progenitors from 10 patients with CML in the mixed (CFU-GEMM) colony culture assay. Used singly, either agent inhibited erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) CML hematopoietic progenitor proliferation in a dose-dependent fashion, with the inhibitory effect being more pronounced on BFU-E than on CFU-GM colony-forming cells. The combination of both drugs in therapeutic concentrations exerted a significant synergistic inhibition on CML stem cells as assessed by the median-effect principle and isobologram equation analysis. A suboptimal dose of AZT (0.5 mumol/l) synergistically augmented the effect of rIFN-alpha 2a whereas an inactive dose of 10 U/ml rIFN-alpha 2a similarly enhanced the CML stem cell growth inhibition exerted by AZT. Our data indicate that AZT may augment the already established therapeutic benefits of IFN-alpha in CML.

Adult↗
PubMed1990

Significance of blasts in low-cell-count cerebrospinal fluid specimens from children with acute lymphoblastic leukemia.

The purpose of this study was to determine whether the presence of more than 5% blasts in a differential count of cytocentrifuged cerebrospinal fluid (CSF) with less than 6 leukocytes/microliter was predictive of central nervous system (CNS) relapse in children with acute lymphoblastic leukemia (ALL). A double concentrate method of cytocentrifuge preparation was used to analyze 4543 consecutive CSF specimens from 349 children with ALL between January 1, 1982, and September 30, 1988. One hundred nine CSF specimens from 58 evaluable children had less than 6 leukocytes/microliter and more than 5% blasts on cytocentrifuge differential count (low-cell-count specimen with blasts [LCB]). During the study period, 25 of 332 evaluable children (7.5%) had CNS leukemic recurrence. In 22 of 25 (88%), the CNS relapse was preceded by at least one abnormal low-cell-count CSF specimen. One of 34 patients with a single LCB at diagnosis (3%) had subsequent CNS relapse compared with five of eight patients (62.5%) with a single LCB during remission (P = 0.0002). Of 16 children with two or more LCB during remission, nine (56%) had CNS relapse defined by standard criteria, whereas six additional patients in this group were declared to be in CNS relapse on the basis of their repetitive LCB. Whether diagnosing CNS recurrence earlier in its course based on a modification of the definition of CNS leukemia will change the frequency of subsequent adverse events or make possible decreased intensity of CNS retreatment remains to be determined.

Adolescent↗
PubMed1990

Hematological and biochemical changes during a short triathlon competition in novice triathletes.

Short-course 'sprint' triathlons have become popular in recent years, often as a precursor to the longer full-course triathlons. We undertook a study investigating the haematological and biochemical changes that occur in novice triathletes between the start and finish and after each of the three legs of a short sprint triathlon involving swimming, cycling and running. The changes that occurred in the triathlon included a significant (P less than 0.003) decrease in weight from 71.7 kg, SD 7.9 to 70.3 kg, SD 7.6. Throughout the time span of the triathlon, the white blood cell count increased significantly (P less than 0.001), as did the platelet count (P less than 0.005) and plateletcrit (P less than 0.001). There were no significant changes during the period of the race in any of the other haematological variables measured. The biochemical variables measured were glucose, triglycerides, sodium, potassium, calcium, lactate dehydrogenase, creatinine and aspartate aminotransferase. Triglyceride, calcium and potassium values did not change between the pre- and post-race samplings. All other biochemical parameters showed a significant change (P less than 0.05 or better). Changes that occurred in the haematological and biochemical parameters between stages were many and varied. There was also a significant change in plasma volume during the swimming event (P less than 0.001), but this returned to normal during the later stages of the triathlon. In conclusion the changes that occurred during the triathlon were many and were similar to those reported elsewhere in the literature for longer events.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartate Aminotransferases↗
PubMed1990

Community-acquired pseudomonas pneumonia in a normal host complicated by metastatic panophthalmitis and cutaneous pustules.

Pseudomonas aeruginosa is a frequent pathogen of patients with chronic underlying disease in the hospital environment. This organism is, however, an extremely rare cause of either community-acquired pneumonia in a normal host, metastatic bacterial endophthalmitis or metastatic cutaneous pustules. We report here a case combining these three rare manifestations in a previously well young woman, to highlight the serious disease that may result from this pathogen and the difficulties of treatment.

Adult↗
PubMed1989

Aggregation by fragilis and non-fragilis Bacteroides strains in vitro.

Bacteroides fragilis is associated with the formation of intra-abdominal abscesses, whereas other Bacteroides species are rarely involved. Since bacterial clumping may contribute to the survival of bacteria in the face of host defence mechanisms, the hypothesis has been put forward that differences in aggregation between fragilis and non-fragilis strains of Bacteroides may account for their differences in survival in vivo. All seven B. fragilis strains tested formed aggregates within 4 h, but strains not associated with intra-abdominal sepsis--B. vulgatus, B. thetaiotaomicron and B. distasonis--did not form aggregates in vitro. Aggregation occurred at 37 degrees C, but not at 4 degrees C or 20 degrees C. Treatment with pronase partially inhibited aggregation. Periodate treatment killed the cells and caused them to form clumps which were distinguishable from the control aggregates. Heat-killed B. fragilis cells formed similar distinct clumps, but cells killed by glutaraldehyde and formaldehyde did so to a lesser degree. No inhibition was found upon addition of carbohydrates, ethylenediaminetetraacetic acid or after treatment with trypsin. These results demonstrate that aggregate formation occurs with B. fragilis strains alone, and that surface proteins probably mediate this interaction.

Bacteroides↗
PubMed1988

Immunogenicity of liposome-bound hyaluronate in mice. At least two different antigenic sites on hyaluronate are identified by mouse monoclonal antibodies.

Hyaluronate (HA) was previously demonstrated to be immunogenic in rabbits. The immunogenicity of HA in mice was studied. Hyaluronidase-digested streptococcal HA (IA1) covalently linked to liposomes (IA1-liposomes) were produced for immunization. Mice immunized with IA1-liposomes developed measurable serum antibodies to IA1, while mice immunized with IA1 in Freund's adjuvant did not. mAbs produced by two stable hybridomas (10G6 and 5F11) from mice immunized with IA1-liposomes produced IgG antibody reactive with HA in ELISA. 10G6 had a much higher avidity for liposome-bound IA1 than free IA1, while 5F11 did not, suggesting that the mode of presentation of IA1 is important in HA immunogenicity and antigenicity. Both mAbs recognized terminal HA immunodeterminants exposed by hyaluronidase treatment. Sonication had no effect on HA reactivity for either mAb. However, ascorbic acid treatment significantly reduced the antigenicity of HA for mAb 5F11, but not 10G6. Only 10G6 was inhibited by glucuronic acid. Electrostatic forces appear to play a role in the binding site of 5F11, but not 10G6. 5F11 crossreacts with heparan sulfate and phosphorylcholine, while 10G6 did not crossreact with any glycosaminoglycans or phosphorylated compounds tested. These results confirm that HA is immunogenic. They suggest that the mode of presentation of HA is important for the induction of the immune response, and in HA antigenicity. At least two different antigenic sites on HA were demonstrated. 10G6 recognizes a terminal HA antigenic site expressed on IA1-liposomes that contains glucuronic acid in its immunodominant site. 5F11 recognizes an HA antigenic site in which electrostatic forces appear to play a role, is sensitive to ascorbic acid treatment, and is crossreactive with heparan sulfate. The use of mAbs should facilitate immunologic studies of HA.

Animals↗
PubMed1988

Long-term survival of children with acute non-lymphoblastic leukemia.

Results of a pilot protocol employing chemoimmunotherapy for treatment of 23 children with acute non-lymphoblastic leukemia consecutively diagnosed between 1975 and 1979 are reported. Twenty-two children achieved remission, ten of whom are surviving 6.5-9.5 years after completion of primary systemic therapy (median 7.8 years). Treatment consisted of intermittent courses of Daunomycin, Cytosine Arabinoside, 6-Thioguanine, VP-16, with or without Decadron, Connaught BCG applied between courses of chemotherapy for the first 8 months of treatment, and cranial irradiation/intrathecal Cytosine Arabinoside in early first remission. Five patients with leukemic cells in spinal fluid at diagnosis had myelomonoblastic or monoblastic subtypes and a median diagnostic white blood cell count (WBC) of 149,000/mm3 compared with a median WBC of 12,000/mm3 for the other 18 patients (P = .007).

Acute Disease↗
PubMed1988

Voltage gating of conductance in lipid bilayers induced by porin from outer membrane of Neisseria gonorrhoeae.

Porins, polypeptides of approximately 35 kDa, are present as integral membrane proteins in the outer membranes of a variety of Gram-negative bacteria. As reported previously for a purified porin from Escherichia coli, voltage gating of conductance was found to be induced in a lipid bilayer by the solubilized purified porin, protein I, from Neisseria gonorrhoeae. The unitary response to an applied potential showed a cascade of current from an initial level through at least three levels, more or less equal, to a persisting lower level. The initial level of current corresponded to 1.0-1.3 nS for 0.2 M NaCl on either side of the bilayer. Briefly reducing the potential to zero restored the current to its initial level. Interpretation of the unitary response is suggested by electron microscopic data obtained on negatively stained outer membranes of E. coli indicating the presence of "pores" appearing in triplets. Moreover, low-resolution x-ray and neutron diffraction studies on crystals obtained with an E. coli porin show that three polypeptides associate to form a unit. Combining such structural data with the present electrical data lends support for the hypothesis that the unitary response results from three pores acting as a unit in response to an applied potential. Evidence obtained with the patch-clamp technique is mounting for a similar mechanism of many channels operating as a unit in a variety of cell membranes. The porin channel holds promise as a concrete model for the analysis of voltage gating of ionic conductance.

Bacterial Outer Membrane Proteins↗
PubMed1988

Fetal development, and placental and maternal plasma concentrations of progesterone in the little brown bat (Myotis lucifugus).

Progesterone concentrations measured in plasma samples from 280 bats captured during pregnancy or early lactation were related to fetal attributes indicative of stage of pregnancy. Fetal weight increased exponentially from 40 mg at crown-rump length of 6 mm to 2000 mg at 23 mm (term). Fetal weights at term accounted for up to 35% of the weight of intact pregnant animals. Progesterone concentrations increased from less than 5 ng/ml at 2 mm estimated crown-rump length to plateau values of approximately 65 ng/ml (geometric means) from 16 mm crown-rump length until the most advanced stages of pregnancy. Mean concentration in 8 post-partum bats, most of which were actively lactating, was 8.4 ng/ml; 11.6 ng/ml was measured in one animal that was carrying a wet neonate when sampled yet was still pregnant when captured 5 h earlier. Placental concentrations of progesterone ranged from 43 to 964 ng/g wet weight of tissue and mean values increased in a similar fashion though were about 4-fold greater than changes in plasma concentrations of the steroid. The concentrations in placental tissue were at least 15- to 20-fold higher than could be expected from blood contamination, indicating that placental steroidogenesis is likely to occur in this species.

Animals↗