ABSTRACT
The Id subfamily of helix-loop-helix (HLH) proteins plays a fundamental role in the regulation of cellular proliferation and differentiation. The major mechanism by which Id proteins are thought to inhibit differentiation is through interaction with other HLH proteins and inhibition of their DNA-binding activity. However, Id proteins have also been shown to interact with other proteins involved in regulating cellular proliferation and differentiation, suggesting a more widespread regulatory function. In this study we demonstrate functional interactions between Id proteins and members of the Pax-2/-5/-8 subfamily of paired-domain transcription factors. Members of the Pax transcription factor family have key functions in regulating several developmental processes exemplified by B lymphopoiesis, in which Pax-5 plays an essential role. Id proteins bind to Pax proteins in vitro and in vivo. Binding occurs through the paired DNA-binding domain of the Pax proteins and results in the disruption of DNA-bound complexes containing Pax-2, Pax-5, and Pax-8. In vivo, Id proteins modulate the transcriptional activity mediated by Pax-5 complexes on the B-cell-specific mb-1 promoter. Our results therefore demonstrate a novel facet of Id function in regulating cellular differentiation by functionally antagonizing the action of members of the Pax transcription factor family.
Subject(s)
DNA-Binding Proteins/antagonists & inhibitors , DNA-Binding Proteins/metabolism , Gene Expression Regulation , Helix-Loop-Helix Motifs , Neoplasm Proteins , Nuclear Proteins/antagonists & inhibitors , Repressor Proteins , Trans-Activators/antagonists & inhibitors , Transcription Factors/antagonists & inhibitors , Transcription Factors/metabolism , 3T3 Cells , Animals , Antigens, CD/genetics , Base Sequence , CD79 Antigens , COS Cells , DNA/genetics , DNA/metabolism , Inhibitor of Differentiation Protein 1 , Inhibitor of Differentiation Protein 2 , Inhibitor of Differentiation Proteins , Mice , Nuclear Proteins/metabolism , Oligodeoxyribonucleotides/genetics , Oligodeoxyribonucleotides/metabolism , PAX2 Transcription Factor , PAX5 Transcription Factor , PAX8 Transcription Factor , Paired Box Transcription Factors , Precipitin Tests , Promoter Regions, Genetic/genetics , Protein Binding , Proto-Oncogene Proteins/metabolism , Receptors, Antigen, B-Cell/genetics , Trans-Activators/metabolism , ets-Domain Protein Elk-1ABSTRACT
Analogues of methotrexate (MTX) were prepared by alkylation of side-chain precursors with 6-(bromomethyl)-2,4-pteridinediamine followed, where necessary, by saponification of the intermediate esters and, in two cases, by electrophilic substitution reactions in the pyridine ring portion of 3-deazamethotrexate. Effects of the various modifications on their ability to inhibit dihydrofolate reductase, cytotoxicity, and activity against L1210 leukemia in mice were examined in light of recent findings concerning active transport of MTX and related compounds and the binding features of the MTX-dihydrofolate reductase complex.
Subject(s)
Methotrexate/analogs & derivatives , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/therapeutic use , Carcinoma, Squamous Cell/drug therapy , Cell Survival/drug effects , Columbidae , Folic Acid Antagonists , Humans , In Vitro Techniques , Leukemia L1210/drug therapy , Liver/enzymology , Methotrexate/chemical synthesis , Methotrexate/pharmacology , Methotrexate/therapeutic use , Mice , Structure-Activity RelationshipABSTRACT
This study suggests that the thermal burden of poorly ventilated parked automobiles can be considerable, particularly when the automobiles are exposed to direct sunlight. Leaving the windows open two inches does not appear to be protective. The pratice of exposing infants and toddlers to such thermal risk appears to be common and the need for adequate ventilation unrecognized. Education measures stressing the use of carseats and other safety devices should include the potential hazards of high temperature in parked automobiles.
Subject(s)
Automobiles , Fever/etiology , Hot Temperature/adverse effects , Accident Prevention , Body Temperature Regulation , Female , Humans , Infant , Infant Care , Sunlight , Ventilation , WeatherABSTRACT
beta cells in the human fetal pancreas are immature in that they release little or no insulin in response to nutrients, such as glucose. The aim of this study was to examine further the immaturity of these cells, specifically regarding the storage and release of the precursor of insulin, proinsulin. Explants of human fetal pancreas were cultured in vitro for 3 weeks. Levels of proinsulin remained relatively constant throughout at 0.04 +/- 0.002 (S.E.M.) pmol/mg per day with a molar ratio of proinsulin to insulin of 2.2 +/- 0.11%. This low ratio was slightly greater than that observed in culture medium conditioned by adult human islets (0.3 +/- 0.1%), but similar to that found in acid-ethanol extracts of cultured explants (1.4 +/- 0.3%). Passaging of human fetal pancreas for 3 months in diabetic nude mice, which should have caused some maturation of the fetal beta cell, did not change the proportion of proinsulin present. Culture of explants in the presence of 12-O-tetra-decanoylphorbol-13-acetate resulted in some inhibition of proinsulin release, but much less than that for insulin, so that the molar ratio increased to 15.4 +/- 1.6% from the control 3.5 +/- 0.3%. Static stimulation of cultured explants with 10 mmol Ca2+/l, 10 mmol theophylline/l, and these two agents together caused 15-, 4- and 10-fold enhancement respectively of proinsulin release; glucose, leucine, arginine and KCl had no effect. In contrast, all these agents caused significant insulin release, the last four to a much smaller extent (less than or equal to three fold) than the first three (10-, 19- and 65-fold respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Islets of Langerhans/embryology , Proinsulin/metabolism , Animals , Calcium/pharmacology , Cytological Techniques , Humans , Insulin/metabolism , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Islets of Langerhans/physiology , Mice , Mice, Nude , Organ Culture Techniques , Radioimmunoassay/methods , Stimulation, Chemical , Tetradecanoylphorbol Acetate/pharmacology , Theophylline/pharmacologyABSTRACT
The immunohistochemical expression of the p53 gene protein was examined in a consecutive series of 143 cases of pure ductal carcinoma in situ (DCIS) of the breast. Expression of wild-type and/or mutant p53 protein was detected in 36 (25.2%) of the cases examined, as evidenced by positive nuclear staining with the monoclonal antibody DO 7. Thirty-four (35.8%) of the large cell cases showed p53 protein expression compared with two (4.1%) of the small cell cases (chi 2 = 15.3 [df = 1], P < .001). p53 Protein expression also was associated with an increased histologic degree of necrosis, with a nearly significant association of negative tumor estrogen receptor status and p53 protein expression. No significant association of p53 protein expression and c-erbB-2 protein expression was seen. Immunohistochemical expression of p53 protein is present in approximately 25% of DCIS cases and is confined almost exclusively to large cell DCIS, a morphologic subtype of in situ breast carcinoma thought to be more biologically aggressive. Expression of p53 protein may be important in the neoplastic progression of DCIS, reflecting the acquisition of p53 gene mutations in large cell DCIS cases. Therefore, p53 may be implicated in mammary tumor evolution from in situ to invasive disease.
Subject(s)
Breast Neoplasms/metabolism , Carcinoma in Situ/metabolism , Carcinoma, Intraductal, Noninfiltrating/metabolism , Proto-Oncogene Proteins/metabolism , Receptors, Estrogen/metabolism , Tumor Suppressor Protein p53/metabolism , Biomarkers, Tumor , Breast Neoplasms/pathology , Carcinoma in Situ/pathology , Carcinoma, Intraductal, Noninfiltrating/pathology , Female , Humans , Immunohistochemistry , Receptor, ErbB-2ABSTRACT
To address the myriad problems and challenges in the next year, the operative word will be partnership. That's according to members of Modern Healthcare's editorial advisory board in their discussion of the healthcare industry in 1991. The experts see the need for hospitals, physicians and the business community to team up to control costs, solve staffing woes and take initial steps toward healthcare reform.
Subject(s)
Hospital Administration/trends , Efficiency , Forecasting , Managed Care Programs , Physicians , United StatesSubject(s)
Folic Acid/chemical synthesis , Animals , Columbidae , Enterococcus faecalis/drug effects , Ethane/chemical synthesis , Ethane/pharmacology , Ethane/therapeutic use , Folic Acid/pharmacology , Folic Acid/therapeutic use , In Vitro Techniques , Leukemia L1210/drug therapy , Mice , Microbial Sensitivity Tests , Propane/chemical synthesis , Propane/pharmacology , Propane/therapeutic use , Protein Binding/drug effects , Structure-Activity Relationship , Tetrahydrofolate Dehydrogenase/metabolismSubject(s)
Folic Acid/chemical synthesis , Animals , Aza Compounds/chemical synthesis , Chemical Phenomena , Chemistry , Chromatography, DEAE-Cellulose , Columbidae , Folic Acid/administration & dosage , Folic Acid/therapeutic use , Folic Acid Antagonists , Hydrolysis , Leukemia L1210/drug therapy , Liver/enzymology , Methods , Mice , Neoplasm Transplantation , Transplantation, HomologousSubject(s)
Folic Acid/chemical synthesis , Thiazoles/chemical synthesis , Animals , Carcinoma , Cell Line , Chromatography, Thin Layer , Columbidae , Enterococcus faecalis/drug effects , Folic Acid/pharmacology , Folic Acid/therapeutic use , Folic Acid Antagonists , Humans , Laryngeal Neoplasms , Leukemia L1210/drug therapy , Liver/enzymology , Magnetic Resonance Spectroscopy , Malaria/drug therapy , Mice , Plasmodium berghei , Structure-Activity Relationship , Thiazoles/pharmacology , Thiazoles/therapeutic useABSTRACT
The impetus for this project is an attempt to describe by comparison and literature review a pain control program that would provide active patient participation in a highly structured, intense, objectively graded program of comprehensive functional restoration that meets governmental, medical, moral, and ethical standards. Brena indicates that "...there are too many facilities which claim to be pain clinics ... bewildering physicians about their choice for referring their patients."
Subject(s)
Pain Management , Humans , Pain/diagnosis , Pain, Intractable/diagnosis , Pain, Intractable/therapy , Patient Care Planning , Patient Participation , Quality of Health CareABSTRACT
This study documents the formation of leukocyte foci in the livers of mice infused with either normal or immune T cells and then challenged intravenously with Listeria monocytogenes. The results show that the transfer of antilisterial resistance occurred before mononuclear cell granuloma formation and was associated instead with the appearance of foci of infiltrating lymphocytes and neutrophils. Numbers of these foci remained low in mice which received immune cells but increased progressively until death in mice which received normal cells. These findings do not support the previous hypothesis that a major component of acquired resistance against Listeria infection involves the rapid generation of mononuclear cell granuloma formation under the control of immune T cells.
Subject(s)
Leukocytes, Mononuclear/immunology , Listeriosis/immunology , Animals , Granuloma/immunology , Granuloma/pathology , Immunization, Passive , Listeriosis/pathology , Liver/microbiology , Liver/pathology , Mice , Neutrophils/immunology , T-Lymphocytes/immunology , Time FactorsABSTRACT
The list of conditions associated with nonimmune hydrops fetalis has been steadily increasing. We describe a liveborn neonate with fetal hepatoblastoma presenting as nonimmune hydrops. The hepatic tumor was diagnosed on prenatal ultrasound. The infant survived for 2 days. The pathophysiology of nonimmune hydrops in this case is also described.
Subject(s)
Carcinoma, Hepatocellular/congenital , Hydrops Fetalis/etiology , Liver Neoplasms/congenital , Carcinoma, Hepatocellular/pathology , Female , Humans , Hydrops Fetalis/diagnosis , Infant, Newborn , Liver/pathology , Liver Neoplasms/pathology , PregnancyABSTRACT
Bacterial chemotactic peptides (F-met-oligopeptides) are secreted by several species of commensal enteric bacteria and can be assayed by bioassay techniques in human colonic luminal fluid. We have previously demonstrated intestinal absorption and enterohepatic circulation of radiolabelled F-met peptides introduced into rat colon, and an eightfold increase in absorption and biliary excretion in rats with experimental colitis. This paper describes the application of a radio-immunoassay to measurements of formyl oligopeptides in human faecal dialysates, colonic and systemic venous blood and bile. All samples were fractionated by reverse-phase high performance liquid chromatography (HPLC) prior to assay. Immunoreactivity was found in faecal dialysates (5-700 nmol/L F-met-leu-phe equivalents) and bile samples (3-150 nmol/L) from normal subjects. After HPLC fractionation, up to five distinct peaks of immunoreactivity were identified. One of these co-chromatographed with authentic F-met-leu-phe; the others probably represented either closely related peptides or peptides of different chain lengths originating from the same F-met-leu-phe precursor protein. Colonic venous blood from two patients with ulcerative colitis contained immunoreactive peptide (10-30 nmol/L) and substantial immunoreactivity was found in ileostomy fluid and bile from two patients with primary sclerosing cholangitis. These results suggest the presence of an enterohepatic circulation of bacterial F-met oligopeptides in man and provide a basis for studies of the role of such pro-inflammatory peptides in patients with inflammatory bowel disease and associated hepatobiliary disorders.
Subject(s)
Chemotactic Factors/analysis , Enterohepatic Circulation/physiology , Inflammatory Bowel Diseases/blood , N-Formylmethionine Leucyl-Phenylalanine/analysis , Radioimmunoassay/methods , Animals , Bile/chemistry , Chromatography, High Pressure Liquid , Feces/chemistry , Humans , RatsABSTRACT
Serum response elements (SREs) play important roles in transforming extracellular signals into specific nuclear responses. The SRE-binding protein, serum response factor (SRF), plays a pivotal role in this process. Several transcription factors have been shown to interact with SRF and thereby create distinct complexes with different regulatory potentials. The ETS domain transcription factor Elk-1 is one such protein and serves to integrate distinct mitogen-activated protein kinase cascades at SREs. Elk-1 uses a short hydrophobic surface presented on the surface of an alpha-helix to interact with SRF. In this study we have used site-directed mutagenesis to identify residues in SRF that comprise the Elk-1 binding surface. The Elk-1 binding surface is composed of residues that lie on a hydrophobic surface-exposed groove located at the junction of the MADS box and C-terminal SAM motif. Different residues are implicated in interactions between SRF and the transcription factor Fli-1, indicating that although some overlap with the Elk-1 binding surface occurs, their interaction surfaces on SRF are distinct. Our data are consistent with the hypothesis that the SRF DNA-binding domain acts as docking site for multiple transcription factors that can bind to small surface-exposed patches within this domain.
Subject(s)
DNA-Binding Proteins/metabolism , Nuclear Proteins/metabolism , Proto-Oncogene Proteins/metabolism , Transcription Factors/metabolism , Amino Acid Sequence , DNA/chemistry , DNA/metabolism , DNA-Binding Proteins/chemistry , DNA-Binding Proteins/genetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Nuclear Proteins/chemistry , Nuclear Proteins/genetics , Nucleic Acid Conformation , Protein Binding , Serum Response Factor , ets-Domain Protein Elk-1ABSTRACT
Urine samples from 36 workers exposed to dichlorobenzidine (DCB)-derived pigments and 12 controls were screened for aromatic amines by a nonspecific colorimetric method and then further analyzed by GC/MS specifically for DCB and monoacetyldichlorobenzidine. Of the samples screened for aromatic amines, six (17%) of the exposed population and one (7%) of the control population registered positive (1.0 part per billion [ppb] or greater). One of the positive samples (5.6 ppb) reflected medication, and the remainder (1.1 to 1.8 ppb) were due to high urinary background. The specific analyses were negative (less than 0.2 ppb) for DCB or monoacetyldichlorobenzidine in all samples.
Subject(s)
3,3'-Dichlorobenzidine/urine , Benzidines/urine , Occupational Diseases/prevention & control , Pigments, Biological , Textile Industry , 3,3'-Dichlorobenzidine/analogs & derivatives , Chromatography, Gas , Colorimetry , Humans , Mass SpectrometryABSTRACT
Bacterial chemotactic peptides are low molecular weight peptides which stimulate a wide range of neutrophil functions following binding to specific leucocyte receptors. Formyl methionyl leucyl phenylalanine (FMLP) is the major chemotactic peptide in Escherichia coli culture supernatants. This paper reports the development and validation of a radio-immunoassay (RIA) for FMLP and its application to the analysis of formyl peptide production by enteric bacteria in vitro. The assay was moderately sensitive (10 nmol/L FMLP) and highly specific showing cross reactivity with F-met-leu-tyr, F-nle-leu-phe and F-met-met-met sequences (ID50 = 200, 100 and 250 nmol/L, respectively) but no significant cross reactivity with non-formylated or other formylated di- and tri-peptides (ID50 = 10(5) nmol/L. Culture supernatants from five species of enteric bacteria were filtered, concentrated and fractionated by reverse phase high performance liquid chromatography before RIA. All five organisms produced immunoreactive F-met peptides. A major peak of immunoreactivity co-chromatographing with authentic FMLP was found in all supernatants, but additional peaks representing more hydrophobic peptides were found in Streptococcus faecalis and Bacteroides fragilis cultures. In E. coli culture supernatants, concentration of immunoreactive FMLP increased in a linear fashion during 3 h of log phase growth reaching 31.2 nmol/L(s.e.m. = 10) with final bacterial concentrations of 3 +/- 0.73 x 10(8)/mL (n = 6). These findings extend earlier work showing production of bioactive formyl oligopeptides by different species of enteric bacteria and suggest that a RIA for FMLP will be a useful tool for investigating the production and metabolic fate of such peptides in man.
Subject(s)
Chemotactic Factors/analysis , N-Formylmethionine Leucyl-Phenylalanine/analysis , Radioimmunoassay/methods , Animals , Bacteroides fragilis/metabolism , Enterococcus faecalis/metabolism , Escherichia coli/metabolism , Klebsiella pneumoniae/metabolism , Proteus vulgaris/metabolism , RabbitsABSTRACT
The expression of oestrogen receptor protein (ER) was examined in 151 cases of symptomatic or screening detected pure ductal carcinoma in situ (DCIS) of the breast by immunocytochemical assay (ERICA), in formalin-fixed paraffin-embedded tissue, with the monoclonal antibody H 222 (Abbott). Forty-eight tumours (31.8%) of cases were ER positive. Twenty-seven (17.9%) of cases showed high level ER expression and 21 (13.9%) of cases showed low level ER immunoreactivity. Significant associations of positive tumour ER immunoreactivity and non-comedo architecture chi 2 = 6.76; (d.f. = 1): P < 0.001, small cell size chi 2 = 4.49; (d.f. = 1): P = 0.034, higher S-phase fraction chi 2 = 4.71; (d.f. = 1): P = 0.03 and lack of c-erbB-2 protein overexpression chi 2 = 7.96; (d.f. = 1): P < 0.01 were identified. No significant associations of ER expression and patient age, histological grade of necrosis in DCIS, or DNA ploidy were found. ER expression is detectable in less than one third of symptomatic and screening detected cases of DCIS, implying that endocrine therapy of DCIS may be a more appropriate form of management for morphological subtypes of DCIS which show higher rates of oestrogen receptor expression, particularly those of non-comedo and small cell type.