Measuring SSRI occupancy of SERT using the novel tracer [123I]ADAM: a SPECT validation study

Purpose Serotonergic brain regions play a crucial role in the modulation of emotion, and serotonergic dysfunction may contribute to several neurological disorders. [¹²³I]ADAM is a novel SPECT tracer which binds with high affinity to serotonin transporters (SERT). The objective of this study was to compare different methods for the quantification of tracer binding and to develop a simplified single-scan protocol for this tracer, as well as to investigate its potential for characterisation of the transporter occupancy versus plasma concentration curve of a selective serotonin re-uptake inhibitor (SSRI).Methods Dynamic SPECT scans were performed on 16 healthy volunteers after administration of 150 MBq [¹²³I]ADAM. Data were acquired from the time of injection until 5.5 h after injection in 30- or 45-min sessions. Each subject was scanned twice: with and without pre-treatment with the SSRI citalopram in various dosage regimens. The plasma concentration of citalopram (C_p) was determined from venous samples. Images were reconstructed by filtered back-projection with scatter and attenuation correction. Tracer binding was quantified for midbrain, striatum and thalamus using cerebellum as a reference region. Quantification was done by kinetic modelling, graphical analysis and multi-linear regression, as well as by the ratio method, with binding potential (BP₂) as the outcome measure. The SERT occupancy by citalopram was determined relative to the baseline scan for each subject, and the occupancy versus C_p curve was fitted with the E_max model.Results The highest binding of [¹²³I]ADAM was in midbrain (mean baseline BP₂±SD=1.31±0.29), with lower binding in thalamus (0.79±0.16) and striatum (0.66±0.13). There was good agreement between BP₂ values obtained by different quantification methods. Using the ratio method, the best agreement with kinetic modelling was obtained with data from the time interval [200,260] min after injection. The fitting of the midbrain occupancy curve yielded a maximum occupancy of 84% and a plasma concentration required to reach 50% of the maximum of 2.5 ng/ml, with a goodness-of-fit variability of 13% (SD).Conclusion Binding of [¹²³I]ADAM to SERT in midbrain can be quantified with a single scan starting 200 min after injection. However, the variability of estimated occupancy values may be too high for critical assessment of occupancy of SERT by SSRI.     

Evaluation of the Anti-Carcinogenic Effect of Centella Asiatica on Oral Cancer Cell Line: In vitro Study

Objective: To evaluate the anti-carcinogenic effect of Centella Asiatica on to evaluate the  Anti-Carcinogenic Effect of Centella Asiatica on Oral Cancer Cell Line oral cancer cell line. Materials and methods:  Oral Cancer cell line and normal oral keratinocyte cell line were procured.Centella asiatica extract was prepared. The cells were then subjected to the test herbal specimens -Centella asiatica extract in succeeding concentrations of 25 µg/ml, 50 µg/ml, 100 µg/ml at time intervals of 24,48 and 72 hours. Cisplatin (2 µg/ml, 4 µg/ml, 6 µg/ml, 8 µg/ml) was used as a positive control. This experiment was done in triplets. Results: The study revealed that the p values were less than 0.05 at concentration 12.5µg/ml, 25µg/ml, 50 µg/ml,100 µg/ml and time period of 24hrs,48hrs,72hrs, thus implying that at these concentrations and time period, the obtained data were statistically significant, thus indicating that there is a statistically significantly decreases in the viable cells as the concentration of the drug as a time period increases The results reveals that  centella asiatica possess potential effect of anti-carcinogenic, effect when compared to positive control (Cisplatin). Conclusion: The current study reveals that Centella asiatica has an potential anti-carcinogenic effect on oral cancer cell line. So this can be used to treat oral cancer with minimal crippling as compared with allopathic drugs.     

Secretion of apolipoprotein E from macrophages occurs via a protein kinase A and calcium-dependent pathway along the microtubule network

Macrophage-specific expression of apolipoprotein (apo)E protects against atherosclerosis; however, the signaling and trafficking pathways regulating secretion of apoE are unknown. We investigated the roles of the actin skeleton, microtubules, protein kinase A (PKA) and calcium (Ca2+) in regulating apoE secretion from macrophages. Disrupting microtubules with vinblastine or colchicine inhibited basal secretion of apoE substantially, whereas disruption of the actin skeleton had no effect. Structurally distinct inhibitors of PKA (H89, KT5720, inhibitory peptide PKI(14-22)) all decreased basal secretion of apoE by between 50% to 80% (P<0.01). Pulse-chase experiments demonstrated that inhibition of PKA reduced the rate of apoE secretion without affecting its degradation. Confocal microscopy and live cell imaging of apoE-green fluorescent protein-transfected RAW macrophages identified apoE-green fluorescent protein in vesicles colocalized with the microtubular network, and inhibition of PKA markedly inhibited vesicular movement. Chelation of intracellular calcium ([Ca2+]i) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate-acetoxymethyl ester (BAPTA-AM) inhibited apoE secretion by 77.2% (P<0.01). Injection of c57Bl6 apoE+/+ bone marrow-derived macrophages into the peritoneum of apoE-/- C57Bl6 mice resulted in time-dependent secretion of apoE into plasma, which was significantly inhibited by transient exposure of macrophages to BAPTA-AM and colchicine and less effectively inhibited by H89. We conclude that macrophage secretion of apoE occurs via a PKA- and calcium-dependent pathway along the microtubule network.     

Plexin-B1 mutations in prostate cancer

Semaphorins are a large class of secreted or membrane-associated proteins that act as chemotactic cues for cell movement via their transmembrane receptors, plexins. We hypothesized that the function of the semaphorin signaling pathway in the control of cell migration could be harnessed by cancer cells during invasion and metastasis. We now report 13 somatic missense mutations in the cytoplasmic domain of the Plexin-B1 gene. Mutations were found in 89% (8 of 9) of prostate cancer bone metastases, in 41% (7 of 17) of lymph node metastases, and in 46% (41 of 89) of primary cancers. Forty percent of prostate cancers contained the same mutation. Overexpression of the Plexin-B1 protein was found in the majority of primary tumors. The mutations hinder Rac and R-Ras binding and R-RasGAP activity, resulting in an increase in cell motility, invasion, adhesion, and lamellipodia extension. These results identify a key role for Plexin-B1 and the semaphorin signaling pathway it mediates in prostate cancer.     

Modified ureterosigmoidostomy (Mainz II): a long-term follow-up

OBJECTIVE: To assess the long-term results in patients treated using a modified ureterosigmoidostomy (Mainz II). PATIENTS AND METHODS: Between 1994 and 1999, 17 patients had their lower urinary tract reconstructed by a ureterosigmoidostomy, modified by reconfiguring the rectum to make a low-pressure reservoir (Mainz II). All patients were followed on a standard protocol. Data were extracted from the database and from a review of the case-notes. In 12 patients the procedure was with a radical cystectomy for carcinoma. Five had a failed conventional ureterosigmoidostomy for bladder exstrophy and therefore proceeded to a Mainz II. The data on continence and complications were retrieved for a retrospective analysis; the mean (range) follow-up was 6.4 (4-8.6) years. RESULTS: Ten of those with bladder cancer and one in the revision group were continent. Two patients in the revision group had sufficiently severe nocturnal incontinence to require conversion to a colonic conduit. Seven of the 17 patients had hyperchloraemic acidosis, one had pyelonephritis and one had renal stones. There were no anastomotic neoplasms. CONCLUSION: The Mainz II has a good outcome if used as the primary procedure. In patients with an existing ureterosigmoidostomy who are incontinent, detubularization of the rectosigmoid alone is unlikely to restore continence.     

Antenatal antioxidant treatment with melatonin to decrease newborn neurodevelopmental deficits and brain injury caused by fetal growth restriction

Fetal intrauterine growth restriction (IUGR) is a serious pregnancy complication associated with increased rates of perinatal morbidity and mortality, and ultimately with long‐term neurodevelopmental impairments. No intervention currently exists that can improve the structure and function of the IUGR brain before birth. Here, we investigated whether maternal antenatal melatonin administration reduced brain injury in ovine IUGR. IUGR was induced in pregnant sheep at 0.7 gestation and a subset of ewes received melatonin via intravenous infusion until term. IUGR, IUGR + melatonin (IUGR + MLT) and control lambs were born naturally, neonatal behavioral assessment was used to examine neurological function and at 24 hr after birth the brain was collected for the examination of neuropathology. Compared to control lambs, IUGR lambs took significantly longer to achieve normal neonatal lamb behaviors, such as standing and suckling. IUGR brains showed widespread cellular and axonal lipid peroxidation, and white matter hypomyelination and axonal damage. Maternal melatonin administration ameliorated oxidative stress, normalized myelination and rescued axonopathy within IUGR lamb brains, and IUGR + MLT lambs demonstrated significant functional improvements including a reduced time taken to attach to and suckle at the udder after birth. Based on these observations, we began a pilot clinical trial of oral melatonin administration to women with an IUGR fetus. Maternal melatonin was not associated with adverse maternal or fetal effects and it significantly reduced oxidative stress, as evidenced by reduced malondialdehyde levels, in the IUGR + MLT placenta compared to IUGR alone. Melatonin should be considered for antenatal neuroprotective therapy in human IUGR.