Novel dual inhibitors of AChE and MAO derived from hydroxy aminoindan and phenethylamine as potential treatment for Alzheimer's disease

Carbamate derivatives of N-propargylaminoindans (Series I) and N-propargylphenethylamines (Series II) were synthesized via multistep procedures from the corresponding hydroxy precursors. The respective rasagiline- and selegiline-related series were designed to combine inhibitory activities of both acetylcholine esterase (AChE) and monoamine oxidase (MAO) by virtue of their carbamoyl and propargylamine pharmacophores. Each compound was tested for these activities in vitro in order to find molecules with similar potencies against each enzyme. Compounds with such dual AChE and MAO inhibitory activities are expected to have potential for the treatment of Alzheimer's disease. The observed SAR also offers insight into the requirements of the active sites on these enzymes. A carbamate moiety was found to be essential for AChE inhibition, which was absent in the corresponding hydroxy precursors. The propargyl group caused 2-70-fold decrease in AChE inhibitory activity (depending on the position of the carbamoyl group) of Series I, but had little or no effect in Series II. Thus, the 6- and 7-carbamyloxyphenyls in Series I were either equipotent to, or slightly (2- to 5-fold) less active as AChE inhibitors than, the corresponding compounds in Series II, while the 4-carbamyloxyphenyls were more potent. The presence of the carbamate moiety in 6- and 7-carbamyloxyphenyls of Series I, considerably decreased MAO-A and -B inhibitory activity, compared to that of the parent hydroxy analogues, while the opposite was true for Series II. Thus, the 6- and 7-carbamyloxyphenyls in Series I were 2-3 orders of magnitude weaker MAO inhibitors while the 4- carbamyloxyphenyls were equipotent with the corresponding compounds in Series II. In both series, N-methylation of the propargylamine enhanced the MAO (A and B equally) inhibitory activities and decreased the AChE inhibitory activity. Two candidates belonging to the indan and tetralin ring systems (24c, 27b) and one phenethylamine (53d) were identified as possible leads for further development based on the following criteria: (a) comparable AChE and MAO-B inhibitory activities, (b) good to moderate AChE inhibitory activity, and (c) lack of strong MAO-A selectivity. However, it is likely that these compounds will be metabolized to the corresponding phenols, with inhibitory activities against AChE and/or MAO-A or -B, different from those of the parent carbamates. Thus, the apparent enzyme inhibition will be a result of the combined inhibition of all of these individual metabolites. The results of our ongoing in vivo screening programs will be published elsewhere.     

Peripheral nerve ischemia: apolipoprotein E deficiency results in impaired functional recovery and reduction of associated intraneural angiogenic response

Apolipoprotein E-knockout (apoE KO) mice have peripheral sensory nerve defects, reduced and delayed response to noxious thermal stimuli, abnormal morphology of unmyelinated fibers, and impaired blood-nerve and blood-brain barriers. In this study, we show that, compared to wild-type mice, peripheral nerves of apoE KO mice have impaired ability to respond to ischemia, as demonstrated by measurement of motor and sensory conduction velocity. In addition, mice lacking apoE exhibit a deficit of reinnervation of ischemic epidermis, evaluated by immunofluorescent staining for the pan-neuronal marker PGP 9.5. Also regional nerve blood flow, measured by laser Doppler, and intraneural angiogenesis after ischemia are significantly compromised in apoE-deficient mice. Finally, upregulation of the angiogenic cytokine vascular endothelial growth factor (VEGF), which physiologically occurs after ischemia in the peripheral nerve of wild-type mice, is severely impaired in apoE KO mice. Among the several neural defects that have already been described in mice lacking apoE, this is the first demonstration that functional recovery to ischemia is impaired in the peripheral nerves of these animals. This deficit is mirrored by the inability of upregulating VEGF and mounting an appropriate intraneural angiogenic response following injury. These findings provide new evidence of possible interdependent relationships between VEGF, angiogenesis, and nerve function and regeneration and may provide new important information on the role of apoE in the nervous system.     

Multiple shifts in the representation of a motor sequence during the acquisition of skilled performance

When do learning-related changes in performance occur? Here we show that the knowledge of a sequence of movements evolves through several distinctive phases that depend on two critical factors: the amount of practice as well as the passage of time. Our results show the following. (i) Within a given session, large performance gains constituted a signature for motor novelty. Such gains occurred only for newly introduced conditions irrespective of the absolute level of performance. (ii) A single training session resulted in both immediate but also time-dependent, latent learning hours after the termination of practice. Time in sleep determined the time of expression of these delayed gains. Moreover, the delayed gains were sequence-specific, indicating a qualitative change in the representation of the task within 24 h posttraining. (iii) Prolonged training resulted in additional between-session gains that, unlike the effects of a single training session, were confined to the trained hand. Thus, the effects of multisession training were qualitatively different than the immediate and time-dependent effects of a single session. Altogether, our results indicate multiple time-dependent shifts in the representation of motor experience during the acquisition of skilled performance.     

Evolution of genomic diversity and sex at extreme environments: fungal life under hypersaline Dead Sea stress

We have found that genomic diversity is generally positively correlated with abiotic and biotic stress levels (1-3). However, beyond a high-threshold level of stress, the diversity declines to a few adapted genotypes. The Dead Sea is the harshest planetary hypersaline environment (340 g.liter-1 total dissolved salts, approximately 10 times sea water). Hence, the Dead Sea is an excellent natural laboratory for testing the "rise and fall" pattern of genetic diversity with stress proposed in this article. Here, we examined genomic diversity of the ascomycete fungus Aspergillus versicolor from saline, nonsaline, and hypersaline Dead Sea environments. We screened the coding and noncoding genomes of A. versicolor isolates by using >600 AFLP (amplified fragment length polymorphism) markers (equal to loci). Genomic diversity was positively correlated with stress, culminating in the Dead Sea surface but dropped drastically in 50- to 280-m-deep seawater. The genomic diversity pattern paralleled the pattern of sexual reproduction of fungal species across the same southward gradient of increasing stress in Israel. This parallel may suggest that diversity and sex are intertwined intimately according to the rise and fall pattern and adaptively selected by natural selection in fungal genome evolution. Future large-scale verification in micromycetes will define further the trajectories of diversity and sex in the rise and fall pattern.     

The increased risk of skin cancer is persistent after discontinuation of psoralen+ultraviolet A: a cohort study

Psoralen+ultraviolet A-treated psoriasis patients are at increased risk for nonmelanoma skin cancer. To assess the persistence of cancer risk among patients who have discontinued psoralen+ultraviolet A and the risk of a first tumor with the passage of time, we prospectively studied the incidence in a cohort of 1,380 psoriasis patients treated with psoralen+ultraviolet A. We observed a total of 27,840 person-years of which 59.4% were considered years without psoralen+ultraviolet. No significant decrease in risk was noted during the first 15 years after psoralen+ultraviolet A was discontinued. Subsequently, the risk of squamous cell carcinoma was reduced (incidence rate ratio=0.79; 95%CI=0.62, 1.01 on treatment vs >15 years off). After 25 years, about 7% of patients with < or =200 psoralen+ultraviolet A treatments and more than half of the patients with > or =400 treatments develop at least one squamous cell carcinoma. After 25 years, almost one third of the patients exposed to > or =200 treatments developed at least one basal cell carcinoma. In conclusion, substantial exposure to psoralen+ultraviolet A dramatically increases the risk of nonmelanoma skin cancer and prior exposure to psoralen+ultraviolet A remains an important issue in the management of patients because the cancer risk associated with psoralen+ultraviolet A is persistent.     

Radioiodinated styrylbenzene derivatives as potential SPECT imaging agents for amyloid plaque detection in Alzheimer's disease

Development of probes for β-amyloid (Aβ) plaques, a critical factor associated with Alzheimer’s disease (AD), provides important tools for studying their role in AD. Previously, we reported [¹²⁵I]IMSB and [¹²⁵I]ISB as excellent probes for Aβ plaque labeling. Despite their exquisite in vitro binding characteristics, low brain uptakes (likely due to two ionizable carboxylic acid groups) limited their potential as in vivo imaging agents. To improve brain penetration, we have successfully prepared a neutral radioiodinated probe [¹²⁵I]3. The improved probe displayed good binding affinity for Aβ aggregates (K_i=2.0 ± 0.2 using Aβ40 aggregates). In addition, the brominated counterpart displayed fluorescent-staining properties of Aβ plaques in postmortem AD brain sections similar to BSB, a fluoroscent probe reported previously. [¹²⁵I]3 gave excellent plaque labeling by film autoradiography of AD brain sections. Unlike [¹²⁵I]IMSB (which preferentially detects Aβ40 plaques), the improved radioioinated probe, [¹²⁵I]3, can readily detect plaques containing aggregates of both Aβ40 and Aβ42. The initial brain uptake of [¹²⁵I]3 in normal mice at 2 min p.i. was moderate (0.18% ID) and displayed a very slow washout from the brain (0.11 %.ID at 4 h p.i). Taken together, these data suggest that [¹²⁵I]3 is useful for in vitro plaque detection, it may not be suitable for in vivo monitoring of Aβ progression and deposition.     

Intranasal immunization with synthetic recombinant vaccine containing multiple epitopes of influenza virus

The oligonucleotides coding for three epitopes (HA91-108, NP55-69, and NP 147-158) of influenza virus, stimulating B-cells, T-helper cells and cytotoxic T lymphocytes (CTLs), respectively, were previously employed for expressing each epitope in flagella that induced specific humoral and cellular immune responses. We have constructed new plasmids expressing all three epitopes as a single recombinant product. Two versions have been prepared-a longer one (Fla-HNN) comprising hybrid flagella containing the epitopes, and a shorter version (HNN). Immunization of BALB/c mice with either constructs induced significant humoral immune response against influenza virus. The mice immunized with these peptides also induced higher T-helper activity, including Th1 type-cytokine (IL-2 and IFN-gamma) release. In addition, the mice immunized with HNN peptide demonstrated significant protection against sublethal viral challenge. Furthermore, this vaccine fully protected mice from lethal challenge and enhanced their recovery process. Our results indicate that a single construct expressing multiple epitopes, which stimulate different arms of the immune system, might be an appropriate candidate when the synthetic recombinant vaccine approach is considered.     

Mammalian heparanase: involvement in cancer metastasis,angiogenesis and normal development

Cleavage of heparan sulphate proteoglycans (HSPGs) affects the integrity and functional state of tissues and thereby fundamental normal and pathological phenomena involving cell migration and response to changes in the extracellular microenvironment. Heparanase, degrading heparan sulphate (HS) at specific intrachain sites, is synthesized as a latent approximately 65 kDa protein that is processed at the N-terminus into a highly active approximately 50 kDa form. The heparanase enzyme is preferentially expressed in human tumours and its overexpression in low-metastatic tumour cells confers a highly invasive phenotype in experimental animals. Heparanase also releases angiogenic factors and accessory fragments of HS from the tumour microenvironment and induces an angiogenic response in vivo. Heparanase may thus facilitate tumour cell invasion, vascularization and survival in a given microenvironment, all critical events in cancer progression. These observations, the anticancerous effect of heparanase-inhibiting molecules, and the unexpected identification of a single predominant functional heparanase suggest that the enzyme is a promising target for drug development.     

Patient, therapist, and supervisor in a psychiatric institution: inner freedom and inner structure

The authors discuss issues concerning the psychotherapeutic process in a psychiatric institution. They develop the concept of the institution as an internalized object in addition to its being an objective object. As such, it has an effect on the inner freedom and the internal structure of the patient, the therapist, and the supervisor. It is claimed that it is crucial for the development of an identity as a psychotherapist that the supervisor be aware of the institution as an inner and real object. The authors raise questions about what kind of "space" is possible in a psychiatric institution and what influence that may have on the therapeutic process. The impact on the therapist's professional identity is discussed. They point to the process of becoming a therapist via supervision and examine some relevant dilemmas. The authors conclude by discussing the duality of inner freedom and internal structure, and their specific manifestations within an institution.     

Mechanisms of gonadotropin desensitization

The gonadotropic hormones, FSH and LH exert a major effect on ovarian and testicular function through interaction with specific seven-transmembrane domain glycoprotein receptors. Desensitization to the hormones, which can occur both in vivo and in vitro, is essential for prevention of overstimulation of the gonadal cells. The long-term process of desensitization to the gonadotropic hormones is probably mediated, in part, by extensive clustering and internalization of the hormone-receptor complex. Short-term desensitization may occur as a result of phosphorylation of serine or threonine residues on the receptor molecules, although a specific receptor kinase has not yet been identified. Recently, we have discovered a novel mechanism of gonadotropin desensitization, which is exerted by down-regulation of StAR expression and steroidogenesis mediated by MAPK activation as a result of hormone-receptor interaction, cAMP accumulation and PKA activation. Thus, PKA not only mediates gonadotropin-induced steroidogenesis, it also activates the down-regulation mechanism that can silence steroidogenesis under certain conditions. Moreover, our findings raise the possibility that activation or inhibition of ERK by other pathways could be an important mechanism for diminution or amplification of gonadotropin-stimulated steroidogenesis. This could contribute to functional luteolysis, a process in which luteinized granulosa cells show reduced sensitivity to LH despite maintenance of LH receptors, or to up-regulation of the steroidogenic machinery during luteinization of granulosa cells.