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M Rubinstein

Publications and source records attributed to M Rubinstein.

At least 91 records · Page 5Linked to original sources
PubMed1994

The secreted tumor-associated antigen 90K is a potent immune stimulator.

Immunization of mice with conditioned media from human breast cancer cells yielded the monoclonal antibody SP-2, which recognized an antigen of approximately 90-95 kDa. This protein, designated 90K, was found to be present in the serum of healthy individuals and at elevated levels in the serum of subpopulations of patients with various types of cancer and AIDS. Here we report the primary structure of the SP-2 antigen and demonstrate its relationship to a family of proteins which carry a scavenger receptor cysteine-rich domain. Northern blot analysis of normal tissues, primary tumors, and tumor-derived cell lines indicates a broad expression spectrum of the 90K gene at widely varying levels. Functional characterization reveals stimulatory effects of 90K on host defense systems, such as natural killer cell and lymphokine-activated killer cell activity, and indicates that its immunostimulatory effects may be mediated through the induction of interleukin-2 and possibly other cytokines.

3T3 Cells↗
PubMed1994

The human interferon alpha/beta receptor: characterization and molecular cloning.

We describe a universal ligand-binding receptor for human interferons alpha and interferon beta (type I IFNs). A soluble 40 kDa IFN-alpha/beta receptor (p40) that blocks the activity of type I IFNs was purified from urine and sequenced. Antibodies raised against p40 completely block the activity of several type I IFNs and immuno-precipitate both a cellular 102 kDa IFN-alpha/beta receptor and its cross-linked complexes with IFN-alpha 2. The receptor is a disulfide-linked dimer, consisting of 51 kDa subunits. We isolated and expressed a 1.5 kb cDNA, coding for the IFN-alpha/beta receptor. Its 331 amino acid sequence includes a leader and a transmembrane region, while its ectodomain corresponds to p40. IFN-alpha/beta receptor is physically associated with the cytoplasmic Tyr kinase JAK1, hence, in addition to ligand binding, it is directly involved in signal transduction.

3T3 Cells↗
PubMed1994

History of in utero cocaine exposure in language-delayed children.

To determine whether children with language delays are more likely to have been exposed to cocaine in utero than children with normal language development, a case-control study was undertaken. Based on routine office screening in our primary-care clinic over a 1-year period, we identified 29 consecutive children, aged 24 to 48 months, as language-delayed. They were compared with an approximate 2:1 match of children without language delay who had been seen in the clinic on the same days and who were of similar age. There was more reported cocaine use during pregnancy (six of 29, 21%) among the language-delayed children than among the controls (five of 71, 7%). This difference is statistically significant (P < 0.05, chi 2 = 3.92; odds ratio = 3.4 +/- 2.2). Discriminant analysis revealed that both cocaine and nicotine exposure were associated with delayed language development--with an unexpected negative, i.e., an antagonistic, protective, interactive effect (F[3,96] = 4.66, R2 = 12.7%, P < .005); neither gender nor caretaker contributed to language development in this sample. These results suggest that children with language delay detected in a clinical setting are more likely to have been exposed in utero to cocaine than children with normal language development. Prenatal cocaine exposure should be a risk factor in monitoring development in children.

Case-Control Studies↗
PubMed1994

In situ hybridization analysis of anterior pituitary hormone gene expression during fetal mouse development.

We used 35S-labeled oligonucleotides and cRNAs (riboprobes) to detect the temporal order and spatial pattern of anterior pituitary hormone gene expression in (B6CBF1 x B6CBF1)F2 fetal mice from embryonic Day 9.5 (E9.5) to postnatal Day 1 (P1). Pro-opiomelanocortin (POMC) mRNA was expressed in the basal diencephalon on Day E10.5, in the ventromedial zone of the pars distalis on Day E12.5, and in the pars intermedia on Day E14.5. The common alpha-glycoprotein subunit (alpha-GSU) mRNA first appeared in the anterior wall of Rathke's pouch on Day E11.5 and extended to the pars tuberalis and ventromedial zone of the pars distalis on Day E12.5. Thyroid-stimulating hormone-beta (TSH beta) subunit mRNA was expressed initially in both the pas tuberalis and ventromedial pars distalis on Day E14.5, with an identical spatial distribution to alpha-GSU at the time. In contrast, luteinizing hormone-beta (LH beta) subunit and follicle-stimulating hormone beta (FSH beta) subunit mRNAs were detected initially only in the ventromedial pars distalis on Days E16.5 and E17.5, respectively, in an identical distribution to each other. POMC-, alpha-GSU-, TSH beta, LH beta-, and FSH beta-positive cells within the pars distalis all increased in number and autoradiographic signal with differing degrees of spatial expansion posteriorly, laterally, and dorsally up to Day P1. POMC expression was typically the most intense and extended circumferentially to include the entire lateral and dorsal surfaces of the pars distalis. The expression of both growth hormone (GH) and prolactin (PRL) started coincidentally on Day E15.5. However PRL cells localized in the ventromedial area similarly to POMC and the glycoprotein hormone subunits, whereas GH cells were found initially in a more lateral and central distribution within the lobes of the pars distalis. Somatotrophs increased dramatically in number and autoradiographic signal, extending throughout the pars distalis except for the most peripheral layer of cells on Day E17.5. Mammotrophs also increased in number but less abundantly than somatotrophs, and PRL expression remained more confined to central-medial and ventrolateral areas of the pars distalis up to Day P1. These data demonstrate distinctive patterns of expression for each of the major anterior pituitary hormone genes during development of the mouse pituitary gland and suggest that different groups of committed cells are the immediate precursors to the terminally differentiated hormone-secreting cell types.

Animals↗
PubMed1994

Isolation and characterization of a soluble form of the LDL receptor, an interferon-induced antiviral protein.

Interferons (IFNs) act by inducing several intracellular antiviral proteins. We report here that IFNs also induce an extracellular soluble protein that inhibits vesicular stomatitis virus (VSV) infection. This protein accounts for 25%-50% of the total antiviral activity elicited by IFN. The antiviral protein was purified to homogeneity from culture supernatants of IFN-treated cells by several chromatographic steps, to give a single 28-kDa active polypeptide. Upon sequencing, this novel protein corresponded to the N-terminal ligand-binding domain of the human 160-kDa low-density lipoprotein receptor (LDLR). In addition, we find that IFN induces the cell surface LDLR and this phenomenon may explain previous reports on reduction of serum cholesterol in IFN-treated patients. Viruses produce soluble cytokine receptors that inhibit their respective cytokines, thereby assisting virus infection. It appears now that host cells employ similar molecules for the opposite role of controlling virus infections.

Amino Acid Sequence↗
PubMed1994

Condom sense.

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Americas↗
PubMed1993

Post-translational processing of proopiomelanocortin (POMC) in mouse pituitary melanotroph tumors induced by a POMC-simian virus 40 large T antigen transgene.

Mice harboring a transgene composed of proopiomelanocortin (POMC) gene promoter sequences (nucleotides -706 to +64) ligated to the simian virus (SV) 40 early gene encoding large T antigen developed large POMC-expressing pituitary tumors. Histologically the tumors arose from the intermediate lobe, contained nuclear SV40 T antigen and POMC peptides, but did not express other pituitary hormones. POMC processing in the pituitary tumors was indistinguishable from normal mouse intermediate lobe melanotrophs and was characterized by high proportions of acetylated and carboxyl-terminal shortened beta-endorphins, and amino-terminal acetylated alpha-melanocyte-stimulating hormone, and virtually no adrenocorticotropic hormone (ACTH)(1-39), beta-lipotropin, or POMC. The tumors contained abundant levels of mRNA for the prohormone convertase PC2 and undetectable levels of PC1. Normal mouse neurointermediate lobe also has a high ratio of PC2/PC1 expression that is distinct from the relative abundance of PC1 in anterior lobe and AtT-20 corticotroph cells. In contrast, extracts from tumors transplanted subcutaneously in nude mice contained predominantly nonacetylated forms of beta-endorphin(1-31) and -(1-27), very little ACTH(1-39), almost no corticotropin-like intermediate peptide or alpha-melanocyte-stimulating hormone, and higher proportions of intact POMC. Surprisingly, despite the less efficient proteolytic cleavage, a transplanted tumor expressed both PC1 and PC2. These studies are the first biochemical documentation of a melanotroph pituitary tumor in a rodent species and provide a new model for the investigation of pituitary oncogenesis and the molecular basis of tissue-specific prohormone post-translational processing.

Adrenocorticotropic Hormone↗
PubMed1993

An antiviral soluble form of the LDL receptor induced by interferon.

Interferons, which induce several intracellular antiviral proteins, also induce an extracellular soluble protein that inhibits vesicular stomatitis virus (VSV) infection. This 28-kilodalton soluble protein was purified to homogeneity and identified by protein sequencing as the ligand-binding domain of the human 160-kilodalton low density lipoprotein receptor (LDLR). The existence of an antiviral soluble LDLR was confirmed by immunoaffinity chromatography with monoclonal antibody to LDLR. This soluble receptor mediates most of the interferon-triggered antiviral activity against VSV, apparently by interfering with virus assembly or budding, and not by inhibiting virus attachment to cells.

Amino Acid Sequence↗
PubMed1993

Real-time measurements of kinetics of EGF binding to soluble EGF receptor monomers and dimers support the dimerization model for receptor activation.

We have tested one aspect of the allosteric dimerization model for the activation of EGF receptor (EGFR) by EGF: whether EGF binding favors dimerization of the receptor. For this to be true, EGF molecules must bind with higher affinity to dimeric receptors than to monomeric receptors. We have tested this directly in a defined system using the soluble, extracellular ligand binding domain of EGFR monomers (sEGFR) and sEGFR dimers stabilized by treatment with a covalent cross-linking agent. We describe real-time kinetic measurements of EGF binding to receptor monomers and dimers employing the method of total internal reflection (surface plasmon resonance). Our data show that sEGFR dimers bound EGF with 30-40-fold higher affinity [KD = (2-3) x 10(-8) M] than did sEGFR monomers. The enhanced binding affinity of sEGFR dimers resulted mainly from a reduced off-rate with k(off) = 0.001 s-1 for sEGFR dimers as compared to k(off) = 0.06 s-1 for sEGFR monomers. These measurements indicate that dimerization of sEGFR increases its affinity for EGF by prolonging the amount of time that EGF remains bound to the receptor. This provides evidence that EGF binding stabilizes receptor dimerization and provides further support for the allosteric dimerization model as a mechanism for ligand induced receptor activation.

Animals↗
PubMed1993

Introduction of a point mutation into the mouse genome by homologous recombination in embryonic stem cells using a replacement type vector with a selectable marker.

The introduction of small mutations instead of null alleles into the mouse genome has broad applications to the study of protein structure-function relationships and the creation of animal models of human genetic diseases. To test a simple mutational strategy we designed a targeting vector for the mouse proopiomelanocortin (POMC) gene containing a single nucleotide insertion that converts the initial tyrosine codon of beta-endorphin 1-31 to a premature translational termination codon and introduces a unique Hpal endonuclease restriction site. The targeting vector also contains a neo cassette immediately 3' to the last POMC exon and a herpes simplex virus thymidine kinase cassette to allow positive and negative selection. Homologous recombination occurred at a frequency of 1/30 clones of electroporated embryonic stem cells selected in G418 and gancyclovir. 10/11 clones identified initially by a polymerase chain reaction (PCR) strategy had the predicted structure without evidence of concatemer formation by Southern blot analysis. We used a combination of Hpa I digestion of PCR amplified fragments and direct nucleotide sequencing to further confirm that the point mutation was retained in 9/10 clones. The POMC gene was transcriptionally silent in embryonic stem cells and the targeted allele was not activated by the downstream phosphoglycerate kinase-1 promoter that transcribed the neo gene. Under the electroporation conditions used, we have demonstrated that a point mutation can be introduced with high efficiency and precision into the POMC gene using a replacement type vector containing a retained selectable marker without affecting expression of the allele in the embryonic stem cells. A similar strategy may be useful for a wide range of genes.

Alleles↗
PubMed1993

Rat and mouse proopiomelanocortin gene sequences target tissue-specific expression to the pituitary gland but not to the hypothalamus of transgenic mice.

The proopiomelanocortin (POMC) gene is expressed predominantly in corticotrophs of the pituitary anterior lobe, melanotrophs of the intermediate lobe and neurons of the arcuate nucleus of the hypothalamus. The different ontogeny of POMC mRNA as well as the complicated hormonal regulation of POMC gene expression in the three different cell types suggests a concerted interaction between several cis-acting elements in the POMC gene and transcription factors located in each of the three cell types. To investigate cell-specific elements in the POMC gene we tested two different constructs in transgenic mice. The construct -4000rPOMCLacZ, carrying 4 kb of the rat POMC promoter fused to the Escherichia coli beta-galactosidase gene, showed appropriate expression in melanotrophs in 50% of the mice analyzed. beta-Galactosidase activity was less evident in corticotrophs under basal environmental conditions. In brain, 7 out of 15 independently derived transgenic founders had ectopic expression of the transgene in different areas; however, none of the animals analyzed expressed beta-galactosidase in neurons of the arcuate nucleus. The construct HAL*, a 'tagged' 10.2-kb mouse genomic fragment, was more efficiently targeted to the pituitary. Using in situ hybridization, we detected uniform expression of HAL* in melanotrophs in 100% of the 6 pedigrees analyzed and transgenic mRNA levels paralleled those of the endogenous POMC mRNA. In corticotrophs, basal expression was low but after adrenalectomy HAL* mRNA levels were comparable to those of POMC. None of the 6 pedigrees had appropriate expression of HAL* in the brain; however, 2 lines had ectopic expression in the dentate gyrus of the hippocampus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Sexually assaultive male juveniles: a follow-up.

OBJECTIVE: The purpose of this study was to investigate the adult outcome of a group of male juveniles who committed sexual assault. METHOD: Nineteen sexually assaultive male juveniles and a comparison group of 58 violent juveniles were studied over an 8-year period through use of criminal records and clinical interviews. RESULTS: Although in adolescence the two groups were similarly violent, on follow-up those who had committed sexual assault were significantly more likely to commit adult sexual offenses. They also committed significantly more violent nonsexual offenses. Childhood sexual abuse, especially by females, was associated with adult sexual offenses. CONCLUSIONS: Sexually assaultive delinquents are at particularly high risk for subsequent violence. Hence, special efforts must be made to treat these delinquents in adolescence. Prevention of violent sexual behavior must include improved methods of detecting sexual abuse, especially that perpetrated by older females.

Adolescent↗