A xanthate transfer radical process for the introduction of the trifluoromethyl group

[reaction: see text]. S-Trifluoromethyl xanthates efficiently add to unactivated alkenes by a radical mechanism to give adducts with a trifluoromethyl group at the least hindered terminus of the olefin.

Effects of MDL 73005 on water-maze performances and locomotor activity in scopolamine-treated rats

The stimulation of 5-HT1A receptors in the raphe or their blockade in the hippocampus can reduce cognitive deficits induced by blockade of muscarinic receptors in the hippocampus. We investigated the effects of MDL 73005 (8-[2-(2,3-dihydro-1,4-benzodioxin-2-ylmethylamino) ethyl]-8-azaspiro[4,5] decane-7,9-dione methyl sulphonate), an agonist at 5-HT1A somatodendritic autoreceptors and an antagonist at postsynaptic 5-HT1A receptors in rats treated systemically with scopolamine. Spatial memory was assessed in a water maze using protocols testing reference and working memory. Home cage locomotor activity was also determined. Working memory and locomotor activity were evaluated before and after para-chlorophenylalanine (pCPA) treatment. Scopolamine produced a weak impairment of reference memory at 0.5 mg/kg, and a more pronounced impairment of working memory at 0.25 and 0.5 mg/kg. MDL 73005 alone (2 mg/kg, i.p.) had no effect, but prevented the memory impairments induced by 0.25 mg/kg of scopolamine. Scopolamine induced hyperlocomotion. MDL 73005 alone did not affect locomotor activity, but exacerbated the hyperlocomotion induced by 0.5 mg/kg of scopolamine. pCPA did not abolish the effects of MDL 73005, suggesting that these effects were not due to an action at presynaptic receptors, or even that they involved receptors other than serotonergic ones (e.g., D2). In conclusion, MDL 73005 is able to antagonise moderate spatial memory dysfunctions induced by systemic muscarinic blockade.

Smad7 inhibits the survival nuclear factor kappaB and potentiates apoptosis in epithelial cells

In this study, we examined the effect of the stable expression of Smad7 in two different cell lines on apoptosis induced by various stimuli including TGF-beta, serum withdrawal, loss of cell adhesion (anoikis) and TNF-alpha. Smad7 increased TGF-beta-mediated apoptosis in Mv1Lu cells as well as anoikis and/or serum withdrawal-induced apoptosis in Mv1Lu and MDCK cells. Smad7 markedly decreased the activity of the survival NF-kappaB transcription factor in MDCK cells. Interestingly, the stable expression of oncogenic Ras in MDCK cells which suppressed Smad7 inhibition of NF-kappaB also suppressed Smad7 potentiation of serum withdrawal-induced apoptosis and anoikis. In addition, Smad7 inhibited TNF-alpha stimulation of NF-kappaB and increased TNF-alpha-mediated apoptosis in MDCK cells. Our results provide the first evidence that Smad7 induces sensitization of cells to different forms of cell death. They moreover demonstrate that Smad7 inhibits the survival NF-kappaB factor, providing a potential mechanism whereby Smad7 potentiates cell death.

Insulin and IGF-1 stimulate the beta-catenin pathway through two signalling cascades involving GSK-3beta inhibition and Ras activation

We examined the interplay between the insulin/IGF-1- and beta-catenin-regulated pathways, both of which are suspected to play a role in hepatocarcinogenesis. Insulin and IGF-1 stimulated the transcription of a Lef/Tcf-dependent luciferase reporter gene by 3-4-fold in HepG2 cells. This stimulation was mediated through the activation of phosphatidylinositol 3-kinase (PI 3-K)/Akt and the inhibition of glycogen synthase kinase-3beta (GSK-3beta) since the effects of insulin and IGF-1 were inhibited by dominant-negative mutants of PI 3-K or Akt and an uninhibitable GSK-3beta. Together with inhibiting GSK-3beta, insulin and IGF-1 increased the cytoplasmic levels of beta-catenin. The PI 3-K/Akt/GSK-3beta pathway was not the sole to mediate insulin and IGF-1 stimulation of Lef/Tcf-dependent transcription. The Ras signalling pathway was also required as (i) the stimulatory effects of insulin and IGF-1 were inhibited by dominant-negative Ras or the MEK1 inhibitor PD98059 and (ii) activated Ha-Ras or constitutively active MEK1 synergized with catalytically inactive GSK-3beta to stimulate Lef/Tcf-dependent transcription. This study provides the first evidence that insulin and IGF-1 stimulate the beta-catenin pathway through two signalling cascades bifurcating downstream of PI 3-K and involving GSK-3beta inhibition and Ras activation. These findings demonstrate for the first time the ability of insulin and IGF-1 to activate the beta-catenin pathway in hepatoma cells and thereby provide new insights into the role of these factors in hepatocarcinogenesis.

When injected into the fimbria-fornix/cingular bundle, not in the raphe, 5,7-dihydroxytryptamine prevents amphetamine-induced hyperlocomotion

The locomotor effects of acute amphetamine treatment (1 mg/kg, i.p.) were assessed in Long-Evans rats after 5,7-dihydroxytryptamine (5, 7-DHT) injections into the fimbria-fornix/cingular bundle (FiFx/CB; 4 microg/side), or the dorsal and median raphe (Raphe; 10 microg). In control rats, amphetamine induced a significant increase of home-cage activity for about 2 h. This effect was similar in Raphe rats, but was absent in FiFx/CB rats. The raphe lesions reduced serotonin concentrations by 50% in the dorsal hippocampus, 75% in the ventral hippocampus and 58% in the fronto-parietal cortex. After FiFx/CB lesions, the reduction amounted 50, 61 and only 25%, in each of these regions, respectively. In the fronto-partietal cortex, dopamine concentration was significantly decreased in Raphe (-27%) and FiFx/CB rats (-65%). The results suggest that a serotonergic denervation of the hippocampus by injections of 5,7-DHT into the FiFx/CB pathways hampers the stimulating effects of amphetamine on locomotor activity. This effect might be related to the reduced dopaminergic tone in the fronto-parietal cortex.

Early (99m)Tc-ethylcysteinate dimer brain SPECT patterns in the acute phase of stroke as predictors of neurological recovery

OBJECTIVES

Accurate prediction of outcome in acute stroke would help in identifying subgroups of patients for therapeutic trials and intravenous thrombolysis. The purpose of this study was to prospectively test the hypothesis that brain SPECT, with (99m)Tc-L, L-ethylcysteinate dimer (ECD), a tracer sensitive to cell function, performed in the first hours after stroke onset, adds predictive power to concomitant neurological evaluation.

METHODS

Twenty-four patients with a first-ever middle cerebral artery stroke were prospectively studied with ECD-SPECT within 12 h after stroke onset. Neurological evaluation was performed using Orgogozo's scale at admission and 3 months later in order to calculate the percent Martinez-Vila evolution indices (EI%). Semiquantitative visual analysis of SPECT images was performed in 6 cortical regions relevant for carotid artery territory. Both the extent and the intensity of cortical reduced ECD uptake were calculated, leading to an 'ischemia' score, corresponding to the sum of regions of interest (ROI) where ECD uptake was between 40 and 80% of the contralateral healthy hemisphere, and an 'irreversibly damaged tissue' (IDT) score, corresponding to an uptake below 40%, and a total score (ischemia + IDT). Each patient was assigned to one of three patterns: (1) pattern I with severe ECD cortical uptake reduction defined by at least one ROI with uptake under 40%, (2) pattern II with moderate ECD cortical uptake reduction (40-80%) only and (3) pattern III with normal ECD uptake.

RESULTS

There were 11 patients (46%) with pattern I ECD-SPECT. This group had almost invariably (10/11 patients) a poor outcome. The 12 patients (50%) classified in pattern II had a variable clinical outcome, ranging from improvement to deterioration. The single patient with a normal SPECT (pattern III) had a full clinical recovery. Both total score and IDT score were strongly significantly correlated with neurological recovery EI% (respectively p = 0.006 and 0.004). Their predictive value was significantly higher than, and independent of, day 0 neurological evaluation. No patient had an increased ECD uptake.

CONCLUSION

Our results show that the degree of ECD cortical uptake reduction, measured on early brain SPECT, is a strong predictor of neurological recovery. ECD-SPECT data have a higher predictive value than day 0 neurological evaluation. The apparently better predictive value of ECD over hexamethylpropyleneamine oxime may reflect this tracer's brain retention mechanisms which are weighted more towards cell function than towards perfusion. ECD-SPECT is easily obtainable and may help in selecting out from therapy those patients who are likely to have either very good or very poor spontaneous outcome, and thus improve the assessment of acute stroke and the choice of therapeutic strategy.

[The behavioral determinants for health centers in health districts of urban Africa: results of a survey of households in Kinshasa, Congo]

This study analyses the choice determinants of the population for health centres through a survey of the behaviour of families in a representative sample of 1,000 households in the health districts of Kinshasa, Congo in 1997. For the most recent episode of illness, the respondents turned to seven types of care: the health centre (37%), private dispensaries (26.5%), self-medication through a pharmacy (23.9%), traditional practitioner (21%), traditional self-medication (16.9%), private outpatients' clinic (16.7%) and a reference hospital (10.4%). Past logistics have shown that patients resort to a health centre rather than another type of care structure (P = 0.05) when looking for quality care, reasonable prices and the availability of varied services. On the other hand, concern about the geographical proximity in relation to the family's residence calls for using the private dispensary. When looking for a doctor or the existence of a 'convention', families are more inclined to choose a private officially recognized outpatients' clinic. Those who had been looking for a solution to a special type of illness opted primarily for a traditional practitioner. In conclusion, the results of this study show that if people choose the care offered by health centres, it is because they judge it to be of good quality. The integrated care offered by the same technician, with a required training, is a major asset in the acceptability of the first line of primary health care in Kinshasa. This study suggests that it would no doubt be beneficial to integrate non-official private care structures into the primary health care system, as far as it is possible for them to achieve a level of quality comparable to that of the health centres. In order that the traditional practitioner might play an important complementary role in the realization of primary health care, even in urban areas, the possibility of promoting sites of communication should be studied. Moreover, considering the weak buying power of the city's inhabitants and the previous existence of tontines out of solidarity, the 'conventions' providing relief of health care costs, under the leadership of the local communities, should be integrated into the organization of the urban health system.

The differential regulation of group II(A) and group V low molecular weight phospholipases A(2) in cultured rat astrocytes

In astrocytes, cytokines stimulate the release of secretory phospholipase A(2) (sPLA(2)) activity and group II(A) sPLA(2) expression. This paper reports that two sPLA(2) isoforms, group II(A) and group V, are in fact expressed by astrocytes. Our studies showed that tumor necrosis factor alpha (TNFalpha) enhanced the mRNA of both isoforms, but the time courses of enhancement differed; group V was induced much faster than group II(A). Moreover, TNFalpha stimulated both the NF-kappaB and mitogen-activated protein (MAP) kinase (extracellular signal-regulated kinase, c-Jun NH(2)-terminal kinase, and p38 MAP kinase) signaling pathways in astrocytes. Interestingly, PI 3-kinase activity also was enhanced by TNFalpha, and NF-kappaB pathway was involved in mediating its effect. Specific inhibitors were used to show that both extracellular signal-regulated kinase and p38 MAP kinase may contribute to the effect of TNFalpha and that blocking phosphatidylinositol 3-kinase activity fully reversed the effect of TNFalpha. Furthermore, in astrocytes, TNFalpha-induced release of sPLA(2) activity was partially reversed by thyroid hormone and almost abolished by growth factors. This phenomenon was accompanied by a less marked increase in both group II(A) and group V sPLA(2) mRNA. In the presence of growth factors, the increase in group V mRNA was inhibited early and transiently, in contrast to what was observed with group II(A), which was more persistently inhibited. Although a transcriptional effect of thyroid hormone or growth factors in astrocytes cannot be definitively excluded, both types of factor interfered with sPLA(2) expression in a manner suggesting the existence of regulation of post-transcriptional events.

Insulin-mediated cell proliferation and survival involve inhibition of c-Jun N-terminal kinases through a phosphatidylinositol 3-kinase- and mitogen-activated protein kinase phosphatase-1-dependent pathway

We previously reported that long term treatment with insulin led to sustained inhibition of c-Jun N-terminal kinases (JNKs) in CHO cells overexpressing insulin receptors. Here we investigated the signaling molecules involved in insulin inhibition of JNKs, focusing on phosphatidylinositol 3-kinase (PI 3-K) and mitogen-activated protein kinase phosphatase-1 (MKP-1). In addition, we examined the relevance of JNK inhibition for insulin-mediated proliferation and survival. Insulin inhibition of JNKs was mediated by PI 3-K, as it was blocked by wortmannin and LY294002 and required the de novo synthesis of a phosphatase(s), as it was abolished by orthovanadate and actinomycin D. MKP-1 was a good candidate because 1) insulin stimulation of MKP-1 expression correlated with insulin inhibition of JNKs; 2) insulin stimulation of MKP-1 expression, like insulin inhibition of JNKs, was mediated by PI 3-K; and 3) the transient expression of an antisense MKP-1 RNA reduced the insulin inhibitory effect on JNKs. The overexpression of a dominant negative JNK1 mutant increased insulin stimulation of DNA synthesis and mimicked the protective effect of insulin against serum withdrawal-induced apoptosis. The overexpression of wild-type JNK1 or antisense MKP-1 RNA reduced the proliferative and/or antiapoptotic responses to insulin. Altogether, these results demonstrate that insulin inhibits JNKs through a PI 3-K- and MKP-1-dependent pathway and provide evidence for a key role for JNK inhibition in insulin regulation of proliferation and survival.

Preserved olfactory short-term memory after combined cholinergic and serotonergic lesions using 192 IgG-saporin and 5,7-dihydroxytryptamine in rats

Young adult Long-Evans female rats were subjected to intracerebroventricular injections of 150 microg 5,7-dihydroxytryptamine (5,7-DHT), 2 microg 192 IgG-saporin, or a combination of both neurotoxins. All rats were tested for olfactory recognition (short-term memory) using a task based on spontaneous exploration of odor sources. Compared with animals undergoing sham operations, 5,7-DHT reduced the concentration of serotonin by 60-80% in the frontoparietal cortex, hippocampus, striatum and the olfactory bulbs. After 192 IgG-saporin treatment, acetylcholine concentrations were reduced by approximately 40% in all these structures, except the striatum. Neither lesion induced a significant deficit in olfactory recognition. These data suggest that combined lesions of cholinergic and serotonergic neurons in the rat brain do not alter olfactory perception or olfactory short-term memory.

Intraseptal infusions of 8-OH-DPAT in the rat impairs water-maze performances: effects on memory or anxiety?

In the rat, 5-HT1A receptors are found on medial septal cholinergic neurons. The effects of intraseptal infusions of the 5-HT1A receptor agonist 8-OH-DPAT (8-hydroxy-2-(di-n-propyl-amino)-tertralin) were assessed on reference memory performances in a water maze. Compared with vehicle infusions, 0.5 and 4 microg of 8-OH-DPAT significantly impaired (but did not prevent) acquisition of the task and probe-trial performances. The results suggest that activation of 5-TH1A receptors in the (medial) septal area impairs spatial learning, perhaps directly by reducing the hippocampal cholinergic tonus, or indirectly by an effect on anxiety.

Implication of D2-like dopaminergic receptors in the median eminence during the establishment of long-day inhibition of LH secretion in the ewe

In ewes, photoperiod modulates LH release and dopaminergic terminals in the median eminence (ME) have a critical role in the establishment of long-day inhibition of LH secretion. This study was undertaken to determine the type of dopaminergic receptors, D1-like or D2-like, that mediate the action of dopamine on LH secretion at the ME level in this situation. This was assessed, in ovariectomized and estradiol-treated ewes, with the use of reverse microdialysis in the ME in three experiments: first, when LH secretion was stimulated by short days, by determining the response to three doses (0.01, 0.1 or 1 mg/ml) of a D1-like (SKF38393) and a D2-like (quinpirole) agonist; secondly, during early long-day inhibition of LH secretion, by determining the ability of SKF38393 and quinpirole (1 mg/ml) to mimic the inhibitory effects of dopamine, after a blockade of its synthesis with alpha-methyl-para-tyrosine (alphaMPT; 2 mg/ml); and thirdly, during early long-day inhibition of LH secretion, by determining the response to three doses (0.009, 0.09 or 0.9 mg/ml) of a D1-like (SCH23390) and a D2-like (sulpiride) antagonist. In none of the conditions was effect of the D1-like analogs on LH secretion found, compared with the control treatments. In contrast, the D2-like analogs caused changes in LH secretion. First, with short days, quinpirole in the highest dose significantly reduced mean LH concentration (P<0.05) and LH pulse frequency (P<0.01). Secondly, with long days, addition of quinpirole to alphaMPT caused a significant decrease in LH secretion relative to alphaMPT alone (P<0.05). Thirdly, with long days, sulpiride at the highest dose significantly increased mean LH concentration (during the first 3 h of treatment, P<0.05) and LH pulse frequency (P<0.05). Prolactin secretion was also determined in these experiments, and D2-like agonist and antagonist caused an inhibition and a stimulation of prolactin secretion, respectively. These results demonstrate that, in the ME, inhibitory action of dopamine on LH secretion, critical for the initiation of long-day-induced inhibition, is mediated by D2-like, not D1-like, dopaminergic receptors.

Insulin antiapoptotic signaling involves insulin activation of the nuclear factor kappaB-dependent survival genes encoding tumor necrosis factor receptor-associated factor 2 and manganese-superoxide dismutase

We recently showed that the antiapoptotic function of insulin requires nuclear factor kappaB (NF-kappaB) activation (Bertrand, F., Atfi, A., Cadoret, A., L'Allemain, G., Robin, H., Lascols, O., Capeau, J., and Cherqui, G. (1998) J. Biol. Chem. 273, 2931-2938). Here we sought to identify the NF-kappaB-dependent survival genes that are activated by insulin to mediate this function. Insulin increased the expression of tumor necrosis factor receptor-associated factor 2 (TRAF2) mRNA and protein in Chinese hamster ovary cells overexpressing insulin receptors (IRs). This effect required (i) IR activation since it was abrogated by IR mutation at tyrosines 1162 and 1163 and (ii) NF-kappaB activation since it was abolished by overexpression of dominant-negative IkappaB-alpha(A32/36) and mimicked by overexpression of the NF-kappaB c-Rel subunit. TRAF2 contributed to insulin protection against serum withdrawal-induced apoptosis since TRAF2 overexpression mimicked insulin protection, whereas overexpression of dominant-negative TRAF2-(87-501) reduced this process. Along with its protective effect, overexpressed TRAF2 increased basal and insulin-stimulated NF-kappaB activities. All effects were inhibited by IkappaB-alpha(A32/36), suggesting that an amplification loop involving TRAF2 activation of NF-kappaB is implicated in insulin antiapoptotic signaling. We also show that insulin increased manganese-superoxide dismutase (Mn-SOD) mRNA expression through NF-kappaB activation and that Mn-SOD contributed to insulin antiapoptotic signaling since expression of antisense Mn-SOD RNA decreased this process. This study provides the first evidence that insulin activates the NF-kappaB-dependent survival genes encoding TRAF2 and Mn-SOD and thereby clarifies the role of NF-kappaB in the antiapoptotic function of insulin.

Alteration of Met protooncogene product expression and prognosis in breast carcinomas

OBJECTIVE

To objectively quantify the expression and prognostic implications of the met protooncogene product (Met) in human breast cancer.

STUDY DESIGN

One hundred eighty-two cases of primary human breast cancer were collected. Both the normal and tumor portions of the original surgical pathology specimen were immunostained for Met and imaged using laser scanning confocal microscopy. Then the cases were ranked according to relative concentrations of normal and tumor Met expression. Subsequently, they were quantified using image analysis and the results correlated with clinical outcome to determine the prognostic value of relative levels of Met.

RESULTS

Using a quantitative index to evaluate the relative levels of Met expression, high levels of Met expression in the tumor as compared with the adjacent normal ducts predicted poor prognosis for overall survival and metastasis-free survival. The risk ratio for elevated Met expression was 3.94 (P = .0009). This new method also allows determination of the clinical relevance of low levels of Met in the tumor. The overall survival between the patient population with higher, lower and unchanged levels of Met in normal tissue as compared to tumor were significantly different (P = .0020).

CONCLUSION

Our studies suggest that in a subpopulation of node-negative breast cancer patients, either high or low levels of Met in tumor tissue relative to normal tissue is an indicator of poor overall survival (P = .0068). Thus, Met expression could be useful for identifying node-negative patients who could benefit from adjuvant therapy.

Median eminence dopaminergic activation is critical for the early long-day inhibition of luteinizing hormone secretion in the ewe

In ewes, photoperiod modulates LH release. The median eminence (ME) dopaminergic activity seems to be implicated in the inhibition of LH secretion by photoperiod. This study investigated the functional importance of ME dopaminergic activity for LH secretion inhibition in three inhibitory photoperiodic treatments: after 33 long days (LD) (LD1 treatment), after 72 LD (LD2 treatment), and after 34 short days. Using reverse microdialysis on three groups of seven ewes, a solution of alpha-methyl-paratyrosine [alphaMPT, an inhibitor of tyrosine hydroxylase (TH); 10 mM in Ringer's lactate] was infused into the ME for 5 h, preceded by a 5-h control period during which only vehicle was infused, in each of the three photoperiodic treatments. AlphaMPT dramatically decreased the 3,4-dihydroxyphenylacetic acid concentration, similarly in all three photoperiodic treatments, suggesting a similar inhibition of TH activity. In the LD1 treatment, alphaMPT significantly increased LH pulse frequency (+1.22 +/- 0.46 pulse/5 h from control period, mean +/- SEM, n = 9; P < 0.05) and mean concentration (+51 +/- 28%; P < 0.001). In the other two photoperiodic treatments, alphaMPT had no significant effect on LH release. Thus, blockade of dopamine synthesis in the ME seems to stimulate LH secretion in early, but not long-term, inhibition by LD nor after the transition to short days. Therefore, dopaminergic activity of the ME seems to be critical for LH secretion inhibition in some photoperiodic inhibitory treatments but not in others.

Oncogene-induced up-regulation of Caco-2 cell proliferation involves IGF-II gene activation through a protein kinase C-mediated pathway

We previously reported that ras and polyoma middle T (PyMT), a constitutive activator of the src protooncogene product, up-regulated Caco-2 cell proliferation along with protein kinase C (PKC) alpha expression and PKC activity. We aimed to investigate whether oncogene-induced up-regulation of Caco-2 cell proliferation involved stimulation of the autocrine IGF-II/IGF-I receptor (IGFIR) loop described in these cells and if so, to analyse the role of overexpressed and activated PKC. Compared with control vector transfected Caco-2 cells, ras- and PyMT-transfected cells exhibited increased expression of the 6.0 and 4.8 kb IGF-II transcripts. This was due to increased activity of the P3 and P4 promoters of the IGF-II gene which correlated with increased expression and DNA-binding activity of Sp1, a transcription factor interacting with several specific sites in P3 and P4 promoters. Oncogene-transfected cells displayed enhanced autocrine IGF-II production, which was fully responsible for the oncogene-induced increase in their proliferation since this increase was blunted by anti-human IGF-II and IGF1R (alphaIR3) antibodies. PKC mediated oncogene activation of the IGF-II gene presumably through action on Sp1 since (i) PKC activation by phorbol 12-myristate 13-acetate increased Sp1 expression, P3 and P4 activity and IGF-II mRNA in control but not in oncogene-transfected cells; and (ii) PKC inhibition by the PKC inhibitor Gö6976 reduced Sp1, P3 and P4 activity and IGF-II mRNA in all three cell lines. This is the first evidence that ras- and PyMT/src oncogenes up-regulate Caco-2 cell proliferation through a PKC-mediated pathway which stimulates IGF-II gene transcription and thereby increases autocrine IGF-II production. The mechanisms underlying IGF-II gene activation by PKC most probably involve action on Sp1.

Insulin induction of protein kinase C alpha expression is independent of insulin receptor Tyr1162/1163 residues and involves mitogen-activated protein kinase kinase 1 and sustained activation of nuclear p44MAPK

We examined the effect of insulin on protein kinase C alpha (PKCalpha) expression and the implication of the mitogen-activated protein kinase kinase 1 mitogen-activated protein kinase (MAPK) pathway in this effect. PKCalpha expression was measured by quantitative RT-PCR and Western blotting using Chinese hamster ovary (CHO) cells overexpressing human insulin receptors of the wild type (CHO-R) or insulin receptors mutated at Tyr1162/1163 autophosphorylation sites (CHO-Y2). In CHO-R cells, insulin caused a time- and concentration-dependent increase in PKCalpha messenger RNA, with a maximum at 6 h and 10-(8)M insulin. This increase involved a transcriptional mechanism, as it was not due to stabilization of PKCalpha messenger RNA and was associated with a similar increase in the immunoreactive PKCalpha level. Insulin induction of PKCalpha expression involved the MEK1MAPK pathway, as it was 1) almost completely suppressed by the potent MEK1 inhibitor PD98059, 2) mimicked by the dominant-active MEK1 (S218D/S222D) mutant, and 3) associated with sustained MAPK activation. In CHO-Y2 cells in which the early phase of MAPK activation by insulin was lost and only the late and sustained phase of activation was observed, insulin signaling of PKCalpha expression was preserved and again involved the MEK1-MAPK pathway. Moreover, we show that in both CHO-R and CHO-Y2 cells, insulin stimulation of PKCalpha gene expression was associated with prolonged activation of nuclear p44MAPK. These results indicate that induction of PKCalpha gene expression by insulin is independent of Tyr1162/1163 autophosphorylation sites and correlates with sustained activation of p44MAPK at the nuclear level.

Causes of locomotor disability and need for orthopaedic devices in a heavily mined Taliban-controlled province of Afghanistan: issues and challenges for public health managers

We conducted a locomotor disability survey on a heavily mined Taliban-controlled province of Afghanistan to document the problem of locomotor disability and to assess the need for orthopaedic rehabilitation devices in a study population of 12065. Global prevalence of locomotor disability was 23/1000 (95% CI: 20-26). )War-related injuries were the leading cause of disability, affecting almost exclusively adult males. Leading causes of disability among women and children were medical and poliomyelitis. Devices most needed were lower limb ortheses (8.2 devices/1000 people; 95% CI: 5.9-10.4) and orthopaedic shoes (6.0/1000; 95% CI:4.1-8.0). The need for lower limb prostheses was less frequent (2.0/1000; 95% CI: 1.1-2.8). Most lower limb amputees (mainly victims of landmine injuries) were fitted with an artificial leg, while rehabilitation needs for other types of disability remained largely unmet. We estimated that it would take at least 3 years to provide enough orthopaedic shoes and 10 years for ortheses, whereas the need for lower limb prostheses could be met in less than 4 months. None of the 27 women with lower limb disability were equipped with an orthopaedic device, although this was the case for 31 of 89 men (35%). The problem of landmines should not divert attention from other causes of disability such as poliomyelitis or from other rehabilitation requirements. Immunization programmes and restoration of the public health infrastructure should be given high priority; rehabilitation services are largely insufficient and should be developed. Extreme gender difference in needs coverage is a matter of concern. Researching culturally sensitive strategies to tackle this problem should be a priority for donors and implementing agencies.

Low environmental pH is responsible for the induction of nitric-oxide synthase in macrophages. Evidence for involvement of nuclear factor-kappaB activation

Stimulation of macrophages with endotoxin and/or cytokines is responsible for the expression of the inducible isoform of nitric oxide synthase (iNOS). Because macrophages are exposed to low pH within the microenvironment of inflammatory lesions, the potential role of acidic pH as an additional regulator of iNOS was investigated. Substitution of the culture medium of rat peritoneal macrophages at pH 7.4 with medium at pH 7.0 up-regulated iNOS activity, as reflected by a 2.5-fold increase in nitrite accumulation. The increase in iNOS activity was associated with a similar increase in iNOS mRNA expression that reflected an increase in iNOS mRNA synthesis rather than stability. Low environmental pH-induced iNOS gene transcription involved the activation of nuclear factor-kappaB (NF-kappaB) transcription factor since exposure of macrophages to low environmental pH both increased NF-kappaB binding activity in the nucleus and enhanced NF-kappaB-driven reporter gene expression. In addition, treatment of macrophages with pyrrolidine dithiocarbamate or n-acetyl-leucinyl-leucinyl-norleucinal, two drugs preventing NF-kappaB translocation to the nucleus, canceled low pH-induced nitrite accumulation. The overall mechanism required the synthesis of tumor necrosis factor alpha (TNFalpha). Indeed, 1) elevated TNFalpha bioactivity was observed in the medium of macrophages exposed to pH 7.0, and 2) incubation of macrophages with a neutralizing anti-TNFalpha antibody impaired both NF-kappaB activation and nitrite accumulation in response to acid challenge. In summary, exposure of macrophages to acidic microenvironment in inflammatory lesions leads to the up-regulation of iNOS activity through the activation of NF-kappaB.

A role for nuclear factor kappaB in the antiapoptotic function of insulin

We previously reported that insulin activates nuclear factor kappaB (NF-kappaB) in Chinese hamster ovary (CHO)-R cells overexpressing wild-type insulin receptors (IRs) through a pathway requiring IR tyrosine kinase and Raf-1 kinase activities. We now investigated whether the activation of NF-kappaB by insulin could serve an antiapoptotic function. Insulin (10(-9)-10(-7) M) inhibited apoptosis induced by serum withdrawal in CHO-R cells in a concentration-dependent manner. Insulin antiapoptotic signaling: (i) was dependent on IR number and IR tyrosine kinase activity since it was reduced in parental CHO cells and was abolished in CHO-Y2 cells overexpressing IRs mutated at Tyr1162/1163; (ii) was, like insulin activation of NF-kappaB, dependent on Raf-1 but not on mitogen-activated protein kinase activity since both processes were decreased by the dominant-negative Raf-1 mutant Raf-C4 whereas they persisted in mitogen-activated protein kinase-depleted cells; and (iii) required NF-kappaB activation since it was decreased by proteasome inhibitors and the dominant-negative IkappaB-alpha (A32/36) mutant and was mimicked by overexpression of the NF-kappaB c-Rel subunit. We also show that insulin antiapoptotic signaling but not insulin activation of NF-kappaB involved phosphatidylinositol 3-kinase (PI 3-kinase), as supported by the inhibition of the former but not of the latter process by the PI 3-kinase inhibitor LY294002. Inhibition of both NF-kappaB and PI 3-kinase totally abolished insulin antiapoptotic signaling. Thus insulin exerts a specific antiapoptotic function which is dependent on IR tyrosine kinase activity and is mediated by both a Raf-1-dependent pathway that leads to NF-kappaB activation and a PI 3-kinase-dependent pathway.

Decreased survival of HTLV-I carriers in leprosy patients from the Democratic Republic of the Congo: a historical prospective study

In this historical prospective study using sera stored for 22 years, we investigated the effect of HTLV-I infection on survival in a population of leprosy patients in the Democratic Republic of the Congo (formerly Zaire). We also determined the distribution of HTLV-I by subpopulation, age, and gender. Stored sera taken from a population of leprosy patients and controls in 1969 were tested for HTLV-I. Follow-up survival data on these patients were obtained in 1991. The sera collected in 1969 from 520 individuals was used to determine the prevalence of HTLV-I. Included in this number were 328 patients resident in the sanatorium. Survival and other data were available for 327 of these. A multivariate survival analysis using a logistic regression model was performed to evaluate the influence of HTLV-I status, age, type of leprosy, gender, duration of hospitalization, and ethnic group on survival. The overall prevalence of HTLV-I among the 520 individuals in the prevalence study was 34%, with 37.4% in the leprosy group and 25.2% in the control group (p < 0.01). Multivariate analysis using logistic regression showed that females of the Mongo and Ngombe ethnic group taken together were significantly more likely to be infected than the other groups (OR = 3.67, 95% CI: 2.14 to 6.30). A comparison of the death rates directly standardized for age and sex showed that the rate was significantly higher for HTLV-I positive (5.5/100 person-years of observation) compared with HTLV-I negative (3.6/100 person-years of observation). A survival analysis using the Cox model showed a risk ratio of 1.4 (CI: 1.04 to 1.89) for those infected with HTLV-I. An increase in the death rate was associated with HTLV-I infection in leprosy inpatients. The decreased survival associated with HTLV-I infection may result from an increased susceptibility to a variety of diseases.

Direct measurement of substrate refractive indices and determination of layer indices in slab-guiding structures

We present a new method for accurate and nondestructive measurement of the refractive indices of substrates and guiding layers in slab waveguides. This method is based on the excitation of leaky waves in substrates and guided waves in guiding layers owing to the etching of grating couplers on the top of structures. It is particularly applicable to high refractive-index materials and to in situ measurements near the energy band gap of semiconductor waveguides. We present results that were obtained for an InP substrate with an InGaAsP epitaxial layer with regard to their refractive indices and temperature coefficients.