Transcranial magnetic stimulation reveals complex cognitive control representations in the rostral frontal cortex.

Convergent evidence suggests that the lateral frontal cortex is at the heart of a brain network subserving cognitive control. Recent theories assume a functional segregation along the rostro-caudal axis of the lateral frontal cortex based on differences in the degree of complexity of cognitive control. However, the functional contribution of specific rostral and caudal sub-regions remains elusive. Here we investigate the impact of disrupting rostral and caudal target regions on cognitive control processes, using Transcranial Magnetic Stimulation (TMS). Participants performed three different task-switching conditions that assessed differences in the degree of complexity of cognitive control processes, after temporally disrupting rostral, or caudal target regions, or a control region. Disrupting the rostral lateral frontal region specifically impaired behavioral performance of the most complex task-switching condition, in comparison to the caudal target region and the control region. These novel findings shed light on the neuroanatomical architecture supporting control over goal-directed behavior.

A shift to a peripheral Th2-type cytokine pattern during the carcinogenesis of cervical cancer becomes manifest in CIN III lesions.

BACKGROUND: A shifted balance between T helper 1 (Th1)-type and Th2-type cytokines has been hypothesised in cervical dysplasia. AIMS: To evaluate possible deregulation of the cytokine network by estimating the expression of peripheral cytokines in different stages of cervical disease and in relation to the presence or absence of high risk human papillomavirus (HR-HPV). METHODS: Twenty one HR-HPV positive women with high grade cervical intraepithelial neoplasia (CIN II-III) and 12 patients with invasive cervical carcinoma formed the study groups. Two control groups consisted of 10 HR-HPV positive and 11 HR-HPV negative women without CIN. Differences in leucocyte subgroups were evaluated by a differential leucocyte count. Plasma concentrations of tumour necrosis factor alpha (TNFalpha), TNFalpha receptors TNFRI and TNFRII, interferon gamma (IFNgamma), interleukin 2 (IL-2), IL-12, IL-4, and IL-10 were determined by enzyme linked immunosorbent assays. RESULTS: Leucocyte counts in patients with CIN III and carcinoma were significantly higher than in controls. Plasma IFNgamma concentrations were significantly lower in patients with CIN III and carcinoma than in women with CIN II or controls. Plasma concentrations of IL-12, IL-2, IL-4, and TNFalpha did not differ significantly between groups, but significantly lower plasma concentrations of TNFRII were found in CIN III and carcinoma compared with CIN II. IL-10 was detected with increased frequency in the plasma of patients with CIN III and carcinoma. CONCLUSIONS: These results indicate that a shift to a Th2-type cytokine pattern during the carcinogenesis of cervical cancer occurs in women with CIN III lesions.

Sentinel lymphonodectomy does not increase the risk of loco-regional cutaneous metastases of malignant melanomas.

With regard to malignant melanoma, the impact of lymph node surgery on the development of loco-regional cutaneous metastases (LCM) has not yet been adequately addressed. However, this aspect is of interest, since sentinel lymphonodectomy (SLNE) has been suspected of causing LCM by inducing entrapment of melanoma cells. We analysed 244 patients with SLNE and compared the data with 199 patients treated with delayed lymph node dissection (DLND) for clinically palpable metastases. Analysis of both groups commenced at the time of excision of the primary tumour, using the Kaplan-Meier method. LCM that appeared as a first recurrence, as well as the overall probability of developing LCM, were recorded. For sentinel-negative patients with a primary melanoma >1mm thick, the 5-year probability of developing LCM as a first recurrence was 6.9 +/- 0.02% (+/-standard error of the mean (SEM)). The probability was 17.6 +/- 0.03% in the DLND group. Comparing the two node-positive subgroups, the probability of developing LCM as a first recurrence was significantly higher in patients with positive SLNE (27.3 +/- 0.05%, P = 0.03). However, the 5-year overall probability of developing LCM did not differ significantly in the node-positive groups (33.3% in the DLND group vs. 33.7% in patients with positive sentinel lymph nodes (SLNs)). Since early excision of lymphatic metastases by SLNE avoids nodal recurrences, thereby prolonging the recurrence-free interval, the chance of LCM to manifest as a first recurrence should inevitably increase. However, the overall in-transit probability is not increased after SLNE.

A close look at autoimmune muscle disorders: association of Lambert-Eaton myasthenic syndrome with dermatomyositis.

Dermatomyositis/polymyositis (DM/PM) and Lambert-Eaton myasthenic syndrome (LEMS) are two autoimmune disorders that have very rarely been reported to occur together in the same patient. We report on two patients with DM who were later diagnosed with concomitant LEMS, and point out diagnostic challenges in identifying LEMS in patients with DM/PM. As specific treatment for LEMS is available, it is important to identify those DM/PM patients who suffer from concomitant LEMS.

Granulocyte colony-stimulating-factor-induced psoriasiform dermatitis resembles psoriasis with regard to abnormal cytokine expression and epidermal activation.

Psoriasis is a chronic inflammatory skin disorder characterized by accumulation of Th1-type T cells and neutrophils, regenerative keratinocyte proliferation and differentiation, and enhanced epidermal production of antimicrobial peptides. The underlying cause is unknown, but there are some similarities with the immunologic defense program against bacteria. Development of psoriasiform skin lesions has been reported after administration of granulocyte colony-stimulating factor (G-CSF), a cytokine induced in monocytes by bacterial antigens. To further investigate the relation between this type of cytokine-induced dermatitis and psoriasis, we analyzed the cutaneous cytokine profile [tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, transforming growth factor-beta1 (TGF-beta1), interleukin-10 (IL-10), IL-12p35 and p40, and IL-8] and expression of markers of epidermal activation [Ki-67, cytokeratin-16, major histocompatibility complex (MHC) class II, intercellular adhesion molecule-1 (ICAM-1)] in a patient who developed G-CSF-induced psoriasiform dermatitis by using quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistology. The histologic picture resembled psoriasis with regard to epidermal hyperparakeratosis and the accumulation of lymphocytes in the upper corium. CD8(+) T cells were found to infiltrate the epidermis which was associated with an aberrant expression of Ki-67, cytokeratin-16, MHC class II, and ICAM-1 on adjacent keratinocytes. As compared to normal skin (n = 7), there was an increased expression of TNF-alpha, IL-12p40, and IL-8, a decreased expression of TGF-beta1, and a lack of IL-10, similar to the findings in active psoriasis (n = 8). Therefore, G-CSF may cause a lymphocytic dermatitis that, similar to psoriasis, is characterized by a pro-inflammatory Th1-type cytokine milieu and an epidermal phenotype indicative of aberrant maturation and acquisition of non-professional immune functions.

Release of tumor necrosis factor-alpha and prostanoids in whole blood cultures after in vivo exposure to low-dose aspirin.

BACKGROUND: The preventive effect of low-dose aspirin in cardiovascular disease is generally attributed to its antiplatelet action caused by differential inhibition of platelet cyclooxygenase-1. However, there is evidence that aspirin also affects release of inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha). It is not known whether this is caused by direct action on the cytokine pathway or indirectly through cyclooxygenase inhibition and altered prostanoid synthesis, or both. METHODS: We assessed the capacity of lipopolysaccharide-activated leukocytes in whole blood cultures of eight healthy subjects following a single oral dose of 80 mg aspirin to release TNF-alpha, prostanoid E2 (PGE2) and prostanoid I2 (PGI2), and thromboxane A2 (TXA2). TNF-alpha and prostanoids were determined by enzyme-linked immunoassays. RESULTS: In seven subjects, TNF-alpha release in blood cultures decreased 24h after intake of aspirin. The effect of aspirin on prostanoid release was assessed in three individuals: PGE2 increased in all subjects, PGI2 increased in two and remained unchanged in one, and TXA2 was reduced in two and unchanged in one individual The presence of DFU, a specific inhibitor of cyclooxygenase 2, did not affect the reduction of TNF-alpha release by aspirin, but abolished prostanoid production in all three individuals. CONCLUSION: The capacity of activated leukocytes to release TNF-alpha is reduced by ingestion of low-dose aspirin, independent of changes in prostanoid biosynthesis.

Circulating bioactive tumor necrosis factor-alpha, tumor necrosis factor-alpha receptors, fibronectin, and tumor necrosis factor-alpha inducible cell adhesion molecule VCAM-1 in uncomplicated pregnancy.

OBJECTIVES: Our goal was to assess in a longitudinal study of uncomplicated pregnancy the course of maternal plasma concentrations of the bioactive cytokine tumor necrosis factor-alpha, the soluble tumor necrosis factor-alpha receptors sTNFRI and sTNFRII, the soluble cell adhesion molecule sVCAM-1, and circulating fibronectin. STUDY DESIGN: Blood was collected from 22 healthy pregnant women at 7 to 17, 18 to 22, 23 to 28, and 30 to 36 weeks' gestation and post partum. Plasma samples were measured by bioassay for bioactive tumor necrosis factor-alpha, by immunoassay for sTNFRI, sTNFRII, and VCAM-1, and by radial immunodiffusion for circulating fibronectin, and data were statistically analyzed. RESULTS: Plasma concentrations of all variables were significantly linked with gestational age. Levels of bioactive tumor necrosis factor-alpha and sTNFRII showed a parallel rise in the second trimester and a decrease thereafter. Values for sTNFRI and sTNFRII and for these receptors and VCAM-1 were correlated, a weak correlation between bioactive tumor necrosis factor-alpha and sTNFRII was observed, and no correlation between circulating fibronectin and other variables was apparent. CONCLUSIONS: All variables studied exhibited a characteristic pattern depending on gestational age, which supports the concept of a physiologic role of tumor necrosis factor-alpha in pregnancy.

Tumor necrosis factor-alpha in response to endotoxin administration in the pregnant guinea pig.

OBJECTIVE: Our purpose was to test the hypothesis that an intramuscular endotoxin challenge induces production of tumor necrosis factor-alpha in the pregnant guinea pig and to investigate some of the metabolic effects. STUDY DESIGN: Twelve randomly selected guinea pigs at 33 days' gestation with a sampling catheter in the carotid artery received an intramuscular injection of a solution of endotoxin isolated from Bacteroides fragilis (n = 6) or of solvent alone (n = 6). Plasma values of tumor necrosis factor-alpha, hematocrit, and 6-keto-prostaglandin F1 alpha were determined before and several hours after injection. RESULTS: Tumor necrosis factor-alpha was detected in five of six guinea pigs, but it could not be demonstrated in five of six placebo animals. The hematocrit was significantly decreased, and prostaglandin F1 alpha significantly increased 24 to 48 hours after endotoxin injection. CONCLUSION: In pregnant guinea pigs an intramuscular endotoxin challenge induces the release of tumor necrosis factor-alpha, followed by a reduced hematocrit and an increased prostacyclin concentration. These effects could be involved in the pathogenesis of endotoxin-induced fetal growth retardation.

Detection of Bacteroides fragilis endotoxin in amniotic fluid by counterimmunoelectrophoresis.

The ability of counter immunoelectrophoresis (CIE) to detect Bacteroides fragilis endotoxin in amniotic fluid in small concentrations was evaluated. A method was developed which, in combination with ultrafiltration, permits detection of B. fragilis endotoxin in amniotic fluid in a concentration of 40 ng/ml or more. The sensitivity threshold was reduced to 2 ng/ml by using a highly reactive IgG-fraction isolated from rabbit anti-B. fragilis IPL E 323 antiserum.

Activity of human peritoneal macrophages against a human tumor: role of tumor necrosis factor-alpha, PGE2 and nitrite, in vitro studies.

Human peritoneal macrophages collected from renal patients on continuous ambulatory peritoneal dialysis (CAPD) during inflammation-free periods were induced to express antitumor activity in vitro when cultured in the presence of bacterial lipopolysaccharide (LPS) and even more activity when they were kept in the presence of LPS + IND (indomethacin). The antitumor activity was expressed against a human tumor-cell line, RC43, either in a cell-to-cell contact set-up between the macrophages and the RC43 target cells or when the tumor cells were exposed to supernatants of the cultured macrophages. The antitumor activity of macrophages was correlated to a marked increase in production of tumor necrosis factor-alpha (TNF alpha), not correlated to an increase in nitrite production and inversely correlated to the production of PGE2. The RC43 tumor cells were susceptible to recombinant human TNF alpha, recombinant human IL-1 beta, sodium nitrite and the leukotriene LTB4. The results obtained suggest that activated human macrophages might represent a useful tool for cancer immunotherapy.

Endotoxin-induced fetal growth retardation in the pregnant guinea pig.

OBJECTIVES: Our purpose was to test the hypothesis that bacterial endotoxin may reduce fetal growth and to assess some of the pathophysiologic mechanisms of such an effect. STUDY DESIGN: Two randomly selected groups of nine guinea pigs at 30 days' gestation were treated with a solution of endotoxin isolated from Bacteroides fragilis or with solvent alone. Antibody titers, glucose, triglycerides, and 6-keto-prostaglandin F1 alpha were determined in maternal or fetal blood samples. Fetal weight was determined at 61 days' gestation. RESULTS: Endotoxin-treated guinea pigs showed positive antiendotoxin antibody titers, reduced weight gain, and significantly higher serum levels of triglycerides and 6-keto-prostaglandin F1 alpha, but not of glucose, than did sham-treated controls. Fetuses of endotoxin-treated animals had significantly lower birth weights and serum glucose concentrations and significantly higher triglyceride levels than did control fetuses. CONCLUSIONS: Bacteroides fragilis endotoxin causes fetal growth retardation in the pregnant guinea pig, which may be due to alterations in carbohydrate and fat metabolism mediated by cytokine action.

A comparison between two methods for measuring tumor necrosis factor in biological fluids.

The current study was undertaken to compare two methods for the efficiency of measuring tumor necrosis factor (TNF-alpha) in biological fluids, which is species undependent, reliable, sensitive, simple and not expensive. We have compared the MTT tetrazolium cytotoxic assay [1,2] and the 3H-thymidine (3H-TdR) incorporation cytostatic assay for measuring the anti-tumor activity of human recombinant TNF-alpha, of human colonic tissue and of supernatants of in vitro stimulated human and rat peritoneal macrophages. Two target cell-lines, namely murine myelomonocytic leukaemia WEHI-164- and L-929-transformed murine fibroblast cell-lines, were used in the MTT assay. The L-929 line was also used in the 3H-TdR assay. WEHI-164 was more sensitive than the L-929 cell-line in the MTT cytotoxic assay. Furthermore, the MTT assay was more sensitive to TNF-alpha than the 3H-TdR assay. Both methods can be used for the detection of anti-tumor activity in biological fluids but the MTT cytotoxic method has the advantage of being more sensitive and more simple.

Uterine artery estrogen receptors in the nonpregnant and pregnant guinea pig.

Uterine artery, heart, and aorta or carotid specimens of nonpregnant, midpregnant, and term pregnant guinea pigs were examined for estrogen receptors by immunocytochemical methods. Estrogen receptors were found in the nuclei of cells in the endothelial, muscle, and adventitia layers of the uterine artery wall. The concentration of estrogen receptors was slightly higher in nonpregnant and term pregnant animals than in midpregnancy. No estrogen receptors were found in the heart, aorta, or carotid specimens of all animals. These results confirm the uterine artery as a target organ of estrogen action that would eventually lead to arterial functional adaptation in different biologic periods.

The effects of deoxycholate and sodium dodecyl sulphate on the serological reactivity of antigens isolated from six Bacteroides reference strains.

The detergents sodium dodecyl sulphate (SDS) and sodium deoxycholate (NaD) are frequently used as solvents for macromolecular polysaccharide complexes in immunochemical and serological techniques. The influence of the disaggregating surfactants on the serological reactivity of endotoxins isolated from six serotype specific reference strains of the Bacteroides fragilis group was investigated by comparing haemagglutinating and precipitating reactivities of antigen solutions in phosphate buffered saline (PBS), NaD and SDS. All antigens were phenol/water extracted endotoxins. Solutions of antigens isolated from serotypes A, B, C and D in PBS exhibited mainly serotype specificity and a few well known low-titer cross reactions; solutions in NaD showed additional cross reactivity, which was enhanced by solubilization of the antigens in SDS. In immunoelectrophoresis endotoxins isolated from serotypes A and C and dissolved in NaD or SDS showed additional precipitation lines compared to solutions of the same antigens in PBS. These changes in the serological reactivity are of relevance for investigations where the serological specificity of antigens is in question.

Immune response to endotoxin isolated from Bacteroides fragilis in the pregnant guinea pig.

The humoral immune response to endotoxin isolated from Bacteroides fragilis was analyzed in the pregnant guinea pig by means of passive hemagglutination, passive hemolysis, a modified Coombs test, and by crossed immunoelectrophoresis. Pregnant animals were immunized with endotoxin on day 30 of gestation, and antibodies were determined on day 61 in maternal and fetal sera, and in amniotic fluid. The IgG and IgM responses in maternal sera were of the same magnitude as in sera of nonpregnant animals. Fetal sera contained IgG and sometimes IgM, and a higher percentage of incomplete antibodies against endotoxin than maternal sera. Low-titer anti-endotoxin antibodies, partially sensitive to dithiothreitol, were found in amniotic fluid. A statistically significant reduction in the growth of fetuses from endotoxin-immunized females was observed.

Mycobacterium scrofulaceum, serovar Cole.

Cole strains of Mycobacterium, originally introduced as M. scrofulaceum serovar No. 44 and later rejected as belonging to M. avium were re-investigated and compared with well-documented strains of M. scrofulaceum. Our data show that the Cole serovar belongs to M. scrofulaceum and should be re-introduced as serovar No. 44 of M. scrofulaceum.