Generation of an induced pluripotent stem cell line (UMi043-A) from an African American patient with Alzheimer's disease carrying an ABCA7 deletion (p.Arg578Alafs)

The ATP-binding cassette, subfamily A (ABC1), member 7 (ABCA7) gene is associated with Alzheimer's disease (AD) risk in populations of African, Asian, and European ancestry1-5. Numerous ABCA7 mutations contributing to risk have been identified, including a 44 base pair deletion (rs142076058) specific to individuals of African ancestry and predicted to cause a frameshift mutation (p.Arg578Alafs) (Cukier et al., 2016). The UMi043-A human induced pluripotent stem cell line was derived from an African American individual with AD who is heterozygous for this deletion and is a resource to further investigate ABCA7 and how this African-specific deletion may influence disease pathology.

Leveraging African American family connectors for Alzheimer's disease genomic studies

INTRODUCTION

The underrepresentation of African Americans (AAs) in Alzheimer's disease (AD) research may limit potential benefits from translational applications. This article describes an approach to recruit AA families into an AD genomic study and characteristics of seeds (family connectors) used to overcome recruitment barriers of AA families into AD research.

METHODS

A four-step outreach and snowball sampling approach relying on family connectors was used to recruit AA families. Descriptive statistics of a profile survey were gathered to understand the demographic and health characteristics of family connectors.

RESULTS

Twenty-five AA families (117 participants) were enrolled in the study via family connectors. Most family connectors self-identified as female (88%), were 60 years of age or older (76%), and attained post-secondary education (77%).

DISCUSSION

Community-engaged strategies were essential to recruit AA families. Relationships between study coordinators and family connectors build trust early in the research process among AA families.

HIGHLIGHTS

Community events were most effective for recruiting African American families. Family connectors were primarily female, in good health, and highly educated. Systematic efforts by researchers are necessary to "sell" a study to participants.

Neuropsychiatric features in a multi-ethnic population with Alzheimer disease and mild cognitive impairment

BACKGROUND

Alzheimer disease (AD) is more prevalent in African American (AA) and Hispanic White (HIW) compared to Non-Hispanic White (NHW) individuals. Similarly, neuropsychiatric symptoms (NPS) vary by population in AD. This is likely the result of both sociocultural and genetic ancestral differences. However, the impact of these NPS on AD in different groups is not well understood.

METHODS

Self-declared AA, HIW, and NHW individuals were ascertained as part of ongoing AD genetics studies. Participants who scored higher than 0.5 on the Clinical Dementia Rating (CDR) Scale (CDR) were included. Group similarities and differences on Neuropsychiatric Inventory Questionnaire (NPI-Q) outcomes (NPI-Q total score, NPI-Q items) were evaluated using univariate ANOVAs and post hoc comparisons after controlling for sex and CDR stage.

RESULTS

Our sample consisted of 498 participants (26% AA; 30% HIW; 44% NHW). Overall, NPI-Q total scores differed significantly between our groups, with HIW having the highest NPI-Q total scores, and by AD stage as measured by CDR. We found no significant difference in NPI-Q total score by sex. There were six NPI-Q items with comparable prevalence in all groups and six items that significantly differed between the groups (Anxiety, Apathy, Depression, Disinhibition, Elation, and Irritability). Further, within the HIW group, differences were found between Puerto Rican and Cuban American Hispanics across several NPI-Q items. Finally, Six NPI-Q items were more prevalent in the later stages of AD including Agitation, Appetite, Hallucinations, Irritability, Motor Disturbance, and Nighttime Behavior.

CONCLUSIONS

We identified differences in NPS among HIW, AA, and NHW individuals. Most striking was the high burden of NPS in HIW, particularly for mood and anxiety symptoms. We suggest that NPS differences may represent the impact of sociocultural influences on symptom presentation as well as potential genetic factors rooted in ancestral background. Given the complex relationship between AD and NPS it is crucial to discern the presence of NPS to ensure appropriate interventions.

The Puerto Rico Alzheimer Disease Initiative (PRADI): A Multisource Ascertainment Approach

Introduction

Puerto Ricans, the second largest Latino group in the continental US, are underrepresented in genomic studies of Alzheimer disease (AD). To increase representation of this group in genomic studies of AD, we developed a multisource ascertainment approach to enroll AD patients, and their family members living in Puerto Rico (PR) as part of the Alzheimer’s Disease Sequencing Project (ADSP), an international effort to advance broader personalized/precision medicine initiatives for AD across all populations.

Methods

The Puerto Rico Alzheimer Disease Initiative (PRADI) multisource ascertainment approach was developed to recruit and enroll Puerto Rican adults aged 50 years and older for a genetic research study of AD, including individuals with cognitive decline (AD, mild cognitive impairment), their similarly, aged family members, and cognitively healthy unrelated individuals age 50 and up. Emphasizing identification and relationship building with key stakeholders, we conducted ascertainment across the island. In addition to reporting on PRADI ascertainment, we detail admixture analysis for our cohort by region, group differences in age of onset, cognitive level by region, and ascertainment source.

Results

We report on 674 individuals who met standard eligibility criteria [282 AD-affected participants (42% of the sample), 115 individuals with mild cognitive impairment (MCI) (17% of the sample), and 277 cognitively healthy individuals (41% of the sample)]. There are 43 possible multiplex families (10 families with 4 or more AD-affected members and 3 families with 3 AD-affected members). Most individuals in our cohort were ascertained from the Metro, Bayamón, and Caguas health regions. Across health regions, we found differences in ancestral backgrounds, and select clinical traits.

Discussion

The multisource ascertainment approach used in the PRADI study highlights the importance of enlisting a broad range of community resources and providers. Preliminary results provide important information about our cohort that will be useful as we move forward with ascertainment. We expect that results from the PRADI study will lead to a better understanding of genetic risk for AD among this population.

Open-label randomized trial of torsemide compared with furosemide therapy for patients with heart failure

PURPOSE

Because the bioavailability of oral furosemide is erratic and often incomplete, we tested the hypothesis that patients with heart failure who were treated with torsemide, a predictably absorbed diuretic, would have more favorable clinical outcomes than would those treated with furosemide.

PATIENTS AND METHODS

We conducted an open-label trial of 234 patients with chronic heart failure (mean [+/- SD] age, 64 +/- 11 years) from an urban public health care system. Patients received oral torsemide (n = 113) or furosemide (n = 121) for 1 year. The primary endpoint was readmission to the hospital for heart failure. Secondary endpoints included readmission for all cardiovascular causes and for all causes, numbers of hospital days, and health-related quality of life.

RESULTS

Compared with furosemide-treated patients, torsemide-treated patients were less likely to need readmission for heart failure (39 [32%] vs. 19 [17%], P <0.01) or for all cardiovascular causes (71 [59%] vs. 50 [44%], P = 0.03). There was no difference in the rate of admissions for all causes (92 [76%] vs. 80 [71%], P = 0.36). Patients treated with torsemide had significantly fewer hospital days for heart failure (106 vs. 296 days, P = 0.02). Improvements in dyspnea and fatigue scores from baseline were greater among patients treated with torsemide, but the differences were statistically significant only for fatigue scores at months 2, 8, and 12.

CONCLUSIONS

Compared with furosemide-treated patients, torsemide-treated patients were less likely to be readmitted for heart failure and for all cardiovascular causes, and were less fatigued. If our results are confirmed by blinded trials, torsemide may be the preferred loop diuretic for patients with chronic heart failure.

A comparison of aorta and vena cava medial message expression by cDNA array analysis identifies a set of 68 consistently differentially expressed genes, all in aortic media

We performed a systematic analysis of gene expression in arteries and veins by comparing message profiles of macaque aorta and vena cava media using a cDNA array containing 4048 known human genes, approximately 35% of currently named human genes (approximately 11,000). The data show extensive differences in RNA expression in artery versus vein media. Sixty-eight genes had consistent elevation in message expression by the aorta, but none were elevated in the vena cava. The most differentially expressed gene was regulator of G-protein signaling (RGS) 5, at an expression ratio of 46.5+/-12.6 (mean+/-SEM). The data set also contained 2 genes already known to be expressed in the aorta, elastin at 5.0+/-1.4, and the aortic preferentially expressed gene 1 (APEG-1) at 2.3+/-0.6. We chose to analyze RGS5 expression further because of its high level of differential expression in the aorta. Levels of RGS5 mRNA were confirmed by Northern analysis and in situ hybridization. A human tissue RNA dot blot showed that RGS5 message is highest in aorta, followed by small intestine, stomach, and then heart. Northern analysis confirmed that RGS5 expression in human aorta is higher than in any region of the heart. RGS5 is a G-protein signaling regulator of unknown specificity most homologous to RGS4, an inhibitory regulator of pressure-induced cardiac hypertrophy. The expression pattern of the 68 differential genes as a whole is a start toward identifying the molecular phenotypes of arteries and veins on a systematic basis.

Plasminogen activator inhibitor type-1 and interleukin-6 in haemolytic uraemic syndrome

OBJECTIVE

Because haemolytic uraemic syndrome (HUS) is an important cause of renal dysfunction in children, the availability of prognostic markers of disease severity could assist in identifying those at risk of developing long-term sequelae. The aim of this study was to test the hypothesis that plasma levels of plasminogen activator inhibitor type-1 (PAI-1) and interleukin-6 (IL-6) in children at the time of diagnosis of HUS would predict renal function outcome in terms of glomerular filtration rate (GFR).

METHODOLOGY

Fourteen children suffering from diarrhoeal HUS were studied. Plasma samples were assayed for PAI-1 and IL-6, and GFR was measured at intervals after discharge from hospital. Twelve months following their recovery from HUS, the children were allocated to one of two outcome groups depending on whether GFR was above (Good Outcome, n = 9), or below (Poor Outcome, n = 5) 80 mL/min per 1.73 m2.

RESULTS

Elevated concentrations of PAI-1 were found in 4 of 5 Poor Outcome and 4 of 9 Good Outcome children. At the same time, increased concentrations of IL-6 were observed in 3 of 5 Poor Outcome and 3 of 9 Good Outcome children. Renal function continued to be compromised in four Poor Outcome children 36 months after diagnosis.

CONCLUSIONS

Our data show that PAI-1 and IL-6 are elevated in the plasma of some children at the time of diagnosis of HUS, but that neither is a definitive prognostic marker of poor outcome 3 years later.

Fas/FADD-mediated activation of a specific program of inflammatory gene expression in vascular smooth muscle cells

Apoptosis of smooth muscle cells is a common feature of vascular lesions but its pathophysiological significance is not known. We demonstrate that signals initiated by regulated Fas-associated death domain protein overexpression in rat vascular smooth muscle cells in the carotid artery induce expression of monocyte-chemoattractant protein-1 and interleukin-8, and cause massive immigration of macrophages in vivo. These chemokines, and a specific set of other pro-inflammatory genes, are also upregulated in human vascular smooth muscle cells during Fas-induced apoptosis, in part through a process that requires interleukin-1alpha activation. Induction of a pro-inflammatory program by apoptotic vascular smooth muscle cells may thus contribute to the pathogenesis of vascular disease.

CART peptides

CART peptides are among the newest putative peptide neurotransmitter/cotransmitters. They show no significant homology to any other peptide, and they are thought to have a role in reward and reinforcement, feeding, development, sensory processing, stress and endocrine control.

CART: from gene to function

CART was identified as a novel mRNA regulated by psychostimulant drugs. CART peptides appear to be neurotransmitters involved in a variety of functions such as feeding. The mouse gene has been characterized and localized to Chromosome 13. The processing of CART peptides is evident in Western blotting studies.

A systematic analysis of 40 random genes in cultured vascular smooth muscle subtypes reveals a heterogeneity of gene expression and identifies the tight junction gene zonula occludens 2 as a marker of epithelioid "pup" smooth muscle cells and a participant in carotid neointimal formation

An accumulation of evidence suggests that vascular smooth muscle is composed of cell subpopulations with distinct patterns of gene expression. Much of this evidence has come from serendipitous discoveries of genes marking phenotypically distinct aortic cultures derived from 12-day-old and 3-month-old rats. To identify more systematic differences, we isolated 40 genes at random from libraries of these 2 cultures and examined message expression patterns. To determine consistency of differential expression, we measured mRNA levels in 4 sets of cultures in 6 phenotypically distinct aortic cell clones and in balloon injured rat carotid arteries to determine the relevance of these differences in vitro to in vivo biology. The following 5 consistently differentially expressed genes were identified in vitro: zonula occludens 2 (ZO-2); peroxisome proliferator-activated receptor delta (PPARdelta); secreted protein, acidic and rich in cysteine (SPARC); alpha1(I)collagen; and A2, an uncharacterized gene. We examined these 5 clones during carotid artery injury and an inconsistently differentially expressed clone Krox-24 because, as an early response transcription factor, it could be involved in the injury response. PPARdelta, A2, and Krox-24 mRNAs were upregulated during the day after injury. ZO-2 and alpha1(I)collagen messages were modulated for up to a month, whereas SPARC message showed no consistent change. An analysis of ZO-2 and other tight junction genes indicates that tight junctions may play a role in smooth muscle biology. These data suggest that a systematic analysis of these libraries is likely to identify a very large number of differentially expressed genes. ZO-2 is particularly intriguing both because of this tight junction gene's pattern of prolonged over-expression after injury and because of its potential role in determining the distinctive epithelioid phenotype of smooth muscle cells identified in rat and other species.

In vitro metabolism of ceftiofur in bovine tissues

The metabolism of ceftiofur in bovine kidney, liver, muscle and lung, and the effects of the presence of cystine and glutathione in the media were evaluated using S-9 and microsomal tissue fractions. Conversion of ceftiofur to desfuroylceftiofur (DFC) was catalyzed by an esterase which was most active in kidney, followed by liver. It was not very active in muscle and lung. After DFC was liberated, it rapidly bound primarily to tissue proteins (> 56%), and was also conjugated to cysteine and glutathione. Production of DFC-cysteine by disulfide exchange of DFC with cystine and production of DFC-glutathione by conjugation of DFC to glutathione occurred in buffer if glutathione and cystine were present in the medium. These conjugations were also observed in incubations with tissue fractions, indicating that they were not inhibited by the tissues endogenous molecules. In addition, the metabolism of DFC-glutathione to DFC-cysteine was observed when tissue proteins were present. The metabolism of DFC-glutathione to DFC-cysteine was faster in kidney than in liver. Metabolites devoid of an intact beta-lactam ring were not observed in these in vitro studies.

Heterophilic NCAM-mediated cell adhesion to proteoglycans from chick embryonic brain membranes

The vertebrate neural cell adhesion molecule NCAM mediates adhesion by both homophilic and heterophilic mechanisms, with heparan sulfate proteoglycans (HSPGs) being likely heterophilic ligands. In this study, transfected chicken NCAM polypeptides expressed on mouse L cells mediated the adhesion of these cells to several different heparan sulfate proteoglycans in nonionic detergent extracts of Embryonic Day 10 chicken brain membranes. In addition, adhesion inhibition experiments suggested a hitherto-undetected role for chondroitin sulfate proteoglycans in the stimulation of NCAM-mediated adhesion to some, but not all, of the HSPG ligands. Our experiments support the view that NCAM is a multivalent adhesive molecule whose function is affected by interactions with extracellular matrix and cell surface molecules.

The large cytoplasmic domain is not required for concentration of N-CAM at cell-cell contacts in transfected mouse neuroblastoma cells

We examined the localization of the 140- and 180-kDa transmembrane isoforms of chicken N-CAM following transfection into mouse N2A neuroblastoma cells. Both isoforms were expressed at the cell surface and became partially or completely localized at areas of cell-cell contact after several days of culture or of in vitro differentiation. These results indicate that the presence of the large cytoplasmic domain of the 180-kDa N-CAM isoform is not necessary to bring about the localization of N-CAM to points of cell-cell contact.

Alpha-thrombin stimulates nuclear diglyceride levels and differential nuclear localization of protein kinase C isozymes in IIC9 cells

The mechanism by which an agonist, binding to a cell surface receptor, exerts an effect on events in the nucleus is not known. We have previously shown (Leach, K. L., Ruff, V. A., Wright, T. M., Pessin, M. S., and Raben, D. M. (1991) J. Biol. Chem. 266, 3215-3221) that alpha-thrombin treatment of IIC9 cells results in increased levels of cellular 1,2-diacylglycerol (DAG) and activation of protein kinase C (PKC). Here, we have examined whether changes in nuclear PKC and nuclear DAG also are induced following alpha-thrombin treatment. IIC9 cells were treated with 500 ng/ml alpha-thrombin, and nuclei were then isolated. Western blot analysis using isozyme-specific antibodies demonstrated the presence of PKC alpha, but not PKC epsilon or zeta in the nuclei of cells treated with either phorbol 12-myristate 13-acetate or alpha-thrombin. The increase in nuclear PKC alpha levels was accompanied by a 10-fold increase in nuclear PKC specific activity and stimulated phosphorylation of at least six nuclear proteins. The rise in nuclear PKC levels occurred rapidly and reached a maximum at 30-60 s, which was followed by a decline back to the control level over the next 15 min. In addition, alpha-thrombin treatment resulted in an immediate rise in DAG mass levels in the nuclear fractions. Kinetic analysis indicated that a maximum increase in DAG levels occurred 2.5-5 min after the addition of alpha-thrombin and remained elevated for at least 30 min. In cells labeled with [3H]myristic acid, alpha-thrombin treatment induced an increase in radiolabeled nuclear diglycerides, suggesting that the stimulated nuclear DAGs are derived, at least in part, from phosphatidylcholine. Our results suggest that increases in both nuclear DAG levels and PKC activity following alpha-thrombin treatment may play a role in mediating thrombin-induced nuclear responses such as changes in gene expression and cellular proliferation.

Tissue distribution and cellular localization of hsp56, an FK506-binding protein. Characterization using a highly specific polyclonal antibody

Heat shock protein 56 (hsp56) has been shown to be involved in two cellular pathways, as an immunophilin for FK506 and as a component of steroid receptor complexes. To help define its role in these cellular pathways, we have developed UPJ56, a polyclonal antibody raised against hsp56 purified from Jurkat cells. In Western blot experiments, hsp56 was highly expressed in rat thymus, liver, and spleen, with low levels in lung and muscle. In immunofluorescence experiments using untreated LLC-PK1 cells, fibrillar staining was seen in the cytoplasm, suggesting a cytoskeletal localization of hsp56. The nuclei were brightly stained, except for the nucleoli. Confocal microscopy demonstrated that the staining was present in all planes of the nucleus. These results suggest that hsp56 is expressed in tissues enriched in steroid receptors and is highly expressed in tissues involved in T cell function. Furthermore, the localization of hsp56 with the cytoskeleton and throughout the nucleus is consistent with its association with steroid receptor complexes.

HIV-1 protease cleaves actin during acute infection of human T-lymphocytes

Actin, one of the most abundant proteins of the cell, is hydrolyzed by the human immunodeficiency virus type 1 (HIV-1) protease during acute infection of cultured human T lymphocytes. The actin fragments produced during the course of infection are identical to those obtained by recombinant HIV-1 protease digests of (1) a lysate from uninfected T lymphocytes and (2) globular actin itself. Hydrolysis by the HIV-1 protease of physiologically important host cellular proteins during infection may have important consequences relative to viral pathogenesis.

Effects of trospectomycin on serum sensitivity of Escherichia coli UC 9451

Trospectomycin sulfate, a chemically synthesized analog of spectinomycin, exhibits a broad range of activity against both aerobes and anaerobes, including the etiological agents of sexually transmitted diseases. Its activity in vitro against Escherichia coli is considered only moderate. At subinhibitory levels, however, trospectomycin induced changes in a pathogenic strain of E. coli, UC 9451, which significantly increased its sensitivity to serum lysis. This strain of E. coli shows high-level resistance to serum in vitro, typically growing twofold within a 45-min incubation period. Following exposure to one-fifth the MIC of trospectomycin, greater than 99% of the bacteria were killed in 25% serum within 15 min. Surviving bacteria were static in this level of serum for over 3 h. Killing was due to lysis mediated by both the classical and alternative complement pathways. The bacteria exposed to trospectomycin were enlarged in both diameter and length, but they still grew at rates comparable to those of untreated bacteria. No other visible morphological changes could be directly related to the increase in serum sensitivity. The profile of outer membrane proteins obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was identical for trospectomycin-treated or untreated bacteria. However, the relative proportion of four major outer membrane proteins varied considerably.

Tumor progression- and metastasis-associated proteins identified using a model of locally recurrent rat mammary adenocarcinomas

A recently established model for local breast cancer recurrence using the 13762NF rat mammary adenocarcinoma was used to evaluate biologic and biochemical properties related to clinical outcome for this class of tumors. Sublines isolated from local tumor regrowths following surgical resection differed from each other and from the 'parental' cell lines for multiple phenotypes, including metastatic propensity. Local recurrence- and primary tumor-derived sublines were examined by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), lectin binding to electrophoretically separated proteins, and lactoperoxidase-catalyzed cell surface iodination; and differential protein patterns were compared to tumor progression and metastatic potential. 2D-PAGE revealed several quantitatively different spots which correlated with lung colonization potential. In particular, quantities of an apparently unique, non-cell-surface protein, P50.9 (Mr approximately 50,900, pI approximately 7.3) correlated inversely with metastatic propensity, suggesting that it may be associated with, among other possibilities, the negative regulation of the metastatic phenotype. P50.9 was unrelated to four similarly sized metastasis-associated proteins--tumor autocrine motility factor; the rat analog of tumor suppressor, p53; rat cytokeratin 14 or procathepsin D--as determined by amino acid analysis. A major wheat germ agglutinin binding sialoglycoprotein, gp93 (Mr approximately 93,000), was present in smaller amounts as cells were passaged in vivo and re-established as in vitro cultures [MTF7 greater than 'primary' tumor-derived lines (sc1, sc3) much greater than local recurrence-derived lines (LR1, LR1a, LR3, LR4, LR5, LR6)]. Besides cell surface glycoprotein losses, two of six local recurrence-derived sublines expressed a wheat germ agglutinin-binding sialoglycoprotein, gp110 (Mr approximately 110,000), previously undetected on any of the other cell lines including the parental populations. gp110 was found in LR3 and LR6 which were relatively highly metastatic; however, correlation with metastatic potential failed because gp110 was not present on the metastatic parental cell line, MTF7. These results demonstrate specific quantitative and qualitative protein differences associated with the selection of locally recurrent mammary tumors.

Rapid modulation of a 64 K dalton fibroblast protein: a PDGF mediated early cellular event

The results presented here reveal a novel platelet derived growth factor (PDGF) mediated early cellular event. Treatment of growth arrested Balb/c3T3 fibroblasts with PDGF induces a specific and rapid modulation of a 64,000 Dalton (64 KD) protein preexisting in quiescent cells. The kinetics of 64 KD protein modulation indicate that, temporally, this PDGF mediated step lies between the membrane associated immediate events such as receptor autophosphorylation or ion mobilization and the earliest known transcriptional event, the activation of the proto-oncogene c-fos.

Dietary management of canine and feline chronic renal failure

Nutritional therapy is the mainstay of management of chronic renal failure in dogs and cats. Diets designed for use in renal failure are typically reduced in protein, phosphorus, and sodium content. These and other dietary modifications are designed to prevent or ameliorate clinical signs of uremia, minimize disturbances associated with excesses or losses of electrolytes and minerals, arrest or retard progression of renal failure, and maintain adequate nutrition.

Mode of fibroblast growth enhancement by human interleukin-1

Previous studies have demonstrated that interleukin-1 (IL-1) stimulates fibroblast growth (Schmidt, J. A., S. B. Mizel, D. Cohn, and I. Green. 1982. J. Immunol. 128:2177-2182) and binds to specific, high affinity receptors of BALB/c3T3 cells (Bird, T. A., and J. Saklatval. 1986. Nature (Lond.). 324:263-265, 266-268). We have investigated the mechanism of fibroblast growth stimulation by IL-1. Addition of fibroblast growth factor derived from platelets (PDGF) to a quiescent culture of BALB/c3T3 cells produced 8-10-fold increase in DNA synthesis during 24-h incubation. The cellular action of PDGF was mediated through competence induction and required synergistic action of plasma-derived factors for full mitogenic activity. When tested at a wide range of concentrations (0.1-100 pM), natural IL-1 or recombinant IL-1 produced only a maximum of 5-10% of DNA synthesis elicited in response to PDGF or serum. Induction of DNA synthesis required continuous presence of IL-1 and did not exhibit synergism with plasma. Competence induction and mitogenic stimulation by PDGF was associated with early induction of proteins P32, P38, P46-48, P75, and changes in cytoskeletal organization. Examination of these early cellular changes showed that IL-1 did not produce similar induction of cellular proteins and the morphological changes associated with growth stimulation. These results suggest that the mode of IL-1 action on BALB/c3T3 was not through competence induction. When IL-1 was added to cells rendered competent by brief exposure to PDGF, 10-15% additional DNA synthesis occurred during the first 24 h. Extended incubation of PDGF-treated cells in the presence of IL-1 revealed that the stimulation by IL-1 occurred predominantly during the subsequent cycle of DNA replication, wherein DNA synthesis reached three- to fivefold higher than the untreated cultures. We conclude (a) IL-1 alone is not a potent mitogen for BALB/c3T3 cells, and does not bring cells out of the growth arrest Go phase, (b) treatment with PDGF renders the cells more responsive to IL-1, (c) part of the IL-1 action on competent cells may be characterized as progression inducing activity, further, (d) our results indicate that action of IL-1 on PDGF-treated cells produces sustained DNA synthesis for an extended period, perhaps by preventing the entry of cells into growth arrest Go phase.

A nonurea electrophoretic gel system for resolution of polypeptides of Mr 2000 to Mr 200,000

A sodium dodecyl sulfate-polyacrylamide gel electrophoresis system which resolves proteins and peptides from Mr 2000 to Mr 200,000 is described. Gradients of polyacrylamide, crosslinker, and glycerol buffered in Tris-phosphate (pH 6.8) are employed. Neither urea nor a stacking gel is required. This system has been used to separate molecules below Mr 3000 which differed by only seven amino acid residues, yet has the capacity to survey masses up to Mr 200,000 on the same gel. Examples are given for separations of myoglobin cyanogen bromide fragments and adrenocorticotropin peptides. Utilizing the same gradient slab gel system in tandem with isoelectric focusing, a two-dimensional separation pattern of mammalian liver cell lysate is shown. A comparison of two different silver stain methods with this system is also given.

The antigenic relatedness of proteins from human and simian prostate fluid

Two-dimensional electrophoretic analysis of human prostate fluid reveals an abundant protein migrating to a molecular weight of 15 kD and an isoelectric point of 5.5. Polyclonal antibodies were raised specifically to microgram quantities of electrophoresed, excised, and eluted PSP15 (prostate secretory protein). Western immunoblot analysis using these antibodies showed they not only react to PSP15, but cross-react with simian prostate and human seminal fluid proteins of similar molecular weights. Two-dimensional gel immunoblots strongly suggest that the seminal protein and PSP15 are the same, thereby providing a more accessible source of the protein. The antibody to the human PSP15 cross-reacted with neither prostate fluid from the ventral lobe of the rat prostate nor the prostate fluid from the beagle dog.

Insulin-induced rapid decrease of a major protein in fat cell plasma membranes

In order to increase our understanding of the mode of action of insulin in rat fat cells, we investigated the effect of insulin on protein concentrations in purified fat cell fractions using two-dimensional electrophoresis in combination with an ultrasensitive color silver stain technique. Incubation of fat cells with insulin caused a 90% decrease in the plasma membrane concentration of a major plasma membrane protein with a molecular mass of 90 kDa. The insulin effect was dose-dependent with a half-maximal effect at 9.5 microunits/ml, and time-dependent with a t 1/2 of less than 20 s. Insulin-like growth factor I, orthovanadate, and lanthanum mimicked the effect of insulin. Likewise, fractionation of adipocytes in the presence of divalent cation chelating agents caused a similar reduction in the concentration of the 90 kDa protein, and it was possible to overcome the effects of the chelating agents by adding equivalent amounts of calcium. This suggests the involvement of calcium. The 90 kDa protein was also found in low and high density microsomes, but it was not affected in those fractions by either insulin or chelators. It is suggested from the study that the movement of a 90 kDa protein in fat cell plasma membranes probably represents part of the transmission system in the mechanism of insulin action in rat adipocytes.

Alloxan-induced hyperglycemia in rats is reduced by 16,16-dimethyl-PGE2

Female rats were treated with subcutaneous 16,16-dimethyl-PGE2 (1-75 micrograms/kg) for 24, 18, and 0.5 h prior to and 6, 24, and 48 h after intravenous beta cell destruction. Protection was assessed by morphological examination of beta cells and the level of fasting hyperglycemia seen 72 h after alloxan treatment. Prostaglandin reduced the degree of alloxan-induced hyperglycemia in a dose-dependent fashion but had no demonstrable effect on morphological assessment of beta cell destruction. However, prostaglandin treatment by itself induced transient (0-2 h) hyperglycemia that could be correlated inversely with the level of fasting blood glucose observed 72 h after alloxan treatment. Administration of oral glucose, which mimics the prostaglandin-induced hyperglycemia, afforded protection against alloxan challenge comparable to that produced by the prostaglandin. Thus, it appears that reduction of alloxan-induced hyperglycemia by 16,16-dimethyl-PGE2 may be linked to the transient hyperglycemia produced prior to alloxan administration.

Measuring various drug use dimensions with a calendar method

This note presents a technique used to acquire a variety of time-specific data on drug use. The calendar technique involves self-reported patterns of consumption and any changes therein, including cessation. Advantages of this technique over other approaches are discussed, and examples of the variety of use measures that can be derived from the calendar method are illustrated.