Human monocytes selectively bind to cells expressing the tumorigenic phenotype

Summary The characteristics of the binding of human monocytes to tumor cells were studied by a newly developed microassay. First, we determined the kinetics and optimal conditions of the binding. Monocytes recognized and bound to tumor cells very rapidly within 10–20 min of cellular interaction. Binding was also more efficient at 37°C suggesting that active metabolism of monocytes is required. Second, we determined that selective binding of monocytes to cells with tumorigenic phenotypes occurs. For this purpose, lymphocytic leukemia cell lines versus normal lymphocytes, and tumorigenic versus nontumorigenic hybrids from the same parental lines were compared as the targets of the binding assay. In both cases, neoplastic cells were selectively bound by monocytes. Although tumor cells were bound rapidly and selectively by monocytes, initial recognition and binding did not necessarily lead to subsequent tumor cell lysis. This is based on the observation that some tumorigenic parental and hybrid lines were avidly bound by monocytes yet not subsequently killed in a cytotoxicity assay.This work was supported in part by a grant from the National Institutes of Health CA42992 and a grant from the Kleberg foundation Abbreviations used: [¹²⁵I]IdUrd [¹²⁵I]iododeoxyuridine; rIFN-, recombinant human interferon ; IL-1, interleukin 1; rTNF, recombinant human tumor necrosis factor     

Calcium channels that are required for secretion from intact nerve terminals of vertebrates are sensitive to omega-conotoxin and relatively insensitive to dihydropyridines. Optical studies with and without voltage-sensitive dyes

Extrinsic absorption changes exhibited by potentiometric dyes have established the ionic basis of the action potential in synchronously activated populations of nerve terminals in the intact neurohypophyses of amphibia and mammals (Salzberg et al., 1983; Obaid et al., 1983, 1985b). Also, large and rapid changes in light scattering, measured as transparency, have been shown to follow membrane depolarization and to be intimately associated with the release of neuropeptides from the nerve terminals of the mouse neurohypophysis (Salzberg et al., 1985; Gainer et al., 1986). We report some experiments that help to define the pharmacological profile of the calcium channels present in intact neurosecretory terminals of vertebrates. For these, we used the peptide toxin omega-conotoxin GVIA (1-5 microM) and the dihydropyridine compounds Bay-K 8644 and nifedipine (2-5 microM), together with the after-hyperpolarization of the nerve terminal action potential. This undershoot depends upon the activation of a calcium-mediated potassium channel, as suggested by its sensitivity to [Ca++]o and charybdotoxin. omega-conotoxin GVIA substantially reduced the after-hyperpolarization in neurosecretory terminals of Xenopus, while neither of the dihydropyridine compounds had any effect under conditions that mimic natural stimulation. The effects of these calcium channel modifiers on the action potential recorded optically from the terminals of the Xenopus neurohypophysis were faithfully reflected in the behavior of the light-scattering changes observed in the neurohypophysis of the CD-1 mouse. omega-conotoxin GVIA (5 microM) reduced the size of the intrinsic optical signal associated with secretion by 50%, while the dihydropyridines had little effect. These observations suggest that the type of calcium channel that dominates the secretory behavior of intact vertebrate nerve terminals is at least partially blocked by omega-conotoxin GVIA and is insensitive, under normal conditions, to dihydropyridines.     

Tissue-specific and age-related variations in repetitive sequences of mouse extrachromosomal circular DNAs

Extrachromosomal circular (ecc) DNA was isolated from mouse brain, liver, and heart tissues at different ages. To determine the abundance of repetitive sequences in eccDNAs, preparations were probed for short-interspersed (B1 and B2), long-interspersed (L1), endogenous retroviral-like (IAP), and tandemly repeated satellite sequences (SAT) of the mouse genome. Together these sequence families comprise approximately 15% of the mouse genome. The hybridization results showed that each tissue had a characteristic pattern of repetitive sequence elements in eccDNAs, and the abundance of repetitive sequences changed as a function of age. Repetitive sequences decreased in liver and brain eccDNAs from 1 month to 8 months of age but appeared to remain stable thereafter. In contrast, repetitive sequence families in heart eccDNAs were constant from 1 month to 16 months of age but declined in 24-month-old mice. The present studies indicate that extrachromosomal sequences exhibit greater flexibility than chromosomal sequences.     

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 areFC(1,90)0, FC63, S1C2,17, andSC(3,2,90)0. The frequencies of two of these four unique Black complotypes,FC(1,90)0 andFC63, were increased significantly when compared to Caucasians (p_corr <0.00042, p_corr=0.00294, respectively). The complotypeFC(1,90)0 was in positive linkage disequilibrium withHLA-DR3 haplotypes containing theB locus antigens Bw42, Bw52, Bw53, and Bw58, whileFC63 was associated withHLA-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.     

Molecular genetic study of human arginase deficiency

We have explored the molecular pathology in 28 individuals homozygous or heterozygous for liver arginase deficiency (hyperargininemia) by a combination of Southern analysis, western blotting, DNA sequencing, and PCR. This cohort represents the majority of arginase-deficient individuals worldwide. Only 2 of 15 homozygous patients on whom red blood cells were available had antigenically cross-reacting material as ascertained by western blot analysis using anti-liver arginase antibody. Southern blots of patient genomic DNAs, cut with a variety of restriction enzymes and probed with a near-full-length (1,450-bp) human liver arginase cDNA clone, detected no gross gene deletions. Loss of a TaqI cleavage site was identified in three individuals: in a homozygous state in a Saudi Arabian patient at one site, at a different site in homozygosity in a German patient, and in heterozygosity in a patient from Australia. The changes in the latter two were localized to exon 8, through amplification of this region by PCR and electrophoretic analysis of the amplified fragment after treatment with TaqI; the precise base changes (Arg291X and Thr290Ser) were confirmed by sequencing. It is interesting that the latter nucleotide variant (Thr290Ser) was found to lie adjacent to the TaqI site rather than within it, though whether such a conservative amino acid substitution represents a true pathologic mutation remains to be determined. We conclude that arginase deficiency, though rare, is a heterogeneous disorder at the genotypic level, generally encompassing a variety of point mutations rather than substantial structural gene deletions.     

Fine needle aspiration of peripheral neuroepithelioma of soft tissues.

Peripheral neuroepithelioma of soft tissue is a malignant primitive neuroectodermal tumor that appears both in children and adults and usually has a poor outcome. Fine needle aspiration on two patients with tumors in the lower limbs showed small round cells with unipolar processes and a tendency to form Homer-Wright rosettes. The cells had a round to oval nucleus with fine chromatin, up to four small, conspicuous nucleoli and vacuolated, periodic acid-Schiff-positive cytoplasm. The diagnosis was supported by electron microscopic study of the aspirate, which showed features of neuroblastic differentiation (i.e., neurosecretory granules), and by histologic, immunohistochemical and cytogenetic study of the resected tumors.     

Embodying illness,embodying cancer

Individuals and societies embody illnesses in different ways, in part determined by the way a person knows and lives his or her diagnosis and prognosis. Based on research in Northern Italy, on the experiences and meanings of cancer and on the practice of nondisclosure of the diagnosis, we find nondisclosure reflects a world divided - life/death, good/bad, mind/body — with the unwanted converted to other. The strong association of cancer with death, suffering, and hopelessness in much of Italy, coupled with the tremendous power attributed to naming and sentencing makes nondisclosure a major mechanism for keeping the condemned in this social world, and keeping death, decay, and suffering in the other. It is the social reality that is dominant here, such that informing a patient of cancer can be tantamount to social death.

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Résumé Les individus et les sociétés incorporent la maladie de façon différente, déterminée en partie de comment une personne connait et vit son diagnostic et prognostic. A partir de la recherche des experiences des significations du cancer et de la pratique de ne pas dire la diagnostic au Nord de l'Italie, on a remarqué que l'habitude de ne rien dire reflète un monde séparé entre la vie et la mort, entre le bon et le mal, entre l'esprit et le corps, de sorte que ce qui West pas voulu soit transfomé en l'autre. L'association forte du cancer à la mort, à la souffrance, au désespérance en toute l'Italie, unie au grand pouvoir donne au fait de dénommer et de donner une sentence, rend ne pas dire un méchanisme important pour garder le condamnd dans ce monde social et pour garder la mort, la décadence et la souffrance dans l'autre. C'est la réalité sociale qui est ici dominante, tel que le fait d'informer un patient de cancer soit comme une mort sociale.

     

A new major histocompatibility complex class I b gene expressed in the mouse blastocyst and placenta

 Because of the role major histocompatibility complex (MHC) class I b molecules may play during mouse embryonic development, we thought it would be interesting to search for additional MHC class I b molecules that might be expressed in preimplantation embryos, and in particular in the trophoblastic lineage. We therefore screened a mouse preimplantation blastocyst cDNA library for MHC class I sequences. This search led to the identification and characterization of a new MHC class I b gene, blastocyst MHC. Sequences identical to the exons and 3′ untranslated region of this gene have been found in many laboratory mouse strains, as well as in the related mouse species Mus spreciligus. The presence of this gene in mouse strains of different MHC class I haplotypes argues that blastocyst MHC is a unique, newly-described gene rather than a new allele of a previously described mouse MHC class I gene. Blastocyst MHC has the structure of an MHC class I b gene, with the six exons characteristic of T-region genes. It is linked to H2-D. The amino acid sequence encoded by this gene maintains all the features of a functional antigen-presentation domain. The blastocyst MHC gene, like the human class I b gene HLA-G, is expressed at the blastocyst stage and in the placenta, and may be the mouse analog for HLA-G. Received: 31 May 1996 / Revised: 19 August 1996     

Identifying DNA polymorphisms in human TCRA/D variable genes by direct sequencing of PCR products

 The T-cell receptor (TCR) is a highly variable molecule composed of two polypeptide chains that recognize antigenic peptides in the context of major histocompatibility complex (MHC) molecules. In this study, we describe a sequence-based search for germline polymorphisms in the variable (V) gene segments of the human TCRA/D locus. Thirty different V gene segments were amplified from six to eight unrelated individuals and sequenced from low melting point agarose. Twenty-seven polymorphisms were identified in 15 V gene segments. These polymorphisms are mainly single nucleotide substitutions, but an insertion/deletion polymorphism and a single dinucleotide repeat with variable length were also seen. Of the 15 sequence variations found in the coding regions, six are silent and nine encode amino acid changes. All of the amino acid changes are found at non-conserved residues, frequently in the hypervariable regions, where they may influence MHC and/or peptide recognition. Therefore, it is possible that germline variations in TCR genes could influence an individual’s immune response, and may also contribute to susceptibility to diseases such as autoimmunity. Received: 9 January 1996 / Revised: 22 February 1996