Dysregulated expression of neutrophil apoptosis in the systemic inflammatory response syndrome

OBJECTIVE

To study the effect of the systemic inflammatory response syndrome (SIRS) or major elective surgery on the apoptosis of circulating polymorphonuclear neutrophils because an activated inflammatory response is terminated, in part, through the programmed cell death, or apoptosis, of its effector cells.

DESIGN

A prospective inception cohort study.

SETTING

A mixed surgical and medical intensive care unit of an adult tertiary care hospital.

PATIENTS

Sixteen patients with SIRS, 7 uninfected patients who had undergone elective aortic aneurysmectomy, and 8 healthy laboratory control subjects.

INTERVENTIONS

Serial blood samples were drawn for evaluation of neutrophil apoptosis, activational state, and surface receptor expression by flow cytometry.

MAIN OUTCOME MEASURES

Spontaneous apoptosis was significantly delayed in neutrophils from patients with SIRS (8.6%+/-6.8%) and patients who had undergone elective aortic aneurysmectomy (11.0%+/-5.0%) when compared with controls (34.9%+/-6.8%). These neutrophils were activated as evidenced by enhanced respiratory burst activity and augmented surface expression of CD11b. Apoptosis in response to engagement of cell surface Fas (also known as CD95 or APO-1) with an agonistic antibody was blunted. Plasma from patients with SIRS or patients who had undergone elective aortic aneurysmectomy suppressed the apoptotic responses of control neutrophils (plasma from patients with SIRS, 18.8%+/-10.3%; plasma from patients who had undergone elective aortic aneurysmectomy, 20.0%+/-6.1%; P<.01). Western blot analysis showed normal expression of the key proapoptotic proteases, interleukin 1beta converting enzyme and CPP32 (also known as YAMA, apopain, and caspase 3), indicating that delayed apoptosis was not a consequence of decreased levels of proapoptotic enzymes.

CONCLUSIONS

Circulating neutrophils from patients with SIRS or from patients who have undergone major elective surgery show delayed expression of constitutive programmed cell death, and antiapoptotic factors are present in the general circulation. While prolonged neutrophil survival may represent an appropriate adaptive response to injury, the presence of activated and apoptosis-resistant cells in an antiapoptotic environment may contribute to the systemic inflammatory injury characteristic of SIRS and predispose to the development of the multiple organ dysfunction syndrome.

Mice lacking tartrate-resistant acid phosphatase (Acp 5) have disrupted endochondral ossification and mild osteopetrosis

Mature osteoclasts specifically express the purple, band 5 isozyme (Acp 5) of tartrate-resistant acid phosphatase, a binuclear metalloenzyme that can generate reactive oxygen species. The function of Acp 5 was investigated by targeted disruption of the gene in mice. Animals homozygous for the null Acp 5 allele had progressive foreshortening and deformity of the long bones and axial skeleton but apparently normal tooth eruption and skull plate development, indicating a role for Acp 5 in endochondral ossification. Histomorphometry and mineralization density analysis of backscattered electron imaging revealed widened and disorganized epiphyseal growth plates with delayed mineralization of cartilage in 6- to 8-week-old mutant mice. The membrane bones of the skull showed increased density at all ages examined, indicating defective osteoclastic bone turnover. Increased mineralization density was observed in the long bones of older animals which showed modelling deformities at their extremities: heterozygotes and homozygous Acp 5 mutant mice had tissue that was more mineralized and occupied a greater proportion of the bone in all regions. Thus the findings reflect a mild osteopetrosis due to an intrinsic defect of osteoclastic modelling activity that was confirmed in the resorption pit assay in vitro. We conclude that this bifunctional metalloprotein of the osteoclast is required for normal mineralization of cartilage in developing bones; it also maintains integrity and turnover of the adult skeleton by a critical contribution to bone matrix resorption.

High-level expression of recombinant human fibrinogen in the milk of transgenic mice

Fibrinogen is a complex plasma protein composed of two each of three different polypeptide chains. We have targeted expression of r-human fibrinogen to the mammary gland of transgenic mice. Three expression cassettes, each containing the genomic sequence for one of the three human fibrinogen chains controlled by sheep whey protein beta-lactoglobulin promoter sequences, were coinjected into fertile mouse eggs. Southern blot analysis demonstrated that more than 80% of the transgenic founders contained all three fibrinogen genes. Reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis of milk from the highest producing founder animal demonstrated the presence of human fibrinogen subunits at concentrations of 2000 micrograms/ml. In several animals with a balanced ratio of the individual fibrinogen subunits, up to 100% of the protein was incorporated into fully assembled fibrinogen hexamers. Incubation of the transgenic milk with thrombin and factor XIII resulted in a cross-linked fibrin clot, indicating that a major portion of the secreted fibrinogen was functional. These studies represent the first report of high-level biosynthesis and secretion of a functional, complex, hexameric protein in the milk of a transgenic animal.

Expression and release of the a and b subunits for human coagulation factor XIII in baby hamster kidney (BHK) cells

The a subunit of coagulation factor XIII lacks a hydrophobic signal sequence for secretion from cells, while the b subunit has a typical signal sequence. To determine whether the a subunit can be synthesized and released, expression vectors containing the cDNA for either subunit were transfected into baby hamster kidney (BHK) cells. Western blotting analysis and gel filtration chromatography demonstrated that the recombinant a and b subunits (rXIIIa and rXIIIb) had the same molecular weights and subunit structures (a2, b2, and a2b2) as the native molecules. rXIIIa was enzymatically active when activated by thrombin. Most rXIIIb was secreted as measured by ELISA, while most rXIIIa was detected in the cytosol by subcellular fractionation. Co-expression with rXIIIb in the same cells did not promote the release of rXIIIa. Treatment of the cells with brefeldin A, a potent inhibitor of protein transportation, blocked the secretion of rXIIIb, although it had no effect on the release of rXIIIa. Several drugs and heat stress induced the release of rXIIIa, which correlated directly with that of cytoplasmic lactate dehydrogenase. These results suggest that the a subunit is released from cells as a consequence of cell injury, which is independent of the classical secretory pathway.

AIDS-related beliefs, attitudes and intentions among Malawian students in three secondary schools

This preliminary investigation into factors influencing the intention of Malawian secondary school students to engage in low-risk AIDS-related behaviours was based on the Theory of Reasoned Action (Ajzen & Fishbein, 1980). A total of 191 male and female subjects (mean age 19.32) from three secondary schools in Malawi filled in a questionnaire that sought to elicit their intention to use condoms and to stick to the one same sexual partner. The study lent support to the theory that intention can be predicted from attitudes and subjective norms, F(2,186) = 31.93, p < 0.001 for condom use and F(2, 187) = 15.23, p < 0.001 for sticking to one sexual partner. The results showed that, for the subjects, the intention to comply with these two behavioural regimens was predominantly under attitudinal control though one sub-sample's intention was under normative influence. The study also provided quantitative data on the sexual behavioural patterns of the subjects and used these data to furnish explanations of the main findings. Behavioural change intervention strategies in the light of the findings are discussed.

Specificity of leptin action on elevated blood glucose levels and hypothalamic neuropeptide Y gene expression in ob/ob mice

Correction of the obese state induced by genetic leptin deficiency reduces elevated levels of both blood glucose and hypothalamic neuropeptide Y (NPY) mRNA in ob/ob mice. To determine whether these responses are due to a specific action of leptin or to the reversal of the obese state, we investigated the specificity of the effect of systemic leptin administration to ob/ob mice (n = 8) on levels of plasma glucose and insulin and on hypothalamic expression of NPY mRNA. Saline-treated controls were either fed ad libitum (n = 8) or pair-fed to the intake of the leptin-treated group (n = 8) to control for changes of food intake induced by leptin. The specificity of the effect of leptin was further assessed by 1) measuring NPY gene expression in db/db mice (n = 6) that are resistant to leptin, 2) measuring NPY gene expression in brain areas outside the hypothalamus, and 3) measuring the effect of leptin administration on hypothalamic expression of corticotropin-releasing hormone (CRH) mRNA. Five daily intraperitoneal injections of recombinant mouse leptin (150 micrograms) in ob/ob mice lowered food intake by 56% (P < 0.05), body weight by 4.1% (P < 0.05), and levels of NPY mRNA in the hypothalamic arcuate nucleus by 42.3% (P < 0.05) as compared with saline-treated controls. Pair-feeding of ob/ob mice to the intake of leptin-treated animals produced equivalent weight loss, but did not alter expression of NPY mRNA in the arcuate nucleus. Leptin administration was also without effect on food intake, body weight, or NPY mRNA levels in the arcuate nucleus of db/db mice. In ob/ob mice, leptin did not alter NPY mRNA levels in cerebral cortex or hippocampus or the expression of CRH mRNA in the hypothalamic paraventricular nucleus (PVN). Leptin administration to ob/ob mice also markedly reduced serum glucose (8.3 +/- 1.2 vs. 24.5 +/- 3.8 mmol/l; P < 0.01) and insulin levels (7,263 +/- 1,309 vs. 3,150 +/- 780 pmol/l), but was ineffective in db/db mice. Pair-fed mice experienced reductions of glucose and insulin levels that were < 60% of the reduction induced by leptin. The results suggest that in ob/ob mice, systemic administration of leptin inhibits NPY gene overexpression through a specific action in the arcuate nucleus and exerts a hypoglycemic action that is partly independent of its weight-reducing effects. Furthermore, both effects occur before reversal of the obesity syndrome. Defective leptin signaling due to either leptin deficiency (in ob/ob mice) or leptin resistance (in db/db mice) therefore leads directly to hyperglycemia and the overexpression of hypothalamic NPY that is implicated in the pathogenesis of the obesity syndrome.

Signal transduction through lipid second messengers

This review emphasizes the generation of glycerolipid and sphingolipid second messengers, and their molecular targets. The role of the phosphatidylinositol transfer protein and phospholipase D in signal transmission, and the structures of the 1, 2-diacylglycerol and calcium-binding sites of protein kinase C are discussed. Further, ceramide signaling through protein kinases and the role of cross-talk in the signaling of apoptosis and inflammation are addressed.

Thrombopoietin-stimulated ex vivo expansion of human bone marrow megakaryocytes

The effect of thrombopoietin (TPO) on megakaryocytopoiesis (MKP) has been mainly studied using clonogenic assays in murine systems. In this study, we evaluated MKP in liquid culture using human bone marrow cells. While interleukin 3 (IL-3) and stem cell factor (SCF) are potent activators of TPO-stimulated MKP in the murine system, only IL-3 exhibited synergistic activity with TPO in cultures of human bone marrow. The IL-3 effect on TPO-stimulated megakaryocyte (MK) proliferation, expressed as the absolute number of MKs per seeded CD34+ cell, was more pronounced with purified CD34+ cell (8 +/- 1.6 SE versus 2.8 +/- 0.7 SE in the presence and absence of IL-3, respectively) than with mononuclear cells (MNC) (16 +/- 2.8 SE versus 11 +/- 2.0 SE). This effect of IL-3 on TPO-stimulated MK proliferation was due to a general proliferation of all cell types since the relative frequency of MKs (32.1 +/- 3 SE and 55.8 +/- 3 SE in MNC and CD34+ cells, respectively) was not affected by IL-3. The effect of TPO alone, TPO + IL-3, TPO + SCF, and TPO + IL-3 + SCF on MK proliferation was examined in MNC and CD34+ cultures. Greater numbers of MK per seeded CD34+ were observed in MNC compared to CD34+ cultures under all conditions except when TPO was added with both IL-3 and SCF. The enhancing effect of MNC was also observed on MK ploidy in the presence of TPO and IL-3. While proliferation and ploidy increase with TPO concentration in the murine system, they are inversely related in the human system. A significant 2.5-fold enhancement of TPO-induced MK proliferation was observed when purified CD34+ cells were cultured in inserts separated from human bone marrow stroma, indicating that soluble stimulatory factors are released from the stroma. These observations will be useful for ex vivo expansion of MKs to treat post-transplant or chemotherapy-associated thrombocytopenia.

Assessment of knowledge, attitudes, and behaviors relative to cervical cancer and the Pap smear among adolescent girls in West Virginia

BACKGROUND AND METHODS

Questionnaires assessing knowledge of, attitudes toward, and behaviors relative to cervical cancer and its prevention were administered to 279 tenth-grade girls.

RESULTS

Eighty-four percent had heard of cervical cancer, and 83% had heard of the Pap smear. Sexual intercourse with multiple partners and cigarette smoking were risk factors identified by 65% and 40% of these students, respectively. Forty-eight percent reported being sexually active. This group, compared with those not sexually active, was more likely to 1) identify the Pap test as a test involving a vaginal examination, 2) use tobacco products, and 3) be exposed to tobacco smoke. The most common barriers to obtaining a Pap test reported by those sexually active were embarrassment (64%), pain/discomfort (57%), fear of cancer (27%), fear of parents discovering sexual activity (25%), and cost (13%).

CONCLUSIONS

Based on the information obtained in this study, the authors recommend changes in school health programs that target adolescent girls: 1) risk factors and behavior should receive more emphasis, and 2) the pelvic examination and Pap test should be described in sufficient detail to address the issues of embarrassment, pain, and discomfort.

Molecular and functional characterization of turkey interferon

The turkey interferon (TkIFN) gene encodes a signal peptide and a mature protein of 30 and 162 amino acids, respectively. TkIFN mRNA expression was induced by reoviral double-stranded RNA in fibroblasts. The recombinant TkIFN protein possessed species-specific antiviral activity and in synergy with lipopolysaccharide (LPS) induced bone marrow macrophages to produce nitric oxide (NO). LPS or TkIFN alone did not induce bone marrow macrophages to produce significant amounts of NO, which showed that TkIFN provided one of the two signals necessary to induce NO production in turkey macrophages. Unlike the anti-inflammatory nature of mammalian alpha/beta IFNs, TkIFN augmented the LPS-induced expression of interleukin-8, a proinflammatory cytokine. This finding suggests a role for TkIFN in inflammatory conditions.

Accelerated reconstitution of platelets and erythrocytes after syngeneic transplantation of bone marrow cells derived from thrombopoietin pretreated donor mice

The recent cloning of the ligand of the c-Mpl hematopoietin receptor has indicated a major role for this cytokine in the development of megakaryocytes. In this study we have applied c-Mpl ligand (thrombopoietin [TPO]) in the setting of syngeneic transplantation in an attempt to accelerate the reconstitution of platelets. Donor mice were treated with 20 kilounits (kU)/d TPO intraperitoneally (ip) for 5 days. This resulted in a 2.5-fold increment in platelet counts from 1,119 x 10(9)/L to 2,582 x 10(9)/L (mean, n = 7). Total numbers of hematopoietic progenitor cells in bone marrow (BM) and spleen, as assessed in a colony-forming unit-granulocyte erythroid monocyte macrophage (CFU-GEMM) colony assay (55.3 v 38.6 x 10(3) CFU/femur; 27.3 v 16.3 x 10(3) CFU/spleen, mean, n = 7) as well as total numbers of burst-forming unit-erythroid (BFU-E) (24.0 v 16.4 x 10(3)/femur; 10.2 v 1.9 x 10(3)/spleen, mean, n = 7), were significantly higher in TPO-treated donors than in saline-treated controls. Female Balb-C mice were lethally (8.5 Gy) irradiated and transplanted with 10(5) BM cells. After transplantation, groups of mice were treated with recombinant murine TPO at a dose of 20 to 30 kU/d ip or subcutaneously (SC) for 5 to 14 days. Using this dose and schedule, TPO did not stimulate the recovery of platelets in comparison with control animals transplanted with equal cell numbers but given vehicle alone. In other experiments, 10(5) BM cells were procured from TPO-treated donor mice and transplanted into lethally irradiated recipient mice. In comparison with animals transplanted with an equal number of BM cells derived from saline-treated controls, recipients of TPO-treated BM cells had significantly faster platelet recovery and higher platelet nadir counts (88 v 30 x 10(9)/L, mean, n = 20). Transplantation of TPO-treated BM cells also resulted in an accelerated recovery of erythrocytes and increased erythrocyte nadir counts (7.2 v 5.0 x 10(12)/L, mean, n = 20). At the day of platelet nadir (day 12 after transplantation) these animals had higher numbers of BFU-Es (770 v 422, mean, n = 5) in the marrow and also had higher reticulocyte counts (44 / 1000 v 8 / 1000 mean, n = 5) in the blood. Therefore, the accelerated recovery of erythrocytes may be a direct effect of TPO on erythropoiesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of L-carnitine treatment on very low density lipoprotein kinetics in the hyperlipidemic rabbit

This study examined the hypolipidemic effect of 4 weeks of L-carnitine treatment (170 mg/kg b.w./day) in New Zealand White rabbits fed a high fat diet (5% corn oil/0.5% cholesterol). Specifically, [3H] glycerol and [125I] very low density lipoprotein (VLDL) turnover studies were conducted to examine the effect of treatment on VLDL kinetics. The masses of plasma VLDL-triglycerides (VLDL-TG) and VLDL-apoprotein B (VLDL-apoB) were significantly increased by the high-fat diet. Four weeks of treatment with L-carnitine significantly reduced these masses. Kinetic analysis indicated that fat feeding reduced the fractional catabolic rates (FCRs) of VLDL-TG and VLDL-apoB relative to chow-fed controls. The transport of these VLDL components was not altered by the diet. L-carnitine treatment had no effect on the FCRs of VLDL-TG and VLDL-apoB or on the transport of VLDL-apoB. Yet, treatment significantly lowered the transport of VLDL-TG. These data indicate that the lipid-lowering effect of L-carnitine in this animal model was due, in part, to a decrease in the transport and not due to an alteration in the fractional catabolic rate of VLDL-TG.

Hypoxic induction of human vascular endothelial growth factor expression through c-Src activation

Angiogenesis, the formation of new microvasculature by capillary sprouting, is crucial for tumour development. Hypoxic regions of solid tumours produce the powerful and directly acting angiogenic protein VEGF/VPF (vascular endothelial growth factor/vascular permeability factor). We now investigate the signal transduction pathway involved in hypoxic induction of VEGF expression. Hypoxia is known to induce a tyrosine kinase cascade that results in the activation of nitrogen-fixation genes in Rhizobium meliloti, and activation of tyrosine kinases is critical in signalling triggered by growth factors and ultraviolet light. We show here that genistein, an inhibitor of protein tyrosine kinase, blocks VEGF induction. Hypoxia increases the kinase activity of pp60c-src and its phosphorylation on tyrosine 416 but does not activate Fyn or Yes. Expression of either a dominant-negative mutant form of c-Src or of Raf-1 markedly reduces VEGF induction. VEGF induction by hypoxia in c-src(-) cells is impaired, although there is a compensatory activation of Fyn. Our results provide an insight into hypoxia-triggered intracellular signalling, define VEGF as a new downstream target for c-SRC, and suggest a role for c-SRc in promoting angiogenesis.

The management of professionals: the preferences of hospital sisters and charge nurses

This analysis of the preferences of how sisters and charge nurses are managed is the result of a two centre descriptive study using theoretical models of professionalism, developing preferences and exercising situational leadership. It was conducted to determine if the management structure preferred by sisters and charge nurses, in a general acute hospital setting, supported the professionalism of nursing. The outcomes were intended to help develop a strategic plan for the future of nursing and the management of nurses. The research instruments were a self-completed questionnaire (19 were returned, a response rate of 31.1%) and four semi-structured interviews. The findings disclosed some dissatisfaction with the present management arrangements. The sisters and charge nurses felt that their priorities for practice and professional issues were better supported by clinically involved, ward-based senior nurses than by unit-based senior nurses with a general management function. However, sisters' and charge nurses' discussions with ward-based senior nurses were apparently less effective than discussions in peer groups which led to influential collegial autonomy. This preferred management style can be supported by the use of situational leadership theory which would enhance collegial autonomy and professional satisfaction. Recognition of the sisters and charge nurses preferences and adjustment of their management would therefore enable them to participate effectively in organizational decision-making.

Transmission of Creutzfeldt-Jakob disease from humans to transgenic mice expressing chimeric human-mouse prion protein

Transgenic (Tg) mice were constructed that express a chimeric prion protein (PrP) in which a segment of mouse (Mo) PrP was replaced with the corresponding human (Hu) PrP sequence. The chimeric PrP, designated MHu2MPrP, differs from MoPrP by 9 amino acids between residues 96 and 167. All of the Tg(MHu2M) mice developed neurologic disease approximately 200 days after inoculation with brain homogenates from three patients dying of Creutzfeldt-Jakob disease (CJD). Inoculation of Tg(MHu2M) mice with CJD prions produced MHu2MPrPSc (where PrPSc is the scrapie isoform of PrP); inoculation with Mo prions produced Mo-PrPSc. The patterns of MHu2MPrPSc and MoPrPSc accumulation in the brains of Tg(MHu2M) mice were different. About 10% of Tg(HuPrP) mice expressing HuPrP and non-Tg mice developed neurologic disease > 500 days after inoculation with CJD prions. The different susceptibilities of Tg(HuPrP) and Tg(MHu2M) mice to Hu prions indicate that additional species-specific factors are involved in prion replication. Diagnosis, prevention, and treatment of Hu prion diseases should be facilitated by Tg(MHu2M) mice.

Recurrent hemobilia after laparoscopic cholecystectomy

Hemobilia occurred 1 month after a laparoscopic cholecystectomy, the result of an aneurysm of the right branch of the hepatic artery. The aneurysm was treated by selective arterial embolization. Recurrent bleeding 28 days later was treated by embolization with platinum coils. The mechanism of occurrence of the aneurysm and its treatment are discussed.

Serial transmission in rodents of neurodegeneration from transgenic mice expressing mutant prion protein

Two lines of transgenic (Tg) mice expressing high (H) levels of the mutant P101L prion protein (PrP) developed a neurologic illness and central nervous system pathology indistinguishable from experimental murine scrapie; these mice were designated Tg(MoPrP-P101L)H. Brain homogenates from Tg(MoPrP-P101L)H mice were inoculated intracerebrally into CD-1 Swiss mice, Syrian hamsters, and Tg196 mice, Tg mice expressing the MoPrP-P101L transgene at low levels. None of the CD-1 mice developed central nervous system dysfunction, whereas approximately 10% of hamsters and approximately 40% of the Tg196 mice manifested neurologic signs between 117 and 639 days after inoculation. Serial transmission of neurodegeneration in Tg196 mice and Syrian hamsters was initiated with brain extracts, producing incubation times of approximately 400 and approximately 75 days, respectively. Although the Tg(MoPrP-P101L)H mice appear to accumulate only low levels of infections prions in their brains, the serial transmission of disease to inoculated recipients argues that prion formation occurs de novo in the brains of these uninoculated animals. These Tg mouse studies, taken together with similar findings in humans dying of inherited prion diseases, provide additional evidence that prions lack a foreign nucleic acid.

Social Identity versus Personal Identity: An Investigation into the Interaction of group and Personal Status with Collective Self-Esteem on Ingroup Favouritism

In this study the authors investigated the effects of three independent variables, personal status (high, low, neutral), group status (high, low, neutral) and private collective self-esteem (CSE), on three dependent variables: ingroup favouritism, self-favouritism, and the difference between these two measures — ‘self versus ingroup favouritism’. Personal and group status were manipulated by providing bogus test feedback to 225 school children aged between 13–15 years. It was found that subjects with high CSE showed greater ingroup relative to self-favouritism (‘self vs ingroup favouritism’) than subjects with low CSE but only when group status was neutral or high. When group status was low there was little difference between high and low CSE subjects. A second study on the validity of private collective self-esteem found that it was moderately correlated with Jewish identification, and not correlated with subtle racism.