Metabolism, Pharmacogenetics, and Metabolic Drug–Drug Interactions of Antipsychotic Drugs

1. Antipsychotic drugs are extensively metabolised by cytochrome P450 (CYP) enzymes.2. Dispositions of a number of antipsychotic drugs have been shown to cosegregate with polymorphism of CYP2D6.3. Metabolic drug–drug interactions have frequently been observed when antipsychotics are coadministered with other drugs.4. Many antipsychotic drugs are converted to active metabolites which can contribute to the therapeutic or side effects of the parent drug.5. Information concerning the individual CYP isoenzymes involved in the metabolism of antipsychotic drugs is important for the safe clinical use of this group of drugs.     

Loneliness,Depression, and Physical Activity in Older Adults: The Therapeutic Role of Human–Animal Interactions

ABSTRACT

The global population of older persons is projected in 2050 to reach approximately 2.1 billion. As people age, feelings of loneliness, depression, and physical inactivity often occur due to a multitude of reasons. These feelings may manifest and cause adverse health outcomes. With the predicted increase of older adults worldwide, the prevalence of loneliness, depression, and physical inactivity may also worsen over time if unattended. Since older adults are subject to psychological and physical changes as they age, it is important to find creative ways to address the health needs of this growing population. Therefore, interventions are needed to prevent or decrease the psychological and physical challenges that older adults face. This paper examines existing literature on human–animal interactions (HAIs) in the lives of older adults in relation to concepts such as loneliness, depression, and physical activity. The psychological and physical health benefits of animals for older adults include decreased loneliness and depression, improved cardiovascular health, and increased physical activity. There is mounting evidence supporting the therapeutic psychological and physical health benefits of animals in the lives of older adults. However, there are practical and financial implications that must be considered. Methodological considerations and future directions for human–animal interaction research with older adults are also discussed.     

Trends in Antiretroviral Therapy and Prevalence of HIV Drug Resistance Mutations in Sweden 1997–2011

Objective

Describe trends in antiretroviral treatments and drug resistance mutations among Swedish HIV-patients over time 1997–2011.

Methods

Treatment histories, viral sequences, and demographic and clinical data were retrieved from the national database InfCareHIV. All ART-experienced patients were included (N = 6537), while resistance tests were restricted to those obtained ≥90 days after ART start. This cohort is fully representative for Sweden since the database covers virtually all diagnosed HIV-patients since the start of the epidemic. Patients were grouped according to the year of first ART, and treatments and mutations were analyzed by calendar year.

Results

The prevalence of major drug resistance mutations decreased dramatically over time, most rapidly between 2003 and 2007. Since then there has been a continued slow decrease for NRTI- and PI-associated mutations with an overall prevalence among all ART-experienced patients at 1.1% (NRTI) and 0.3% (PI) in 2011. NNRTI resistance reached the lowest level in 2007–2009 (0.6%), but is now increasing (0.9% in 2011). Patients with first ART exposure before 2001 are still highly overrepresented among those with PI and, to a lesser extent, NRTI resistance. In contrast, almost half of the patients with NNRTI mutations in 2011 initiated their first ART after 2007.

Conclusions

Tremendous improvements in ART options and knowledge have resulted in rapidly declining levels of resistance, and most of the current NRTI and PI mutations are found among patients with a history of suboptimal treatments. However, NNRTI resistance is increasing and is primarily found in patients infected in low- and middle-income countries who initiated ART in recent years. It is plausible that these patients were infected with resistant strains and it is therefore suggested that resource-rich countries like Sweden should test for resistance in minor quasispecies or use PI-based first-line regimens in patients who are at increased risk of carrying resistant virus.     

Epigenetics of Host–Pathogen Interactions: The Road Ahead and the Road Behind

A growing body of evidence points towards epigenetic mechanisms being responsible for a wide range of biological phenomena, from the plasticity of plant growth and development to the nutritional control of caste determination in honeybees and the etiology of human disease (e.g., cancer). With the (partial) elucidation of the molecular basis of epigenetic variation and the heritability of certain of these changes, the field of evolutionary epigenetics is flourishing. Despite this, the role of epigenetics in shaping host–pathogen interactions has received comparatively little attention. Yet there is plenty of evidence supporting the implication of epigenetic mechanisms in the modulation of the biological interaction between hosts and pathogens. The phenotypic plasticity of many key parasite life-history traits appears to be under epigenetic control. Moreover, pathogen-induced effects in host phenotype may have transgenerational consequences, and the bases of these changes and their heritability probably have an epigenetic component. The significance of epigenetic modifications may, however, go beyond providing a mechanistic basis for host and pathogen plasticity. Epigenetic epidemiology has recently emerged as a promising area for future research on infectious diseases. In addition, the incorporation of epigenetic inheritance and epigenetic plasticity mechanisms to evolutionary models and empirical studies of host–pathogen interactions will provide new insights into the evolution and coevolution of these associations. Here, we review the evidence available for the role epigenetics on host–pathogen interactions, and the utility and versatility of the epigenetic technologies available that can be cross-applied to host–pathogen studies. We conclude with recommendations and directions for future research on the burgeoning field of epigenetics as applied to host–pathogen interactions.     

Dissolution Properties and Physical Characterization of Telmisartan–Chitosan Solid Dispersions Prepared by Mechanochemical Activation

Solid dispersion systems of telmisartan (a poorly water-soluble antihypertension drug) with biopolymer carrier chitosan have been investigated in this study. The mechanism of solubilization of chitosan for drug has been studied. In addition, the influence of several factors was carefully examined, including the preparation methods, the drug/carrier weight ratios, and the milling time. Drug dissolution and physical characterization of different binary systems were studied by in vitro dissolution test, particle size distribution, Fourier transform infrared spectroscopy, differential scanning calorimetry, powder X-ray diffractometry, and scanning electron microscopy. The results presented that the weak basic property of chitosan appeared as the main driving force for the drug dissolution enhancement. Other effects such as decreased drug crystallinity and size played a positive contributory role. Among the preparation methods, cogrinding was the best method showing strong drug amorphization, reduced particle size, and enhanced dissolution. The drug dissolution markedly improved with increasing the amount of chitosan in solid mixtures. As a result, a significant effect of chitosan increasing telmisartan dissolution has been demonstrated, and cogrinding in a roll ball mill was the best way to prepare solid dispersions, which had high degree of uniformity in drug content and had a practical application in manufacturing.     

The Physical and Geometric Properties of Human Transposon Stem–Loop Structures under Natural Selection

Secondary RNA structures play an important role in transposition, in particular, in RNA recognition by transposon proteins. Previously, we found a conserved structure at the 3′-end of human transposons and proposed a hypothesis about the role of this structure in transposition. Although there is no similarity at the sequence level, the conserved position of this structure points to the fact that structural properties occur that are under positive natural selection. In this paper, the physical and geometric properties of stem-loop structures at the 3′-end of human transposons are identified and compared with properties of the structures of other genome regions. Each stem-loop structure was characterized by a set of ten characteristics: the Gibbs free energy, enthalpy, entropy, hydrophilicity, Shift, Slide, Rise, Tilt, Roll, and Twist. A model has been built using machine-learning methods, which recognizes stem-loop structures according to their physical and geometric characteristics with 94% accuracy. The most important parameters in the recognition model are hydrophilicity, enthalpy, Rise, and Twist. These properties of transposon structure are thought to be under positive natural selection.     

The Origin of Chinese Traditional Drug “Shuigaoben” from Hubei

A new variety of Ligusticum L. (Umbelliferae), L. sinense var. hupehense collected from Hubei province, is described in this paper.. Cytological investigation shows that the new plant is a diploid, with the karyotypic formula 2n=22=14m+ 8sm. The parameters of chromosomes and the idiogram are given. The comparison of ARC (arm ratio curve) diagram between the new variety andL. sinense is also given.     

Occurrence and Abundance of Antibiotics and Resistance Genes in Rivers,Canal and near Drug Formulation Facilities – A Study in Pakistan

Antibiotic resistance (AR) is a global phenomenon that has severe epidemiological ramifications world-wide. It has been suggested that antibiotics that have been discharged into the natural aquatic environments after usage or manufacture can promote the occurrence of antibiotic resistance genes (ARG). These environmental ARGs could serve as a reservoir and be horizontally transferred to human-associated bacteria and thus contribute to AR proliferation. The aim of this study was to investigate the anthropogenic load of antibiotics in Northern Pakistan and study the occurrence of ARGs in selected samples from this region. 19 sampling sites were selected; including six rivers, one dam, one canal, one sewage drain and four drug formulation facilities. Our results show that five of the rivers have antibiotic levels comparable to surface water measurements in unpolluted sites in Europe and the US. However, high levels of antibiotics could be detected in the downstream river in close vicinity of the 10 million city Lahore, 1100, 1700 and 2700 ng L⁻¹ for oxytetracycline, trimethoprim, and sulfamethoxazole respectively. Highest detected levels were at one of the drug formulation facilities, with the measured levels of 1100, 4100, 6200, 7300, 8000, 27000, 28000 and 49000 ng L⁻¹ of erythromycin, lincomycin, ciprofloxacin, ofloxacin, levofloxacin, oxytetracycline, trimethoprim and sulfamethoxazole respectively. ARGs were also detected at the sites and the highest levels of ARGs detected, sulI and dfrA1, were directly associated with the antibiotics detected at the highest concentrations, sulfamethoxazole and trimethoprim. Highest levels of both antibiotics and ARGs were seen at a drug formulation facility, within an industrial estate with a low number of local residents and no hospitals in the vicinity, which indicates that the levels of ARGs at this site were associated with the environmental levels of antibiotics.     

IRG and GBP Host Resistance Factors Target Aberrant, “Non-self” Vacuoles Characterized by the Missing of “Self” IRGM Proteins

Interferon-inducible GTPases of the Immunity Related GTPase (IRG) and Guanylate Binding Protein (GBP) families provide resistance to intracellular pathogenic microbes. IRGs and GBPs stably associate with pathogen-containing vacuoles (PVs) and elicit immune pathways directed at the targeted vacuoles. Targeting of Interferon-inducible GTPases to PVs requires the formation of higher-order protein oligomers, a process negatively regulated by a subclass of IRG proteins called IRGMs. We found that the paralogous IRGM proteins Irgm1 and Irgm3 fail to robustly associate with “non-self” PVs containing either the bacterial pathogen Chlamydia trachomatis or the protozoan pathogen Toxoplasma gondii. Instead, Irgm1 and Irgm3 reside on “self” organelles including lipid droplets (LDs). Whereas IRGM-positive LDs are guarded against the stable association with other IRGs and GBPs, we demonstrate that IRGM-stripped LDs become high affinity binding substrates for IRG and GBP proteins. These data reveal that intracellular immune recognition of organelle-like structures by IRG and GBP proteins is partly dictated by the missing of “self” IRGM proteins from these structures.     

The Cell Wall of the Arabidopsis Pollen Tube��Spatial Distribution, Recycling, and Network Formation of Polysaccharides

The pollen tube is a cellular protuberance formed by the pollen grain, or male gametophyte, in flowering plants. Its principal metabolic activity is the synthesis and assembly of cell wall material, which must be precisely coordinated to sustain the characteristic rapid growth rate and to ensure geometrically correct and efficient cellular morphogenesis. Unlike other model species, the cell wall of the Arabidopsis (Arabidopsis thaliana) pollen tube has not been described in detail. We used immunohistochemistry and quantitative image analysis to provide a detailed profile of the spatial distribution of the major cell wall polymers composing the Arabidopsis pollen tube cell wall. Comparison with predictions made by a mechanical model for pollen tube growth revealed the importance of pectin deesterification in determining the cell diameter. Scanning electron microscopy demonstrated that cellulose microfibrils are oriented in near longitudinal orientation in the Arabidopsis pollen tube cell wall, consistent with a linear arrangement of cellulose synthase CESA6 in the plasma membrane. The cellulose label was also found inside cytoplasmic vesicles and might originate from an early activation of cellulose synthases prior to their insertion into the plasma membrane or from recycling of short cellulose polymers by endocytosis. A series of strategic enzymatic treatments also suggests that pectins, cellulose, and callose are highly cross linked to each other.Upon contact with the stigma, the pollen grain swells through water uptake and develops a cellular protrusion, the pollen tube. During its growth in planta, the pollen tube invades the transmitting tissue of the pistil and finds its way to the ovary to deliver the male gametes for double fertilization to happen (Heslop-Harrison, 1987). Depending on the species, pollen tubes can grow extremely rapidly both in planta and in in vitro conditions. To fulfill its biological function, the pollen tube has to (1) adhere to and invade transmitting tissues (Hill and Lord, 1987; Lennon et al., 1998), (2) provide physical protection to the sperm cells, and (3) control its own shape and invasive behavior (Parre and Geitmann, 2005b; Geitmann and Steer, 2006). For all of these functions, the pollen tube cell wall plays an important regulatory and structural role. Although the pollen tube does not form a conventional secondary cell wall layer, its wall is assembled in two phases. The “primary layer” is mainly formed of pectins and other matrix components secreted at the apical end of the cell. The “secondary layer” is assembled by the deposition of callose in more distal regions of the cell (Heslop-Harrison, 1987). Depending on the species, cellulose microfibrils have been found to be associated either with the outer pectic or with the inner callosic layer. Unlike most other plant cells, cellulose is not very abundant representing only 10% of total neutral polysaccharides in Nicotiana alata pollen tubes, whereas callose accounts for more than 80% in this species (Schlüpmann et al., 1994).The biochemical composition of the pollen tube cell wall has been well characterized in many species such as Lilium longiflorum (Lancelle and Hepler, 1992; Jauh and Lord, 1996), tobacco (Nicotiana tabacum; Kroh and Knuiman, 1982; Geitmann et al., 1995; Ferguson et al., 1998; Derksen et al., 2011), Petunia hybrida (Derksen et al., 1999), Pinus sylvestris (Derksen et al., 1999), and Solanum chacoense (Parre and Geitmann, 2005a). But for Arabidopsis (Arabidopsis thaliana), the model for plant molecular biology studies (Arabidopsis Genome Initiative, 2000), there is a striking lack of quantitative information concerning the composition of the pollen tube cell wall as well as the spatial distribution of its components. This is all the more surprising because numerous mutants defective in enzymes involved in cell wall synthesis exhibit a pollen tube phenotype (for example, Jiang et al., 2005; Nishikawa et al., 2005; Wang et al., 2011). Two studies have characterized the Arabidopsis pollen germinating in vitro (Derksen et al., 2002) and in vivo (Lennon and Lord, 2000), but both are qualitative rather than quantitative. A biochemical study by Dardelle and coworkers investigated the cell wall sugar composition in a more quantitative way but does not provide any detailed spatial information (Dardelle et al., 2010; Lehner et al., 2010). This lack of information is not surprising given that until recently Arabidopsis pollen was known to be rather challenging to germinate reproducibly in vitro and more difficult to manipulate than the pollen of many other plant species (Bou Daher et al., 2009). With the publication of optimized methods for in vitro germination (Boavida and McCormick, 2007; Bou Daher et al., 2009), it has become much more feasible to germinate healthy-looking Arabidopsis pollen tubes in vitro in a highly reproducible way.The precisely controlled spatial distribution of biochemical components in the pollen tube cell wall is crucial for shape generation and maintenance of this perfectly cylindrical cell (Geitmann and Parre, 2004; Aouar et al., 2010; Fayant et al., 2010; Geitmann, 2010). The pollen tube, therefore, represents an ideal model system to study the link between intracellular signaling, biochemistry, cell mechanical properties, and morphogenesis in plant cells. Because of its typically fast growth rates, it responds quickly to any environmental triggers such as pharmacological, hormone, or enzymatic treatments. Adding Arabidopsis to the group of commonly studied pollen tube species is particularly timely, because one-third of the approximately 800 cell wall synthesis genes identified in this species are expressed in or are specific to its pollen (Pina et al., 2005). Therefore, the Arabidopsis pollen tube has become a valuable system for cell wall studies, especially with the increasing availability of cell wall mutant lines (Liepman et al., 2010).Here we describe the biochemical composition of the Arabidopsis pollen tube cell wall grown in in vitro conditions using immunocytochemical labeling coupled with epifluorescence and electron microscopic techniques. Rather than relying on imaging alone, we developed a quantitative strategy to assess the precise spatial distribution of cell wall components. This quantitative approach will provide an important tool and baseline dataset for the investigation of mutant phenotypes and for the interpretation of pharmacological studies. Furthermore, we used selective and strategically combined enzymatic digestions to determine the degree of connectivity between the individual types of cell wall polysaccharide networks.     

Prevalence and Clinical Significance of HIV Drug Resistance Mutations by Ultra-Deep Sequencing in Antiretroviral-Na?ve Subjects in the CASTLE Study

Background

CASTLE compared the efficacy of atazanavir/ritonavir with lopinavir/ritonavir, each in combination with tenofovir-emtricitabine in ARV-naïve subjects from 5 continents.

Objectives

Determine the baseline rate and clinical significance of TDR mutations using ultra-deep sequencing (UDS) in ARV-naïve subjects in CASTLE.

Methods

A case control study was performed on baseline samples for all 53 subjects with virologic failures (VF) at Week 48 and 95 subjects with virologic successes (VS) randomly selected and matched by CD4 count and viral load. UDS was performed using 454 Life Sciences/Roche technology.

Results

Of 148 samples, 141 had successful UDS (86 subtype B, 55 non-B subtypes). Overall, 30.5% of subjects had a TDR mutation at baseline; 15.6% only had TDR(s) at <20% of the viral population. There was no difference in the rate of TDRs by B (30.2%) or non-B subtypes (30.9%). VF (51) and VS (90) had similar rates of any TDRs (25.5% vs. 33.3%), NNRTI TDRs (11.1% vs.11.8%) and NRTI TDRs (24.4% vs. 25.5%). Of 9 (6.4%) subjects with M184V/I (7 at <20% levels), 6 experienced VF. 16 (11.3%) subjects had multiple TAMs, and 7 experienced VF. 3 (2.1%) subjects had both multiple TAMs+M184V, and all experienced VF. Of 14 (9.9%) subjects with PI TDRs (11 at <20% levels): only 1 experienced virologic failure. The majority of PI TDRs were found in isolation (e.g. 46I) at <20% levels, and had low resistance algorithm scores.

Conclusion

Among a representative sample of ARV-naïve subjects in CASTLE, TDR mutations were common (30.5%); B and non-B subtypes had similar rates of TDRs. Subjects with multiple PI TDRs were infrequent. Overall, TDRs did not affect virologic response for subjects on a boosted PI by week 48; however, a small subset of subjects with extensive NRTI backbone TDR patterns experienced virologic failure.     

Cryo-EM Structure (4.5-Å) of Yeast Kinesin-5–Microtubule Complex Reveals a Distinct Binding Footprint and Mechanism of Drug Resistance

Kinesin-5s are microtubule-dependent motors that drive spindle pole separation during mitosis. We used cryo-electron microscopy to determine the 4.5-Å resolution structure of the motor domain of the fission yeast kinesin-5 Cut7 bound to fission yeast microtubules and explored the topology of the motor–microtubule interface and the susceptibility of the complex to drug binding. Despite their non-canonical architecture and mechanochemistry, Schizosaccharomyces pombe microtubules were stabilized by epothilone at the taxane binding pocket. The overall Cut7 footprint on the S. pombe microtubule surface is altered compared to mammalian tubulin microtubules because of their different polymer architectures. However, the core motor–microtubule interaction is tightly conserved, reflected in similar Cut7 ATPase activities on each microtubule type. AMPPNP-bound Cut7 adopts a kinesin-conserved ATP-like conformation including cover neck bundle formation. However, the Cut7 ATPase is not blocked by a mammalian-specific kinesin-5 inhibitor, consistent with the non-conserved sequence and structure of its loop5 insertion.