Involvement of adenylate cyclase and tyrosine kinase signaling pathways in response of crayfish stretch receptor neuron and satellite glia cell to photodynamic treatment

Neuroglial interactions are most profound during development or damage of nerve tissue. We studied the responses of crayfish stretch receptor neurons (SRN) and satellite glial cells to photosensitization with sulfonated aluminum phthalocyanine Photosens. Although Photosens was localized mainly in the glial envelope, neurons were very sensitive to photodynamic treatment. Photosensitization gradually inhibited and then abolished neuron activity. Neuronal and glial nuclei shrank. Some neurons and glial cells lost the integrity of the plasma membrane and died through necrosis after the treatment. The nuclei of other glial cells but not neurons become fragmented, indicating apoptosis. The number of glial nuclei around neuron soma increased, probably indicating proliferation for enhanced neuron protection. Adenylate cyclase (AC) inhibition by MDL-12330A, or tyrosine kinase (TK) inhibition by genistein, shortened neuron lifetime, whereas AC activation by forskolin or protein tyrosine phosphatases (PTP) inhibition by sodium orthovanadate prolonged neuronal activity. Therefore, cAMP and phosphotyrosines produced by AC and TK, respectively, protected SRN against photoinactivation. AC inhibition reduced photodamage of the plasma membrane and subsequent necrosis in neuronal and glial cells. AC activation prevented apoptosis in photosensitized glial cells and stimulated glial proliferation. TK inhibition protected neurons but not glia against photoinduced membrane permeabilization and subsequent necrosis whereas PTP inhibition more strongly protected glial cells. Therefore, both signaling pathways involving cAMP and phosphotyrosines might contribute to the maintenance of neuronal activity and the integrity of the neuronal and glial plasma membranes. Adenylate cyclase but not phosphotyrosine signaling pathways modulated glial apoptosis and proliferation under photooxidative stress.     

High-density lipoprotein as a key component in the prevention of premature atherosclerotic disease in the insulin resistance syndrome

The occurrence of insulin resistance syndrome (IRS), which is also called the metabolic syndrome, has rapidly increased over the last decade. IRS involves such major clinical features as premature atherosclerosis and its related complications. The major proatherogenic phenotype includes elevated plasma levels of apolipoprotein B-containing lipid particles. Another lipid particle of high-density lipoprotein (HDL) plays a key role in the prevention of atherosclerotic disease. Decreased levels of HDL cholesterol are found in IRS; however, little is known about metabolic pathways related to HDL antiatherogenic properties in this pathological condition. Hitherto, in other dyslipidemic populations, the antiatherogenic properties of HDL have been most frequently characterized in vitro. Recently, knowledge about antiatherogenic pathways in which HDL particles are involved in vivo has been accumulating. Consistent with these developments, new therapeutic strategies can be envisaged for IRS, including treatment with recombinant HDL particles and inhibitors of cholesteryl ester transfer protein.     

Determination of dopamine by flow-injection analysis coupled with luminol-hexacyanoferrate(III) chemiluminescence detection

A novel flow-injection method (FIA) for the determination of dopamine based on the inhibition of the intensity of chemiluminescence (CL) from luminol-hexacyanoferrate(III) system in basic medium is described. The present method allows the determination of dopamine over the range 30-100 microg l(-1) and 400-3000 microg l(-1). The relative standard deviation is 2.32% for 70 microg l(-1) dopamine and 1.22% for 1500 microg l(-1) dopamine (n = 20). The detection limit is 5 microg l(-1) with the sampling rate of 135 samples h(-1). This method has been applied for the determination of dopamine in commercial pharmaceutical injection samples. The results obtained by this method agreed with those by the official method.     

Quantitative analysis of high-frequency oscillations (80-500 Hz) recorded in human epileptic hippocampus and entorhinal cortex

High-frequency oscillations (100-200 Hz), termed ripples, have been identified in hippocampal (Hip) and entorhinal cortical (EC) areas of rodents and humans. In contrast, higher-frequency oscillations (250-500 Hz), termed fast ripples (FR), have been described in seizure-generating limbic areas of rodents made epileptic by intrahippocampal injection of kainic acid and observed in humans ipsilateral to areas of seizure initiation. However, quantitative studies supporting the existence of two spectrally distinct oscillatory events have not been carried out in humans nor has the preferential appearance of FR within seizure generating areas received statistical evaluation based on analysis of a large sample of oscillatory events. Interictal oscillations within the bandwidth of 80-500 Hz were detected in Hip and EC areas of patients with mesial temporal lobe epilepsy using wideband EEG recorded during non-rapid eye-movement sleep from chronically implanted depth electrodes. Power spectral analysis showed that oscillations detected from Hip and EC areas were composed of two spectrally distinct groups. The lower-frequency ripple group was defined by a frequency of 96 +/- 14 Hz (median +/- width), while the higher-frequency FR group had a frequency of 262 +/- 59 Hz. FR oscillations were significantly shorter in duration compared with ripple oscillations (P < 0.0001). In regard to the occurrence of FR and ripples in epileptic Hip and EC, the mean ratio of the number of FR to ripples generated in areas ipsilateral to seizure onset was significantly higher compared with the mean ratio of FR to ripple generation from contralateral areas (P = 0.008). Furthermore, sites ipsilateral to seizure onset with hippocampal atrophy had significantly higher ratios compared with sites contralateral to both seizure onset and hippocampal atrophy (P = 0.001). These data provide compelling quantitative and statistical evidence for the existence of two spectrally distinct groups of limbic oscillations that have frequency and duration characteristics similar to those previously described in epileptic rat and human Hip and EC. The strong association between FR and regions of seizure initiation supports the view that FR reflects pathological hypersynchronous events crucially associated with seizure genesis.     

Free flaps for type III complex pharyngoesophageal defects after enlarged ablative surgery for advanced cancer of larynx and hypopharynx

Free tissue transfer has become a useful technique for reconstruction of type III complex pharyngoesophageal defects after enlarged laryngectomy and partial or total pharyngoesophageal resection. We present a retrospective analysis of our experience with 36 patients who received free flaps for reconstruction of complex pharyngoesophageal defects associated with skin and soft-tissue defects. Free fasciocutaneous flaps and jejunum combined with a deltopectoral flap and musculocutaneous pectoralis major flap, gastro-omental flap, and combined latissimus dorsi musculocutaneous and cutaneous scapular flaps were used for reconstruction. Adjuvant therapy included preoperative or postoperative radiotherapy. Free flap failure occurred in 2 of 36 patients. Twenty-eight patients had good swallowing function. Better results with fewer complications in reconstruction of type III complex pharyngoesophageal defects were obtained with the use of a combined latissimus dorsi and scapular flap.     

Radiologic and Endoscopic Evaluation for Laparoscopic Adjustable Gastric Banding: Preoperative and Follow-Up

Background: Laparoscopic adjustable silicone gastric banding (LASGB) has replaced vertical banded gastroplasty (VBG) as the most widespread restrictive bariatric operation in Europe. Although these two procedures are similar in principle, the experience concerning the preoperative examinations and follow-up cannot be arbitrarily transferred from VBG to LASGB.The reasons for and consequences drawn from radiologic and endoscopic examinations are described. Methods: From December 1996 to January 2000, 148 patients (84% women, average age 39 years, body weight 127 kg, BMI 45 kg/m²) underwent LASGB. The mean follow-up was 17 months. Upper GI series, abdominal ultrasound, and gastroscopy were done before operation. The postoperative stoma adjustments were performed under radiological observation. All adjustments were analyzed. Results: Preoperative: Of 147 upper GI series, 74 showed hiatal hernia, 2 motility disorders, and 1 an incomplete malrotation. In 104 gastroscopies, 35 reflux and 53 gastritis with 24 Helicobacter pylori infections were found. Postoperative: On average, 2.7 radiological adjustments were done per patient. Until satisfactory satiety and weight reduction, 78% of the patients needed 0-3 adjustments. Besides routine adjustments, an additional 57 upper GI series were done in 35 patients, 44 times with opening of the stoma-diameter. A total of 14 slippages and 4 pouch enlargements were found. A gastroscopy was required in 12 patients. Conclusion: Radiologic and endoscopic examinations before LASGB revealed pathology needing therapy in 42% of the patients and provided important additional information influencing the operative procedure. At an average follow-up of 17 months, 24% of the 148 patients needed unplanned additional upper GI series.     

Congestive cardiomyopathy (pathologo-anatomic study of the heart)

A pathomorphologic study of 40 cases of congestive cardiomyopathy (CCMP) demonstrated that circulatory insufficiency was the cause of death in 70% of cases, while sudden death occurred in 25%. Morphometric investigation identified 3 CCMP patterns: cardiosclerosis-free and accompanied with small-focal (diffuse) and large-focal cardiosclerosis. The mean duration of the disease and the mean age at death were the smallest in the cardiosclerosis-free group where the dilatation of heart cavities was found to be the greatest. A direct relationship was demonstrated between the duration of the disease and the myocardial fibrous tissue content. Blood flow deceleration due to circulatory insufficiency in CCMP cases was shown to be conducive to thrombogenesis both in heart cavities, and in minor pulmonary arteries and myocardial veins.     

The role of group-A10 dopamine neurons of the ventral tegmental area in analgesia evoked by electrocutaneous pain stimulation and morphine

The activity of antinociceptive mechanisms induced by footshock (FS) and morphine injection was studied in experiments on rats with bilateral destruction of group A10 neurones of the ventral tegmental area. The latent periods of the hot plate and tail flick pain reactions to FS and morphine increased significantly in the experimental and control groups as compared to the initial values. In morphine injection these indices were the same in the experimental and control groups. In FS the latent periods of the reaction were significantly greater in the experimental group. Thus, destruction of dopaminergic neurons of A10 nuclei intensifies the antinociceptive effects in FS but has no effect on the pain-relieving action of systemic morphine injection.     

Organization of the nervous tissue (hippocampus and septum) developing in the anterior eye chamber. III. Axonal processes and their synaptic endings

Embryonal tissue of rat's septum and hippocampus developing in the anterior eye chamber for three to four months was investigated. Electron microscopic analysis of axonal processes and synaptic boutons is presented in this paper. Dense neuropil of the grafts includes myelinated and unmyelinated fibers. Some of them have definite structural features of peripheral fibers; there are also some transitory forms, combining the traits of peripheral and central axons. Synapses of presumed monoaminergic nature and other unidentified synaptic contacts with the neurons are formed by peripheral fibers entering the grafts from the iris. The majority of axons belongs to the neuronal elements of the grafts themselves. Distribution of the synapses upon neuronal somata and dendritic trees seems to be quite normal. Synapses of symmetric type are present mainly upon neuronal bodies and dendritic shafts; synapses with dendritic and somatic spines are asymmetric. At the same time some unusual features are observed: the presence of the axonal growth cones, long ribbon-like axonal terminals, forming numerous serial synapses with elements of neuropil or neuronal bodies, pseudo-glomerular synaptic contacts encapsulated by glial processes. Increased pinocytotic and microphagocytotic activity between various elements of neuropil is present within the grafts. Spinular complexes, which are often encountered in interneuronal contacts, possibly also participate in processes of exocytosis-endocytosis. Some ultrastructural characteristics of the grafted tissue indicate to its incomplete maturation which may result from deficit of normal afferentation or from absence of some more general developmental factors in the intraocular grafts.     

Association among Fas expression in leucocytes,serum Fas and Fas‐ligand concentrations and hepatic inflammation and fibrosis in chronic hepatitis C

Background: Replication of the hepatitis C virus (HCV) in peripheral blood mononuclear cells (PBMC) may impair immune functions and establish persistent infection. The aim of this study was to assess the influence of HCV on PBMC and their susceptibility to apoptosis in relation to liver inflammation and fibrosis. Methods: Eighty‐one patients with chronic hepatitis C (CHC) were enrolled in this study. Flow cytometry was used to determine the amount of T cells (CD4⁺, CD8⁺), B cells (CD19⁺), monocytes (CD14⁺) and natural killer cells (CD16⁺) in the peripheral blood and the expression of CD95⁺ (CD95/APO‐1) in each subset. Serum concentrations of sFas and sFasL were assessed by the enzyme‐linked immunosorbent assay method. Results: An increased expression of Fas was observed in CD4⁺ and CD8⁺ cells in CHC. There was a more prominent expression of Fas on CD4⁺ cells in HCV genotype 1b in contrast to 3a. Increased Fas expression on CD4⁺ cells was seen in advanced stages of liver disease. Fas expression on monocytes was lower in advanced stages of liver inflammation and fibrosis. Serum sFas concentration was higher in CHC compared with the control group. There was an association between sFasL concentration and inflammatory activity in the liver. Serum sFasL concentration correlated positively with the mean intensity of fluorescence of the Fas receptor in CD4⁺ and CD8⁺ cells, granulocytes and monocytes. Conclusion: These findings indicate that there is an increased susceptibility of PBMC to apoptosis, which can be attributed to the constant contact of leucocytes with the inflamed liver tissue, or from direct HCV influence.