PT-ACRAMTU, A Platinum–Acridine Anticancer Agent, Lengthens and Aggregates, but does not Stiffen or Soften DNA

We used atomic force microscopy (AFM) to study the dose-dependent change in conformational and mechanical properties of DNA treated with PT-ACRAMTU ([PtCl(en)(ACRAMTU-S)](NO₃)₂, (en = ethane-1,2-diamine, ACRAMTU = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea. PT-ACRAMTU is the parent drug of a family of non-classical platinum-based agents that show potent activity in non-small cell lung cancer in vitro and in vivo. Its acridine moiety intercalates between DNA bases, while the platinum group forms mono-adducts with DNA bases. AFM images show that PT-ACRAMTU causes some DNA looping and aggregation at drug-to-base pair ratio (r _b) of 0.1 and higher. Very significant lengthening of the DNA was observed with increasing doses of PT-ACRAMTU, and reached saturation at an r _b of 0.15. At r _b of 0.1, lengthening was 0.6 nm per drug molecule, which is more than one fully stretched base pair stack can accommodate, indicating that ACRAMTU also disturbs the stacking of neighboring base pair stacks. Analysis of the AFM images based on the worm-like chain (WLC) model showed that PT-ACRAMTU did not change the flexibility of (non-aggregated) DNA, despite the extreme lengthening. The persistence length of untreated DNA and DNA treated with PT-ACRAMTU was in the range of 49–65 nm. Potential consequences of the perturbations caused by this agent for the recognition and processing of the DNA adducts it forms are discussed.     

Infectious salmon anaemia virus (ISAV) isolated from the ISA disease outbreaks in Chile diverged from ISAV isolates from Norway around 1996 and was disseminated around 2005, based on surface glycoprotein gene sequences

Background

All viruses in the family Bunyaviridae possess a tripartite genome, consisting of a small, a medium, and a large RNA segment. Bunyaviruses therefore possess considerable evolutionary potential, attributable to both intramolecular changes and to genome segment reassortment. Hantaviruses (family Bunyaviridae, genus Hantavirus) are known to cause human hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome. The primary reservoir host of Sin Nombre virus is the deer mouse (Peromyscus maniculatus), which is widely distributed in North America. We investigated the prevalence of intramolecular changes and of genomic reassortment among Sin Nombre viruses detected in deer mice in three western states.

Methods

Portions of the Sin Nombre virus small (S) and medium (M) RNA segments were amplified by RT-PCR from kidney, lung, liver and spleen of seropositive peromyscine rodents, principally deer mice, collected in Colorado, New Mexico and Montana from 1995 to 2007. Both a 142 nucleotide (nt) amplicon of the M segment, encoding a portion of the G2 transmembrane glycoprotein, and a 751 nt amplicon of the S segment, encoding part of the nucleocapsid protein, were cloned and sequenced from 19 deer mice and from one brush mouse (P. boylii), S RNA but not M RNA from one deer mouse, and M RNA but not S RNA from another deer mouse.

Results

Two of 20 viruses were found to be reassortants. Within virus sequences from different rodents, the average rate of synonymous substitutions among all pair-wise comparisons (π_s) was 0.378 in the M segment and 0.312 in the S segment sequences. The replacement substitution rate (π_a) was 7.0 × 10^-4 in the M segment and 17.3 × 10^-4 in the S segment sequences. The low π_a relative to π_s suggests strong purifying selection and this was confirmed by a Fu and Li analysis. The absolute rate of molecular evolution of the M segment was 6.76 × 10^-3 substitutions/site/year. The absolute age of the M segment tree was estimated to be 37 years. In the S segment the rate of molecular evolution was 1.93 × 10^-3 substitutions/site/year and the absolute age of the tree was 106 years. Assuming that mice were infected with a single Sin Nombre virus genotype, phylogenetic analyses revealed that 10% (2/20) of viruses were reassortants, similar to the 14% (6/43) found in a previous report.

Conclusion

Age estimates from both segments suggest that Sin Nombre virus has evolved within the past 37–106 years. The rates of evolutionary changes reported here suggest that Sin Nombre virus M and S segment reassortment occurs frequently in nature.     

Segmental identity and cerebellar granule cell induction in rhombomere 1

Background  

Cerebellar granule cell precursors are specifically generated within the hindbrain segment, rhombomere 1, which is bounded rostrally by the midbrain/hindbrain isthmus and caudally by the boundary of the Hoxa2 expression domain. While graded signals from the isthmus have a demonstrable patterning role within this region, the significance of segmental identity for neuronal specification within rhombomere 1 is unexplored. We examined the response of granule cell precursors to the overexpression of Hoxa2, which normally determines patterns of development specific to the hindbrain. How much does the development of the cerebellum, a midbrain/hindbrain structure, reflect its neuromeric origin as a hindbrain segment?     

Modeling and Statistical Analysis of the Spatio-Temporal Patterns of Seasonal Influenza in Israel

Background

Seasonal influenza outbreaks are a serious burden for public health worldwide and cause morbidity to millions of people each year. In the temperate zone influenza is predominantly seasonal, with epidemics occurring every winter, but the severity of the outbreaks vary substantially between years. In this study we used a highly detailed database, which gave us both temporal and spatial information of influenza dynamics in Israel in the years 1998–2009. We use a discrete-time stochastic epidemic SIR model to find estimates and credible confidence intervals of key epidemiological parameters.

Findings

Despite the biological complexity of the disease we found that a simple SIR-type model can be fitted successfully to the seasonal influenza data. This was true at both the national levels and at the scale of single cities.The effective reproductive number R_e varies between the different years both nationally and among Israeli cities. However, we did not find differences in R_e between different Israeli cities within a year. R_e was positively correlated to the strength of the spatial synchronization in Israel. For those years in which the disease was more “infectious”, then outbreaks in different cities tended to occur with smaller time lags. Our spatial analysis demonstrates that both the timing and the strength of the outbreak within a year are highly synchronized between the Israeli cities. We extend the spatial analysis to demonstrate the existence of high synchrony between Israeli and French influenza outbreaks.

Conclusions

The data analysis combined with mathematical modeling provided a better understanding of the spatio-temporal and synchronization dynamics of influenza in Israel and between Israel and France. Altogether, we show that despite major differences in demography and weather conditions intra-annual influenza epidemics are tightly synchronized in both their timing and magnitude, while they may vary greatly between years. The predominance of a similar main strain of influenza, combined with population mixing serve to enhance local and global influenza synchronization within an influenza season.     

Mutations in the gene PRRT2 cause paroxysmal kinesigenic dyskinesia with infantile convulsions

Paroxysmal Kinesigenic Dyskinesia with Infantile Convulsions (PKD/IC) is an episodic movement disorder with autosomal dominant inheritance and high penetrance, but the causative gene is unknown. We have now identified four truncating mutations involving the PRRT2 gene in the vast majority (24/25) of well characterized families with PKD/IC. PRRT2 truncating mutations were also detected in 28 of 78 additional families. The PRRT2 gene encodes a proline-rich transmembrane protein of unknown function that has been reported to interact with the t-SNARE, SNAP25. PRRT2 localizes to axons but not to dendritic processes in primary neuronal culture and mutants associated with PKD/IC lead to dramatically reduced PRRT2 protein levels leading ultimately to neuronal hyperexcitability that manifests in vivo as PKD/IC.     

Comparative Effectiveness of Homoeopathic vs. Conventional Therapy in Usual Care of Atopic Eczema in Children: Long-Term Medical and Economic Outcomes

Background

One in five children visiting a homeopathic physician suffers from atopic eczema.

Objectives

We aimed to examine the long-term effectiveness, safety and costs of homoeopathic vs. conventional treatment in usual medical care of children with atopic eczema.

Methods

In this prospective multi-centre comparative observational non-randomized rater-blinded study, 135 children (48 homoeopathy, 87 conventional) with mild to moderate atopic eczema were included by their respective physicians. Depending on the specialisation of the physician, the primary treatment was either standard conventional treatment or individualized homeopathy as delivered in routine medical care. The main outcome was the SCORAD (SCORing Atopic Dermatitis) at 36 months by a blinded rater. Further outcomes included quality of life, conventional medicine consumption, safety and disease related costs at six, 12 and 36 months after baseline. A multilevel ANCOVA was used, with physician as random effect and the following fixed effects: age, gender, baseline value, severity score, social class and parents’ expectation.

Results

The adjusted mean SCORAD showed no significant differences between the groups at 36 months (13.7 95% CI [7.9–19.5] vs. 14.9 [10.4–19.4], p = 0.741). The SCORAD response rates at 36 months were similar in both groups (33% response: homoeopathic 63.9% vs. conventional 64.5%, p = 0.94; 50% response: 52.0% vs. 52.3%, p = 0.974). Total costs were higher in the homoeopathic versus the conventional group (months 31–36 200.54 Euro [132.33–268.76] vs. 68.86 Euro [9.13–128.58], p = 0.005).

Conclusions

Taking patient preferences into account, while being unable to rule out residual confounding, in this long-term observational study, the effects of homoeopathic treatment were not superior to conventional treatment for children with mild to moderate atopic eczema, but involved higher costs.