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Biomedical subjects

R Stein

Publications and source records attributed to R Stein.

At least 217 records · Page 12Linked to original sources
PubMed1990

Murine monoclonal antibodies raised against human non-small cell carcinoma of the lung: specificity and tumor targeting.

The tumor targeting properties of murine monoclonal antibodies (MAbs) generated in our laboratory against non-small cell carcinoma of the lung have been investigated in nude mouse xenograft models. The MAbs selected for evaluation, RS5-4H6, RS7-3G11, and R511-51, have pancarcinoma reactivity, as shown by immunoperoxidase staining of the majority of tumors from the lung as well as breast, colon, kidney, and ovary. The localization of the three MAbs which bind to distinct antigens, and exhibit different levels of cross-reactivity with normal human epithelial tissues, are compared. The MAbs are of the IgG1 isotype. Since these MAbs were reactive with Calu-3, a human adenocarcinoma of the lung cell line grown as xenografts in nude mice, this system was selected as our initial tumor target. The MAbs were found to localize preferentially to the heterotransplanted tumors, with from 6.6 to 8.6% of the injected dose per gram accreting in the tumor at 7 days. Tumor/nontumor ratios of up to 9.7 were seen with one MAb at day 14. The targeting of MAb RS11-51 and F(ab')2 fragments of RS11-51 in GW-39, a human colon cancer grown in nude mice, was also studied. Accretion of intact RS11-51 and F(ab')2 fragments into GW-39 was greatly increased compared to Calu-3. In view of the high frequency of antigen expression on a wide variety of tumors, and the ability to target in vivo, these new MAbs may have potential use in the imaging and therapy of cancer.

Animals↗
PubMed1990

Effect of nerve growth factor and fibroblast growth factor on SCG10 and c-fos expression and neurite outgrowth in protein kinase C-depleted PC12 cells.

The role of protein kinase C (PKC) in mediating nerve growth factor (NGF) or basic fibroblast growth factor (bFGF)-stimulated SCG10 and c-fos expression as well as neurite outgrowth was studied in PC12 cells. Activators of PKC such as phorbol 12-myristate 13-acetate (PMA) or 1-oleoyl 2-acetyl glycerol mimicked the stimulatory effect of NGF and bFGF on SCG10 mRNA levels. Induction involved a protein synthesis-dependent mechanism and was maximal within 12-24 h of exposure. Chronic treatment of the cells with PMA for up to 8 days resulted in a substantial decrease (approximately 90%) in total PKC activity in the continued presence of PMA. PKC depletion did not affect NGF- or bFGF-stimulated SCG10 mRNA induction and bFGF-stimulated c-fos mRNA induction. However, NGF-stimulated c-fos mRNA induction was attenuated. In addition, induction of neurite outgrowth was not abolished in PKC-depleted cells. The results imply that PKC is not involved in NGF- and bFGF-stimulated SCG10 mRNA induction and neurite outgrowth. Furthermore, while the effect of bFGF on c-fos mRNA induction is PKC-independent, that of NGF is mediated by PKC-dependent and -independent pathways.

Adrenal Gland Neoplasms↗
PubMed1990

Carcinoembryonic antigen and alpha-fetoprotein expression and monoclonal antibody targeting in a human hepatoma/nude mouse model.

Hep G2, a human hepatocellular carcinoma, was grown s.c. in nude mice, as well as in tissue culture. This line retains the normal liver parenchymal cell capacity to synthesize human plasma proteins such as albumin, but there is no indication that it harbors the hepatitis B virus. We have detected the oncofetal antigens alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) in both Hep G2 xenografts and spent tissue culture media by Ouchterlony double diffusion assays, enzyme-linked immunosorbent assay, and immunohistology. By enzyme-linked immunosorbent assay, the AFP levels were 544.9 ng/ml in the cell culture and 1.6 microgram/g in saline extracts of the xenograft. The CEA levels were 35.2 ng/ml in the cell culture and 5.4 micrograms/g in the xenograft. The biodistribution of a radioiodinated anti-AFP murine monoclonal antibody and an anti-CEA monoclonal antibody were studied separately in nude mice bearing s.c. Hep G2 xenografts in comparison to an isotype-matched irrelevant IgG (Ag8). Anti-CEA antibody showed a preferential localization for Hep G2, but anti-AFP antibody did not. Immunohistochemical studies of the Hep G2 tumor, using biotinylated anti-AFP and anti-CEA, indicate both cytoplasmic and luminal staining of CEA and AFP in the tumor. These results suggest that Hep G2 may be a useful cell line for radioimmunodetection and radioimmunotherapy studies using anti-CEA and possibly anti-AFP monoclonal antibodies.

Animals↗
PubMed1990

Monoclonal antibody targeting of human non-small cell carcinoma of the lung.

Murine monoclonal antibody RS5-4H6 is an IgG1, which was raised against a crude membrane preparation of Calu-3, a human adenocarcinoma of the lung cell line. MAb RS5-4H6 reacts with the majority (14 of 15) of surgical specimens of non-small cell carcinomas of the lung by immunoperoxidase staining. Reactivity with this antibody was not limited to tumors of the lung but rather exhibited pancarcinoma reactivity, staining 87% of tumors from all organs tested. In this study we examined the potential of radiolabeled RS5-4H6 to target Calu-3 xenografts in nude mice. The monoclonal antibody was found to localize preferentially to the heterotransplanted tumors, with 6.6% of the injected dose/g accreting in the tumor at 7 days, a 3-fold higher level than an anti-carcinoembryonic antigen monoclonal antibody which was used as a negative control.

Animals↗
PubMed1990

Indications for selective coupling to phosphoinositide hydrolysis or to adenylate cyclase inhibition by endogenous muscarinic receptor subtypes M3 and M4 but not by M2 in tumor cell lines.

The muscarinic receptor subtype mRNAs expressed in cell lines were determined by Northern blot analysis. The biochemical responses of the muscarinic receptors in these cell lines (phosphoinositide hydrolysis and cAMP levels) were studied and correlated to the corresponding muscarinic receptor subtype as determined by mRNA expression. PC12 cells that expressed M4 subtype mRNA exhibited muscarinically dependent adenylate cyclase inhibition, whereas C6 and SK-N-SH cells expressing M3 subtype mRNA exhibited muscarinically dependent phosphoinositide hydrolysis. IMR-32 cells (M2 subtype mRNA) exhibited both muscarinically dependent phosphoinositide hydrolysis and adenylate cyclase inhibition. These results suggest that endogenous M3 and M4 receptor subtypes are selectively coupled to phosphoinositide hydrolysis and adenylate cyclase inhibition, respectively, whereas the M2 receptor subtype is coupled to both responses.

Adenylyl Cyclases↗
PubMed1990

Complotypes in individuals of African origin: frequencies and possible extended MHC haplotypes.

We analyzed the frequency distribution of 106 complotypes [four allele sets of the major histocompatibility complex (MHC) genes for the complement proteins factor B, C2, C4A, and C4B] from 32 Black families residing in Boston and Washington, DC. Twenty-five different complotypes were identified, among which there were four complotypes that had not been previously observed in our large database of complotypes compiled from family studies of Boston Caucasians and that are, presumably, unique to individuals of African origin. These four African-derived complotypes are FC(1,90)0, FC63, S1C2, 17, and SC(3,2,90)0. The frequencies of two of these four unique Black complotypes, FC(1,90)0 and FC63, were increased significantly when compared to Caucasians (pcorr less than 0.00042, pcorr = 0.00294, respectively). The complotype FC(1,90)0 was in positive linkage disequilibrium with HLA-DR3 haplotypes containing the B locus antigens Bw42, Bw52, Bw53, and Bw58, while FC63 was associated with HLA-Bw70, -DR5. These findings demonstrate the extensive polymorphism of complotypes in Blacks, and also suggest that it may be possible to define unique extended haplotypes of African origin.

Alleles↗
PubMed1990

Survey of cardiac rehabilitation centers in New York City.

Out-patient cardiac rehabilitation centers in New York City were surveyed in order to determine current practices. All 24 centers operating as of May, 1987 were sent questionnaires; 16 responded for a return rate of 67 percent. In general, practices of the centers were in accord with guidelines of the American Heart Association (AHA) and the American College of Sports Medicine. The incidence of medical complications in the centers was quite rare, perhaps accounting for the failure of centers to follow all emergency guidelines of the AHA, such as daily testing of the defibrillator. The major aim of the centers was to enhance physiological status, rather narrowly defined as aerobic fitness and cardiovascular function. Little attention was paid to nutrition, body composition and strength, despite the fact that the value of broadening the concept of fitness to include these parameters is becoming evident. Lifestyle counseling to help in long-term rehabilitation was also rare. Third party payers should be encouraged to support such components of a rehabilitation program so that centers would be more likely to incorporate them.

Ambulatory Care↗
PubMed1990

A cell type-preferred silencer element that controls the neural-specific expression of the SCG10 gene.

SCG10 is a growth-associated protein that is expressed early in the development of neuronal derivatives of the neural crest. We describe here the isolation of the SCG10 chromosomal gene and the identification of regulatory regions that control its expression. The SCG10 transcription unit spans approximately 40 kb. Like other neural-specific genes, SCG10 contains multiple transcription initiation sites. The gene contains a constitutive enhancer-like element in the promoter-proximal region and a silencer located farther upstream. This silencer preferentially suppresses the activity of the enhancer in nonneuronal cells. Furthermore, the silencer is able to confer such preferential suppression upon a heterologous promoter in an orientation-independent manner. These data suggest that the expression of SCG10 in neuronal cells depends predominantly upon specific derepression.

Animals↗
PubMed1990

Risk factors for Pseudomonas aeruginosa colonization in cystic fibrosis patients.

In an attempt to study the association between Pseudomonas aeruginosa colonization and clinical factors present before colonization, we studied 502 patients who attended our cystic fibrosis (CF) clinic between 1975 and 1988 and who were not colonized with P. aeruginosa before the study period. Twelve percent of the patients became colonized with P. aeruginosa before the age of 1 year and 44% by the age of 7 years. In a birth cohort followed from diagnosis during the study period, 23% were colonized with P. aeruginosa before age 1 year and 67% before age 7 years. Early P. aeruginosa colonization was associated with early diagnosis of CF. Presence of meconium ileus, gastrointestinal symptoms and pancreatic insufficiency at the time of diagnosis was also associated with early colonization. There was no association between the presence of respiratory symptoms at the time of diagnosis and age at first P. aeruginosa colonization. In families in which more than one sibling had CF, the age of P. aeruginosa acquisition was similar in the first colonized and the subsequently colonized siblings. In the year before the colonization patients with P. aeruginosa who were older than 1 year had higher rates of hospitalization and spent more days in hospital compared with patients without P. aeruginosa. In conclusion most P. aeruginosa colonization occurs at a younger age than previously reported. Early age at diagnosis and presence of CF-associated gastrointestinal abnormalities increase the likelihood of earlier colonization of P. aeruginosa.

Age Factors↗
PubMed1990

Identification of a pancreatic beta-cell insulin gene transcription factor that binds to and appears to activate cell-type-specific expression: its possible relationship to other cellular factors that bind to a common insulin gene sequence.

The insulin gene is expressed almost exclusively in pancreatic beta-cells. Previous work in our laboratory has shown that pancreatic beta-cell-specific expression of the rat insulin II gene is controlled by a number of positive and negative cis-acting DNA elements within the enhancer. We have shown that one element within the enhancer, located between nucleotides -100 and -91 (GCCATCTGCT; referred to as the insulin control element [ICE]) relative to the transcription start site, is controlled by both positive- and negative-acting cellular transcription factors. The positive-acting factor appears to be uniquely active in beta-cells. To identify the nucleotides within the ICE that mediate positive cell-type-specific regulation, point mutations within this element were generated and assayed for their effects on expression. Base pairs -97, -94, -93, and -92 were found to be crucial for the activator function of this region, while mutations at base pairs -100, -96, and -91 had little or no effect on activity. The gel mobility shift assay was used to determine whether specific cellular factors associated directly with the ICE. Several specific protein-DNA complexes were detected in extracts prepared from insulin-producing and non-insulin-producing cells, including a complex unique to beta-cell extracts. The ability of unlabeled wild-type and point mutant versions of the ICE to compete for binding to these cellular factors demonstrated that the beta-cell-specific complex appears to contain the insulin gene activator protein(s). Interestingly, the adenovirus type 2 major late promoter upstream element (USE; GCCACGTGAC) also competed in the gel mobility shift assay for binding of cellular proteins to the ICE. These results suggested that the cellular factor that binds to the USE (i.e., USF) also interacts with the ICE. This was directly demonstrated by showing that ICE and USE sequences completed for the USF required for adenovirus type 2 major late promoter transcription in vitro and by showing that reticulocyte lysate-translated human USF products bound to the ICE. However, the USE sequences were unable to stimulate beta-cell-type-specific activity in vivo. We discuss the possible relationship of these observations to positive and negative control mediated by the ICE.

Animals↗
PubMed1990

Predicting the need for hospitalization in children with acute asthma.

In an attempt to identify factors which influence the decision of physicians to admit patients with acute asthma to the hospital, we studied prospectively 200 children (age 5.6 +/- 3.1 years, mean +/- SD) presenting to our emergency room with acute asthma. The children were assessed on arrival, and on disposition from the Emergency Room by one of the investigators. After obtaining historic data, a clinical score was assigned, and oxygen saturation and pulmonary function were measured. Of the 134 (67 percent) children who were discharged home from the Emergency Room, five returned within seven days and one was subsequently admitted. The clinical score on disposition was the sole variable found to best predict the decision for hospitalization (sensitivity 73 percent, specificity 95 percent). Of the variables obtained at presentation, the resulting decision tree found the clinical score to predict the decision for hospitalization (sensitivity 79 percent, specificity 75 percent). When the individual components of the clinical score were analyzed, the degree of dyspnea, as assessed by the investigator, was chosen as the rule to predict the hospitalization decision (sensitivity 88 percent, specificity 71 percent). We conclude that the decision with respect to the need for hospitalization in acute childhood asthma, is in practice based mainly on careful clinical evaluation. Pulmonary function and SaO2 measurements, although helpful adjuncts in the assessment of acute asthma, do not appear to contribute to the identification of patients who need hospital admission.

Asthma↗
PubMed1990

Response of acute asthma to a beta 2 agonist in children less than two years of age.

The management of the young asthmatic child is still controversial and it has been questioned whether the infant and very young child with asthma respond to beta 2 agonists. We studied the response to nebulized beta 2 agonists in 43 children under the age of 2 years who presented to the emergency room with acute asthma. Clinical score and oxygen saturation were determined on admission to the emergency room and at least 30 minutes after each inhalation. The clinical score was defined as the sum of five variables (heart rate, respiratory rate, dyspnea, accessory muscle use, and wheezing), each graded as 0 or 1. The mean clinical score improved significantly after nebulized albuterol (mean +/- SD, 3.75 +/- 1.2 versus 2.80 +/- 1.65, P less than .01). Mean oxygen saturation did not change significantly (mean +/- SD, 94.8% +/- 2.85 versus 95.2% +/- 2.54). Only three patients had a decrease in arterial oxygen saturation of greater than 2% (3% in each one of them) following bronchodilator therapy. Our results suggest beta 2 inhalation to be beneficial to the majority of asthmatic children younger than 2 years of age and safe to administer. The combination of clinical score and oxygen saturation provides a simple noninvasive method of monitoring the response to therapy in young children with acute asthma.

Acute Disease↗
PubMed1990

A new look at the theory of Melanie Klein.

This paper tried to show that Melanie Klein's theory can very profitably be viewed as a descriptive theory of strong emotions rather than an instinct or developmental theory. Furthermore, since in Klein's thinking feelings 'create' objects, the primacy of feelings in this theory is central. The paper contains a short chronological study of Klein's formulations of psychic phenomena in terms of affects. It is also maintained that the paranoid-schizoid and the depressive positions are constellations of affects and of reactions to them; that psychic development is essentially in terms of the capacity to tolerate feelings, and that the basic conflict in mental life is between feelings of love and hate and associated feelings. Such a view solves many of the conceptual difficulties of Kleinian theory and in addition promises rewarding insights into the world of feelings.

Affect↗
PubMed1989

Human lung carcinoma monoclonal antibody specific for the Thomsen-Friedenreich antigen.

A monoclonal antibody, RS1-114, was raised against the human adenocarcinoma of the lung cell line A549. By studying the reactivity of RS1-114 with A549 cells following chemical and enzymatic treatments, it was shown that the epitope is a galactose-containing carbohydrate, which is devoid of sialic acid. Hemagglutination of desialylated RBCs, enzyme-linked immunosorbent assay studies with glycoprotein antigens before and after desialylation, and competition studies using peanut agglutinin indicate that monoclonal antibody RS1-114 recognizes the Thomsen-Friedenreich antigen, a cryptic determinant on human erythrocytes which can be exposed by neuraminidase treatment. It is expressed in an unhidden form on a large percentage of carcinomas and is therefore an important human tumor marker. RS1-114 is reactive with cryptic determinants of the Thomsen-Friedenreich antigen on white blood cells as well as red blood cells, and it reacts with unhidden determinants on human tumor cell lines. The number of binding sites on carcinoma cells is further increased by neuraminidase treatment. By immunohistochemical staining, it was shown that 75% of the human tumors tested are reactive with RS1-114. These include tumors of the breast, colon, lung, kidney, ovary, and rectum.

Adenocarcinoma↗
PubMed1989

A semicontinuous, high-performance liquid chromatography-based assay for stromelysin.

A search for low molecular weight peptide substrates for the metalloendoproteinase, human fibroblast stromelysin, resulted in the discovery that substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2) is a substrate for this enzyme and is cleaved exclusively at the Gln6-Phe7 bond. On the basis of this observation, a semicontinuous HPLC-based assay was developed that monitors the production of the hydrolysis product, fragment 7-11 (SP7-11). Steady-state velocities for the production of SP7-11 have been determined as a function of substrate concentration and obey simple, Michaelis-Menten kinetics. For a 1-ml reaction volume, Vmax = (2.4 nmol SP7-11/min)/micrograms protein and Km = 0.38 mM.

Chromatography, High Pressure Liquid↗