Telehealth delivery of group-format cognitive rehabilitation to older veterans with TBI: a mixed-methods pilot study

Traumatic brain injury (TBI) is common among Veterans and may interact with aging, increasing risk for negative cognitive, emotional, and functional outcomes. However, no accessible (i.e., in-home) group interventions for TBI targeted to older adults exist. Goal Oriented Attentional Self-Regulation (GOALS) is a manualized, group cognitive rehabilitation training that improves executive function and emotional regulation among Veterans with TBI and healthy older adults. Our objectives were to adapt GOALS for delivery to older Veterans via in-home video telehealth (IVT) and evaluate feasibility and participant-rated acceptability of the telehealth GOALS intervention (TeleGOALS). Six Veterans 69+, with multiple TBIs completed the 10-session intervention in groups of 2. One participant withdrew, and another completed the remaining sessions alone (total n enrolled = 8). Required adaptations were noted; questionnaire responses were quantified; and feedback was analyzed and coded to identify themes. Quantitative and qualitative methods were used to examine feasibility (i.e., recruitment and retention) and participant-rated acceptability. Minimal adaptations were required for IVT delivery. Key themes emerged: (a) the importance of telehealth logistics, (b) facilitators' roles in prioritizing interpersonal connection, and (c) telehealth's capability to create opportunities for community reintegration. Thematic saturation (the point at which feedback from respondents is consistent and no further adaptations are required) was achieved. Participants stated they would likely recommend TeleGOALS to other Veterans. Although further study with a larger, more diverse sample is required, the adapted TeleGOALS intervention appears highly feasible and acceptable for older Veterans with TBI able and willing to participate in a group-format IVT intervention.

Telehealth Delivery of Group Format Cognitive Rehabilitation to Older Veterans With TBI

Traumatic brain injury (TBI) is common among older adults, with significant public health costs, and advanced age is a risk factor for poor outcomes after TBI. Older Veterans with TBI-related cognitive and emotional dysfunction without dementia may benefit from cognitive rehabilitation, particularly executive function training, and technology may promote optimal functioning for these patients by increasing access to such treatments. Dr. Kornblith will present pilot data on one such promising group intervention, Goal-Oriented Attentional Self-Regulation (GOALS), administered via in-home video telehealth. Themes gleaned from qualitative feedback collected throughout the intervention and post-treatment feedback questionnaires include the importance of communication and a smooth process with clear instructions for joining study sessions. Preliminary data suggest that only minor adaptions to the existing GOALS protocol are required for telehealth delivery and that delivering group-based executive function training to older TBI-exposed older Veterans with cognitive complaints via telehealth is feasible and acceptable.

Symptoms of depression in a large healthy population cohort are related to subjective memory complaints and memory performance in negative contexts

BACKGROUND

Decades of research have investigated the impact of clinical depression on memory, which has revealed biases and in some cases impairments. However, little is understood about the effects of subclinical symptoms of depression on memory performance in the general population.

METHODS

Here we report the effects of symptoms of depression on memory problems in a large population-derived cohort (N = 2544), 87% of whom reported at least one symptom of depression. Specifically, we investigate the impact of depressive symptoms on subjective memory complaints, objective memory performance on a standard neuropsychological task and, in a subsample (n = 288), objective memory in affective contexts.

RESULTS

There was a dissociation between subjective and objective memory performance, with depressive symptoms showing a robust relationship with self-reports of memory complaints, even after adjusting for age, sex, general cognitive ability and symptoms of anxiety, but not with performance on the standardised measure of verbal memory. Contrary to our expectations, hippocampal volume (assessed in a subsample, n = 592) did not account for significant variance in subjective memory, objective memory or depressive symptoms. Nonetheless, depressive symptoms were related to poorer memory for pictures presented in negative contexts, even after adjusting for memory for pictures in neutral contexts.

CONCLUSIONS

Thus the symptoms of depression, associated with subjective memory complaints, appear better assessed by memory performance in affective contexts, rather than standardised memory measures. We discuss the implications of these findings for understanding the impact of depressive symptoms on memory functioning in the general population.

Multiphonon relaxation in rare-earth doped fluorozirconate-based glasses containing BaCl2 nanocrystals

Nd3+-doped fluorozirconate-based glasses which contain hexagonal BaCl2 nanocrystals are analyzed for their photoluminescence and multiphonon relaxation (MPR) properties. The MPR rates of various Nd3+ levels are obtained from time-resolved spectroscopy using selective laser pulse excitation. The nonradiative decay rates are estimated from the difference between measured and calculated radiative decay rates as well as from the analysis of luminescence rise times. The MPR rates display an exponential dependence on the energy gap. Temperature-dependent studies of the decay indicate that phonons of the BaCl2 nanocrystals are involved in the MPR processes leading to extremely low MPR rates which are orders of magnitude lower than in conventional oxide and halide glasses. Photoluminescence emissions,which are usually quenched by MPR, and enhanced radiative quantum efficiencies are found.

Turning unreactive copper acetylides into remarkably powerful and mild alkyne transfer reagents by oxidative umpolung

Upon oxidation, copper acetylides formally behave as highly electrophilic species that could be trapped by a wide range of nucleophiles.

Crystallization studies on rare-earth co-doped fluorozirconate-based glasses

This work focuses on the structural changes of barium chloride (BaCl₂) nanoparticles in fluorochlorozirconate-based glass ceramics when doped with two different luminescent activators, in this case rare-earth (RE) ions, and thermally processed using a differential scanning calorimeter. In a first step, only europium in its divalent and trivalent oxidation states, Eu²⁺ and Eu³⁺, is investigated, which shows no significant influence on the crystallization of hexagonal phase BaCl₂. However, higher amounts of Eu²⁺ increase the activation energy of the phase transition to an orthorhombic crystal structure. In a second step, nucleation and nanocrystal growth are influenced by changing the structural environment of the glasses by co-doping with Eu²⁺ and trivalent Gd³⁺, Nd³⁺, Yb³⁺, or Tb³⁺, due to the different atomic radii and electro-negativity of the co-dopants.

Mössbauer spectroscopy of europium-doped fluorochlorozirconate glasses and glass ceramics: optimization of storage phosphors in computed radiography

Eu(2+)-doped fluorochlorozirconate (FCZ) glasses and glass ceramics, which are being developed for medical and photovoltaic applications, have been analysed by Mössbauer spectroscopy. The oxidation state and chemical environment of the europium ions, which are important for the performance of these materials, were investigated. Routes for maximizing the divalent europium content were also investigated. By using EuCl2 instead of EuF2 in the starting material a fraction of about 90% of the europium was maintained in the Eu(2+) state as opposed to about 70% when using EuF2. The glass ceramics produced by subsequent thermal processing contain BaCl2 nanocrystals in which Eu(2+) is incorporated, as shown by the narrower linewidth in the Mössbauer spectrum. Debye temperatures of 147 K and 186 K for Eu(2+) and Eu(3+), respectively, were determined from temperature dependent Mössbauer measurements. The f-factors were used to obtain the Eu(2+)/Eu(3+) ratio from the area ratio of the corresponding absorption lines.

The oxidation state of europium in halide glasses

The luminescent properties of divalent europium ions can be exploited to produce storage phosphors for x-ray imaging applications. The relatively high cost and limited availability of divalent europium halides makes it desirable to synthesize them from the readily available trivalent salts. In this work, samples of pure EuCl(3) and fluoride glass melts doped with EuCl(3) were processed at 700-800 °C in an inert atmosphere furnace. The Eu oxidation state in the resulting materials was determined using fluorescence and Mössbauer spectroscopy. Heat treatment of pure EuCl(3) for 10 min at 710 °C resulted in a material comprising approximately equal amounts of Eu(2+) and Eu(3+). Glasses made using mixtures of EuCl(2) and EuCl(3) in the starting material contained both oxidation states. This paper describes the sample preparation and analysis and discusses the results in the context of chemical equilibria in the melts.

Structural properties of fluorozirconate-based glass ceramics doped with multivalent europium

The structure/property relationships of fluorochlorozirconate glass ceramics as a function of divalent and trivalent europium (Eu) co-doping and thermal processing have been investigated; the influence of doping ratio on the formation of barium chloride (BaCl(2)) nanocrystals therein was elucidated. X-ray absorption near-edge structure spectroscopy shows that the post-thermal annealing changes the Eu valence of the as-poured glass slightly, but during the melting process Eu(3+) is more strongly reduced to Eu(2+), in particular, when doped as a chloride instead of fluoride compound. The Eu(2+)-to-Eu(3+) doping ratio also plays a significant role in chemical equilibrium in the melt. X-ray diffraction measurements indicate that a higher Eu(2+) fraction leads to a BaCl(2) phase transition from hexagonal to orthorhombic structure at a lower temperature.

The metastatic potential of canine mammary tumours can be assessed by mRNA expression analysis of connective tissue modulators

Metastases are the crucial factor for the prognosis of canine mammary tumours (CMTs). In women, the peptide hormone relaxin is linked with metastatic breast cancer. Therefore, the impact of relaxin and its receptors on matrix metalloproteinase (MMP) expression, metastatic disease and survival was analysed using qRT-PCR and immunohistochemistry of CMT samples from 59 bitches. The expression of relaxin and its receptor RXFP1 (relaxin family peptide receptor 1) was discovered on gene and protein levels. Intratumoural relaxin mRNA expression and relaxin plasma levels had no prognostic value. High mRNA levels RXFP1 were an independent marker of metastatic potential, with a more than 15-fold risk increase, and a predictor for shorter survival. Also, MMP-2 expression was associated with early death because of CMT. The mRNA expressions of relaxin, RXFP1 and MMP-2 were positively correlated indicating a common pathogenetic linkage. Thus, RXFP1 is proposed as a new early marker of metastatic potential in CMT and a possible therapeutic target.

Crystallization behavior of rare-earth doped fluorochlorozirconate glasses

A series of fluorochlorozirconate (FCZ) glasses, each doped with a different rare-earth, was prepared and examined to determine thermal stability and activation energy, E_a , of the dopant dependent BaCl₂ crystallization. Non-isothermal differential scanning calorimetry (DSC) measurements were done to investigate the endothermic and exothermic reactions upon heat treatment of the glass samples. In comparison to the rare-earth free FCZ glass, significant changes in the Hruby constant, H_r , and E_a were found due to the addition of a rare-earth and also between the individual dopants.

Differential scanning calorimetry investigations on Eu-doped fluorozirconate-based glass ceramics

The properties of Eu-doped fluorochlorozirconate (FCZ) glass ceramics upon thermal processing and the influence of Eu-doping on the formation of BaCl(2) nanocrystals therein have been investigated. Differential scanning calorimetry indicates that higher Eu-doping shifts the crystallization peak of the nanocrystals in the glass to lower temperatures, while the glass transition temperature remains constant. The activation energy and the thermal stability parameters for the BaCl(2) crystallization are determined.

Saturation effects in the upconversion efficiency of Er-doped fluorozirconate glasses

A series of transparent erbium-doped fluorozirconate glasses has been investigated using differential scanning calorimetry, optical absorption, and upconverted fluorescence spectroscopy. The upconverted fluorescence intensity versus excitation power dependence shows that the ratio of the two-photon upconverted emission in the near infrared at 980 nm to the three-photon upconverted emissions in the visible at 530, 550, and 660 nm decreases with increasing excitation power. The integrated upconverted fluorescence intensity to excitation power ratio shows 'saturation' with increasing excitation power, while the point of saturation shifts to lower excitation power with increasing erbium concentration. The experimental lifetime of the upconverted fluorescence decreases with increasing erbium concentration.

Scanning translucent glass-ceramic x-ray storage phosphors

A simple benchtop apparatus has been built, to measure the x-ray imaging properties of fluorozirconate-based glass-ceramic x-ray storage phosphor materials. The MTF degradation due to stimulating light spreading in the plate is lower in comparison to optically turbid screens resulting in higher image MTF. In addition, the degree of transparency, or the amount of light scattering at the wavelength of the stimulating (laser) light is adjustable by means of the glass preparation process. The amount of stimulating exposure required for plate readout is generally higher than in previous systems, but well within the range of commercially available laser systems, for practical readout times. The effects of flare or unwanted readout due to back-reflection from the imaging plate is also less than in previous systems.A novel telecentric scanning system has been developed that is able to rapidly read out the latent image stored in the translucent imaging plates. This system features a reflective primary scan mirror to achieve telecentricity, optical correction for scan line bow, and the design should enable the construction of a relatively inexpensive scanner system for the translucent x-ray storage plates.

Eu oxidation state in fluorozirconate-based glass ceramics

The influence of InF(3) doping and remelting on Eu-doped fluorozirconate-based glass ceramics was investigated using near-edge x-ray absorption and optical spectroscopy. It was found that the addition of InF(3) to the melt decreases the Eu(2+)Eu(3+) mole ratio, while remelting leads to a significant change in the Eu(2+)Eu(3+) ratio in favor of Eu(2+). Photoluminescence spectroscopy shows that additional annealing steps lead to the formation of BaCl(2) nanoparticles in the glass. In as-made glass ceramics containing InF(3), a phase transition of the nanoparticles from hexagonal to orthorhombic structure is observed. This phase transition is not observed in the remelted glasses studied here.

Crystallization in heat-treated fluorochlorozirconate glasses

Crystallization phenomena of fluorochlorozirconate glasses were investigated by means of differential scanning calorimetry and inelastic neutron scattering. The precipitation of barium chloride nanoparticles from the glass matrix upon heat treatment was found to be suppressed when re-melting the glass with a reducing agent but not if the agent was present in the initial synthesis. Addition of small amounts of oxide to the predominantly fluoride melt was found to maintain the presence of nanoparticles but not to induce the predicted phase transition of the barium chloride nanoparticles from hexagonal to orthorhombic structure. Inelastic neutron scattering performed on an 'as-made' glass and a heat-treated glass showed an increase in 'hardness', consistent with a more ordered structure.

Sedation with propofol for interventional endoscopy by trained nurses in high-risk octogenarians: a prospective, randomized, controlled study

BACKGROUND AND STUDY AIMS

Sedation with the short-acting anesthetic agent propofol has shown several advantages, particularly in interventional endoscopy. So far, however, there are no valid data on the safety of nurse-administered propofol sedation (NAPS) during interventional endoscopy in elderly high-risk patients.

PATIENTS AND METHODS

A total of 150 patients aged > 80 years with high comorbidity were randomized to receive midazolam plus meperidine (n = 75) or propofol alone (n = 76) for sedation during endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), or double-balloon endoscopy (DBE). Sedation was supervised by a trained nurse and a trained physician both of whom were not involved in the endoscopic procedure. Vital signs were continuously monitored as well as patient cooperation and tolerance. Mortality and morbidity at 30 days was analyzed.

RESULTS

The overall cardiopulmonary complication rate was 16 % in the midazolam group and 23.7 % in the propofol group ( P > 0.05). The mean decline in oxygen saturation (initial vs. lowest O (2) saturation) and the mean decline of blood pressure (initial vs. lowest blood pressure) were significantly greater with propofol (7 % +/- 3 % vs. 4 % +/- 2 % [ P < 0.05] and 10 % +/- 2 % vs. 8 % +/- 2 %, respectively [ P < 0.05]). No procedure had to be interrupted due to serious adverse events. Patient cooperation was statistically significantly better in the propofol group (7 +/- 2 vs. 5 +/- 2 points). Patients sedated with propofol showed a significantly lower oxygen saturation rate during recovery time (8 % vs. 28 %; P < or = 0.01).

CONCLUSION

NAPS during interventional endoscopy is as safe as midazolam/pethidine sedation even in high-risk patients aged > 80 years.

Upconverted fluorescence in Nd(3+)-doped barium chloride single crystals

Upon excitation at 796 nm, Nd(3+)-doped BaCl(2) single crystals show several upconverted fluorescence bands in the visible spectral range, with the most intense bands at 530, 590 and 660 nm, in addition to the typical fluorescence bands in the infrared spectral range. The power dependence of the infrared fluorescence and the two-photon upconversion fluorescence intensities as well as the corresponding radiative lifetimes have been investigated. No 'saturation' of the fluorescence intensities was observed upon increasing the excitation power.

Paramagnetic hyperfine splitting in the Eu Mössbauer spectra of CaF(2):Eu

(151)Eu Mössbauer spectra in zero magnetic field of highly dilute (0.1 mol%) Eu(2+) ions in CaF(2) showed an almost temperature-independent asymmetrically split pattern, arising from the paramagnetic hyperfine interaction AS. I in a cubic crystal field with slow electron spin relaxation; in a small external magnetic field B of 0.2 T such that gμ(B)B>A an almost symmetrical pattern was observed. Both the spectra with and without external field are well described using the spin Hamiltonian and previous electron paramagnetic resonance data. A more concentrated (2 mol% Eu(2+)) sample exhibited a strongly broadened symmetrical resonance line due to an increased Eu-Eu spin relaxation rate; in an external magnetic field of 0.2 T the Mössbauer spectra exhibited further broadening and additional magnetic structures due to the reduced relaxation rate. When a large field of 6 T was applied such that gμ(B)B is much larger than the crystal field splitting, a fully resolved hyperfine pattern was observed at 2.5 K, with an effective field at the Eu nuclei of -33.7 T; at higher temperatures superimposed patterns originating from excited electronic states were observed in the spectra. The present results on the highly dilute CaF(2) : 0.1%Eu(2+) sample deliver a straightforward explanation for previous observations of a seemingly large dependence of the Eu(2+) isomer shift on europium concentration.

Centrosome aberrations as a possible mechanism for chromosomal instability in non-Hodgkin's lymphoma

Recently, centrosome aberrations have been described as a possible cause of aneuploidy in many solid tumors. To investigate whether centrosome aberrations occur in non-Hodgkin's lymphoma (NHL) and correlate with histologic subtype, karyotype, and other biological disease features, we examined 24 follicular lymphomas (FL), 18 diffuse large-B-cell lymphomas (DLCL), 33 mantle cell lymphomas (MCL), and 17 extranodal marginal zone B-cell lymphomas (MZBCL), using antibodies to centrosomal proteins. All 92 NHL displayed numerical and structural centrosome aberrations as compared to nonmalignant lymphoid tissue. Centrosome abnormalities were detectable in 32.3% of the cells in NHL, but in only 5.5% of lymphoid cells from 30 control individuals (P<0.0001). Indolent FL and MZBCL contained only 25.8 and 28.8% cells with abnormal centrosomes. In contrast, aggressive DLCL and MCL harbored centrosome aberrations in 41.8 and 35.0% of the cells, respectively (P<0.0001). Centrosomal aberrations correlated to lymphoma grade, mitotic, and proliferation indices, but not to the p53 labeling index. Importantly, diploid MCL contained 31.2% cells with abnormal centrosomes, while tetraploid samples harbored centrosome aberrations in 55.6% of the cells (P<0.0001). These results indicate that centrosome defects are common in NHL and suggest that they may contribute to the acquisition of chromosomal instability typically seen in NHL.

Stimulation of leukotriene synthesis in intact polymorphonuclear cells by the 5-lipoxygenase inhibitor 3-oxo-tirucallic acid

Commercially available extracts from Boswellia serrata resin used as anti-inflammatory drugs or phytonutrients show paradoxical concentration-dependent potentiating and inhibitory actions on 5-lipoxygenase (5-LO) product synthesis in stimulated PMNs. In our attempt to characterize the stimulating constituents, we identified the tetracyclic triterpene 3-oxo-tirucallic acid (3-oxo-TA), which, in the range from 2.5 to 15 microM, enhanced 5-LO product formation in ionophore-challenged polymorphonuclear cells (PMNs) (e.g., from 1981 +/- 177 to 3042 +/- 208 pmol at 10 microM 3-oxo-TA), and initiated Ca(2+) mobilization, MEK-1/2 phosphorylation, 5-LO translocation, and 5-LO product formation in resting cells (534 +/- 394 pmol/5 x 10(6) PMNs). In cell-free 5-LO assays, 3-oxo-TA acted only inhibitory (IC(50) value of about 3 microM), demonstrating the pivotal role of intact cell structure for its activating property. In 3-oxo-TA-challenged PMNs, the mitogen-activated protein kinase kinase (MEK)-1/2 inhibitor PD098059 abolished 5-LO product formation, along with inhibition of MEK-1/2 phosphorylation and 5-LO translocation. The 3-acetoxy derivative of 3-oxo-TA acted like 3-oxo-TA in intact PMNs, whereas 3-hydroxy-TA barely stimulated MEK phosphorylation in resting cells and showed only inhibition on ionophore-induced 5-LO product synthesis. Steroid-type tetracycles neither induced 5-LO activation nor had enhancing or inhibitory effects. In summary, defined natural tetracyclic triterpenes, which act as inhibitors of the 5-LO in the cell-free assay, initiate 5-LO activation by a MEK-inhibitor sensitive mechanism and potentiate stimulated product synthesis in intact cells. Because TAs contribute significantly to the overall biological effects of B. serrata resin extracts, special precaution for standardization is recommended when using B. serrata preparations as drugs or dietary supplements.

Acetyl-11-keto-beta-boswellic acid, a constituent of a herbal medicine from Boswellia serrata resin, attenuates experimental ileitis

The gum resin extract from Boswellia serrata (H15), an herbal product, was recently shown to have positive therapeutic effects in inflammatory bowel disease (IBD). However, the mechanisms and constituents responsible for these effects are poorly understood. This study examined the effect of the Boswellia extract and its single constituent acetyl-11-keto-beta-boswellic acid (AKBA) on leukocyte-endothelial cell interactions in an experimental model of IBD. Ileitis was induced by two subcutaneous injections of indomethacin (7.5 mg/kg) in Sprague-Dawley rats 24 h apart. Rats also received oral treatment with the Boswellia extract (H15) or AKBA at two different doses (low and high) equivalent to recommendations in human disease over 2 days. Controls received only the carriers NaHCO3 (subcutaneously) and tylose (orally). Effects of treatment were assessed by intravital microscopy in ileal submucosal venules for changes in the number of rolling and adherent leukocytes and by macroscopic and histological scoring. Increased leukocyte-endothelial cell adhesive interactions and severe tissue injury accompanied indomethacin-induced ileitis. Treatment with the Boswellia extract or AKBA resulted in a dose-dependent decrease in rolling (up to 90%) and adherent (up to 98%) leukocytes. High-dose Boswellia extract as well as both low- and high-dose AKBA significantly attenuated tissue injury scores. Oral therapy with the Boswellia extract or AKBA significantly reduces macroscopic and microcirculatory inflammatory features normally associated with indomethacin administration, indicating that the anti-inflammatory actions of the Boswellia extract in IBD may be due in part to boswellic acids such as AKBA.

3-Acetoxy group of genuine AKBA (acetyl-11-keto-beta-boswellic acid) is alpha-configurated

The pentacyclic triterpenoid 3-acetyl-11-keto-beta-boswellic acid (AKBA) from the resin of Boswellia spec. is a potent inhibitor of 5-lipoxygenase (5-LO). We noticed discrepancies in the nomenclature and stereochemistry of the 3-acetoxy group of boswellic acids. Isolation of AKBA under mild conditions and the data from the first X-ray crystallography study evidence the 3 alpha-orientation of AKBA's acetoxy function.

A facile stereocontrolled synthesis of anti-alpha-(trifluoromethyl)-beta-amino alcohols

A short stereocontrolled preparation of anti-alpha-(trifluoromethyl)-beta-amino alcohols is described, involving an initial CF(3) transfer to cinnamaldehyde and a one-step, three-component condensation of 3,3,3-trifluorolactic aldehyde, an alkenyl (aryl) boronic acid, and an amine. Applying this methodology to chiral 3,3,3-trifluorolactic aldehyde allowed us to generate an amino alcohol enantioselectively in 92% ee.

Workup-dependent formation of 5-lipoxygenase inhibitory boswellic acid analogues

Pentacyclic triterpenes from the 11-keto-boswellic acid series were identified as the active principal ingredients of Boswellia resin, inhibiting the key enzyme of leukotriene biosynthesis, 5-lipoxygenase (5-LO). Of the genuine boswellic acids hitherto characterized, 3-O-acetyl-11-keto-beta-boswellic acid, AKBA (1), proved to be the most potent inhibitor of 5-LO. In the course of purification of further boswellic acid derivatives from Boswellia resin, we observed the degradation of the natural compound 3-O-acetyl-11-hydroxy-beta-boswellic acid (2) to the thermodynamically more stable product 3-O-acetyl-9, 11-dehydro-beta-boswellic acid (4). The metastable intermediate of this conversion, under moderate conditions of workup in methanolic solutions, was identified as 3-O-acetyl-11-methoxy-beta-boswellic acid (3). The novel artifactual boswellic acid derivatives inhibited 5-LO product formation in intact cells with different characteristics: 4 almost totally abolished 5-LO activity, with an IC(50) of 0.75 microM, whereas 3 and 9,11-dehydro-beta-boswellic acid (5), the deacetylated analogue of 4, were incomplete inhibitors. The data suggest that the conditions chosen for the workup of Boswellia extracts could significantly influence the potency of their biological actions and their potential therapeutic effectiveness.

Concentration-dependent potentiating and inhibitory effects of Boswellia extracts on 5-lipoxygenase product formation in stimulated PMNL

Preparations from the gum of Boswellia spec. have been used in the traditional medicine for the treatment of inflammatory diseases. Extracts from B. serrata gum were shown to inhibit leukotriene biosynthesis by impairing the 5-lipoxygenase (5-LO) activity. In order to identify the minimal effective concentrations of extracts in vitro we studied the effects of ethanolic extracts from commercially available resins from two regions (B. serrata gum from India and Olibanum in granis from Arabia) on the 5-LO product formation from endogenous substrate in calcium and ionophore stimulated neutrophils in a defined concentration range. Both extracts inhibited 5-LO product formation in vitro in concentrations greater than 10 to 15 micrograms/ml as reported previously for an ethanolic B. serrata extract. In contrast, lower concentrations of extracts (1 to 10 micrograms/ml) even potentiated 5-LO product formation, especially the biosynthesis of 5(S)-HETE. The in vitro data underline the major importance of drug standardization when Boswellia resin containing preparations are used for the treatment of diseases.

Characterization of an acetyl-11-keto-beta-boswellic acid and arachidonate-binding regulatory site of 5-lipoxygenase using photoaffinity labeling

AKBA (acetyl-11-keto-beta-boswellic acid), a natural pentacyclic triterpene, is an orally active leukotriene-synthesis inhibitor, which acts by a 5-lipoxygenase-directed, non-redox, non-competitive mechanism. It is the only leukotriene-synthesis inhibitor so far identified that inhibits 5-lipoxygenase activity as an allosteric regulator and not by a reducing or competitive mechanism. To characterize AKBA's effector site we prepared azido125I-KBA (4-azido-5-125iodo-salicyloyl-beta-alanyl-11-keto-beta-bo swellic acid) as a photoaffinity analogue, which inhibited 5-lipoxygenase activity as efficiently as the lead compound and specifically labeled human 5-lipoxygenase protein. The labeling of 5-lipoxygenase by azido-125I-KBA strictly depended on the presence of calcium ([Ca2+]free > 500 nM) and was abolished by heat denaturation or by prior incubation with a series of pentacyclic triterpenes (e.g., amyrin, beta-boswellic acid, AKBA and 18a-glycyrrhetinic acid). In contrast, 18-beta-glycyrrhetinic acid and competitive 5-lipoxygenase inhibitors (e.g., ZM-230,487 and L-739,010) did not affect labeling. Arachidonic acid, in enzyme-activity-inhibiting concentrations, reduced photoincorporation (IC50 about 10 microM), whereas a variety of other long-chain fatty acids and their derivatives (e.g., arachidinic acid, arachidonic acid methyl ester, lipoxins A4 and B4) had no effect. The inhibitory arachidonate action on labeling was not affected by blocking the substrate-binding site by micromolar amounts of the competitive inhibitor L-739,010. Therefore, we suggest that AKBA binds in presence of calcium to a site which is distinct from the substrate binding site of 5-lipoxygenase. The AKBA-binding site is likely to be identical with a regulatory, second arachidonate binding site of the enzyme.