A comparison of shock intensity in the treatment of longstanding and severe self-injurious behavior

A comparison of shock intensity was conducted while treating a young woman with mental retardation and severe self-injurious behavior (SIB). Two levels of shock intensity were evaluated: 3.5 milliamps (mA) delivered via the Self-Injurious Behavior Inhibiting System (SIBIS) and 18.5 mA delivered via the Hot Shot Power Mite. A combined reversal and multiple baseline across behaviors design was used to evaluate treatment effects. SIBIS in conjunction with differential reinforcement and extinction of self-injurious escape behavior produced minimal reductions in SIB. The Hot Shot combined with extinction of self-injurious escape behavior and reinforcement for compliance resulted in immediate and large reductions in SIB. Residential staff were trained to implement contingencies by the fourth day of treatment with excellent generalization from 30-min sessions to the natural environment across all waking hours. Continuous protective restraints were eliminated within the first month of treatment. Progress occurred in personal care, vocational training, independence, and communication. Treatment effects were maintained for approximately 6 months until a relapse occurred after home visits.

Induction of flavin-containing monooxygenase (FMO B) in rabbit lung and kidney by sex steroids and glucocorticoids

Modulation of lung and kidney levels of flavin-containing monooxygenase (FMO) isoform B following sc administration of dexamethasone, progesterone, beta-estradiol, aldosterone, or beta-estradiol plus progesterone was examined in male rabbits. Both dexamethasone and progesterone increased FMO B protein levels in lung. N-Oxygenation of N,N'-dimethylaniline (DMA) was significantly induced in lung microsomes from rabbits treated with progesterone. In kidney, only dexamethasone was effective in inducing FMO B protein levels and DMA N-oxygenation. Surgical implantation of osmotic pumps containing beta-estradiol or progesterone into non-pregnant female rabbits resulted in elevated plasma levels of these steroids after 4-5 days at which point the lung levels of FMO B were induced by 35 and 82% for beta-estradiol and progesterone, respectively. The responsiveness of FMO B in lung to both progesterone and glucocorticoids and in kidney to only the latter is consistent with the developmental pattern of both maternal FMO B and peak plasma levels of these steroids during pregnancy.

Mycobacterium avium-intracellulare complex: evaluation with CT

Pulmonary Mycobacterium avium-intracellulare (MAI) complex has been reported with increasing frequency, but computed tomographic (CT) evaluation of pulmonary MAI complex has been seldom reported. The authors retrospectively reviewed chest CT examinations performed in 62 patients with positive MAI cultures within 1 month of CT. Of the 62 patients, 40 had bronchiectasis and 60 had infiltrates, usually of the nodular variety (39 patients). All 35 patients with small nodular infiltrates had bronchiectasis. These 35 patients did not have concurrent malignancy or clinical evidence of immunocompromise, and 29 (83%) of them were women (mean age, 66 years). Of the 27 patients without small nodular infiltrates and bronchiectasis, 25 had underlying malignancy or immunocompromise. The predominance of older women without underlying malignancy or immunocompromise but with findings of small nodular infiltrates and bronchiectasis at chest CT may indicate such patients to be a subtype of patients with pulmonary MAI complex.

Protective effects of recombinant human interleukin-1 alpha in doxorubicin-treated normal and tumor-bearing mice

Experiments were performed to determine whether treatment with recombinant human IL-1 alpha (rhuIL-1 alpha) would protect C3H mice from the toxic effects of the widely used chemotherapeutic agent, doxorubicin (DXR). Pretreatment of mice with rhuIL-1 alpha was found to protect 85-90% of mice tested from the acute toxic effects of a lethal dose of doxorubicin (25 mg/kg). Late deaths (> 20 days post-DXR) were observed in a substantial proportion (40-45%) of rhuIL-1 alpha-pretreated mice. However, the data clearly demonstrate a beneficial effect of rhuIL-1 alpha pretreatment on the overall survival of mice challenged with DXR, since both the median survival (32 days) and proportion (53%) of surviving mice were significantly increased (P < 0.0001) compared to the control group (8 days and 14%, respectively). The beneficial effects mediated by rhuIL-1 alpha treatment were both dose- and schedule-dependent and were associated with decreases in the level and duration of DXR-induced neutropenia, and amelioration of the suppressive effects of DXR on myeloid progenitor cells (granulocyte/monocyte colony forming units) as evidenced by milder depressions in marrow cellularity and enhanced recovery of granulocyte/monocyte colony forming unit activity. Finally, pretreatment of mice bearing a solid tumor with rhuIL-1 alpha permitted effective dose escalation with DXR that resulted in decreased tumor growth rates and increased survival (90%) as compared to non-rhuIL-1 alpha-treated groups (20% survival). Thus, effective chemotherapeutic dose escalation is made feasible by rhuIL-1 alpha pretreatment of mice, but may ultimately be limited by nonhematological toxicities associated with DXR.

Mast cell growth factor (C-kit ligand) in combination with granulocyte-macrophage colony-stimulating factor and interleukin-3: in vivo hemopoietic effects in irradiated mice compared to in vitro effects

In the presence of hemopoietic cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), mast cell growth factor (MGF; also known as steel factor, stem cell factor, and c-kit ligand) has proven to be a potent hemopoietic regulator in vitro. In these studies, we examined the in vivo effects of MGF in combination with GM-CSF or GM-CSF plus IL-3. Effects were based on the ability of these cytokines to stimulate recovery from radiation-induced hemopoietic aplasia. Female B6D2F1 mice were exposed to a sublethal 7.75-Gy dose of 60Co radiation followed by subcutaneous administration of either saline, recombinant murine (rm) MGF (100 micrograms/kg/day), rmGM-CSF (100 micrograms/kg/day), rmIL-3 (100 micrograms/kg/day), or combinations of these cytokines on days 1-17 postirradiation. Recoveries of bone marrow and splenic spleen colony-forming units (CFU-s), granulocyte macrophage colony-forming cells (GM-CFC), and peripheral white blood cells (WBC), red blood cells (RBC) and platelets (PLT) were determined on days 14 and 17 during the postirradiation recovery period. MGF administered in combination with GM-CSF or in combination with GM-CSF plus IL-3 either produced no greater response than GM-CSF alone or down-regulated the GM-CSF-induced recovery. These results sharply contrasted results of in vitro studies evaluating the effects of these cytokines on induction of GM-CFC colony formation from bone marrow cells obtained from normal or irradiated B6D2F1 mice, in which MGF synergized with GM-CSF or GM-CSF plus IL-3 to increase both GM-CFC colony numbers and colony size. These studies demonstrate a dichotomy between MGF-induced effects in vivo and in vitro and emphasize that caution should be taken in attempting to predict cytokine interactions in vivo in hemopoietically injured animals based on in vitro cytokine effects.

Psychophysiological and MMPI personality assessment of headaches: an integrative approach

Multiple psychophysiological measures and personality assessment techniques were combined to facilitate the diagnosis of headache type and improve upon existing methodology. Twenty-four migraine, 24 chronic tension headache patients, and 24 normal age- and gender-matched controls were assessed with bilateral measures of frontalis and occipitalis EMG and blood volume pulse. All subjects completed the MMPI. Results suggest that headache subjects could be differentiated on baseline heart rates and MMPI scales 1,2,3, and 7. Only one physiological measure served as an index of psychological distress, suggesting issues of an interaction between psychophysiological and personality variables, as well as the chronicity of the headache.

The etiology of lung cancer

The association between tobacco smoking and lung cancer has been noted for more than 50 years and continues to dominate the etiologic milieu of this malignant disease. Other agents, many discovered in the occupational setting, have also been substantiated as lung carcinogens. Inherent predisposition to the disease has long been suspected, and recent investigations suggest several potential mechanisms and a possible mode of inheritance. Considerable progress has been made in deciphiring the molecular defects present in lung cancer cells. These recent findings have been incorporated into two well-known models of lung carcinogenesis. As the details of the carcinogenic process are unraveled, one goal is to identify intermediate (preneoplastic) markers of exposure and inherent predisposition that will help assess the risk of lung cancer for individuals as well as for groups.

Hepatocarcinogenic potency of mixed and pure enantiomers of trans-7,8-dihydrobenzo[a]pyrene-7,8-diol in trout

The hepatocarcinogenic potency of pure and racemic trans-7,8-dihydrobenzo[a]pyrene-7,8-diol was investigated in embryos and sac-fry rainbow trout. Embryos microinjected with (+/-)-trans-7,8-dihydrobenzo[a]pyrene-7,8-diol ((+/-) BP-7,8-DHD) developed liver tumors 9 months after hatching. However, this exposure protocol resulted in high mortalities. Microinjection of newly hatched sac-fry with 0.01-1.0 microgram of (+/-) BP-7,8-DHD resulted in a dose-dependent production of liver tumors (0-13%) similar to the results with embryos but without the problem of high mortalities. Co-injection of sac-fry with (+/-) BP-7,8-DHD and either beta-naphthoflavone or carbon tetrachloride significantly enhanced the tumor response (approx. 3-fold). The relative carcinogenic potencies of the pure (+) and (-) enantiomers of BP-7,8-DHD were evaluated by microinjection into sac-fry at doses of 0.5-5.0 micrograms. The results demonstrated that the (-) enantiomer was 4-18 times more potent than the (+). Mixed carcinomas were the most prevalent liver tumors observed. These results demonstrate that trout embryos and sac-fry are both responsive to hepatocarcinogenesis initiation by injection with BP-7,8-DHD. The marked enhancement seen with co-injection of sac-fry with beta-naphthoflavone or carbon tetrachloride suggests that both cytochrome P-450-dependent and lipid peroxidation-dependent pathways could be involved in bioactivation of this compound, presumably through epoxidation at the 9,10-position. As is the case with mammals, the (-) enantiomer of BP-7,8-DHD is a more potent carcinogen than the (+) enantiomer.

Factor structure of the Motivation Assessment Scale

The Motivation Assessment Scale (MAS) was developed to provide clinical information on four hypothesized functions that may control problem behaviour in persons with developmental disabilities. The original four-factor structure of the MAS was based on face validity, with the items being grouped in terms of each of the hypothesized functions. Validation of the scale was provided in terms of correlations between teacher ratings of eight children on the MAS and ranking of the controlling variables from functional analogue tests. In this study, staff in residential facilities rated 60 residents and teachers in schools rated 96 students on the MAS. The target behaviour rated for both samples was self-injury, with the institutional sample engaging in the behaviour more than 15 times an hour and the school sample, less than 15 times an hour. The results of factor analyses, with varimax rotation, provided a conceptually meaningful factor structure with the institutional sample, but not with the school sample. The 16 MAS items resolved into four factors that were conceptually related to four conditions that may maintain problem behaviour (i.e. sensory, escape, attention and tangible). The results suggested that the original MAS has a robust factor structure and may be clinically useful in predicting the controlling functions of problem behaviours, if the target behaviours occur at a rate no less than 15 responses per hour.

Biology and behavior. A set-point hypothesis of psychological functioning

This article provides a broad overview of an exploratory thesis designed to enhance an understanding of perturbations and rigidities of psychological functioning--a set-point hypothesis of psychological functioning. Historical precedents and parallels with Keesey's set-point theory of obesity are offered. Basic tenets of the hypothesis are detailed, and relevance to clinical behavioral theory is outlined. It is concluded that the set-point hypothesis may provide a framework for conceptualizing clinical cases and optimizing interventions. The thesis appears to be testable; however, the articulation of specific methodologies and research designs must be undertaken before the ultimate usefulness of the set-point hypothesis can be determined.

Thymus reconstitution by c-kit-expressing hematopoietic stem cells purified from adult mouse bone marrow

The introduction of clonal assays and long-term culture systems has resulted in considerable progress in the understanding of the early events that control self-renewal and commitment to differentiation of pluripotent hematopoietic stem cells (PHSC). Relatively little is known about the factors that control the commitment of PHSC to the lymphoid lineages, especially the T cell lineage. In the present study, the expression of the proto-oncogene c-kit was used to isolate and study the capacity of highly purified day 14 colony-forming units-spleen (CFU-S) to reconstitute the thymus of sublethally irradiated Thy-1 congenic recipient mice. We demonstrate here that one c-kit positive (c-kitpos) stem cell upon intrathymic transfer can effectively reconstitute the thymus of a sublethally irradiated recipient. After a lag phase of 15 d, high levels of donor-derived thymocytes (Thy-1.1pos) could be detected until 65 d after transplantation in Thy-1.2pos host mice. Donor-derived cells were only detected in the lobe of the thymus in which cells were previously injected and not in the noninjected lobe. These data suggest that c-kitpos stem cells do not migrate from one lobe to another and that they do not re-seed the thymus after having migrated to the bone marrow. The level and duration of reconstitution was found to be cell dose dependent, suggesting that, over time, endogenous stem cells compete with donor stem cells for available sites in the thymus microenvironment. The data presented in this paper demonstrate that commitment of purified adult bone marrow-derived c-kitpos stem cells to the T cell differentiation pathway can occur in the thymus and does not have to happen in the bone marrow.

Recombinant murine steel factor stimulates in vitro production of granulocyte-macrophage progenitor cells

The ability of murine Steel factor to promote the in vitro production of granulocyte-macrophage progenitor cells (CFU-GM) was examined in short-term liquid cultures. Bone marrow from C57BL/6J or Sl/Sld mice was placed in culture for seven days with either Steel factor alone or in the presence of IL-3. CFU-GM responsive to GM-CSF, IL-3, and CSF-1 were measured in the input population and again after 3 or 7 days in culture. Steel factor alone increased the number of all CFU-GM types as early as 3 days after culture initiation, with further increases at day 7. This effect was potentiated by the addition of IL-3. Production of CFU-GM by C57BL/6J or Sl/Sld marrow was comparable except for enhanced production of CSF-1 responsive progenitors by Sl/Sld marrow. A recombinant Sld protein was also shown to be equivalent to the wild-type protein in its capacity to promote CFU-GM production from normal bone marrow.

Retroviral vector-mediated gene transfer into primitive human hematopoietic progenitor cells: effects of mast cell growth factor (MGF) combined with other cytokines

Retroviral vector-mediated gene transfer into human hematopoietic stem cells may permit gene therapy of numerous genetic diseases. Stimulation of marrow with hematopoietic growth factors (HGFs) has been shown to increase the level of retroviral transduction. We have examined the effects of recombinant human mast cell growth factor (MGF), alone and in combination with other HGFs, on the efficiency of gene transfer into human hematopoietic progenitor cells. MGF acts in concert with interleukin 3 (IL-3) and interleukin 6 (IL-6) to increase the percentage of CD34+ progenitors transduced with a retroviral vector expressing the neo gene. The most potent combination of growth factors that we examined, interleukin 1 (IL-1)/IL-3/IL-6/MGF, resulted in the conferral of G418 resistance to 45% of progenitors and long-term culture-initiating cells. Extending the time of cocultivation of the marrow cells with the vector-producing cells did not further increase gene transfer frequency, suggesting that the amount of available vector is not limiting. To analyze the effects of the HGF on gene transfer into more primitive hematopoietic progenitors, CD34+ cells were isolated from marrow samples that were purged of committed progenitor cells by treatment with 4-hydroperoxycyclophosphamide (4-HC). Preculturing the CD34+ 4-HC-treated cells with the combination of four HGF (IL-1/IL-3/IL-6/MGF) permitted transduction of 20%-28% of the progenitors that formed colonies after 30 days in culture. These results demonstrate that MGF in combination with other HGFs enhances gene transduction of human hematopoietic progenitor cells.

Steel factor is required for maintenance, but not differentiation, of melanocyte precursors in the neural crest

Skin melanocytes are derived from neural crest cells that migrate into the dermis during embryogenesis. Two mouse mutants, Steel and White dominant-spotting, which have defects in melanocyte production, have recently been shown to have deletions in the genes that code for a new growth factor, steel factor (SLF), and its receptor, respectively. Here, we have investigated the role that SLF plays in melanogenesis using cultures of mouse neural crest and found that its primary action is the maintenance of melanocyte precursors. It has no effect on the final stage of melanocyte differentiation, the production of melanin, which appears to require an additional factor whose action is mimicked by the phorbol ester TPA (12-O-tetradecanoyl-phorbol-13-acetate).

Pharmacokinetic parameters of recombinant mast cell growth factor (rMGF)

The gene product of the murine Steel (Sl) locus encodes an early-acting hematopoietic growth factor that is a ligand for the c-kit protooncogene. Several cDNAs for the Sl gene product, known as mast cell growth factor (MGF), stem cell factor (SCF), or kit ligand (KL), have recently been isolated, and both soluble and membrane-associated versions have been shown to be biologically active. The potential for therapeutic usage of recombinant MGF (rMGF) indicated a need for determining the biodistribution and elimination parameters of this cytokine. Pharmacokinetic studies demonstrated that radiolabeled rMGF had a distribution half-life of 2 min and an elimination half-life of 2.1 h in wild-type mice following iv injection, during which a striking localization of labeled rMGF in the lungs was noted. When administered by subcutaneous injection the elimination half-life was prolonged to 8.4 h. The primary sites of rMGF elimination appeared to be the kidneys and the liver. Pharmacokinetic analysis of labeled rMGF in mutant Sl/Sld mice, which are mast cell deficient, demonstrated similar distribution and elimination half-lives compared to wild-type mice (1.4 min and 1.8 h, respectively). In addition, the biodistribution pattern of the labeled rMGF in Sl/Sld mice was similar to that observed in wild-type mice, including the striking localization to the lungs. Binding of radiolabeled rMGF to lungs in vivo subsequent to iv injection was completely inhibited by excess unlabeled rMGF. Interestingly, mice that received an iv injection of the higher doses of rMGF (15 micrograms) demonstrated profound respiratory distress and hypotension within minutes of administration. Histologic analysis of lungs from such mice revealed extensive mast cell degranulation, which was associated with vasodilatation and pronounced hyperemia of virtually all pulmonary vessels. The respiratory distress in normal mice was probably a consequence of mast cell degranulation induced by rMGF since similar findings were not observed in Sl/Sld mice injected with identical concentrations of rMGF.

Developmental abnormalities in Steel17H mice result from a splicing defect in the steel factor cytoplasmic tail

The murine dominant White spotting (W) and Steel (Sl) loci encode the c-kit tyrosine kinase receptor and its cognate ligand steel factor (SLF), respectively. Mutations at either locus produce deficiencies in the same three migratory cell populations--those giving rise to pigment cells, germ cells, and blood cells. The identification of the gene products of these two loci combined with the plethora of W and Sl mutations available for molecular analysis offers a unique opportunity to dissect the role of a tyrosine kinase receptor and its cognate ligand during development in a fashion not possible for most other mammalian genes. Among the most interesting Sl mutations available for study are those that induce sterility in only one sex. In studies described here, we show that one of these alleles, Sl17H, which in the homozygous condition induces sterility in males but not females, is the result of a splicing defect in the SLF cytoplasmic tail. We also characterize the nature of the germ cell defects in male and female Sl17H mice and show that both sexes are affected equally during embryonic but not postnatal development. These studies provide new insights into the role of SLF in germ cell development and indicate that the cytoplasmic domain of SLF is important for its normal biological function.

Influence of recombinant human interleukin (IL)-7 on disease progression in mice infected with Friend virus complex

Recombinant human (rhu) IL-7 was evaluated for its influence on disease progression in mice infected with the polycythemia-inducing strain of the Friend virus complex (FVC). DBA/2 mice were injected i.v. with FVC, and then treated s.c. with rhuIL-7. IL-7 significantly prolonged survival time and decreased spleen focus-forming virus (SFFV) levels, expression of SFFV mRNA and SFFV protein production in FVC-infected mice. IL-7 did not appear to directly inactivate SFFV. Although both splenic weight and cellularity in FVC-infected mice treated with IL-7 were higher than those of normal mice, they were respectively 58% and 66% lower than those of the untreated FVC-infected mice. NK-cell activity was substantially lower in FVC-infected mice than in normal mice, while IL-7 restored NK-cell activity to normal levels. IL-6 and IFN-gamma levels were markedly reduced in FVC-infected mice compared to normal mice, but treatment of FVC-infected mice with IL-7 restored these cytokine levels. While the actual mechanisms of these effects are not yet known, the results suggest the potential therapeutic efficacy of IL-7 for certain hematopoietic and viral disorders, possibly mediated through an action on accessory cells and cytokine production.

Dietary hydrogen peroxide enhances hepatocarcinogenesis in trout: correlation with 8-hydroxy-2'-deoxyguanosine levels in liver DNA

The tumor-enhancing effect of hydrogen peroxide (H2O2) in N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-initiated rainbow trout hepatocarcinogenesis was investigated and correlated with the levels of the mutagenic DNA adduct 8-hydroxy-2'-deoxyguanosine (oh8dG). In addition, the protective role of vitamin E was examined in relation to tumor enhancement and oh8dG levels in liver DNA. Trout were fed diets containing two levels of vitamin E (1000 or 20 mg/kg wet wt), each of which were made up to contain three levels of H2O2 (0, 600 or 3000 p.p.m.). Dietary vitamin E levels had no significant effect on tumor incidence or levels of oh8dG in liver DNA. On the other hand, dietary H2O2 enhanced liver tumors in a dose-dependent manner. Liver tumor incidence correlated significantly with the mean level of liver DNA oh8dG content (r = 0.87). We conclude that the H2O2 tumor-enhancing effect coincides with higher levels of oh8dG in the trout liver genome. Thus, rainbow trout may be a useful model for the study of the relationship of oh8dG levels in vivo to enhancement or promotion of carcinogenesis and its modulation by dietary enhancers and inhibitors of oxidative stress.

Alterations in lipid peroxidation, antioxidant enzymes, and carcinogen metabolism in liver microsomes of vitamin E-deficient trout and rat

Feeding rainbow trout for 16 weeks a diet in which the levels of vitamin E were reduced 70-fold resulted in marked depletion (18-fold) of vitamin E levels in liver microsomes from these fish. The susceptibility of hepatic microsomes to lipid peroxidation in vitro and the levels of plasma and liver microsomal lipid hydroperoxides generated in vivo were markedly elevated in vitamin E-depleted trout. No appreciable alterations were observed in the liver microsomal cytochrome P450-dependent mixed-function oxidase system or in the fatty acid composition of trout liver microsomal membranes. Livers from rats fed a vitamin E-deficient diet for 10 weeks also had significantly lower levels of microsomal vitamin E. In addition, total cytochrome P450 levels were depressed (15%) and cytosolic glutathione was enhanced (40%) in livers from rats fed the vitamin E-depleted diet. Covalent binding of [3H]-(+)-benzo[a]pyrene-7,8-dihydrodiol to exogenous DNA in vitro was enhanced with liver microsomes from vitamin E-deficient trout and these fish were much more sensitive to the acute toxicity of this carcinogenic polycyclic aromatic hydrocarbon. These results indicate that trout may be a useful model for studying the significance of peroxidative pathways in carcinogenesis and their manipulation by dietary antioxidants.

Effect of mast cell growth factor (c-kit ligand) on clonogenic leukemic precursor cells

Mast cell growth factor (MGF), the ligand for the c-kit receptor, has been shown to be a hematopoietic growth factor that preferentially stimulates the proliferation of immature hematopoietic progenitor cells (HPC). We studied the effect of MGF on the in vitro growth of clonogenic leukemic precursor cells in the presence or absence of interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and/or erythropoietin (EPO). Leukemic blood and bone marrow cells from patients with various types of acute myeloid leukemia (AML), chronic myeloid leukemia (CML) in chronic phase, as well as bone marrow samples from patients with myelodysplastic syndromes (MDS) were studied. MGF as a single factor did not induce significant colony formation by clonogenic leukemic precursor cells. In the presence of IL-3 and/or GM-CSF, MGF weakly stimulated the colony formation by clonogenic precursor cells from patients with AML. In contrast, in the presence of IL-3 and/or GM-CSF, MGF strongly induced both size and number of leukemic colonies from patients with CML in chronic phase. Furthermore, in the presence of EPO, MGF strongly stimulated erythroid colony formation by CML precursor cells. Cytogenetic analysis of the colonies showed that all metaphases after 1 week of culture were derived from the leukemic clone. In patients with MDS, MGF strongly stimulated myeloid colony formation in the presence of IL-3 and/or GM-CSF (up to fourfold), and erythroid colony formation in the presence of EPO (up to eightfold). Not only the number, but also the size of the colonies increased. In the presence of MGF, the percentage of normal metaphases increased in three patients tested after 1 week of culture compared with the initial suspension, suggesting that the normal HPC were preferentially stimulated compared with the preleukemic precursor cells. In the absence of exogenous EPO and in the presence of 10% human AB serum, MGF in the presence of IL-3 and/or GM-CSF induced erythroid colony formation from normal bone marrow and patients with MDS or CML, illustrating that MGF greatly diminished the EPO requirement for erythroid differentiation. These results indicate that MGF may be a candidate as a hematopoietic growth factor to stimulate normal hematopoiesis in patients with acute myeloid leukemia, or with myelodysplastic syndromes.

Letter matching: effects of age, Alzheimer's disease, and major depression

We compared Alzheimer's disease (AD) patients and Major Depressive Disorder (MDD), Aged normal, and Young normal controls on a letter-matching task designed to measure the time needed to access overlearned linguistic information in long-term memory. Name identity (NI) and physical identity (PI) reaction time and the NI-PI difference were compared for ADs, MDDs, and Aged normals and separately for Aged and Young normal groups. AD subjects had slower NI and PI reaction times and a bigger NI-PI difference than Aged normal and MDD subjects, suggesting that speed of access to overlearned letter-name information in long-term memory is slowed for ADs. There were no reliable differences between Aged normal and MDD subjects. Aged normals had slower NI and PI reaction times and a bigger NI-PI difference than Young normals, suggesting that the highly practiced operations needed to access letter-name information slow with age. A discriminant analysis was used to evaluate the usefulness of the "easy to perform" letter-matching task for diagnostic purposes. Ninety percent of normal and MDD subjects but only 68% of AD subjects were classified correctly.

Effects of timolol, betaxolol, and levobunolol on human tenon's fibroblasts in tissue culture

Evidence has been found suggesting that long-term therapy with topical antiglaucoma medications may decrease the success of glaucoma filtering surgery. To investigate this question further, the antiproliferative effects of the preservative benzalkonium chloride and three pure and commercially available beta-adrenergic antagonist preparations (timolol, betaxolol, and levobunolol) were studied on tissue cultures of human Tenon's capsule fibroblasts. Each drug preparation was tested on three different cell lines. Fibroblast growth was measured with tritiated thymidine uptake and hexosaminidase assays. Trypan blue uptake was used to assess cell viability microscopically. The commercially available preparations containing benzalkonium chloride and those of betaxolol and levobunolol without the preservative had similar inhibitory doses for 50% of cells. The timolol preparation without preservative was significantly less toxic than its commercially available one. The three tested beta-adrenergic blockers did not stimulate fibroblast proliferation directly in this in vitro model. Even when the cultures were washed free of the drugs, growth continued to be suppressed, suggesting that the inhibition was not reversible. An increase in fibroblasts and inflammatory cells after long-term antiglaucoma medical therapy thus may be caused not by a direct stimulation of cell proliferation but by chronic inflammation from the irritating effects of antiglaucoma medications and/or their preservatives.

The Steel factor

Steel factor (SLF) is a recently identified growth factor which is the gene product of the murine Steel locus and a ligand for the c-kit tyrosine kinase receptor, the product of the dominant white spotting locus (W). Defects at these genetic loci result in aberrant melanocyte, germ cell, and hematopoietic development. Both the receptor (c-kit) and the ligand (SLF) have been shown to undergo tissue-specific mRNA splicing to produce distinct isoforms which have unique biological functions. As predicted by the phenotype of these mutations, SLF influences the growth and differentiation of melanocytes, primordial germ cells, and a broad spectrum of cell types in the hematopoietic progenitor and stem cell hierarchy. SLF has also been shown to have effects on hematopoietic lineages not predicted by defects seen in the Steel mouse.

Ex vivo expansion of peripheral blood progenitor cells with recombinant cytokines

Peripheral blood mononuclear cells were isolated and cultured in the presence of Steel factor and/or PIXY321, a GM-CSF/IL-3 fusion protein. We compared the number of colony forming cells (CFC) per culture on day zero to the number of CFC after liquid culture in the presence of these cytokines. After a four day incubation with PIXY321 and Steel factor the number of CFU-GM increased 5.6-fold and the number of BFU-E increased 2.2-fold in four separate experiments. The expansion on day 8 post incubation was 16.1-fold for myeloid colony formation and 9.7-fold for erythroid colony formation. These studies demonstrate the potential to expand CFC from peripheral blood with a simple ex vivo culture procedure.