Pharmacokinetics and pharmacodynamics of a pasireotide subcutaneous depot (CAM4071) and comparison with immediate and long-acting release pasireotide.

PURPOSE: To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of subcutaneous depot CAM4071, a novel, ready-to-use pasireotide formulation. METHODS: This was a phase 1, randomised, open-label study in healthy volunteers. After a single 600 µg dose of pasireotide immediate release (IR), participants were randomised to one of eight groups to receive either a CAM4071 upper thigh (5, 10, 20, 40 or 80 mg) or buttock (20 mg) injection or multiple pasireotide IR 900 µg upper thigh injections twice daily or a single pasireotide long-acting release (LAR) 60 mg intramuscular buttock injection. RESULTS: Ninety-four participants were randomised. For all CAM4071 doses, initial pasireotide release was relatively rapid compared to pasireotide LAR and sustained over the 2-month observation period, with a slow decay in plasma concentrations. CAM4071 maximum plasma concentrations increased slightly greater than dose proportionally; area under the curve extrapolated to infinity increased approximately dose proportionally. Relative bioavailability of pasireotide for different doses of CAM4071 versus pasireotide IR 600 µg ranged from 0.752 (90% confidence interval [CI]: 0.58, 0.98) to 1.68 (1.32, 2.14), and versus pasireotide LAR: 0.517 (0.37, 0.72) to 1.15 (0.84, 1.58). CAM4071 doses >5 mg exhibited rapid initial reductions of insulin-like growth factor 1 (IGF-1) compared to pasireotide LAR. Maximum IGF-1 inhibition was greatest for CAM4071 80 mg. CAM4071 injections ≤40 mg were well tolerated and comparable with currently available pasireotide formulations. CONCLUSION: CAM4071 provided long-acting release of pasireotide over at least one month, with high bioavailability and onset and duration of IGF-1 suppression similar to pasireotide LAR. TRIAL REGISTRATION: EudraCT: 2014-003783-20.

Characteristics, complications, and a comparison between early and late tracheostomy: A retrospective observational study on tracheostomy in patients with COVID-19-related acute respiratory distress syndrome.

Background and Aims: As the coronavirus disease 2019 (COVID-19) pandemic spread worldwide in 2020, the number of patients requiring intensive care and invasive mechanical ventilation (IMV) has increased rapidly. During the pandemic, early recommendations suggested that tracheostomy should be postponed, as the potential benefits were not certain to exceed the risk of viral transmission to healthcare workers. The aim of this study was to assess the utility of tracheostomy in patients with COVID-19-related acute respiratory distress syndrome, in terms of patient and clinical characteristics, outcomes, and complications, by comparing between early and late tracheostomy. Methods: A multicenter, retrospective observational study was conducted in Jönköping County, Sweden. Between 14 March 2020 and 13 March 2021, 117 patients were included. All patients ≥18 years of age with confirmed COVID-19, who underwent tracheostomy were divided into two groups based on the timing of the procedure (≤/>7 days). Outcomes including the time on IMV, intensive care unit (ICU) length of stay, and mortality 30 days after ICU admission, as well as complications due to tracheostomy were compared between the groups. Results: Early tracheostomy (<7 days, n = 56) was associated with a shorter median duration of mechanical ventilation (7 [12], p = 0.001) as well as a shorter median ICU stay (8 [14], p = 0.001). The most frequent complication of tracheostomy was minor bleeding. With the exception of a higher rate of obesity in the group receiving late tracheostomy, the patient characteristics were similar between the groups. Conclusion: This study showed that early tracheostomy was safe and associated with a shorter time on IMV as well as a shorter ICU length of stay, implicating possible clinical benefits in critically ill COVID-19 patients. However, it is necessary to verify these findings in a randomized controlled trial.

Effect of Dihydroartemisinin-Piperaquine on the Pharmacokinetics of Praziquantel for Treatment of Schistosoma mansoni Infection.

Praziquantel (PZQ) and dihydroartemisinin-piperaquine (DHP) combination recently showed superior effectiveness than PZQ alone to treat intestinal schistosomiasis. In this follow-up study, we investigated the effect of DHP co-administration on the pharmacokinetics of PZQ and its enantiomers among 64 Schistosoma mansoni infected children treated with PZQ alone (n = 32) or PZQ + DHP combination (n = 32). Plasma samples collected at 0, 1, 2, 4, 6, and 8 h post-dose were quantified using UPLCMS/MS. The geometric mean (GM) of AUCs for total PZQ, R-PZQ and S-PZQ were significantly higher among children who received PZQ + DHP than PZQ alone. The geometric mean ratio (GMR) and (90% CI) of AUC0-∞ for PZQ + DHP to PZQ for total PZQ, R-PZQ, and S-PZQ were 2.18 (1.27, 3.76), 3.98 (2.27, 7.0) and 1.86 (1.06, 3.28), respectively. The GMR and (90% CI) of AUC0-8 for total PZQ, R-PZQ, and S-PZQ were 1.73 (1.12, 2.69), 2.94 (1.75, 4.92), and 1.50 (0.97, 2.31), respectively. The GM of Cmax for total PZQ, R-PZQ and S-PZQ were significantly higher among those who received PZQ + DHP than PZQ alone. The GMR (90% CI) of Cmax of PZQ + DHP to PZQ for total PZQ, R-PZQ, and S-PZQ were 1.75 (1.15, 2.65), 3.08 (1.91, 4.96), and 1.50 (1.0, 2.25%), respectively. The 90% CI of the GMRs for both AUCs and Cmax for total PZQ, R-PZQ, and S-PZQ were outside the acceptable 0.80-1.25 range, indicating that the two treatment arms were not bioequivalent. DHP co-administration significantly increases systemic PZQ exposure, and this may contribute to increased effectiveness of PZQ + DHP combination therapy than PZQ alone to treat schistosomiasis.

Nicotine Population Pharmacokinetics in Healthy Smokers After Intravenous, Oral, Buccal and Transdermal Administration.

BACKGROUND: In 4 decades, numerous nicotine replacement therapy products have been developed. Population pharmacokinetic models can support exposure-response modeling and inform nicotine replacement therapy product development, but only limited model-based cross-study population pharmacokinetic analyses for nicotine replacement therapy products have been published. OBJECTIVES: The aim of this retrospective analysis was to assess the population pharmacokinetics of nicotine across intravenous, oral, transdermal and oromucosal (mouth spray, chewing gum, lozenge and inhaler) routes and formulations in healthy smoking subjects. METHODS: Data on 930 unique subjects (46,016 observations) from 29 single- and repeated-dose studies with multiple formulations across intravenous, oral, transdermal and oromucosal routes of administration were included. Data from intravenous and extravascular routes of administration were modelled separately for run efficiency reasons. For developing extravascular models, clearance and disposition parameters and their inter-individual variabilities were fixed to the estimates for intravenously delivered nicotine. Detectable pre-dose nicotine concentrations were modelled as a hypothetical nicotine bolus into the central compartment at the start of wash-out. Modelling repeated-dose oral and buccal administrations required a time-dependent increase in clearance or decrease in bioavailability to describe the data adequately. RESULTS: Disposition of intravenous nicotine was best described by a three-compartment model with initial and terminal half-lives of 7 min and 4.5 h, respectively, and the absorption of single oral doses was best described with a first-order absorption rate constant of 1.55 h-1. The data of buccal formulations were modelled with parallel oromucosal absorption and gastrointestinal absorption of a part of the dose that is swallowed. For transdermal nicotine, parallel zero- and first-order release from the patch and a transit-compartment absorption model best described the data. Key pharmacokinetic parameters were reliably estimated, with typical values for clearance (67 L/h for a 70-kg subject), volume of distribution (4.3 L/kg), oral bioavailability (40%) and transdermal bioavailability (76%) within expected ranges. The estimated fraction of the dose swallowed for buccal formulations ranged from 55% (gum) to 69% (lozenge). CONCLUSIONS: Robust population pharmacokinetic models were developed for five nicotine replacement therapy product types and for intravenous and oral nicotine. These population pharmacokinetic models are used in exposure-response analyses and simulation-based nicotine replacement therapy product design.

A Time-to-Event Model Relating Integrated Craving to Risk of Smoking Relapse Across Different Nicotine Replacement Therapy Formulations.

Smoking increases the risk of cancer and other diseases, causing an estimated 7 million deaths per year. Nicotine replacement therapy (NRT) reduces craving for smoking, therefore, increasing an individual's probability to remain abstinent. In this work, we for the first time quantitatively described the relationship between craving and smoking abstinence, using retrospectively collected data from 19 studies, including 3 NRT formulations (inhaler, mouth spray, and patch) and a combination of inhaler and patch. Smokers motivated to quit were included in the NRT or placebo arms. Integrated craving (i.e., craving over a period of time) was assessed with 4-category, 5-category, or 100-mm visual analogue scale. The bounded integer model was used to assess latent craving from all scales. A time-to-event model linked predicted integrated craving to the hazard of smoking relapse. Available data included 9,323 adult subjects, observed for 3 weeks up to 2 years. At the study end, 9% (11% for NRT and 5% for placebo), on average, remained abstinent according to the protocol definition. A Gompertz-Makeham hazard best described the data, with a hazard of smoking relapse decreasing over time. Latent integrated craving was positively related to the hazard of smoking relapse, through a sigmoidal maximum effect function. For the same craving, being on NRT was found to reduce the hazard of relapse by an additional 30% compared with placebo. This work confirmed that low craving is associated with a high probability of remaining smoking abstinent and that NRT, in addition to reducing craving, increases the probability of remaining smoking abstinent.

Relating Nicotine Plasma Concentration to Momentary Craving Across Four Nicotine Replacement Therapy Formulations.

Tobacco use is a major health concern. To assist smoking cessation, nicotine replacement therapy (NRT) is used to reduce nicotine craving. We quantitatively described the relationship between nicotine pharmacokinetics (PKs) from NRTs and momentary craving, linking two different pharmacodynamic (PD) scales for measuring craving. The dataset comprised retrospective data from 17 clinical studies and included 1,077 adult smokers with 39,802 craving observations from four formulations: lozenge, gum, mouth spray, and patch. A PK/PD model was developed that linked individual predicted nicotine concentrations with the categorical and visual analogue PD scales through a joint bounded integer model. A maximum effect model, accounting for acute tolerance development, successfully related nicotine concentrations to momentary craving. Results showed that all formulations were similarly effective in reducing craving, albeit with a fourfold lower potency for the patch. Women were found to have a higher maximal effect of nicotine to reduce craving, compared with men.

Effect of nicotine 6 mg gum on urges to smoke, a randomized clinical trial.

BACKGROUND: Ability to manage urges to smoke is fundamental to maximizing the chances of success in smoking cessation. Previous studies have linked a higher dose of nicotine in nicotine replacement therapy to a higher success rate for smoking cessation. Thus, this study was performed to compare relief of urges to smoke, up until 5 h following treatment with a new 6 mg nicotine gum versus currently marketed 4 mg nicotine gum. METHODS: This was a randomized crossover clinical study. Following 12 h of abstinence from smoking, either one 6 mg or one 4 mg nicotine gum was given to 240 healthy adult smokers. Thereafter, urges to smoke were scored on a 100 mm Visual Analogue Scale repeatedly over 5 h. RESULTS: The reductions in urges to smoke over the first 1 and 3 h after administration were statistically significantly greater with 6 mg than 4 mg gum, (p < 0.005). A 50% reduction in perceived urges to smoke was reached in 9.4 min with 6 mg gum compared to 16.2 min with 4 mg gum (median values). The median duration of a 50% or more reduction in VAS urges to smoke score was 111 min with the 6 mg gum, versus 74 min for the 4 mg gum. CONCLUSION: This study provides evidence that the 6 mg nicotine gum provided a greater reduction, faster and longer relief of urges to smoke than the 4 mg nicotine gum. TRIAL REGISTRATION: EudraCT Number: 2010-023268-42. Study was first entered in EudraCT 2011-02-23.

Carbamazepine, lamotrigine, levetiracetam and valproic acid in dried blood spots with liquid chromatography tandem mass spectrometry; method development and validation.

Monitoring of antiepileptic drugs in children with epilepsy require multiple visits at a clinic for blood collection. Dried blood spot sampling is an alternative way of collection, performed at home by self-collection and can save time and costs for patients and family members. The aim was to develop and validate an LC-MS/MS dried blood spot method for carbamazepine, lamotrigine, levetiracetam and valproic acid with the requirements of using standard equipment and material in a routine laboratory setting. Whatman-903 filter paper was utilized, and discs were punched into a 96 well plate with an automated puncher and barcode reading. Extraction with methanol/water solution including internal standards on an orbital shaker was followed by a vacuum centrifuge step and reconstitution in mobile phase. Bioanalytical validation was performed according to guidelines from European Medicines Agency and additional dried blood spot specific validation. Calibration curves of the four included drugs had R2 values ≥0.994. Therapeutic relevant concentrations were well within measuring ranges. Within and -between run precision had %CV:s of 2.9-10.5%. Accuracy (%bias) was between -16.5% (lower limit of quantification) to +7.4%. Blood spots in a volume range of 15-50µL with hematocrit in expected ranges for this patient group were within precision and accuracy limits. To test the method, concentrations from dried blood spot venous and capillary patient samples (n=50) were compared with plasma concentrations. Good correlations for all four drugs with R2 of >0.92 was shown. In summary, a fast method for dried blood spots based on a 96 well format was developed for four commonly prescribed antiepileptic drugs. This validated method with traceability in sample preparation by bar code reading makes it suitable for the clinical laboratory.

Single-Dose and Multiple-Dose Pharmacokinetics of Nicotine 6 mg Gum.

INTRODUCTION: Under-dosing is a recognized problem with current nicotine replacement therapy (NRT). Therefore, a new 6mg nicotine gum has been developed. To compare the nicotine uptake from the 6mg gum versus currently available NRT products, two pharmacokinetic studies were performed. METHODS: In one randomized crossover study, 44 healthy adult smokers received single doses of 6, 4, and 2mg nicotine gum, and 4mg nicotine lozenge on separate occasions. In a separate randomized crossover multiple-dose study over 11 hours, 50 healthy adult smokers received one 6mg gum every hour and 90 minutes, respectively, one 4mg gum every hour, and one 4mg lozenge every hour. In both studies, blood samples were collected over 12 hours to determine single-dose and multiple-dose pharmacokinetic variables. RESULTS: In the single-dose study, the amount of nicotine released from the 2, 4, and 6mg gums (1.44, 3.36, and 4.94mg) as well as the resulting maximum concentration and area under the curve (5.9, 10.1, and 13.8ng/mL, and 17.1, 30.7, 46.2ng/mL × h, respectively) increased with dose. The maximum concentration and area under the curve of the 6mg gum were 44% and 30% greater, respectively, than those for 4mg lozenge. Upon hourly administration, the steady-state average plasma nicotine concentration with 6mg gum (37.4ng/mL) was significantly higher than those for 4mg lozenge (28.3ng/mL) and 4mg gum (27.1ng/mL). CONCLUSIONS: Nicotine delivery via the 6mg gum results in higher plasma nicotine concentrations after a single dose and at steady state than with currently available oral NRT. IMPLICATIONS: Under-dosing is a recognized problem with current NRT. Therefore, a new 6mg nicotine gum has been developed. Our studies show that upon single-dose and multiple-dose administration, the 6mg gum releases and delivers more nicotine to the systemic circulation than 2mg gum, 4mg gum, and 4mg lozenge. Thus, each 6mg nicotine gum provides a higher degree of nicotine substitution and/or lasts for a longer period of time than currently available nicotine gums and lozenges.

District nurses' perspectives on detecting mental health problems and promoting mental health among community-dwelling seniors with multimorbidity.

AIMS AND OBJECTIVES: To describe district nurses' perspectives on detecting mental health problems and promoting mental health among homebound older people with multimorbidity. BACKGROUND: Mental health problems among older people with multiple chronic conditions, that is, multimorbidity, are challenging issues. These patients' homes often serve as arenas in which district nurses can promote health. Mental health promotion must be studied in greater depth within primary care because older people with multimorbidity are particularly prone to developing poor mental health, which can go undetected and untreated. DESIGN: A descriptive, qualitative study using semi-structured interviews and content analysis. METHODS: Twenty-five district nurses completed individual or focus group interviews. Data were analysed using qualitative content analysis. RESULTS: Most district nurses stated that detecting mental health problems and promoting mental health were important tasks but that they typically focused on more practical home health care tasks. The findings revealed that district nurses focused on assessment, collaboration and social support as means of detecting mental health problems and promoting mental health. CONCLUSIONS: The district nurses described various factors and actions that appeared to be important prerequisites for their involvement in primary mental health care. Nevertheless, there were no established goals for mental health promotion, and district nurses often seemed to depend on their collaboration with other actors. Our findings indicated that district nurses cannot bear the primary responsibility for the early detection of mental health problems and early interventions to promote mental health within this population. RELEVANCE TO CLINICAL PRACTICE: The findings of this study indicated that workforce training and collaboration between different care providers are important elements in the future development of this field. Early detection and early treatment of mental health-related issues should also be stated as explicit objectives in the provision of care to community-dwelling older people with multimorbidity.

Home care assistants' perspectives on detecting mental health problems and promoting mental health among community-dwelling seniors with multimorbidity.

INTRODUCTION: Elderly people with multiple chronic conditions, or multimorbidity, are at risk of developing poor mental health. These seniors often remain in their homes with support from home care assistants (HCAs). Mental health promotion by HCAs needs to be studied further because they may be among the first to observe changes in clients' mental health status. AIM: To describe HCAs' perspectives on detecting mental health problems and promoting mental health among homebound seniors with multimorbidity. METHODS: We applied a descriptive qualitative study design using semi-structured interviews. Content analyses were performed on five focus group interviews conducted in 2014 with 26 HCAs. RESULTS: Most HCAs stated that they were experienced in caring for clients with mental health problems such as anxiety, depression, sleep problems, and high alcohol consumption. The HCAs mentioned as causes, or risk factors, multiple chronic conditions, feelings of loneliness, and social isolation. The findings reveal that continuity of care and seniors' own thoughts and perceptions were essential to detecting mental health problems. Observation, collaboration, and social support emerged as important means of detecting mental health problems and promoting mental health. CONCLUSION: The HCAs had knowledge of risk factors, but they seemed insecure about which health professionals had the primary responsibility for mental health. They also seemed to have detected early signs of mental health problems, even though good personal knowledge of the client and continuity in home visits were crucial to do so. When it came to mental health promotion, the suggestions related to the aim of ending social isolation, decreasing feelings of loneliness, and increasing physical activity. The results indicate that the HCAs seemed dependent on supervision by district nurses and on care managers' decisions to support the needed care, to schedule assignments related to the detection of mental health problems, and to promote mental health.

Zeolites relieves inhibitory stress from high concentrations of long chain fatty acids.

Protein and fat rich slaughterhouse waste is a very attractive waste stream for the production of biogas because of the high biochemical methane potential of the substrate. The material has however some drawbacks as the sole material for biogas production due to the production of several process disturbing metabolites such as ammonia, sulfides and long chain fatty acids. We can in this work present results that show that zeolites have the potential to relieve inhibitory stress from the presence of long chain fatty acids. Moreover, the results strongly indicate that it is mainly acetic acid consumers that are most negatively affected by long chain fatty acids and that the mechanism of stress relief is an adsorption of long chain fatty acids to the zeolites. In addition to this, it is shown that the effect is immediate and that only a small amount of zeolites is necessary to cancel the inhibitory effect of long chain fatty acids.

Landowners' incentives for constructing wetlands in an agricultural area in south Sweden.

Eutrophication of the Baltic Sea has in Sweden led to the initiation of government schemes aiming to increase wetland areas in agricultural regions and thereby reduce nutrient transport to the sea. Landowners play a significant role as providers of this ecosystem service and are currently offered subsidies to cover their costs for constructing and maintaining wetlands. We undertook a grounded theory study, in which landowners were interviewed, aiming at identifying landowners' incentives for constructing wetlands on their land. The study showed that adequate subsidies, additional services that the wetland could provide to the landowner, local environmental benefits, sufficient knowledge, and peers' good experiences could encourage landowners to construct wetlands. Perceived hindrances were burdensome management, deficient knowledge, time-consuming application procedures and unclear effectiveness of nutrient reduction. The main reason for not creating a wetland, however, was that the land was classified as productive by the landowner, i.e., suitable for food production. Current schemes are directed toward landowners as individuals and based on subsidies to cover costs. We propose that landowners instead are approached as ecosystem service entrepreneurs and contracted after a tendering process based on nutrient reduction effects. This would lead to new definitions of production and may stimulate improved design and placement of wetlands.

Effects of nicotine mouth spray on urges to smoke, a randomised clinical trial.

OBJECTIVE: A new nicotine mouth spray was shown to be an effective stop-smoking treatment. This study was set up to examine the speed with which it relieves urges to smoke, and how it compares with nicotine lozenge in this respect. DESIGN: Randomised, cross-over trial that compared nicotine mouth spray 2 mg versus nicotine lozenge 2 or 4 mg. SETTING: Clinical pharmacology research unit. PARTICIPANTS: 200 Volunteer smokers who smoked their first cigarette of the day within 30 min of waking. INTERVENTIONS: Subjects abstained from smoking the night before the morning they attended the laboratory. Treatment was administered following 5 h of witnessed abstinence. PRIMARY AND SECONDARY OUTCOME MEASURES: Urge to smoke was rated before and at 1, 3, 5, 10, 15, 25, 30, 45 min and 1, 1.5, and 2 h after treatment administration. The primary outcome concerned change during the first 1, 3 and 5 min after treatment administration. RESULTS: Nicotine mouth spray achieved greater reductions in craving than either lozenge during the first 1, 3 and 5 min postadministration. After using mouth spray, half of the users experienced 50% reduction in craving within 3.40 min, while the same treatment effect was achieved within 9.92 and 9.20 min for the 2 and 4 mg lozenge, respectively. Adverse events with both mouth spray and lozenge were mostly mild. Hiccups, local irritation, nausea and dyspepsia were more frequent with spray than lozenge. CONCLUSIONS: Nicotine mouth spray provides a faster relief of cravings than nicotine lozenge.

Single-dose pharmacokinetics of nicotine when given with a novel mouth spray for nicotine replacement therapy.

INTRODUCTION: As the efficacy of nicotine replacement therapy might be improved by faster systemic nicotine uptake, a new nicotine mouth spray has been developed. The current study was performed to evaluate the single-dose pharmacokinetics of nicotine at 3 doses of the mouth spray and to compare the speed of nicotine uptake from the spray versus nicotine lozenge and gum. METHODS: In a randomized crossover study, 45 healthy adult smokers received single doses of nicotine mouth spray 1, 2, and 4 mg, nicotine lozenge 4 mg, and nicotine gum 4 mg on separate occasions. Blood samples were collected for 12 hr to determine pharmacokinetic variables. RESULTS: Mean plasma nicotine concentrations during the first 10 min, measured using area under the curve (AUC(10 min)), were 3 times as high with spray 4 mg as with lozenge or gum. The AUC(10 min) with 2 and 1 mg doses of spray, respectively, was twice and 1.5 times as high as the AUC(10 min) with lozenge or gum. The maximum baseline-corrected plasma nicotine concentration (cC(max)) with 4 mg spray exceeded that for lozenge and gum by 34% and 20%; the median time to reach C(max) was 10-12.5 min for the 3 doses of spray, 45 min for lozenge, and 30 min for gum. The mean baseline-corrected area under the plasma nicotine concentration-versus-time curve (cAUC(∞)) with 4 mg spray was 15% higher than that with gum but did not differ significantly from that with lozenge. CONCLUSION: Nicotine delivered via the mouth spray is absorbed considerably faster than nicotine given via gum or lozenge.

The effect of shaped wheelchair cushion and lumbar supports on under-seat pressure, comfort, and pelvic rotation.

AIM: A wheelchair seat and position help clients perform daily activities. The comfort of the wheelchair can encourage clients to participate in daily activities and can help prevent future complications. PURPOSE: This study evaluates how a shaped seat-cushion and two different back supports affect under-seat pressure, comfort, and pelvic rotation. METHOD: Thirty healthy subjects were tested using two differently equipped manual wheelchairs. One wheelchair had a Velcro adjustable back seat and a plane seat-cushion. The other wheelchair had a non-adjustable sling-back seat and a plane cushion. The second wheelchair was also equipped with a shaped cushion and/or a detachable lumbar support. Under-seat pressure, estimated comfort, and pelvic rotation were measured after 10 min in each wheelchair outfit. RESULTS: Peak pressure increased with the shaped cushion compared to the plane cushion. No significant difference in estimated comfort was found. Pelvic posterior-rotation was reduced with the adjustable or detachable back-support irrespective of the shape of the seat cushion. CONCLUSIONS: To support a neutral pelvic position and spinal curvature, a combination of a shaped cushion and a marked lumbar support is most effective.

Proteolytic processing of OPA1 links mitochondrial dysfunction to alterations in mitochondrial morphology.

Many muscular and neurological disorders are associated with mitochondrial dysfunction and are often accompanied by changes in mitochondrial morphology. Mutations in the gene encoding OPA1, a protein required for fusion of mitochondria, are associated with hereditary autosomal dominant optic atrophy type I. Here we show that mitochondrial fragmentation correlates with processing of large isoforms of OPA1 in cybrid cells from a patient with myoclonus epilepsy and ragged-red fibers syndrome and in mouse embryonic fibroblasts harboring an error-prone mitochondrial mtDNA polymerase gamma. Furthermore, processed OPA1 was observed in heart tissue derived from heart-specific TFAM knock-out mice suffering from mitochondrial cardiomyopathy and in skeletal muscles from patients suffering from mitochondrial myopathies such as myopathy encephalopathy lactic acidosis and stroke-like episodes. Dissipation of the mitochondrial membrane potential leads to fast induction of proteolytic processing of OPA1 and concomitant fragmentation of mitochondria. Recovery of mitochondrial fusion depended on protein synthesis and was accompanied by resynthesis of large isoforms of OPA1. Fragmentation of mitochondria was prevented by overexpressing OPA1. Taken together, our data indicate that proteolytic processing of OPA1 has a key role in inducing fragmentation of energetically compromised mitochondria. We present the hypothesis that this pathway regulates mitochondrial morphology and serves as an early response to prevent fusion of dysfunctional mitochondria with the functional mitochondrial network.

Somatic mtDNA mutations cause aging phenotypes without affecting reactive oxygen species production.

The mitochondrial theory of aging proposes that reactive oxygen species (ROS) generated inside the cell will lead, with time, to increasing amounts of oxidative damage to various cell components. The main site for ROS production is the respiratory chain inside the mitochondria and accumulation of mtDNA mutations, and impaired respiratory chain function have been associated with degenerative diseases and aging. The theory predicts that impaired respiratory chain function will augment ROS production and thereby increase the rate of mtDNA mutation accumulation, which, in turn, will further compromise respiratory chain function. Previously, we reported that mice expressing an error-prone version of the catalytic subunit of mtDNA polymerase accumulate a substantial burden of somatic mtDNA mutations, associated with premature aging phenotypes and reduced lifespan. Here we show that these mtDNA mutator mice accumulate mtDNA mutations in an approximately linear manner. The amount of ROS produced was normal, and no increased sensitivity to oxidative stress-induced cell death was observed in mouse embryonic fibroblasts from mtDNA mutator mice, despite the presence of a severe respiratory chain dysfunction. Expression levels of antioxidant defense enzymes, protein carbonylation levels, and aconitase enzyme activity measurements indicated no or only minor oxidative stress in tissues from mtDNA mutator mice. The premature aging phenotypes in mtDNA mutator mice are thus not generated by a vicious cycle of massively increased oxidative stress accompanied by exponential accumulation of mtDNA mutations. We propose instead that respiratory chain dysfunction per se is the primary inducer of premature aging in mtDNA mutator mice.

A desymmetrization route to fused Troger's base analogues: synthesis, isolation, and characterization of the first anti-anti diastereomer of a fused tris-Troger's base analogue.

A desymmetrization route to fused Troger's base analogues was developed. In this way, the synthesis of the first example of an anti-anti diastereomer of a fused tris-Troger's base analogue was accomplished. The resulting compound 5b is a nonlinear symmetric regioisomer obtained from p-bromoaniline in 7% yield. The corresponding syn-anti diastereomer 5a was obtained in 4% yield.

Abnormal Ca(2+) release and catecholamine-induced arrhythmias in mitochondrial cardiomyopathy.

Mitochondrial dysfunction is implicated in numerous cardiac disorders. It has been assumed that the functional defects are directly related to a decreased rate of mitochondrial ATP production, but recent studies have challenged this idea. Here, we used mice with tissue-specific knockout of mitochondrial transcription factor A (Tfam) that leads to progressive cardiomyopathy. The role of changes in the excitation-contraction (E-C) coupling in cardiomyocytes of these mice was studied by measuring the free cytosolic Ca(2+) concentration and by analyzing the expression of genes encoding E-C coupling proteins. Action potential-mediated Ca(2+) transients, measured with the fluorescent indicator fluo-3 in isolated cardiomyocytes, were smaller and faster in Tfam knockout cardiomyocytes when compared with controls. The total sarcoplasmic reticulum (SR) Ca(2+) content was decreased in Tfam knockout cells. The gene for the SR Ca(2+) binding protein calsequestrin-2 (CASQ2), as well as other genes encoding proteins involved in SR Ca(2+) handling, showed decreased expression in Tfam knockout hearts. Decreased CASQ2 levels have been linked to severe arrhythmias triggered by beta-adrenergic stimulation. In line with this, application of the beta-adrenergic agonist isoproterenol resulted in frequent doublet Ca(2+) transients in Tfam knockout cardiomyocytes. In conclusion, our results show that mitochondrial dysfunction in the heart induces specific down-regulation of the expression of genes encoding proteins involved in E-C coupling. These changes predispose to cardiac arrhythmias and terminal heart failure and are thus important in the pathogenesis of mitochondrial cardiomyopathy.