Congenital high-grade sarcoma presenting as skin nodules and respiratory distress in a neonate.

We report, to our knowledge, the first case of a congenital, widespread, aggressive high-grade sarcoma, presented as multiple skin nodules and respiratory distress in a neonate that had a t(9;22)(q22;q11-12) cytogenetic abnormality suggestive of a more indolent extraskeletal myxoid chondrosarcoma (EMC). EMC is generally thought of as a slow-growing tumor that presents between the fourth and sixth decades of life. Our patient was a 45,XY, t(13;14) newborn who presented at birth with subcutaneous nodules involving the face, scalp, back and extremities, as well as multiple intrathoracic, intraabdominal and intracranial masses. Diagnosis was made using electron microscopy and immunohistochemical and cytogenetic studies. Despite attempts to control rapid growth of lesions using high-dose steroids and cis-retinoic acid, patient's clinical status continued to deteriorate and life support was withdrawn at the 26 day of life.

Hyperbaric oxygen in treatment of neonatal arterial thromboembolism of lower extremities.

Arterial thromboembolism (TE) in the absence of current or recent history of a central catheter is a rare condition in newborn period. We report a case of severe lower extremities arterial TE of unclear etiology in a full-term neonate. By adding hyperbaric oxygenation to thrombolytic and antithrombotic therapy, we achieved improved perfusion of the upper leg tissues, preserving the knee and enabling below-the-knee amputation.

Interleukin-1 induces transcription of keratin K6 in human epidermal keratinocytes.

Keratinocytes respond to injury by releasing the proinflammatory cytokine interleukin-1, which serves as the initial "alarm signal" to surrounding cells. Among the consequences of interleukin-1 release is the production of additional cytokines and their receptors by keratinocytes and other cells in the skin. Here we describe an additional effect of interleukin-1 on keratinocytes, namely the alteration in the keratinocyte cytoskeleton in the form of the induction of keratin 6 expression. Keratin 6 is a marker of hyperproliferative, activated keratinocytes, found in wound healing, psoriasis, and other inflammatory disorders. Skin biopsies in organ culture treated with interleukin-1 express keratin 6 in all suprabasal layers of the epidermis, throughout the tissue. In cultured epidermal keratinocytes, the induction of keratin 6 is time and concentration dependent. Importantly, only confluent keratinocytes respond to interleukin-1, subconfluent cultures do not. In the cells starved of growth factors, epidermal growth factor or tumor necrosis factor-alpha, if added simultaneously with interleukin-1, they synergistically augment the effects of interleukin-1. Using DNA-mediated cell transfection, we analyzed the molecular mechanisms regulating the keratin 6 induction by interleukin-1, and found that the induction occurs at the transcriptional level. We used a series of deletions and point mutations to identify the interleukin-1 responsive DNA element in the keratin 6 promoter, and determined that it contains a complex of C/EBP binding sites. The transcription factor C/EBPbeta binds this element in vitro, and the binding is augmented by pretreatment of the cells with interleukin-1. The interleukin-1 responsive element is clearly distinct from the epidermal growth factor responsive one, which means that the proinflammatory and proliferative signals independently regulate the expression of keratin 6. Thus, interleukin-1 initiates keratinocyte activation not only by triggering additional signaling events, but also by inducing directly the synthesis of keratin 6 in epidermal keratinocytes, and thus changing the composition of their cytoskeleton.

Close linkage of the two keratin gene clusters in the human genome.

Mapping studies of functional keratin genes in the human genome have localized most of the acidic keratin genes to chromosome 17q12-q21 and the basic keratin genes to chromosome 12q11-q13. Within the acidic keratin locus two clusters were identified, one containing the genes for K15 and K19, the other the genes for K14, K16, and K17. The relative positions and the distance between the two clusters have not been determined previously. In this paper we describe our analysis of P1 clones containing multiple acidic keratin genes, which were studied using restriction analysis and Southern blot hybridization with PCR-amplified probes specific for functional human keratin genes 15, 17, and 19. Our results show that the two clusters are very closely linked to each other, within a 55-kb region in the human genome. The genes are organized 5' to 3' in the following order: 5'-K19-K15-K17-K16-K14. Between K15 and K17 at least one additional, unidentified keratin gene is present.

Characterization of nuclear protein binding sites in the promoter of keratin K17 gene.

Keratin K17, while not present in healthy skin, is expressed under various pathological conditions, including psoriasis and cutaneous allergic reactions. The regulatory circuits involved in transcription of the human keratin K17 gene are poorly understood. To begin an analysis of the molecular mechanisms that regulate K17 gene transcription, we have studied the interactions between the nuclear proteins and the promoter region of the human K17 gene. That promoter region comprised 450 bp upstream from the translation initiation site. For these studies, we used electrophoretic mobility-shift assays, computer analysis, site-directed mutagenesis, and DNA-mediated cell transfection. In addition to the previously characterized interferon-gamma-responsive elements, we identified eight protein binding sites in the promoter. Five of them bind the known transcription factors NF1, AP2, and Sp1 and three others bind still unidentified proteins. Using site-directed mutagenesis, we have demonstrated the importance of the protein binding sites for the promoter function involved in both constitutive and interferon-induced expression of the K17 keratin gene.

[Mycoplasmas and AIDS]. / Mikoplazme i ejds (AIDS).

Recent findings by a number of investigators suggest the association of mycoplasma and HIV or AIDS. Mycoplasmas have been implicied as a possible cofactor in AIDS pathogenesis. These mycoplasmas include Mycoplasma fermentans, Mycoplasma pirum, Mycoplasma genitalium and Mycoplasma penetrans. These mycoplasmas have been showed to have the capacity to invade cells and to be potent immunomodulators. To better understand the role of mycoplasma infections in AIDS we must continue to learn the fundamental biology of this group of unique organisms so that we may improve our diagnostic techniques in molecular genetics, serology, tissue diagnosis and isolation techniques by culture.

Sequence and structure of cmp, the replication enhancer of the Staphylococcus aureus plasmid pT181.

The Staphylococcus aureus plasmid pT181 possesses a DNA replication enhancer element, called cmp, that is required in cis for optimal utilization of the initiator protein by the origin of replication. The minimal nucleotide sequence required for cmp activity was defined by testing progressively smaller DNA fragments for their ability to restore cmp activity in a plasmid mutant deleted for cmp. These experiments indicate that cmp is a sequence of 100 base pairs (bp) characterized by a loosely repeated sequence motif and phased oligo(dT) tracts. Intrinsic DNA bending at cmp was detected by a circular permutation assay of the locus using polyacrylamide-gel electrophoresis and by computer modeling. The cmp element was found to contain two loci of intrinsically bent DNA that confer an overall bent conformation to this replication enhancer.