General Anesthesia Disrupts Complex Cortical Dynamics in Response to Intracranial Electrical Stimulation in Rats.

The capacity of human brain to sustain complex cortical dynamics appears to be strongly associated with conscious experience and consistently drops when consciousness fades. For example, several recent studies in humans found a remarkable reduction of the spatiotemporal complexity of cortical responses to local stimulation during dreamless sleep, general anesthesia, and coma. However, this perturbational complexity has never been directly estimated in non-human animals in vivo previously, and the mechanisms that prevent neocortical neurons to engage in complex interactions are still unclear. Here, we quantify the complexity of electroencephalographic (EEG) responses to intracranial electrical stimulation in rats, comparing wakefulness to propofol, sevoflurane, and ketamine anesthesia. The evoked activity changed from highly complex in wakefulness to far simpler with propofol and sevoflurane. The reduced complexity was associated with a suppression of high frequencies that preceded a reduced phase-locking, and disruption of functional connectivity and pattern diversity. We then showed how these parameters dissociate with ketamine and depend on intensity and site of stimulation. Our results support the idea that brief periods of activity-dependent neuronal silence can interrupt complex interactions in neocortical circuits, and open the way for further mechanistic investigations of the neuronal basis for consciousness and loss of consciousness across species.

Fractal dimension analysis of states of consciousness and unconsciousness using transcranial magnetic stimulation.

BACKGROUND AND OBJECTIVE: Knowing whether a subject is conscious or not is a current challenge with a deep potential clinical impact. Recent theoretical considerations suggest that consciousness is linked to the complexity of distributed interactions within the corticothalamic system. The fractal dimension (FD) is a quantitative parameter that has been extensively used to analyse the complexity of structural and functional patterns of the human brain. In this study we investigate FD to assess whether it can discriminate between consciousness and different states of unconsciousness in healthy individuals. METHODS: We study 69 high-density electroencephalogram (hd-EEG) measurements after transcranial magnetic stimulation (TMS) in 18 healthy subjects progressing from wakefulness to non-rapid eye movement (NREM) sleep and sedation induced by different anaesthetic agents (xenon and propofol). We quantify the integration of thalamocortical networks by calculating the FD of a spatiotemporal voxelization obtained from the locations of all sources that are significantly activated by the perturbation (4DFD). Moreover, we study the temporal evolution of the evoked spatial distributions and compute a measure of the differentiation of the response by means of the Higuchi FD (HFD). Finally, a Fractal Dimension Index (FDI) of perturbational complexity is computed as the product of both quantities: integration FD (4DFD) and differentiation FD (HFD). RESULTS: We found that FDI is significantly lower in sleep and sedation when compared to wakefulness and provides an almost perfect intra-subject discrimination between conscious and unconscious states. CONCLUSIONS: These results support the combination of FD measures of cortical integration and cortical differentiation as a novel paradigm of tracking complex spatiotemporal dynamics in the brain that could provide further insights into the link between complexity and the brain's capacity to sustain consciousness.

Sleep-like cortical OFF-periods disrupt causality and complexity in the brain of unresponsive wakefulness syndrome patients.

Unresponsive wakefulness syndrome (UWS) patients may retain intact portions of the thalamocortical system that are spontaneously active and reactive to sensory stimuli but fail to engage in complex causal interactions, resulting in loss of consciousness. Here, we show that loss of brain complexity after severe injuries is due to a pathological tendency of cortical circuits to fall into silence (OFF-period) upon receiving an input, a behavior typically observed during sleep. Spectral and phase domain analysis of EEG responses to transcranial magnetic stimulation reveals the occurrence of OFF-periods in the cortex of UWS patients (N = 16); these events never occur in healthy awake individuals (N = 20) but are similar to those detected in healthy sleeping subjects (N = 8). Crucially, OFF-periods impair local causal interactions, and prevent the build-up of global complexity in UWS. Our findings link potentially reversible local events to global brain dynamics that are relevant for pathological loss and recovery of consciousness.

Local Juvenile Hormone activity regulates gut homeostasis and tumor growth in adult Drosophila.

Hormones play essential roles during development and maintaining homeostasis in adult organisms, regulating a plethora of biological processes. Generally, hormones are secreted by glands and perform a systemic action. Here we show that Juvenile Hormones (JHs), insect sesquiterpenoids synthesized by the corpora allata, are also synthesized by the adult Drosophila gut. This local, gut specific JH activity, is synthesized by and acts on the intestinal stem cell and enteroblast populations, regulating their survival and cellular growth through the JH receptors Gce/Met and the coactivator Tai. Furthermore, we show that this local JH activity is important for damage response and is necessary for intestinal tumor growth driven by activating mutations in Wnt and EGFR/Ras pathways. Together, our results identify JHs as key hormonal regulators of gut homeostasis and open the possibility that analogous hormones may play a similar role in maintaining vertebrate adult intestinal stem cell population and sustaining tumor growth.

Abnormal brain oscillations persist after recovery from bipolar depression.

When directly perturbed in healthy subjects, premotor cortical areas generate electrical oscillations in the beta range (20-40Hz). In schizophrenia, major depressive disorder and bipolar disorder (BD), these oscillations are markedly reduced, in terms of amplitude and frequency. However, it still remains unclear whether these abnormalities can be modulated over time, or if they can be still observed after treatment. Here, we employed transcranial magnetic stimulation (TMS) combined with EEG to assess the frontal oscillatory activity in eighteen BD patients before/after antidepressant treatments (sleep deprivation and light therapy), relative to nine healthy controls. In order to detect dominant frequencies, event related spectral perturbations (ERSP) were computed for each TMS/EEG session in all participants, using wavelet decomposition. The natural frequency at which the cortical circuit oscillates was calculated as the frequency value with the largest power across 300ms post-stimulus time interval. Severity of depression markedly decreased after treatment with 12 patients achieving response and nine patients achieving remission. TMS/EEG resulted in a significant activation of the beta/gamma band response (21-50Hz) in healthy controls. In patients, the main frequencies of premotor EEG responses to TMS did not significantly change before/after treatment and were always significantly lower than those of controls (11-27Hz) and comparable in patients achieving remission and in those not responding to treatment. These results suggest that the reduction of natural frequencies is a trait marker of BD, independent from the clinical status of the patients. The present findings shed light on the neurobiological underpinning of severe psychiatric disorders and demonstrate that TMS/EEG represents a unique tool to develop biomarkers in psychiatry.

Dissecting the mechanism of torso receptor activation.

Regulated activation of receptor tyrosine kinases depends both on the presence of the receptors at the cell surface and on the availability of their ligands. In Drosophila the torso (tor) tyrosine kinase receptor is distributed along the surface of the embryo but it is only activated at the poles by a diffusible extracellular ligand generated at each pole which is trapped by the receptor, thereby impeding further diffusion. However, it is not well understood how this signal is generated, although it is known to depend on the activity of many genes such as torso-like (tsl) and trunk (trk). To further investigate the mechanism involved in the local activation of the tor receptor we have altered the normal expression of the tsl protein by generating females in which the tsl gene is expressed in the oocyte under the control of the tor promoter rather than in the ovarian follicle cells. Analysis of the phenotypes generated by this hybrid gene and its interactions with mutations in other genes in the pathway has enabled us to further dissect the mechanism of tor receptor activation and to define more precisely the role of the different genes acting in this process.

Characterization of platyhelminth POU domain genes: ubiquitous and specific anterior nerve cell expression of different epitopes of GtPOU-1.

POU domain proteins are a large family of transcription factors that have been identified in a variety of metazoans, from freshwater sponges, planarians and nematodes to arthropods, echinoderms and vertebrates. Many of these proteins are implicated in the development and establishment of the nervous system. In this paper we describe the identification of the planarian genes GtPOU-1, GtPOU-3 and GtPOU-4, which belong to the subclasses III and IV of POU-domain genes. Their similarity with other members of the POU family is restricted to the POU and homeo domains, plus some peptide sequences scattered in the linker and flanking regions. As with other subclass III POU genes, GtPOU-1 is devoid of introns. Axial transcript distribution by RT-PCR and immunohistochemical assays, performed with a polyclonal antibody raised against the GtPOU-1 fusion protein, indicate that both the GtPOU-1 transcript and protein are continuously expressed along the antero-posterior axis. A monoclonal antibody raised against the same fusion protein indicates that a GtPOU-1-specific epitope, probably obtained by post-translational modification, is present in neural cells from both the central and peripheral nerve systems of the adult planarian's anterior third. Moreover, the GtPOU-1-specific epitope shows a dynamic expression pattern during regeneration, always marking the most anterior region of the planarian nervous system. Both the rapid and general GtPOU-1-specific epitope modification, during posterior regeneration, indicate that regeneration is a global process involving all planarian regions, including those that are far from the wound, by a combination of morphallactic and epimorphic mechanisms.

Planarian homeobox gene Dtprd-1 is expressed in specific gland cells and belongs to a new family within the paired-like class.

The genome of the planarian (Platyhelminthes; Turbellaria; Tricladida) Dugesia (Girardia) tigrina includes a paired-like type of homeobox gene. The Dtprd-1 gene encodes a protein of 382 amino acids. The open reading frame of Dtprd-1 is interrupted by two short introns of 65 and 56 bp, and one long intron of 4.8 kb. The intron positions are not located in the homeobox and are not shared with any other known paired-like gene. The Dtprd-1 homeodomain conserves most of the residues characteristic of the paired-like class. Similarity with other members of this class is low, except with the rat, mouse and Caenorhabditis elegans proteins PHD1, Uncx-4.1 and unc-4, with 86-83% of similarity in the homeodomain, plus several peptides in the flanking regions. Such proteins share specific residues in their homeodomains that can be used to define a new family in the paired-like class of genes. The spatial distribution of gene transcript and product in adult tissues, as revealed by RT-PCR, northern blots and polyclonal antibody, demonstrates that Dtprd-1 is highly expressed in cyanophilic gland cells located in the ventral parenchyma close to the nervous system. No expression is observed during the early stages of regeneration (0-3 days). This suggests a possible role for this homeobox gene within these secretory gland cells, but not in the pattern formation mechanisms known to occur at the early stages of regeneration.

Age-related distribution of endocrine cells in the human prostate: a quantitative study.

A morphometric analysis was performed to obtain quantitative data on age-related changes in prostatic endocrine cell (PrEC) density. Sixty prostates from subjects aged 14-74 years were studied with a semi-automatic image analysis system (ASM 68K, Leitz) applied to sections immunostained for chromogranin A-reactive cells. The highest density of PrECs (0.366 cells/mm of epithelial length) was found in the 25-54 year age group, which was significantly different from that found in prostates of the younger (0.311 cells/mm) and the older (0.261 cells/mm) age groups. The data probably reflect the higher incidence of incompletely developed glandular units in the younger group and the formation of new alveoli related to the usual glandular hyperplasia that occurs with increasing age in the older group.

Intra- and extrahepatic arterial resistances in chronic hepatitis and liver cirrhosis.

Thirty patients with chronic hepatitis (CH), 84 with liver cirrhosis (LC) and 42 controls, underwent noninvasive measurement of hepatic artery resistance index (RI) by means of Doppler ultrasound (US), at the porta hepatis and in the intrahepatic branches, in order to investigate possible changes related to: (a) the liver disease; (b) the site of measurement; and (c) ageing. The intrahepatic RI differed among LC, CH and controls (0.731, 0.690 and 0.643, p < 0.05), whereas the RI at the porta hepatis did not (0.754, 0.748 and 0.729, respectively). Intrahepatic RI correlated with age in LC (r = 0.51, p < 0.0001) and in controls (r = 0.49, p < 0.001). In LC, it correlated also with the presence and size of esophageal varices (r = 0.32, p < 0.05). In conclusion, an increase of hepatic artery RI in chronic liver diseases can be demonstrated when assessed in the intraparenchymal branches. The increase of hepatic artery RI with ageing should be considered in future studies.

Red pulp arterial terminals in congestive splenomegaly. A morphometric study.

A quantitative analysis of the red pulp arterial terminals (comprising arterioles = penicilli, arterial capillaries and sheathed capillaries) has been carried out in congestive splenomegaly occurring in active chronic hepatitis, hepatic cirrhosis and idiopathic portal hypertension. Comparisons have been made with control spleens surgically removed for accidental trauma. Red pulp volume enlargement appears to be associated with a progressive lengthening of arterial terminals, which present a length density similar to that of normal spleens. Moreover, a different rearrangement of the various components of the arterial tree is present: in particular, the percent and absolute volumes of arterioles and arterial capillaries show a higher increase than those of sheathed capillaries. The present study points out the involvement of arterial terminals in the pathological rearrangement of the red pulp in congestive spleens, so supporting the hypothesis that splenomegaly does not result simply from passive congestion.

Quantitative analysis of intrahepatic bile duct component in normal adult human liver and in primary biliary cirrhosis.

The volume density of bile ducts in adult normal liver has been analyzed in order to provide stereometric parameters to which refer on performing quantitative evaluations of bile duct loss in acquired liver diseases. Five livers were studied by applying a semi-automatic image analysis system (ASM 68K Leitz) to histological sections. No significant differences (P > 0.10) were found for all measures and the following values were derived from the pooled data: (1) mean % volume of bile ducts in liver = 0.318 +/- 0.171; (2) mean % volume of portal tracts in liver = 4.351 +/- 2.860; (3) mean % volume of bile ducts in portal tracts = 6.567 +/- 3.813. The parallelism of bile duct to arterial components of portal tracts was also investigated and expressed as the ratio of their respective volume fractions (mean ratio = 1.72). The validity of the obtained parameters was tested by comparing them with values determined in five cases of primary biliary cirrhosis (PBC). All PBC cases showed a marked decrease in both bile duct % volume in liver (ranging between 0.028 and 0.057) and bile duct % volume in portal tracts (ranging between 0.673 and 0.914), as well as inversion of the bile duct to artery volume ratio in portal tracts (ranging between 0.246 and 0.437).

13-cis retinoic acid and interferon alfa-2a in the treatment of metastatic renal cell carcinoma.

Eleven patients, pre-treated with chemotherapy and immunotherapy, with renal cell carcinoma were given 13-cis-retinoic acid (CRA) in association with interferon alfa-2a (IFN 2a). 13-ci retinoic acid was administered at the dose of 1 mg/Kg/die while interferon alfa-2a at the dose of 3X10 U.I./die s.c. All patients had been previously treated with chemotherapy in association with immunotherapy. Therapy was not discontinued until neoplastic progression occurred. Clinical results were as follows: partial responses (PR) were observed in two patients, disease stabilization (SD) in 5 and progression (PD), with 8-month median treatment duration, in 4. Side effects were mild.

Letrozole for the treatment of pretreated advanced breast cancer patients: preliminary report.

Twenty patients (pts) with metastatic breast cancer with disease progression, previously treated with chemotherapy and tamoxifen, were administered oral letrozole (2.5 mg/day) therapy. Fifteen of the patients were postmenopausal and 5 were premenopausal. Ten were estrogen receptor (ER)-positive, 7 were unknown and 3 were ER-negative. All the patients were assessed after 6 months (mo) of chemotherapy. Nine pts (45%) presented a partial response (PR), five (25%) had a stable disease (SD) and six (30%) had a progressive disease (PD). In the pts with PD, six out of 15 (33%) obtained a PR while undergoing tamoxifen therapy. The treatment caused no significant toxicity.

Gemcitabine in pre-treated advanced renal carcinoma: a feasibility study.

Eigtheen patients affected by metastatic renal cell carcinoma, 16 which were assesable, were treated with 1 g/m2 of Gemcitabine (GCB) on days 1, 8 and 15 of a 28-day treatment cycle up to a maximun of ten cycles. All patients in neoplastic progression were treated with chemo- and immunotherapy (5 FU, IL-2, IFN alpha d 13-cis-retinoic acid.) Out of the 16 assessable patients, 5/16 (31%) showed overall response (ICR, 4 PR), 5 (31%) stable disease (SD) and 6 (38%) progression of disease (PD). Toxicity was limited to WHO grades I only, primarily hematological.

Triple combination antimicrobial regimen in the treatment of infections of neutropenic cancer patients.

Twenty-six cancer patients (pts) with chemotherapy-related neutropenic fever were treated with vancomycin 30 mg/m2/day i.v. every 12 hrs, imipenem 1500 mg/day i.v. every 8 hrs, and pefloxacin 800 mg/day i.v. every 12 hrs. Twelve fevers of unknown origin (FUO), 10 gram-positive, 3 gram-negative and 1 mycoplasma were also treated. Globally, cure was observed in 22 pts (84%) and failure in 4 pts (16%); in gram-positive infections alone, cure was observed in 10 pts (80%) and failure in 4 pts (20%). Defervescence was obtained within 3 days in 77% pts. No relevant side effects were observed.

Immunohistochemical detection of cell-cycle associated markers on paraffin embedded and formalin fixed needle biopsies of prostate cancer: correlation of p120 protein expression with AgNOR, PCNA/cyclin, Ki-67/MIB1 proliferation-scores and Gleason gradings.

Paraffin embedded and formalin fixed needle biopsies of prostate cancer (PC) were used to immunocytochemically detect the p120 nucleolar protein in relation to the Gleason histological gradings (GHG), the labelling indices of proliferating nuclear immunocytochemical markers (PCNA/Cyclin, Ki-67/MIB1) and the argyrophilic nucleolar region (AgNOR) rate. The twenty-six cases of PC (6 from large histological samples and 20 from needle biopsies) were equally distributed into low (< or = 6) or high (> or = 7) GHG groups. The p120 nucleolar protein immunocytochemical reaction was randomly expressed in large histological sections but uniformly distributed without gaps in needle biopsy sections. Only on the latter were quantitative values of PCNA/Cyclin (23.2 in low and 45.3 in high GHG), Ki-67/MIB1 (13.8 in low and 43.3 in high GHG) and AgNOR (5.0 in low and 7.5 in high GHG) related to those of p120 nucleolar protein (0.8 in low and 3.8 in high GHG). The values of all these cell cycle markers increased from low to high GHG of PC, all four reaching high statistical significance between the two groups (ANOVA-two tailed p < 0.0001). The PCNA/Cyclin index showed a higher positivity than the Ki-67/MIB1 index in PC with low GHG but not in PC with high GHG. In conclusion, paraffin embedded and formalin fixed PC needle biopsies exhibit a higher diagnostic PCNA/Cyclin than Ki-67/MIB1 index for cases presenting differentiated features, whereas p120 nucleolar protein detection seems to be a suitable marker of poorer outcome of PC.

Short-term results of combined radioimmunotherapy in inoperable lung cancer.

Fifty-three inoperable lung cancer patients were treated with radiotherapy combined with immunostimulation with BCG. A good response was obtained in 30 patients (56%); the results were not significantly different than those obtained with a control group of 50 lung cancer patients matched by age, sex and stage of the disease (24 out of 50 equals 46%). These short-term results were compared with the immunologic "status" of patients evaluated before treatment by the parameters monitoring in vivo and in vitro delayed type hypersensitivity. The good response to therapy was documented in a higher percentage of patients with positive skin tests to recall and standard antigens and with normal values of lymphocyte transformation with PHA and Rosette E-forming cells, in comparison with patients with low levels of immunocompetence. An impairment of the cell-mediated immune response was found after combined therapy, presumably due to radiotherapy. BCG was not able to restore the patient's immunocompetence, no effect on host's immune reactivity was demonstrated. As regards humoral immunity, the patients with low levels of IgG before treatment (12/14) showed a good response.

A case of mycotic keratitis caused by Fusarium solani.

A 36-year-old black man, without history of systemic disease or ocular trauma developed a corneal infection in his left eye. He was treated with antibacterial antibiotic and corticosteroids for one month prior to diagnosis. Fungal hyphae and chlamydospores were found in a KOH preparation of the corneal scrapings, and positive cultures for Fusarium solani were obtained in Sabouraud dextrose agar. It is emphasized the cautious use of antibiotics and steroids in corneal diseases, and the need of considering the involvement of opportunistic fungi in the etiology of these infections.

In vitro susceptibility to antifungal agents of clinical and environmental Cryptococcus neoformans isolated in Southern of Brazil.

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed.