Monokine production by microglial cell clones

Cytokines have been suggested to act as intermediates between the immune and the central nervous system, but little is known about the type of cells synthesizing them in the brain. We have immortalized with oncogenic retroviruses primary brain cell cultures from mouse embryos and have generated clones of microglial cells that have been characterized. Three of the clones studied produce interleukin 1 (IL 1); IL 6 and tumor necrosis factor-alpha as assessed by biological assays and by Northern blot analysis. Our data raise the question on the role of these cytokines in the brain and suggest that early resident microglial cells might play an important role in development processes and in the adult brain.

Global air quality and climate

Emissions of air pollutants and their precursors determine regional air quality and can alter climate. Climate change can perturb the long-range transport, chemical processing, and local meteorology that influence air pollution. We review the implications of projected changes in methane (CH(4)), ozone precursors (O(3)), and aerosols for climate (expressed in terms of the radiative forcing metric or changes in global surface temperature) and hemispheric-to-continental scale air quality. Reducing the O(3) precursor CH(4) would slow near-term warming by decreasing both CH(4) and tropospheric O(3). Uncertainty remains as to the net climate forcing from anthropogenic nitrogen oxide (NO(x)) emissions, which increase tropospheric O(3) (warming) but also increase aerosols and decrease CH(4) (both cooling). Anthropogenic emissions of carbon monoxide (CO) and non-CH(4) volatile organic compounds (NMVOC) warm by increasing both O(3) and CH(4). Radiative impacts from secondary organic aerosols (SOA) are poorly understood. Black carbon emission controls, by reducing the absorption of sunlight in the atmosphere and on snow and ice, have the potential to slow near-term warming, but uncertainties in coincident emissions of reflective (cooling) aerosols and poorly constrained cloud indirect effects confound robust estimates of net climate impacts. Reducing sulfate and nitrate aerosols would improve air quality and lessen interference with the hydrologic cycle, but lead to warming. A holistic and balanced view is thus needed to assess how air pollution controls influence climate; a first step towards this goal involves estimating net climate impacts from individual emission sectors. Modeling and observational analyses suggest a warming climate degrades air quality (increasing surface O(3) and particulate matter) in many populated regions, including during pollution episodes. Prior Intergovernmental Panel on Climate Change (IPCC) scenarios (SRES) allowed unconstrained growth, whereas the Representative Concentration Pathway (RCP) scenarios assume uniformly an aggressive reduction, of air pollutant emissions. New estimates from the current generation of chemistry-climate models with RCP emissions thus project improved air quality over the next century relative to those using the IPCC SRES scenarios. These two sets of projections likely bracket possible futures. We find that uncertainty in emission-driven changes in air quality is generally greater than uncertainty in climate-driven changes. Confidence in air quality projections is limited by the reliability of anthropogenic emission trajectories and the uncertainties in regional climate responses, feedbacks with the terrestrial biosphere, and oxidation pathways affecting O(3) and SOA.

Targeting vectors for intracellular immunisation

We define intracellular immunization as the inhibition or inactivation of the function of a molecule by the ectopic intracellular expression of antibody binding domains which recognise the molecule. Such recombinant antibodies can be directed to different compartments of eukaryotic cells by means of previously defined targeting signals, thus permiting the study of any molecule in any cellular compartment for which an antibody is available. For this purpose, we have created a set of vectors based on the VHExpress vector described [Persic, L., Roberts, A., Wilton, J., Cattaneo, A., Bradbury, A. and Hoogenboom, H.R. (1997) An integrated vector system for the eukaryotic expression of antibodies or their fragments after selection from phage display libraries. Gene 187, 000-000], which has been modified to express scFvs (single chain fragments) linked to specific targeting signals. These permit the localisation of scFvs to different intracellular compartments: the endoplasmic reticulum (scFvE-er), the nucleus (scFvE-nuclear), the mitochondria (scFvE-mit), the cytoplasm (scFvE-cyto), and as secreted proteins (scFvE-sec). The function of these vectors has been assessed by the immunofluorescence of COS cells transiently transfected with constructs containing the alphaD11 scFv.

The effect of future ambient air pollution on human premature mortality to 2100 using output from the ACCMIP model ensemble

Ambient air pollution from ground-level ozone and fine particulate matter (PM_2.5) is associated with premature mortality. Future concentrations of these air pollutants will be driven by natural and anthropogenic emissions and by climate change. Using anthropogenic and biomass burning emissions projected in the four Representative Concentration Pathway scenarios (RCPs), the ACCMIP ensemble of chemistry-climate models simulated future concentrations of ozone and PM_2.5 at selected decades between 2000 and 2100. We use output from the ACCMIP ensemble, together with projections of future population and baseline mortality rates, to quantify the human premature mortality impacts of future ambient air pollution. Future air pollution-related premature mortality in 2030, 2050 and 2100 is estimated for each scenario and for each model using a health impact function based on changes in concentrations of ozone and PM_2.5 relative to 2000 and projected future population and baseline mortality rates. Additionally, the global mortality burden of ozone and PM_2.5 in 2000 and each future period is estimated relative to 1850 concentrations, using present-day and future population and baseline mortality rates. The change in future ozone concentrations relative to 2000 is associated with excess global premature mortality in some scenarios/periods, particularly in RCP8.5 in 2100 (316 thousand deaths/year), likely driven by the large increase in methane emissions and by the net effect of climate change projected in this scenario, but it leads to considerable avoided premature mortality for the three other RCPs. However, the global mortality burden of ozone markedly increases from 382,000 (121,000 to 728,000) deaths/year in 2000 to between 1.09 and 2.36 million deaths/year in 2100, across RCPs, mostly due to the effect of increases in population and baseline mortality rates. PM_2.5 concentrations decrease relative to 2000 in all scenarios, due to projected reductions in emissions, and are associated with avoided premature mortality, particularly in 2100: between -2.39 and -1.31 million deaths/year for the four RCPs. The global mortality burden of PM_2.5 is estimated to decrease from 1.70 (1.30 to 2.10) million deaths/year in 2000 to between 0.95 and 1.55 million deaths/year in 2100 for the four RCPs, due to the combined effect of decreases in PM_2.5 concentrations and changes in population and baseline mortality rates. Trends in future air pollution-related mortality vary regionally across scenarios, reflecting assumptions for economic growth and air pollution control specific to each RCP and region. Mortality estimates differ among chemistry-climate models due to differences in simulated pollutant concentrations, which is the greatest contributor to overall mortality uncertainty for most cases assessed here, supporting the use of model ensembles to characterize uncertainty. Increases in exposed population and baseline mortality rates of respiratory diseases magnify the impact on premature mortality of changes in future air pollutant concentrations and explain why the future global mortality burden of air pollution can exceed the current burden, even where air pollutant concentrations decrease.

Molecular cloning of the avian acute transforming retrovirus MH2 reveals a novel cell-derived sequence (v-mil ) in addition to the myc oncogene

Mill-Hill-2 virus (MH2) proviral DNA was cloned from a transformed non-producer cell culture (MH2QB2) through insertion of randomly cut high mol. wt. cellular DNA in the lambdoid vector L47.1. Restriction analysis of a suitable recombinant phage by Southern DNA blotting and hybridization with different probes allowed us to characterize the genetic organization of the provirus and to identify a novel MH2-specific sequence of at least 1.1kbp. Such a sequence, for which we propose the name v-mil, from MilI-Hill-2 virus, is not homologous to v-myc, the previously described oncogene of MH2, nor to avian leukaemia virus-related sequences. Evidence is presented here that v-mil has a cellular counterpart (c-mil) phylogenetically conserved in birds and mammals, including man, and expressed as a single RNA species at least in some tissues. MH2 virus might thus be regarded, like avian erythroblastosis virus or E26, as another example of retroviruses having recombined with more than one cellular gene.

Short-term versus long-term antimicrobial prophylaxis in oncologic head and neck surgery

BACKGROUND

Although antimicrobial prophylaxis is mandatory in major clean-contaminated oncologic surgery of the head and neck, both the choice of specific antimicrobial compounds and the treatment duration are still discussed.

METHODS

A prospective, randomized trial was carried out to compare efficacy and tolerability of clindamycin-cefonicid administered for 1 day versus 3 days in reducing the rate of wound and systemic infections. The following potential risk factors for surgical wound infection were evaluated: type of surgery, stage of disease, preoperative tracheostomy, preoperative radiotherapy, and diabetes mellitus.

RESULTS

One-hundred sixty-two patients were evaluable; 81 received 1-day chemoprophylaxis, while the remaining 81 were treated according to the 3-day schedule. During the first 20 days after surgery, wound infections occurred in 2 (2.5%) and 3(3.7%) patients, respectively, in the 1-day and 3-day treatment groups, so that no significant difference was found among the two evaluated chemoprophylaxis schedules.

CONCLUSION

A 3-day schedule did not prove useful in preventing wound and systemic infections. All presumed risk factors were not associated with an increased rate of wound infections, although preoperative radiotherapy was associated with a greater severity of infections and a higher risk of late wound complications.

Blocking the NGF-TrkA interaction rescues the developmental loss of LTP in the rat visual cortex: role of the cholinergic system

Although nerve growth factor (NGF) is a crucial factor in the activity-dependent development and plasticity of visual cortex, its role in synaptic efficacy changes is largely undefined. We demonstrate that the maintenance phase of long-term potentiation (LTP) is blocked by local application of exogenous NGF in rat visual cortex at an early stage of postnatal development. Long-term depression (LTD) and bidirectional plasticity are unaffected. At later postnatal ages, blockade of either endogenous NGF by immunoadhesin (TrkA-IgG) or TrkA receptors by monoclonal antibody rescues LTP. Muscarinic receptor activation/inhibition suggests that LTP dependence on NGF is mediated by the cholinergic system. These results indicate that NGF regulates synaptic strength in well-characterized cortical circuitries.

Extending filamentous phage host range by the grafting of a heterologous receptor binding domain

fd and IKe are two similar filamentous phage which infect their hosts by means of pili found on the host membrane: fd infects bacteria bearing F pili, whereas IKe infects bacteria bearing N or I pili. Infection is mediated by the gene 3 protein (g3p), which of the nine proteins found in both phage is the most diverse. Previous attempts to incorporate g3p from one phage into the other by complementation have been unsuccessful [Bross et al. (1988) J. Gen. Microbiol. 134, 461-471]. Here we have grafted different parts of IKe g3p to the end of fd g3p and so augmented the host range of fd phage. We show that phage bearing such chimeric g3p are able to infect bacteria bearing both N and F pili providing they contain at least the receptor domain of IKe g3p, the infection of N bearing bacteria occurring at a level 70,000 times greater than background. This level of infection can be increased tenfold by including the glycine-rich domain as well. Addition of the penetration domain does not improve the level of infection above that of the receptor domain alone, indicating that the fd penetration domain is functional in the infection of bacteria bearing either N or F pili. Similarly derived fd phagemid also show increased infection of bacteria bearing N pili, albeit at much lower levels, suggesting that efficient infection requires more than one functional g3p on the surface of the phage.

A non-radioactive in situ hybridization method that does not require RNAse-free conditions

This report describes a quick and versatile method to perform non-radioactive in situ hybridization in which none of the hybridization steps are performed under RNAse-free conditions. This study demonstrates that in situ hybridization can be performed without an RNAse-free environment provided that the concentration of RNAse introduced during the experiment does not reach 0.1 microg/ml, a concentration that is unlikely to be achieved through an accidental contamination. Moreover, evidence is provided that the only step sensitive to RNAse degradation is the pretreatment since degradation during the hybridization step can not occur due to a very efficient protective effect exerted by formamide. Finally, our data suggest that endogenous RNAse activity might be readily neutralized through paraformaldehyde fixation. A feature of this method is the strong fixation that ensures a perfect tissue preservation, even at level of the fine structure of the cell processes. The method allows a uniform tissue penetration by sodium periodate and sodium borohydride treatment and can be easily used in combination with diaminobenzidine immunohistochemistry for double labeling experiments.

Hep Par 1 in gastric and bowel carcinomas: an immunohistochemical study

AIMS

Hep Par 1 has been described as a specific marker of hepatocellular differentiation and its immunohistochemical use has been suggested as a helpful tool for hepatocellular carcinoma (HCC) diagnosis. Most metastatic liver tumours come from the gastrointestinal tract and usually can be distinguished from HCC only through histology. We evaluated by immunohistochemistry the specificity of Hep Par 1, studying the presence of the epitope that reacts with Hep Par 1 in primary gastric and colorectal cancers.

METHODS

A series of 39 cases of primary gastric and 18 cases of colorectal carcinoma were selected. Twenty-six of the 39 gastric carcinomas were of the intestinal type, six of the diffuse type, three of the mixed type and five had hepatoid differentiation. Two of the 18 colorectal adenocarcinomas were well differentiated, 14 moderately differentiated, one poorly differentiated and one was of the mucinous type. Five-microm sections were stained by immunohistochemistry using Hep Par 1 as primary antibody.

RESULTS

Immunohistochemical staining was observed in 26 gastric carcinomas (69%) and nine large bowel carcinomas (50%). Fifteen of the 26 positive-stained gastric cancers were of intestinal type, four of diffuse type and two of mixed type cases. All of the five hepatoid type cases stained positively. Two of the nine positively stained colorectal cancers were well differentiated, six were moderately differentiated and one was a mucinous type adenocarcinoma. The staining pattern was cytoplasmic and granular as described in benign and malignant hepatocytes. The percentage of immunostained cells was graded as follows: 0 (no staining); 1 (>0-5%); 2 (> 5-50%); 3 (> 50%). Of the 26 positive gastric tumours, 13 showed a staining score of 1, eight scored 2, and five scored 3. Four of the nine positive intestinal carcinomas showed a staining score of 1, and five scored 2.

CONCLUSIONS

Our results show that Hep Par 1 is a highly sensitive marker of hepatocellular differentiation as demonstrated by the expression in gastric tumours with hepatoid histotype. However, the frequent reaction with neoplastic cells of gastric and bowel carcinomas shows a low grade of specificity of this antibody.

myc-immortalized microglial cells express a functional platelet-activating factor receptor

The autacoid platelet-activating factor (PAF) takes part in a complex network of interactions regarding the cellular components of nervous tissues. Efforts aimed at characterizing the effects of PAF in the brain have been recently focalized on neurons because PAF exerts pleiotropic effects on these cells. Less attention has instead been paid to the glial component of the brain. We have used microglial cell lines immortalized from 13-day-old mouse embryo brains by a myc-transducing retrovirus. When exposed to physiological doses of PAF, immortalized microglial cells showed increases in intracellular free calcium concentrations due to release of calcium from internal stores, as well as to extracellular calcium influxes. These profiles of reactivity were independent from the immortalizing process, being observable in primary microglial cultures and in immortalized clones showing different proliferative rates. PAF was also able to induce transient expression of the c-fos protooncogene in serum-starved cultures and induced a strong chemotactic response in microglial cells. In contrast with control macrophage cultures, PAF did not promote prostaglandin or leukotriene synthesis in immortalized cells. This was most likely due to the low amount of total arachidonic acid found in immortal microglia, with respect to that observed in freshly isolated cells. Our data suggest that several of the effects observed after PAF stimulation might be independent from PAF-induced arachidonic acid metabolism. The availability of an in vitro microglial model might now help in studying the proinflammatory effects of PAF, both direct or microglia mediated, in the neural environment.

Fascicular nerve stimulation and recording using a novel double-aisle regenerative electrode

OBJECTIVE

As artificial prostheses become more refined, they are most often used as a therapeutic option for hand amputation. By contrast to extra- or intraneural interfaces, regenerative nerve electrodes are designed to enable electrical interfaces with regrowing axonal bundles of injured nerves, aiming to achieve high selectivity for recording and stimulation. However, most of the developed designs pose an obstacle to the regrowth mechanisms due to low transparency and cause impairment to the nerve regeneration.

APPROACH

Here we present the double-aisle electrode, a new type of highly transparent, non-obstructive regenerative electrode. Using a double-side thin-film polyimide planar multi-contact electrode, two nerve fascicles can regenerate without physical impairment through two electrically isolated aisles.

MAIN RESULTS

We show that this electrode can be used to selectively record and stimulate fascicles, acutely as well as chronically, and allow regeneration in nerve gaps of several millimeters without impairment.

SIGNIFICANCE

This multi-aisle regenerative electrode may be suitable for neuroprosthetic applications, such as prostheses, for the restoration of hand function after amputation or severe nerve injuries.

The human DNA locus related to the oncogene myb of avian myeloblastosis virus (AMV): molecular cloning and structural characterization

Chicken and human cell DNA contains sequences homologous to the avian myeloblastosis virus oncogene, v-myb. These cellular sequences, c-myb (human) and c-myb (chicken), were isolated from libraries of human or chicken cell DNA fragments, generated by partial digestion with the restriction enzymes AluI and HaeIII, and compared. The chicken c-myb locus isolated from two distinct overlapping recombinant phages, contained five contiguous EcoRI fragments of 5.4, 1.1, 2.1, 2.2 and 9 kbp, accounting for all the bands seen with a v-myb probe in a complete EcoRI digest of chicken cellular DNA. Likewise, the screening of the human library yielded a recombinant phage hybridizing with the v-myb specific probe, that contained five EcoRI fragments of 2.8, 2.6, 2.0, 1.2 and 5.0 kbp (the last ending with an artificial EcoRI site, due to the construction of the library) belonging to the c-myb (human) locus. Probes using the EcoRI chicken DNA cloned fragments revealed corresponding contiguous EcoRI fragments in the human clone. Subsequent analyses of cellular polyadenylated mRNA extracted from human and chicken cells allowed the identification of single RNA species of 3.8 and 4.0 kb, respectively, as the representative transcripts of the c-myb locus in the two species. Thus, c-myb appears as a single locus in man and chicken, conserved with a similar structure in the two distantly related species. Our preparation of a specific human c-myb probe with an increased sensitivity on DNA/RNA blots should facilitate analyses concerning this gene in human normal or tumour cells or tissues.

Mouse macrophage clones immortalized by retroviruses are functionally heterogeneous

Murine macrophage clones were generated from thymus, spleen, brain, and bone marrow by in vitro immortalization with recombinant retroviruses carrying an avian v-myc oncogene. The cloned cell lines express F4/80 molecules, exert phagocytosis, have nonspecific esterase activity, and express class II molecules after interferon gamma activation. The macrophage clones are diploid and their karyotypes have remained stable for greater than 3 years in culture. After the macrophage clones were activated, their pattern of cytokine production was investigated. Functional heterogeneity in cytokine transcription was demonstrated: one of six liposaccharide-activated macrophages was unable to transcribe interleukin 1 alpha, whereas all of the liposaccharide-activated clones were able to transcribe tumor necrosis factor alpha. Interleukin 6 production was detected in three of six clones. The production of nitrite and tumor necrosis factor alpha as effector molecules of cytotoxicity was detected in all clones, thus showing that a single macrophage can exert more than one cytotoxic mechanism. The results indicate that immortalized and cloned macrophages have a differentially regulated expression of cytokine genes, adding further evidence for the existence of functional heterogeneity among cloned macrophages. This heterogeneity seems to derive from differentiation-related mechanisms rather than from external constraints.

DMSO reduces CSF-1 receptor levels and causes apoptosis in v-myc immortalized mouse macrophages

We have investigated the antiproliferative potentialof dimethyl sulfoxide (DMSO) on v-myc immortalized mouse macrophages on account of the cytotoxic effect induced by DMSO on myeloid cells. DMSO caused significant apoptosis in two immortalized macrophage celllines constitutively secreting colony-stimulating factor 1 (CSF-1). In contrast to the results described for mouse erythroleukemia cells, DMSO did not markedly decrease the level of the Spi-1/PU.1 transcription factor. However, DMSO caused a specific reduction in the protein level of the CSF-1 receptor (CSF-1R) compared to the FcgammaRIIIA immunoglobulin receptor, v-myc, and beta-actin proteins. To investigate if the level of CSF-1R might inversely correlate with DMSO-induced cell death, we derived a macrophage culture (named DN-11) that could be cultured in the presence of DMSO. Immunoblot analysis of DN-11, grown with or without DMSO, revealed significant amounts of CSF-1R under both conditions, suggesting a pivotal role for CSF-1R in the survival of DMSO-treated macrophages. Therefore, in these cells, DMSO seems to trigger apoptosis by interrupting an autocrine survival loop involving the CSF-1 receptor.

Parasite-altered host behavior in the face of a predator: manipulation or not?

Parasitologists have generally accepted the idea that parasite-induced alterations in host behavior increase the chance for parasite survival and transmission or ensure the completion of its life cycle. The aim of the present study was to investigate modifications in the behavior of Taenia crassiceps-infected BALB/c mice in the face of a predator. The experiments showed modifications in the response of infected mice in comparison with uninfected controls on exposure to a predator final host. However, different studies lead us to suggest that the observed modifications are likely to be a secondary effect of the impact of the parasite on host physiology and immunity that favors its development and proliferation.

Climate impact of biofuels in shipping: global model studies of the aerosol indirect effect

Aerosol emissions from international shipping are recognized to have a large impact on the Earth's radiation budget, directly by scattering and absorbing solar radiation and indirectly by altering cloud properties. New regulations have recently been approved by the International Maritime Organization (IMO) aiming at progressive reductions of the maximum sulfur content allowed in marine fuels from current 4.5% by mass down to 0.5% in 2020, with more restrictive limits already applied in some coastal regions. In this context, we use a global bottom-up algorithm to calculate geographically resolved emission inventories of gaseous (NO(x), CO, SO(2)) and aerosol (black carbon, organic matter, sulfate) species for different kinds of low-sulfur fuels in shipping. We apply these inventories to study the resulting changes in radiative forcing, attributed to particles from shipping, with the global aerosol-climate model EMAC-MADE. The emission factors for the different fuels are based on measurements at a test bed of a large diesel engine. We consider both fossil fuel (marine gas oil) and biofuels (palm and soy bean oil) as a substitute for heavy fuel oil in the current (2006) fleet and compare their climate impact to that resulting from heavy fuel oil use. Our simulations suggest that ship-induced surface level concentrations of sulfate aerosol are strongly reduced, up to about 40-60% in the high-traffic regions. This clearly has positive consequences for pollution reduction in the vicinity of major harbors. Additionally, such reductions in the aerosol loading lead to a decrease of a factor of 3-4 in the indirect global aerosol effect induced by emissions from international shipping.

Hepatitis B vaccination in dialysis patients and nutritional status

35 dialysis patients underwent anti-HBV vaccination. We classified patients in responders or non-responders using an anti-HBs titer of 50 UI/l as the discriminating serum level and tried to assess whether the antibody response bears any relationship with the nutritional status. 26 patients (74%) reached the target atb titer, which was maintained during follow-up (average 360 UI/l). The weak response in the other 9, with values never exceeding 20 UI/l, was short-lived. Anthropometric and impedenziometric parameters were higher in responders than in nonresponders, but the difference did not reach statistical significance. We conclude that the atb titer which discriminates uremics in responders or not must be greater than 50 UI/l and that the nutritional status may interfere with the seroconversion rate, but this conclusion needs to be validated in a wider population.

The second oncogene mil of avian retrovirus MH2 is related to the src gene family

The nucleotide sequence of a PstI fragment prepared from a cloned MH2 virus genome, pMH2-Hd, has been deduced using chemical and enzymatic methods. This fragment, 1862 nucleotides in length, starts with the gag gene, encodes the v-mil sequence and stops within the v-myc gene. This sequence shows that the v-mil gene is fused to the gag gene giving rise to a fused polyprotein of 98 000 daltons: 515 amino acids at the amino terminus would correspond to p10, p19, p27 and part of p12 determinants, 347 amino acids at the carboxy terminus correspond to the v-mil specific sequence. The mil protein shares homology with a number of onc proteins such as src, fes, fms, mos, yes, fps and erbB, as well as with the catalytic chain of the cAMP-dependent protein kinase. This PstI fragment also encodes the beginning of the myc gene which was integrated in MH2 along with the 3' end of the preceding intron placing an acceptor splice site in front of the used open reading frame. As deduced from the sequence, the MH2 myc protein is not identical to the MC29 myc protein. It differs at its amino terminus, which contains little or no gag determinants, depending on the ATG used to initiate translation.

Two different types of transcription for the myelocytomatosis viruses MH2 and CMII

The four avian defective leukemia retroviruses (DLVs) MC29, CMII, MH2 and OK10 all transform primarily macrophages in an in vitro bone marrow transformation assay, and contain specific nucleotide sequences closely related to the myc gene of MC29. These viruses were thought to express their oncogenic potential through a gag-myc fusion polyprotein, since fusion polyproteins were found in all tested cells transformed by MC29. We show here that MH2 virus does not conform to this model. Whereas MC29 produces only one mRNA detectable by RNA blotting in productively transformed cells, we reported recently that OK10 induced the synthesis of two myc-containing mRNAs, the smaller species being a spliced mRNA and a possible candidate for a transforming protein lacking gag determinants. However, the studies with OK10 were ambiguous because this virus produced also, in infected cells, a fusion protein containing gag, pol and myc determinants. We have therefore investigated the transcription pattern of the two other members of this group of viruses, namely CMII and MH2. Our results show that CMII resembles MC29 whereas MH2 produces, as OK10, two mRNAs containing myc-related sequences. However, unlike OK10, the MH2 fusion protein of 100 kd described previously cannot contain myc determinants and thus is likely to produce from its subgenomic mRNA a v-myc protein-lacking gag determinants. We thus conclude that the product of the v-myc oncogene is transforming with (MC29) or without (MH2) its fusion to gag determinants and that the multiple oncogenic spectrum is not basically affected since MH2 and MC29 both transform macrophages, fibroblasts and epithelial cells.

Cellular sources and effects of tumor necrosis factor-alpha on pituitary cells and in the central nervous system

Cytokine-mediated communication between the immune system and the nervous system has been shown in the past few years. The precise cellular sources of these molecules in the brain is still a controversial issue. We have thus immortalized primary cell cultures from mouse embryonic brains to analyze cloned cells involved in cytokine production. The cell clones obtained were identified as microglial cells and shown to produce several monokines. Among these, TNF alpha was detected by molecular analysis and cytotoxicity assays and shown to be expressed by microglial cells, after activation with LPS. Surprisingly, the TNF alpha-mediated cytotoxic activity, which was neutralized by specific antisera, was not detected in the cell supernatants but was mediated through cell-to-cell contact. Using antibodies to TNF alpha in FACS analysis, specific cell membrane staining on live microglial cells was shown. The results suggest that in the brain the form of TNF alpha detectable by standard procedures is the cell bound form and not the most common form, secreted TNF alpha. In addition, the effects of recombinant TNF alpha in vitro and in vivo were evaluated. In vitro, rTNF alpha stimulated beta-endorphin, GH, and PRL release from cultured cells prepared from rat anterior pituitary glands. In vivo, the administration of rTNF alpha to rats was able to modify analgesic responses. The concomitant administration of naloxone, an opiate receptor antagonist, or monoclonal anti-IL-1 antibody decreased the analgesic effects induced by rTNF alpha. This indicates that the analgesic effect might not be mediated directly by rTNF alpha but by other mediators, whose action is under the control of TNF alpha.

Clindamycin/cefonicid in head and neck oncologic surgery: one-day prophylaxis is as effective as a three-day schedule

The aim of our study was to evaluate the optimal duration of antibiotic prophylaxis in major oncologic surgery of the head and neck using a novel broad spectrum drug combination: clindamycin and cefonicid. A prospective randomized study was carried out on 126 evaluable patients undergoing clean-contaminated (skin to mucosa) surgery for cancer of larynx, pharynx or oral cavity. Cases at high surgical risk (because of need of pedicled or microvascular free flaps reconstruction), were excluded from the study. Within 20 days after surgery, only one case of wound infection was recorded among the 62 patients treated with the one-day schedule, versus three cases registered among the 64 subjects receiving three-day chemoprophylaxis. Episodes of systemic infections and eventual wound complications occurring in the first 20 days after surgery have also been recorded. The role of potential risk factors for postoperative complications has been evaluated. According to our findings, a three-day antibiotic regimen is not more effective than a short-term (one-day) schedule in preventing wound or systemic infection in clean-contaminated head and neck cancer surgery without flap reconstruction.