Crystalline and disordered state of poly(dihexylsilylene) copolymers

A systematic comparison of random copolymers, derived from poly(dihexylsilylene) (PDHS) by incorporation of monomeric units with shorter unbranched alkyl side chains, has been carried out based on calorimetry, variable temperature UV spectroscopy, and ²⁹Si MAS (magic angle spinning) solid state NMR investigations. Also, hexylmethylsilylene units and branched monomers have been copolymerized. Up to 10% comonomer with shorter linear side chains (i. e., pentyl to propyl) could be incorporated into PDHS without impeding the all-trans order of the crystalline phase. In this case, the UV absorption maximum of the crystalline low-temperature phase was affected only slightly according to the length and fraction of the comonomer side chains. A less ordered crystal structure (λ_max = 345–355 nm) was observed when the content of comonomers with shorter side chains was about 20%. Yet, all these materials form conformationally disordered mesophases. A clear disordering transition and corresponding thermochromism was not observed any more when 50% of propyl side chains were incorporated. The order of the crystalline and the mesophase is also strongly perturbed if only a small fraction (4%) of the side chains are branched at C².     

Dioxygen sensitivity of a photoexcited thin film of phthalocyanine dispersed in poly(N-vinylcarbazole)

Thin films (thickness 0,3 μm) of a mixture of phthalocyaninatozinc(II) ( 1 ) and poly(1-vinylcarbazole) ( 2 ) are prepared by coating from a solution on ITO glass. The blue coloured films are investigated in an electrochemical cell under irradiation with visible light. In the presence of dioxygen from air the films exhibit an intensive cathodic photocurrent. The action spectrum of the photocurrent corresponds to the absorption spectrum of the phthalocyanine. The results show a device which can be switched by air and visible light.     

Eccentric visual acuity in patients with macular disease

A series of cards each containing a two dimensional array of identical Snellen "E's" was used to determine best eccentric visual acuity in patients with macular disease having Snellen visual acuity of 20/70 or worse. Each "full field E" card simultaneously presents the same letter to foveal and parafoveal areas. This test can therefore determine quickly if potentially useful vision is present in any area of the central visual field. In our study of 37 eyes, 70% demonstrated potential visual acuity at least two times better than visual acuity measured by conventional methods, and 20% demonstrated at least a fourfold improvement. This suggests that most patients with macular disease do not spontaneously employ their best remaining area of retina for fixation.     

Demonstration of Ri-type adenosine receptors in bovine myocardium by radioligand binding

Summary Adenosine has been shown to have negative inotropic, chronotropic and dromotropic effects on the heart. The pharmacological profiles of these effects suggest that they are mediated via R_i (A₁) adenosine receptors, but a direct demonstration of these receptors is still missing. In the present study we report direct labelling of these receptors with (-)N⁶-[¹²⁵I]-p-hydroxyphenylisopropyladenosine ([¹²⁵I]HPIA). The radioligand bound in a saturable and reversible manner to a crude membrane preparation, the B _max-value was 30.5 fmol/mg protein and the K _D-value 1.1 nmol/l. A similar affinity of the ligand was obtained in kinetic and competition experiments. Competition experiments with a variety of adenosine analogues gave a pharmacological profile characteristic of R_i adenosine receptors with high affinities of N⁶-substituted derivatives and a marked stereospecificity for N⁶-phenylisopropyladenosine (PIA). Purification of the membrane preparation by density gradient centrifugation resulted in a 30-fold increase in the number of binding sites which was paralleled by a similar increase in the number of binding sites for [³H]ouabain. Guanine nucleotides decreased binding of [¹²⁵I]HPIA in a dose-dependent manner, but the IC₅₀-values were considerably higher than those reported in other tissues. Finally, binding of [¹²⁵I]HPIA appeared to be entropy-driven which has been shown to be characteristic of agonist binding to R_i adenosine receptors. These results suggest the presence of R_i adenosine receptors in ventricular myocardium which may be responsible for the mediation of the effects of adenosine and its analogues.Abbreviations [¹²⁵I]HPIA (-)N⁶-[¹²⁵I]-p-hydroxyphenylisopropyladenosine - (-)IHPIA (-)N⁶-iodo-p-hydroxyphenylisopropyladenosine - (+)/(-)PIA (+)/(-)N⁶-phenylisopropyladenosine - CHA N⁶-cyclohexyladenosine - NECA 5-N-ethylcarboxamidoadenosine - App(NH)p 5-adenylylimidodiphosphate - Gpp(NH)p 5-guanylylimidodiphosphate     

ZK 91296, a partial agonist at benzodiazepine receptors

ZK 91296 (ethyl 5-benzyloxy-4-methoxymethyl--carboline-3-carboxylate) is a potent and selective ligand for benzodiazepine (BZ) receptors. Biochemical investigations indicate that ZK 91296 may be a partial agonist at BZ receptors. Such partial agonism may explain to some extent why ZK 91296 needs higher BZ receptor occupancy than diazepam for the same effect against chemical convulsants and for behavioural effects. The lack of sedatiye effects, and the very potent inhibition of reflex epilepsy, spontaneous epilepsy and DMCM-induced seizures suggest, furthermore, that ZK 91296 may possess pharmacological selectivity for a particular type of BZ receptor interaction, perhaps including topographic as well as receptor subtype differentiation.     

Long-Term Outcomes of Everolimus Therapy in De Novo Liver Transplantation: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BackgroundRisk of nephrotoxicity in liver transplant patients on calcineurin inhibitors (CnIs) is a concern. Several controlled trials reported benefit of everolimus (EVR) in minimizing this risk when combined with a reduced CnI dose.BackgroundTo systematically review the efficacy and safety of EVR, alone or with reduced CnI dose, as compared to CnI alone post-liver transplantation.MethodsWe searched MEDLINE, Scopus, and the Cochrane Library for randomized controlled trials comparing EVR- and CnI-based regimens post-liver transplantation. Assessment of studies and data extraction were undertaken independently.ResultsEight studies were selected, describing 769 patients. Cockcroft-Gault GFR was higher at one (P = .05), 3, and 5 years (P = .030) in patients on EVR compared to those receiving CnI therapy. The composite endpoint of efficacy failure was similar between the 2 arms after 1, 3, and 5 years of study. More patients discontinued EVR due to adverse effects in 1 year; however, no difference was noted after 3 or 5 years. A higher rates of proteinuria, peripheral edema, and incisional hernia occurred in patients on EVR.ConclusionsThe analysis confirms noninferiority of EVR and reduced CnI combination. Combination regimen resulted in better renal function compared to standard CnI therapy.     

Factors associated with insomnia symptoms: A cross-sectional study during a Covid-19 fully restrictive lockdown

Insomnia is the most frequent sleep disorder and a public health concern that increased during the Covid 19 pandemic. Fully restrictive lockdowns during Covid are interesting periods to examine the impact of environmental and behavioural changes on the emergence of insomnia symptoms. In this cross-sectional study we aimed to (1) determine the main factors associated with insomnia symptoms during a Covid-19 fully restrictive lockdown examining the associated daily life alterations and (2) create a predictive model of insomnia symptoms. We used the data drawn from the “Covid-RythmE” study that reached volunteers from the general French population through an online survey during the last 2 weeks of the 2 month full lockdown. Associations with insomnia symptoms were tested and significant associations were entered in a Backward Stepwise Logistic Regression (BSLR) to assess the best combination to classify individuals with or without insomnia symptoms. From the 1624 participants, 50.64% suffered from mild to severe insomnia symptoms as assessed by the ISI. The best combination for explaining insomnia symptoms with 74.26% of accuracy included: age (OR = 1.15), females (OR = 1.26), smaller home sizes (OR = 0.77), environmental noises (OR = 1.59), anxiety symptoms (OR = 1.24), depressive symptoms (OR = 1.15), regularity of sleep–wake schedules (OR = 1.25), exposure to screen during the morning (OR = 1.13), and LED light during the evening (OR = 1.17). Thus, lifestyle schedule and exposure to natural synchronizers such as light, are primordial in considering in insomnia physiopathology, prevention and treatment, as well as the associated mental health status.     

DNA measurement,proliferation markers,and other factors in pituitary adenomas

To assess the proliferative activity of pituitary adenomas, 36 surgically removed adenomas were studied by light microscopical parameters; mitotic count; expression of PCNA, Ki-67, cathepsin D, and EGF; and image cytometry. Three adenomas (9%) showed high, 11 (34%) medium, 17 (53%) moderate, and 1 (3%) low structural differentiation. In 10 adenomas (31%), no mitosis was observed. The average was 2.4 mitoses/100 HPF; the highest count was 7.1 mitoses/100 HPF. Eleven adenomas (33.3%) were PCNA-negative; in 20 adenomas (60.6%), between 0.05 and 3.9, and in 2 adenomas (6.0%), between 10.5 and 16.4 PCNA-positive nuclei were observed. Only a recurrent null-cell adenoma (9%) was Ki-67-negative. Three adenomas (9.1%) were EGF-negative, 28 (84.8%) showed up to 10% positive cells, and 2 (6.1 %) showed between 10 and 30% positive cells; 19 adenomas (68%) were cathepsin D-negative, including all endocrine-inactive adenomas. Half the adenomas had an euploid DMA stem line. Endocrine-inactive adenomas displayed a higher rate of euploid DNA stem lines than endocrine-active adenomas. The S-phase fraction varied between 2.97 and 28%, with a mean value of 14.4%. Half the adenomas showed an S-phase fraction of 11.65% or lower.