Fatal complete atrioventricular block as a complication of bacterial sepsis in a premature newborn.

We report on a premature infant with a body weight < 900 g who developed complete heart block as a complication of Enterobacter bacteremia. The infant could be successfully paced using a transcutaneous pacemaker for a limited time. Histopathological examination of the heart did not reveal any abnormalities of the specialized conduction system.

The combination of zidovudine and interferon alpha-2B in the treatment of adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATL) is frequently a very aggressive malignancy with a poor survival despite aggressive multiagent chemotherapy. The combination of the antiretroviral drug zidovudine (AZT) and interferon alpha (IFNalpha) has been reported to induce remissions in patients with ATL. The purpose of this study was to evaluate the clinical response and toxicity following administration of a combination of IFNalpha-2b and AZT in patients with human T-cell lymphotropic virus type I (HTLV-I)-associated ATL. Eighteen patients with ATL (chronic. crisis, acute or lymphoma type) were treated with the combination of AZT (50 - 200 mg orally 5 times a day) and IFNalpha-2b (2.5 - 10 million units subcutaneously daily). Three patients had objective responses lasting more than one month. One patient had a clinical complete remission, lasting 21.6 months and two patients had partial remissions lasting 3.7 and 26.5 months. Six patients were not considered evaluable for response due to short and/or interrupted periods of treatment. Seventeen patients have died with a median survival time after initiation of therapy of 6 months. Neutropenia and thrombocytopenia were the dose limiting toxicities. In conclusion, the response rate in this study was lower than noted in the two previous published series. This may be due to the amount and type of prior treatment our patients had received.

The use of hypothermia: a role in the treatment of neonatal asphyxia?

Perinatal asphyxia remains one of the most devastating neurologic processes. Although the understanding of the pathophysiology after perinatal asphyxia is extensive, there are few therapeutic interventions available to prevent or even mitigate the devastating process that unfolds after injury. The search for a safe and efficacious therapy has prompted scientists and clinicians to consider various promising therapies. One such therapy is therapeutic hypothermia. On the basis of adult, pediatric, and animal research, there is increasing evidence to suggest that therapeutic hypothermia may be an effective intervention to lessen the secondary neuronal injury that ensues after a hypoxic-ischemic insult. In this article the historic and modern-day uses of therapeutic hypothermia are first reviewed. The pathophysiology of neonatal asphyxia is examined next, with emphasis on the changes that occur when therapeutic hypothermia is implemented. Potential side-effects of the therapy in the neonate and the debate over systemic vs selective hypothermia are discussed. Lastly, although hypothermia as a potential treatment modality for neonates with hypoxic-ischemic encephalopathy is supported by numerous studies, the need for well-designed multicenter trials with detailed patient entry criteria and therapeutic conditions is emphasized.

Detection of intracellular tumor necrosis factor alpha in stimulated fetal cells.

BACKGROUND: It is unknown if immature fetal cells produce tumor necrosis factor (TNF) alpha in the same manner that adult cells do. The aim of this study was to determine the feasibility of early detection of intracellular TNF produced by circulating human monocytes (Mo) and lymphocytes (Ly) using flow cytometry and to compare the stimulation profiles of mature and fetal cells. MATERIAL AND METHODS: Fetal umbilical cord blood (n = 10) and adult volunteer blood (n = 10) were obtained. In vitro stimulation with endotoxin (LPS) and ionomycin-PMA was performed. Brefeldin A was added to prevent extracellular transport of TNF. Cell type was determined by using CD-14 marker separating monocyte and lymphocyte populations. Anti-human TNF monoclonal antibody was used to detect intracellular TNF by flow cytometry analysis. RESULTS: Thirty to sixty thousand cells were analyzed per sample. Average TNF expression of stimulated fetal Mo was 28.2%, and that of fetal Ly was only 1.1%. Adult stimulated Ly had an average TNF expression of 31.9%, and adult Mo, 29.6% (P < 0.05 for adult Ly vs fetal Ly). CONCLUSION: TNF flow cytometry analysis allows assessment of individual cell types and their ability to produce that cytokine. Fetal cells are able to produce TNF when stimulated, but the stimulation profile of Ly differs from that of adult samples. This observation may be of clinical importance in evaluating the response of immature cells to a septic stimulus. Flow cytometry is reliable, reproducible, quick, and easily obtained from a small sample of peripheral blood. Clinical use will be applicable once appropriate controls are developed, as reported in this study.

IL-2R alpha on one cell can present IL-2 to IL-2R beta/gamma(c) on another cell to augment IL-2 signaling.

IL-2Ralpha augments IL-2 signaling. Although this is generally believed to occur only when the three known components of IL-2R are associated within a single cell membrane, we demonstrate here an intercellular interaction. Cocultivation of cells individually expressing chimerae incorporating the extracellular domain of IL-2Ralpha alone with cells expressing chimerae of IL-2Rbeta alone permitted IL-2 dose-dependent oligomerization of the chimerae. Likewise, native IL-2Ralpha-bearing cells augmented the IL-2 proliferative response of ex vivo large granular lymphocytic leukemia cells expressing IL-2Rbeta/gamma(c) but lacking IL-2Ralpha. In both cases, the response was inhibitable by an Ab to IL-2Ralpha. Intercellular augmentation of cytokine effects, acting in trans, has important implications for biology and medicine.

Mosaic vs. nonmosaic trisomy 9: report of a liveborn infant evaluated by fluorescence in situ hybridization and review of the literature.

We report on a newborn infant with multiple congenital anomalies and apparent nonmosaic trisomy 9 in the blood (by conventional cytogenetic studies) who died shortly after birth. Clinical observations at birth and autopsy are compared with phenotypes of mosaic and nonmosaic trisomy 9 cases reported previously. Unlike the initial cytogenetic analysis, fluorescence in situ hybridization (FISH) studies of metaphase and interphase blood cells and skin fibroblasts detected the presence of euploid and trisomy 9 cells. These results suggest that earlier reports of trisomy 9, which relied on conventional chromosome analysis of a few metaphase cells and/or only one tissue type, may not have excluded mosaicism, and that trisomy 9 may be viable only in the mosaic state.

Expression of v-src in T cells correlates with nuclear expression of NF-kappa B.

NF-kappa B is a rapidly inducible transcriptional activator that responds to a variety of signals and influences the expression of many genes involved in the immune response. Protein tyrosine kinases transmit signals from cytokine and immune receptors. Very little information exists linking these two important classes of signaling molecules. We now demonstrate that v-src expression correlates with nuclear expression of a kappa B binding complex similar to that induced by phorbol ester and ionomycin, as detected by electrophoretic mobility shift assay using a variety of kappa B sites. This complex was blocked by the tyrosine kinase inhibitor, herbimycin A. The v-src-induced complex comprised the p50 and p65 components of NF-kappa B, as determined by supershift and immunoblot analysis. As a functional correlate of this finding, transient co-transfection of HIV-1 LTR reporter constructs in a different T cell line demonstrated that v-src activated this promoter in a kappa B-dependent manner. We found that transactivation of the HIV-1 LTR by v-src was more sensitive to mutations of the proximal, rather than the distal, kappa B element. The implications for T cell receptor signaling and HIV-1 gene expression are considered.

Possible autocrine/paracrine actions of insulin-like growth factors during embryonic development: expression and action of IGFs in undifferentiated P19 cells.

The insulin-like growth factors I and II (IGF I and II) and their cell surface receptors are expressed in the mammalian embryo and may function as autocrine or paracrine growth factors during early development. P19 embryonic carcinoma cells, derived from a 7.5 day mouse embryo, were used as a model for a functional study of the IGF system in post-implantation embryogenesis. Undifferentiated P19 cells synthesized IGF I and II, the type I and II IGF receptors, and IGF binding proteins (IGF BP2, IGF BP3, and IGF BP4). P19 cells showed an increase in thymidine incorporation of 150% of control with a 4 hour incubation of IGF I (10 ng/ml) or IGF II (100 ng/ml) and an increase in cell viability compared to control cells during 24 hours of serum starvation. In both experiments IGF I was more potent than IGF II. Endogenous concentrations of IGF I and II in conditioned media were low compared to the doses of exogenous IGFs required for biologic effect, but nonetheless contributed significantly to baseline DNA synthesis, as demonstrated by inhibition of IGF actions with specific antibodies. Cell surface associated IGF BPs bound more radiolabeled IGF than IGF receptors, as determined by binding studies and affinity cross-linking. IGF I and IGF II appeared to regulate production of IGF BP2, suggesting that the IGFs may regulate their own actions by altering the abundance of their binding proteins.

Modulation of leukemic cell sensitivity to lymphokine-activated killer cytolysis: role of intercellular adhesion molecule-1.

The role of CD11/CD18 leukocyte adhesion molecules and their ligands in mediating non-major histocompatibility complex (MHC) restricted lymphocyte cytotoxicity is controversial. In order to examine the role of target cell intercellular adhesion molecule-1 (ICAM-1; CD54), a ligand of lymphocyte function-associated antigen (LFA-1) (CD11a/CD18), we exposed the human leukemia cell line, HL-60, to a variety of agents implicated in modulating ICAM-1 expression and/or sensitivity to lymphocyte cytolysis. Exposure of HL-60 cells to retinoic acid (RA), interferon (IFN)-alpha, IFN-beta, and IFN-gamma induced protection from lymphokine-activated killer (LAK) cytolysis. Only RA and IFN-gamma induced ICAM-1 expression. Tumor necrosis factor and vitamin D3, which also induced ICAM-1 expression, increased HL-60 sensitivity to LAK lysis. Granulocyte-macrophage colony-stimulating factor also increased sensitivity to LAK lysis; ICAM-1 was not induced. The state of cellular differentiation and expression of class I and II MHC antigens also did not correlate with sensitivity to LAK cytolysis. Exposure of untreated HL-60 cells and HL-60 cells expressing ICAM-1 to monoclonal antibody (mAb) versus ICAM-1 did not modulate LAK sensitivity. Exposure of LAK cells to mAb versus LFA-1 partially inhibited cytolysis; mAb versus CD18 inhibited cytolysis more completely. HL-60 cells were resistant to natural killer lysis; exposure to the various experimental agents did not alter sensitivity. We conclude that leukemic cell sensitivity to LAK cytolysis can be modulated by a variety of agents. Although our results suggest a role for leukocyte CD11/CD18 adhesion molecules in LAK cytolysis, the poor correlation between ICAM-1 expression and sensitivity to LAK lysis suggest that interactions other than LFA-1/ICAM-1 conjugation may be more central to the processes involved.

Modulation of adhesion molecules on human large granular lymphocytes by interleukin-2 in vivo and in vitro.

The modulation of adhesion molecules on human large granular lymphocytes (LGL) by interleukin (IL)-2 was investigated both in vivo and in vitro. Intercellular adhesion molecule-1 (ICAM-1; CD54) expression increased on LGL of cancer patients receiving IL-2 adoptive immunotherapy. ICAM-1 expression on LGL isolated by Percoll gradient centrifugation, LGL purified, and expanded by adherence to plastic surfaces and LGL identified by Leu 19 (CD56) monoclonal antibody were increased significantly in response to IL-2 in vitro. Exposure of LGL to IL-1, interferon (IFN)-gamma, and tumor necrosis factor (TNF) in vitro did not induce ICAM-1. The expression of LFA-1 (CD11a/CD18), a receptor for ICAM-1, and other leukocyte adhesion molecules, including Mac-1 (CD11b/CD18) and p150,95 (CD11c/CD18), was only maintained by IL-2. IL-2 induction of ICAM-1 and the maintenance of CD18 complex expression on small lymphocytes separated by Percoll gradients were similar to that on LGL. We conclude that IL-2 enhances the expression of ICAM-1 on multiple human lymphocyte populations including LGL effectors. Expression of the CD18 complex on LGL does not appear to be highly regulated by IL-2. These findings may have implications relevant to the role of these adhesion molecules in the activities of LGL modulated by IL-2.

Phagocytosis mediated by three distinct Fc gamma receptor classes on human leukocytes.

We have evaluated the capacity of the three major classes of human Fc gamma R to mediate phagocytosis by measuring the ability of adherent phagocytes to internalize erythrocytes coated with anti-Fc gamma R mAb. Five different cell types were studied, freshly purified monocytes, cultured monocytes, alveolar macrophages, freshly purified polymorphonuclear neutrophilic leukocytes, and PMNs cultured in IFN-gamma. Fc gamma RI and Fc gamma RII on whichever cells they were expressed were capable of phagocytosing anti-Fc gamma R mAb-coated erythrocytes. Furthermore, Fc gamma RIII on mononuclear phagocytes, which appears to be a conventional integral membrane protein that spans the lipid bilayer, was capable of phagocytosing anti-Fc gamma RIII-coated erythrocytes. However, Fc gamma RIII on neutrophils, a molecule linked to the membrane by a phosphatidylinositol-glycan moiety, although binding anti-Fc gamma RIII-coated erythrocytes vigorously was incapable of mounting a phagocytic response. This deficiency correlates with the limited capacity of Fc gamma RIII on neutrophils to mediate superoxide generation and antibody-dependent cell-mediated cytotoxicity and it may be related to the unique structural features of Fc gamma RIII.

Synthetic and natural speech preferences of male and female listeners in four age groups.

The purpose of this investigation was to examine the preferences of listeners of both sexes in four age groups with regard to natural and computer-generated synthetic speech in six different contexts. The subjects (listeners) for this study included 5 males and 5 females in each of four age groups (6-8 year olds, 10-12 year olds, adolescents, and adults). The listeners rated their preferences for 11 different voices (four natural and seven synthetic) on a 5-point Likert scale. Their preferences were rated for six communication contexts dependent on the potential user of the voice (adult male, adult female, child male, child female, computer, and self). The data were analyzed separately for each of the six communication contexts. In general, female listeners across the age range indicated that only natural female voices (adult or child) were acceptable alternatives to their own speech, thus rejecting the natural male voices as well as the synthetic voices. Male listeners appeared to be somewhat more flexible in terms of gender-appropriateness for themselves and other adult men, but selected female-sounding voices for women and female children. Children preferred to have computers produce synthesized speech, while adults preferred computers with more natural-sounding voices. The results of this investigation raise a number of issues related to the combined effects of age and gender-appropriateness of natural and synthetic speech. These are discussed in terms of their implications for the future development of synthetic speech technology used in communication devices.