Enhanced absorption of TiO2 nanotubes by N-doping and CdS quantum dots sensitization: insight into the structure

Anodization of titanium film sputtered on fluorine doped tin oxide (FTO) glass was performed to obtain highly ordered ∼2 μm long and ∼60 nm wide TiO₂ nanotubes. The titania films were annealed in ammonia atmosphere to enable the doping with N. The annealing did not affect the nanotubular morphology and the porosity remained open which is a very important requirement for further deposition of CdS quantum dots. The analysis done by transmission electron microscopy (TEM) has shown that the N-doped nanotubes have a smaller interplanar distance as compared to the undoped ones, whose interplanar distance corresponded to anatase phase. This difference was attributed to the N doping and the Sn migration from the substrate, as demonstrated by energy dispersive spectroscopy (EDS) combined with electron energy loss spectroscopy (EELS). The near edge X-ray absorption fine structure (NEXAFS) analysis clearly demonstrated that also the doped TiO₂ film has anatase phase. Regarding the chemical composition of the studied samples, the X-ray photoelectron spectroscopy (XPS) and synchrotron radiation photoelectron spectroscopy (SRPES) analyses have shown that N is incorporated both interstitially and substitutionally in the TiO₂ lattice, with a decreased contribution of the interstitial after ionic sputtering. The shift of the valence band maximum (VBM) position for the doped TiO₂vs. the undoped TiO₂ proved the narrowing of the band gap. The CdS/TiO₂ films show bigger VBM shifting that can be attributed to CdS deposit. Comparing the absorption spectra of the bare undoped and doped TiO₂ samples, it was noticed that the doping causes a red shift from 397 to 465 nm. Furthermore, the CdS deposition additionally enhances the absorption in the visible range (575 nm for undoped TiO₂/CdS and 560 nm for doped TiO₂/CdS films).

A simple two-step procedure to shift the absorption of TiO₂ nanotubes to the visible range.     

Surgery for thyroid Hürthle cell tumours--a single institution experience.

AIMS: The objective of the study was to report a series of patients with Hürthle cell tumours. METHODS: We reviewed medical records of single institution from January 1982 to December 2002, including follow-up information. RESULTS: We identified 199 patients with Hürthle cell tumours (HCT), 88 patients with Hürthle cell carcinoma (HCC) and 111 patients with Hürthle cell adenoma (HCA). The HCC group had significantly longer duration of the disease and larger tumours (4.8 vs 3.8 cm) compared with HCA group. Gender appeared to play significant role in patients with HCT (women outnumbered man by 7:1; p < 0.01). Surgical management for 80% of patients with HCA consisted of hemithyroidectomy and total thyroidectomy in 87% patients in the HCC group. Temporary laryngeal nerve palsy and temporary hypoparathyroidismus were not seen in HCA group, in HCC group were confirmed in 2.27 and 3.41%, respectively. Four patients with HCC relapsed and two died of HCC. CONCLUSIONS: HCC has outlook for favorable outcome when treated radically with total thyroidectomy.     

Short-term effects of repetitive arm work and dynamic exercise on glucose metabolism and insulin sensitivity

AIM: To determine whether repetitive arm work, with a large component of static muscle contraction alters glucose metabolism and insulin sensitivity. METHOD: Euglycemic clamps (2 h) were started in ten healthy individuals 15 min after 37 min periods of: (1) repetitive arm work in a simulated occupational setting; (2) dynamic concentric exercise on a cycle ergometer at 60% of VO(2max) and (3) a resting regime as a control. During the experimental periods, blood samples were collected, blood pressure was measured repeatedly and electrocardiogram (ECG) was recorded continuously. During the clamps, euglycemia was maintained at 5 mmol l(-1) and insulin was infused at 56 mU m(-2) min(-1) for 120 min. RESULTS: The insulin-mediated glucose disposal rate (M-value) for the steady-state period (60-120 min) of the clamp, tended to be lower following arm work than for both cycling and resting regimes. When dividing the steady-state period into 20-min intervals, the insulin sensitivity index (ISI) was significantly lower for arm work compared with the resting control situation between 60-80 min (P = 0.04) and 80-100 min (P = 0.01), respectively. Catecholamines increased significantly for arm work and cycling compared with resting regime. Data from heart rate variability (HRV) measurements indicated significant sympathetic activation during repetitive arm work. CONCLUSION: The results indicate that repetitive arm work might acutely promote insulin resistance, whereas no such effect on insulin resistance was produced by dynamic concentric exercise.     

In Vivo and Ex Vivo Inhibition of Spinal Nerve Ligation-Induced Ectopic Activity by Sodium Channel Blockers Correlate to In Vitro Inhibition of NaV1.7 and Clinical Efficacy: A Pharmacokinetic-Pharmacodynamic Translational Approach

Purpose

In vivo and ex vivo inhibition of ectopic activity of clinically used and newly developed sodium channel (NaV) blockers were quantified in the rat spinal nerve ligation (SNL) model using a pharmacokinetic-pharmacodynamic (PKPD) approach and correlated to in vitro NaV1.7 channel inhibition and clinical effective concentrations.

Methods

In vivo, drug exposure and inhibition of ectopic activity were assessed in anaesthetized SNL rats at two dose levels. Ex vivo, compounds were applied at increasing concentrations to dorsal root ganglias isolated from SNL rats. The inhibitory potency (IC ₅₀ ) was estimated using PKPD analysis. In vitro IC ₅₀ was estimated using an electrophysiology-based assay using recombinant rat and human NaV1.7 expressing HEK293 cells.

Results

In vivo and ex vivo inhibition of ectopic activity correlated well with the in vitro inhibition on the rat NaV1.7 channel. The estimated IC _50s for inhibition of ectopic activity in the SNL model occurred at similar unbound concentrations as clinical effective concentrations in humans.

Conclusions

Inhibition of ectopic activity in the SNL model could be useful in predicting clinical effective concentrations for novel sodium channel blockers. In addition, in vitro potency could be used for screening, characterization and selection of compounds, thereby reducing the need for in vivo testing.     

Ten years' experience in subtotal parathyroidectomy of hemodialysis patients

Secondary hyperparathyroidism (SHP) is a frequent complication of long-term dialysis patients, and surgical parathyroidectomy remains necessary in patients resistant to medical therapy. The present paper reports single center results in subtotal parathyroidectomy, presenting diagnostic procedure, indications for parathyroidectomy, and postoperative course of metabolic and endocrine disorders. Forty-seven patients (25 males and 22 females), aged 25-60 years, regularly hemodialyzed between 3-23 years, have undergone parathyroidectomy at our Clinical Center during the last 10 years. The patients had plasma iPTH levels 8-45 times higher than the top normal limit, high values of alkaline phosphatase, calcemia on the upper normal level, and hyperphosphatemia. Radiographic changes characteristic for SHP were seen in all patients before parathyroidectomy, and the most common were subperiosteal resorptions (100%), bone cysts and periosteal neostosis (66%), and extraskeletal calcifications (98%). Enlarged parathyroid glands were seen by ultrasound in 62% of patients. All patients manifested pruritus and bone pain, 89% of them had myopathy, while other symptoms and signs were present in lower proportions. After parathyroidectomy, pruritus and myopathy reduced significantly, while pain in bones and joints remained. One patient had brown tumor at the maxillary bone that regressed gradually after parathyroidectomy. Significant decreases of phosphate and calcium levels were recorded in all but two patients on the very first postoperative day. Regular peroral and parenteral supplementations of calcium and vitamin D metabolites were used, but calcemia was not normalized until the end of the third week of the postoperative period. Serum alkaline phosphatase showed an increase after the surgery, thereupon a sudden and then slower decrease up to 1 year from the surgery. Plasma iPTH levels, checked on the 21st postoperative day, were close to the lower normal limit in all but two (4.3%) patients with persistent SHP, who required reoperation. In conclusion, subtotal parathyroidectomy was proved as a successful and safe treatment for patients with SHP resistant to medical therapy, and treatment was followed by improvement of clinical symptoms and metabolic disorders.     

Fatigue-related depression of the feline monosynaptic gastrocnemius–soleus reflex

In decerebrate cats, changes in the monosynaptic reflex (MSR) of gastrocnemius–soleus (G–S) motoneurones were studied after fatiguing stimulation (FST) of the G–S muscles. Monosynaptic reflexes were evoked by stimulation of Ia fibres in the G–S nerve and recorded from a filament of ventral root (VR) L7. FST (intermittent 40 s⁻¹ stimulation for 10–12 min) was applied to the distal part of the cut VR S1. FST reduced MSR amplitudes to 0.64 ± 0.04 (mean ± s.e.m .) of the prefatigue values. The suppression remained stable for approximately 25 min and then MSR amplitudes gradually returned towards the normal. To test for the involvement of presynaptic and recurrent inhibition, MSRs were conditioned by stimulation of the nerve to the posterior biceps and semitendinosus (PBSt) muscles or a filament of VR L7, respectively. The intensity of presynaptic inhibition (reduction of the normalized value of MSR amplitude during conditioning) increased from 0.19 ± 0.02 in prefatigue to 0.44 ± 0.04 within a 5.3–18.2 min interval after FST, followed by a recovery. In contrast, the intensity of recurrent inhibition first diminished from 0.23 ± 0.02 in prefatigue to 0.15 ± 0.01 within 15.6–30.1 min after FST and then gradually recovered. Both primary afferent depolarization and the intensity of antidromic discharges in primary afferents increased with the presynaptic inhibition intensity. These results demonstrate a fatigue-related suppression of Ia excitation of synergistic motoneurones, probably arising from the activation of group III and IV afferents. The effects could in part be due to increased presynaptic inhibition, while recurrent inhibition plays a minor role.     

Distinctive pattern of c-fos expression in the feline cervico-lumbar spinal cord after stimulation of vanilloid receptors in dorsal neck muscles

In the present study, c-fos expression in the spinal cord has been used as a marker of neuronal activation induced by capsaicin-sensitive sensory afferents from the dorsal neck muscles in cats (n = 6). The number of Fos-immunoreactive neurons, which were revealed using the avidin-biotin-peroxidase method, was significantly increased in the cervical and lumbar spinal cord. In contrast to the control group (n = 3), 2 h after intramuscular capsaicin injection, c-fos expression was more extensive ipsilaterally to the injected side in the C3-C6 segments, and bilaterally in the L4-L6 segments. Most labeled neurons in the cervical spinal cord were small and giant cells, predominantly located in the middle and lateral parts of lamina I and, additionally, at the neck of the dorsal horn (lamina V), i.e., within the zones of termination of high-threshold muscle afferents. The widespread distribution of labeled cells throughout the cervical cord within the intermediate zone (lamina VII) coincided with the sites of last-order premotor interneurons and cells of origin of long crossed and uncrossed descending propriospinal pathways to the lumbar spinal cord. These findings suggest possible mechanisms for spreading of nociceptive signals between cervical and lumbar regions.