Municipal wastewater treatment plants as removal systems and environmental sources of human-virulent microsporidian spores

Municipal wastewater treatment plants play a vital role in reducing the microbial load of sewage before the end-products are discharged to surface waters (final effluent) or local environments (biosolids). This study was to investigate the presence of human-virulent microsporidian spores (Enterocytozoon bieneusi, Encephalitozoon intestinalis, and Encephalitozoon hellem) and enterococci during treatment processes at four Irish municipal secondary wastewater treatment plants (plants A–D). Microsporidian abundance was significantly related to seasonal increase in water temperature. Plant A had the least efficient removal of E. intestinalis spores (32%) in wastewater, with almost 100% removal at other plants both in April and July. Some negative removal efficiencies were obtained for E. bieneusi (at plants C and D, −100%) and for E. hellem (at plants A and D, −90% and −50%). In addition, a positive correlation was found between the levels of enterococci and E. bieneusi in July (r _s = 0.72, P < 0.05). In terms of the dewatered biosolids, a median concentration as high as 32,000 spores/Kg of E. hellem was observed at plant D in July. Plant C sewage sludge contained the lowest microsporidian loadings (E. bieneusi; 450 spores/L and 1,000 spores/L in April and July, respectively). This study highlights the seasonal variation in concentrations of microsporidian spores in the incoming sewage. Spores in final effluents and dewatered biosolids can be the source of human-virulent microsporidian contamination to the local environment. This emphasizes a considerably high public health risk when sewage-derived biosolids are spread during summer months. This study also suggested enterococci as a potential indicator of the presence of microsporidian spores in wastewater, especially for E. bieneusi.     

Astrocytes as brain interoceptors

Astrocytes form a vascular-neuronal interface and provide CNS neural networks with essential structural and metabolic support. They embrace all penetrating arterioles and capillaries, enwrap multiple neuronal somata, thousands of individual synapses, and upon activation release gliotransmitters (ATP, glutamate and D-serine) capable of modulating neuronal activity. The aim of this brief report is to review recent data implicating astrocytes in the brain mechanisms responsible for the detection of different sensory modalities and transmitting sensory information to the relevant neural networks controlling vital behaviours. The concept of astrocytes as brain interoceptors is strongly supported by our recent data obtained from studies of the central nervous mechanisms underlying the chemosensory control of breathing. At the level of the medulla oblongata, astrocytes indeed act as functional central respiratory chemoreceptors, sensing changes in the arterial blood and brain levels of /pH and then imparting these changes on the activity of the respiratory network to induce adaptive changes in lung ventilation.     

Arthroscopic operations in joint tuberculosis

We assessed the usefulness of arthroscopy in bone and joint tuberculosis (11 knees, 1 elbow and 1 ankle). In all 11 patients with knee joint involvement the arthroscopic operation were successful with a significant improvement in the range of motion (P=0.007) and knee score (P=0.003). There were no cases of reactivation or recurrence during a follow-up period of 15-42 months. In contrast, in the two patients with ankle or elbow joint involvement and bone destruction, arthroscopy had to be converted to open operation. Minor trauma, a short hospitalization time and a short post-operative rehabilitation period combined with good cosmetic and clinical results favor the use of the arthroscopic technology in the surgical treatment of tuberculous arthritis of the knee.     

Effects of the 2-ethylthiobenzimidazole hydrobromide (bemithyl) on carbohydrate metabolism in cirrhotic rat liver

The effect of the actoprotector bemithyl (2-ethylthiobenzimidazole hydrobromide) on the content of glycogen and activities of glycogen synthase, glycogen phosphorylase, and glucose-6-phosphatase was studied in the cirrhotic rat liver. The content of glycogen and its fraction was determined by a cytofluorimetric method (Kudryavtseva et al. 1974). It has been shown that in cirrhosis the content of total glycogen in hepatocytes increases about 3 times and the content of its stable fraction increases 7.5 times. The activity of glucose-6-phosphatase fell to a level as low as 25% of normal. Activities of glycogen synthase and glycogen phosphorylase in the cirrhotic liver did not differ from normal. In the cirrhotic liver, bemithyl produced a decrease of the total glycogen content which was associated with a decrease of the glycogen synthase activity and an increase of the glucose-6-phosphatase and glycogen phosphorylase activities. Thus, the results of our studies indicate a favorable effect of bemithyl on the cirrhotic liver.     

Impulse magnetic stimulation facilitates synaptic regeneration in rats following sciatic nerve injury

The current studies describing magnetic stimulation for treatment of nervous system diseases mainly focus on transcranial magnetic stimulation and rarely focus on spinal cord magnetic stimula-tion.Spinal cord magnetic stimulation has been confirmed to promote neural plasticity after injuries of spinal cord,brain and peripheral nerve.To evaluate the effects of impulse magnetic stimulation of the spinal cord on peripheral nerve regneration,we compressed a 3 mm segment located in the middle third of the hip using a sterilized artery forceps to induce ischemia.Then,all animals un-derwent impulse magnetic stimulation of the lumbar portion of spinal crod and spinal nerve roots daily for 1 month.Electron microscopy results showed that in and below the injuryed segment,the inflammation and demyelination of neural tissue were alleviated,apoptotic cells were reduced,and injured Schwann cells and myelin fibers were repaired.These findings suggest that high-frequency impulse magnetic stimulation of spinal cord and corresponding spinal nerve roots promotes synaptic regeneration following sciatic nerve injury.     

Influence of N-hydroxymethyl-p-isopropoxyphenylsuccinimide on the anticonvulsant action of different classical antiepileptic drugs in the mouse maximal electroshock-induced seizure model

Experimental epileptology is mainly focused on searching for some active compounds suppressing seizures that could become efficacious antiepileptic drugs. Accumulating evidence indicates that succinimide derivatives would be good candidates for novel antiepileptic drugs. Therefore, the aim of this study was to determine the effects of N-hydroxymethyl-p-isopropoxyphenyl-succinimide (HMIPPS) on the protective action of four classical antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) in the maximal electroshock-induced seizure test in mice. Tonic hind limb extension (seizure activity) was evoked in adult male albino Swiss mice by a current (sine-wave, 25 mA, 500 V, 50 Hz, 0.2s stimulus duration) delivered via auricular electrodes. Acute adverse-effect profiles with respect to motor performance, long-term memory and skeletal muscular strength were measured along with total brain antiepileptic drug concentrations. Results indicate that HMIPPS administered intraperitoneally at 100mg/kg significantly elevated the threshold for electroconvulsions in mice (P<0.05). HMIPPS at doses of 12.5, 25 and 50mg/kg had no impact on the threshold for electroconvulsions in mice. Moreover, HMIPPS (50mg/kg) significantly enhanced the anticonvulsant activity of phenobarbital and valproate in the mouse maximal electroshock-induced seizure model by reducing their median effective doses (ED(50) values) from 23.25mg/kg to 16.82 mg/kg (P<0.01; for phenobarbital) and from 259.3mg/kg to 189.7 mg/kg (P<0.001; for valproate), respectively. In contrast, HMIPPS (50mg/kg) had no impact on the protective action of carbamazepine or phenytoin in the maximal electroshock seizure test in mice. HMIPPS (25mg/kg) significantly potentiated the anticonvulsant action of valproate by reducing its ED(50) value from 259.3mg/kg to 210.6 mg/kg (P>0.05), but not that of phenobarbital, phenytoin and carbamazepine in the mouse maximal electroshock-induced seizure model. Pharmacokinetic experiments revealed that HMIPPS did not alter total brain concentrations of phenobarbital or valproate in mice. Moreover, none of the examined combinations of HMIPPS (50mg/kg) with carbamazepine, phenobarbital, phenytoin and valproate (at their ED(50) values from the maximal electroshock-induced seizure test) affected motor coordination in the chimney test, long-term memory in the passive avoidance task, and muscular strength in the grip-strength test in mice, indicating no possible acute adverse effects in animals. In conclusion, the enhanced anticonvulsant action of phenobarbital and valproate by HMIPPS in the mouse maximal electroshock-induced seizure model, lack of pharmacokinetic interactions and no potential acute adverse effects make the combinations of HMIPPS with phenobarbital and valproate worthy of consideration for further experimental and clinical studies. The combinations of HMIPPS with carbamazepine and phenytoin are neutral from a preclinical viewpoint.     

Cannabinoid type-1 receptor reduces pain and neurotoxicity produced by chemotherapy

Painful peripheral neuropathy is a dose-limiting complication of chemotherapy. Cisplatin produces a cumulative toxic effect on peripheral nerves, and 30-40% of cancer patients receiving this agent experience pain. By modeling cisplatin-induced hyperalgesia in mice with daily injections of cisplatin (1 mg/kg, i.p.) for 7 d, we investigated the anti-hyperalgesic effects of anandamide (AEA) and cyclohexylcarbamic acid 3'-carbamoyl-biphenyl-3-yl ester (URB597), an inhibitor of AEA hydrolysis. Cisplatin-induced mechanical and heat hyperalgesia were accompanied by a decrease in the level of AEA in plantar paw skin. No changes in motor activity were observed after seven injections of cisplatin. Intraplantar injection of AEA (10 μg/10 μl) or URB597 (9 μg/10 μl) transiently attenuated hyperalgesia through activation of peripheral CB? receptors. Co-injections of URB597 (0.3 mg/kg daily, i.p.) with cisplatin decreased and delayed the development of mechanical and heat hyperalgesia. The effect of URB597 was mediated by CB? receptors since AM281 (0.33 mg/kg daily, i.p.) blocked the effect of URB597. Co-injection of URB597 also normalized the cisplatin-induced decrease in conduction velocity of Aα/Aβ-fibers and reduced the increase of ATF-3 and TRPV1 immunoreactivity in dorsal root ganglion (DRG) neurons. Since DRGs are a primary site of toxicity by cisplatin, effects of cisplatin were studied on cultured DRG neurons. Incubation of DRG neurons with cisplatin (4 μg/ml) for 24 h decreased the total length of neurites. URB597 (100 nM) attenuated these changes through activation of CB? receptors. Collectively, these results suggest that pharmacological facilitation of AEA signaling is a promising strategy for attenuating cisplatin-associated sensory neuropathy.     

In vivo alterations in calcium buffering capacity in transgenic mouse model of synucleinopathy

Abnormal accumulation of α-synuclein is centrally involved in the pathogenesis of many disorders with Parkinsonism and dementia. Previous in vitro studies suggest that α-synuclein dysregulates intracellular calcium. However, it is unclear whether these alterations occur in vivo. For this reason, we investigated calcium dynamics in transgenic mice expressing human WT α-synuclein using two-photon microscopy. We imaged spontaneous and stimulus-induced neuronal activity in the barrel cortex. Transgenic mice exhibited augmented, long-lasting calcium transients characterized by considerable deviation from the exponential decay. The most evident pathology was observed in response to a repetitive stimulation in which subsequent stimuli were presented before relaxation of calcium signal to the baseline. These alterations were detected in the absence of significant increase in neuronal spiking response compared with age-matched controls, supporting the possibility that α-synuclein promoted alterations in calcium dynamics via interference with intracellular buffering mechanisms. The characteristic shape of calcium decay and augmented response during repetitive stimulation can serve as in vivo imaging biomarkers in this model of neurodegeneration, to monitor progression of the disease and screen candidate treatment strategies.     

GM1485, a nonimmunosuppressive immunophilin ligand, promotes neurofunctional improvement and neural regeneration following stroke

Stroke is the leading cause of disability in the industrialized world, and the development of pharmacologic strategies to promote poststroke recovery is of paramount importance. GM1485, a nonimmunosuppressive immunophilin ligand, promotes regeneration of multiple cell types following injury. In the present study, we evaluated the effect of GM1485 treatment on functional recovery and neurogenesis following rat stroke. Transient cerebral ischemia was induced in rats receiving daily GM1485 (5 mg/kg) beginning 24 hr postischemia and continuing for a total of 6 weeks. Neurological function was evaluated over this period using a battery of neurobehavioral tests, and immunostaining for stem-cell markers was performed following animal sacrifice. An in vitro model of oxidative stress was also employed to evaluate the ability of GM1485 to mediate stem-cell-like induction and plasticity. GM1485-treated rats demonstrated improved neurological function as well as increased Sox2(+) cells in the ipsilateral SVZ and striatum relative to vehicle-treated rats. Additionally, GM1485-treated fibroblasts subjected to oxidative stress were reprogrammed to a stem-cell-like phenotype and were able to differentiate down a neuronal lineage. These data demonstrate that GM1485 administration improves neurological function and is consistent with an upregulation of endogenous neurogenesis following stroke in rats. Further experiments are necessary to characterize the molecular pathways involved in these processes.