Cognitive effects attributed to angiotensin II may result from its conversion to angiotensin IV.

This study tests the hypothesis that the facilitation of learning and improvement of memory observed after an intracerebroventricular (i.c.v.) injection of angiotensin II (Ang II) is, in fact, caused by its derivative angiotensin IV (Ang IV). We ran two memory tests as well as an auxiliary test assessing motor performance in rats injected (i.c.v., 1 nmol in 2 microl saline) with Ang II or Ang IV. There were separate groups receiving peptide or saline five, 10 and 15 minutes before testing. Ang IV significantly increased step-through latencies in a passive avoidance paradigm as well as improved discrimination between familiar and unfamiliar objects in an object recognition test in all groups showing better retrieval of memory of aversive as well as appetitive stimuli in the peptide-treated groups regardless of the time of its injection. In contrast, rats treated with Ang II demonstrated significant improvement of memory of aversive and appetitive stimuli in the same tests only 15 minutes after its i.c.v. injection, with no effect in the groups injected five minutes before testing and slight efficacy in those injected 10 minutes before the test. Numbers of crossings, rearings and bar approaches in an open field were similar both in the peptide-treated and control groups making it unlikely that changes in motor performance affected the memory tests. In line with the present views on the intracellular metabolism of Ang II, these results suggest degradation to Ang IV by aminopeptidases A and N is necessary before the cognitive effects can occur.     

The effects of hyaluronan on bone resorption and bone mineral density in a rat model of estrogen deficiency-induced osteopenia

Hyaluronan, or hyaluronic acid (HA), is an essential component of extracellular matrices. HA of appropriate molecular weight and concentration can induce osteoblast differentiation and bone formation in vitro. The aim of our study was to evaluate the effects of HA of different molecular weights on ovariectomy (OVX)-induced bone loss in rats. Adult female Sprague Dawley rats were subjected to bilateral OVX or sham surgical procedure (sham). OVX rats were treated with: HA of molecular weight of 0.75 MDa at a dose of 1 mg/kg/day and with HA of molecular weight of 1.62 MDa at a dose of both 0.5 mg/kg/day and 1 mg/kg/day. HA was applied orally once a day during the 8-week period after ovariectomy. Body weight, urinary pyridinoline (Pyr), deoxypyridinoline (DPyr) corrected for urinary creatinine, serum nitrite/nitrate concentrations and whole body and femoral bone mineral density (BMD) were measured. HA treatment had no effect on the body weight gain in OVX rats. Excretion of urinary Pyr and Dpyr significantly increased in OVX rats compared to sham controls. The higher molecular weight HA (1.62 MDa) significantly reduced urinary Pyr and DPyr concentrations measured on day 28 after ovariectomy (p < 0.001). Serum concentrations of nitric oxide metabolites, nitrite/nitrate significantly decreased in OVX rats in comparison with sham controls (p < 0.001). HA of both 0.75 MDa and 1.62 MDa molecular weights significantly enhanced serum nitrite/nitrate concentrations in OVX rats. There was a clear reduction of whole body and femoral BMD in untreated OVX rats. The higher molecular weight HA decreased both whole body and femoral BMD loss. Our results show that orally applied HA of high molecular weight (1.62 MDa) inhibits bone resorption and provides a protective effect on bone density in ovariectomized rats.     

Induction of apoptosis/necrosis in various human cell lineages by Haemophilus ducreyi cytolethal distending toxin.

We investigated the impact of highly purified Haemophilus ducreyi cytolethal distending toxin (HdCDT) on the apoptosis and necrosis of various human cells; including myeloid cells, epithelial cells, keratinocytes, and primary fibroblasts. The levels of apoptosis and necrosis induced in these cells were compared to those induced by HdCDT in human T cells and in the Jurkat T cell line. Levels of caspase-3 activity were measured, and membrane changes like phosphatidylserine (PS) translocation was evaluated after double-staining with the fluorescein isothiocyanate (FITC)-labeled annexin V and propidium iodide (PI) using flow cytometry. HdCDT induced various degrees of apoptosis and necrosis in dose- and time-dependent manners in cells of various lineages. Early and late apoptosis (annexin V-stained cells) were induced in more than 90% of T cells and monocytes after treatment with 100 ng/ml HdCDT for 24 and 48 h, respectively. The corresponding numbers for epithelial cells, keratinocytes, and fibroblasts were 26-32% after treatment with 100 ng/ml HdCDT for 48 h. HdCDT appears to eliminate effectively by inducing apoptosis those cells that are involved in immune responses. Epithelial cells, keratinocytes and fibroblasts, which are important for the healing of chancroid ulcers, are eliminated by apoptosis or necrosis after contact with HdCDT, albeit slower and to a lesser extent than T cells.     

Influence of 40% Cold Working and Annealing on Precipitation in AISI 316L Austenitic Stainless Steel

Intergranular corrosion is one of the most important processes affecting the behaviour of austenitic stainless steels. Factors such as steel chemical composition, the degree of prior deformation and the exposure temperature affect the degree of sensitisation. AISI 316L (0% CW) steel was annealed at 650 °C for 5, 10, 30, 100, 300 and 1000 h to analyse the influence of isothermal annealing on the precipitation of secondary phases. AISI 316L steel after 40% cold working and subsequent annealing at 650 °C for 1, 1.5, 2, 5 and 10 h was investigated. Time–temperature sensitisation (TTS) diagrams were created based on corrosion test (ASTM A 262, practice A) results. In the case of AISI 316L (0% CW), M₂₃C₆, chi and sigma phases precipitated at grain boundaries, and the Laves phase was mainly inside of the grains. In the case of AISI 316L (40% CW), sigma, chi, Laves and M₂₃C₆ were identified and precipitated mainly along the grain boundaries as well as on the shear bands within different annealing times. It was confirmed that the increase in the annealing time caused an increase in the amounts of secondary phases. Secondary phases in the equilibrium state were calculated using Thermo-Calc software.     

Thyroid remnant ablation with radioiodine activity of 30, 60, and 100 mCi in patients with differentiated thyroid cancer – a prospective comparison of long-term outcomes

IntroductionThe aim of this prospective study was to evaluate long-term outcomes in differentiated thyroid cancer (DTC) patients postoperatively treated with distinct RAI activities of 30 mCi, 60 mCi, and 100 mCi.Material and methodsThe analysis involved 277 low-risk and 46 intermediate-risk patients, who underwent radioiodine (RAI) ablation with 30 mCi, 60 mCi or 100 mCi under prospective, randomized clinical trials. Seventy-eight patients from the low-risk group received 30 mCi, whereas 125 and 74 patients received 60 mCi and 100 mCi, respectively. Regarding the intermediate-risk group, 20 patients were given 60 mCi, and 26 subjects were given 100 mCi. The mean time of follow-up was 11 years.ResultsAn excellent treatment response was obtained in 88%, 89% and 90% of low-risk patients treated with 30 mCi, 60 mCi, and 100 mCi, respectively, and in 85% of intermediate-risk patients, who were administered 60 or 100 mCi. An indeterminate response was achieved in 9.4% and 6.5%, whereas an incomplete structural response was obtained in 1.4% and 6.5% of low-risk and intermediate-risk patients, respectively. An incomplete biochemical response was observed only in 2.2% of intermediate-risk patients. The differences in treatment response regarding RAI activity were not significant.ConclusionsRAI activity of 30 mCi demonstrates a comparable efficacy as 60 mCi and 100 mCi in low-risk DTC. RAI activity of 60 mCi seems to be effective in intermediate-risk DTC.     

Structure of synovial lymphatic capillaries in rheumatoid arthritis and juvenile idiopathic arthritis

The structure of lymphatic capillaries (LC) of the synovial membrane (SM) from patients with rheumatoid arthritis and juvenile idiopathic arthritis obtained by synovectomy was investigated by transmission electron microscopy. This method allows comparison of the structure of the same vessel under light and electron microscope and clear differentiation between lymphatic and blood capillaries and venules. Synovial LC were localized in the subintimal connective tissue of the SM in the vicinity of venules. The shape of some LC was irregular, suggesting edema of the interstitium. Lymphatic endothelium has extremely attenuated cytoplasm with the exception of the perinuclear region. Many nuclei of endothelial cells had distinct nucleoli. The basal lamina was discontinuous. The walls of LC showed close connection with the interstitium represented by anchoring filaments that were attached to the endothelial cells and to the surrounding connective tissue. In some LC connective tissue appeared to be disconnected from endothelium and gaps between their walls and the interstitium were seen. Mononuclear cells were accumulated adjacent to some LC. Specialized interendothelial junctions (endothelial microvalves) were observed in the LC walls. Their structure and function in the migration of cells and debris from synovial interstitium into LC lumina in rheumatoid arthritic synovium deserves further investigation. In the lumina of some of the LC lymphocytes, monocytes, macrophages, cell debris and enlarged endothelium were observed. Accumulation of such material may cause obstruction of tiny LC. We suggest that reported alterations of the fine synovial lymphatic vessels can contribute to the progression of the inflammatory process to chronicity.     

Efficient total synthesis of (+)-dihydropinidine, (-)-epidihydropinidine, and (-)-pinidinone

The 2,6-disubstituted piperidine alkaloids (+)-dihydropinidine (1), (-)-epidihydropinidine (2) (as HCl salts), and (-)-pinidinone (3) were efficiently synthesized from (S)-epichlorohydrin (7) as common substrate using regioselective Wacker-Tsuji oxidation of alkenylazides 10 and 14 as well as a highly diastereoselective reduction of cyclic imine 11 as key steps. The protecting group free total syntheses represent the up to date shortest routes with highest overall yields for all three naturally occurring alkaloids (1-3). The first single-crystal X-ray analysis of (-)-epidihydropinidine hydrochloride (2·HCl) confirmed its proposed absolute configuration to be (2S,6S), corresponding to that of the isolated natural product.