Live Pups from Evaporatively Dried Mouse Sperm Stored at Ambient Temperature for up to 2 Years

The purpose of this study is to develop a mouse sperm preservation method based on evaporative drying. Mouse sperm were evaporatively dried and stored at 4°C and ambient temperature for 3 months to 2 years. Upon rehydration, a single sperm was injected into a mature oocyte to develop into a blastocyst after culture or a live birth after embryo transfer to a recipient female. For the samples stored at 4°C for 3, 6, 12, 18, and 24 months, the blastocyst formation rate was 61.5%, 49.1%, 31.5%, 32.2%, and 41.4%, respectively. The blastocyst rate for those stored at ambient temperature (∼22°C) for 3, 6, 12, and 18 months was 57.8%, 36.2%, 33.6%, and 34.4%, respectively. Fifteen, eight and three live pups were produced from sperm stored at room temperature for 12, 18, and 24 months, respectively. This is the first report of live offspring produced from dried mouse sperm stored at ambient temperature for up to 2 years. Based on these results, we suggest that evaporative drying is a potentially useful method for the routine preservation of mouse sperm

3D Multi-isotope Imaging Mass Spectrometry Reveals Penetration of 18O^{18}O-Trehalose in Mouse Sperm Nucleus

The prevalence of genetically engineered mice in medical research has led to ever increasing storage costs. Trehalose has a significant beneficial effect in preserving the developmental potential of mouse sperm following partial desiccation and storage at temperatures above freezing. Using multi-isotope imaging mass spectrometry, we are able to image and measure trehalose in individual spermatozoa. We provide the first evidence that trehalose penetrates the nucleus of a mammalian cell, permitting tolerance to desiccation. These results have broad implications for long-term storage of mammalian cells

Active restructuring of cytoskeleton composites leads to increased mechanical stiffness, memory, and heterogeneity

The composite cytoskeleton, comprising interacting networks of semiflexible actin and rigid microtubules, actively generates forces and restructures using motor proteins such as myosins to enable key mechanical processes including cell motility and mitosis. Yet, how motor-driven activity alters the mechanics of cytoskeleton composites remains an open challenge. Here, we perform optical tweezers microrheology on actin-microtubule composites driven by myosin II motors to show that motor activity increases the linear viscoelasticity and elastic storage of the composite by active restructuring to a network of tightly-packed filament clusters and bundles. Our nonlinear microrheology measurements performed hours after cessation of activity show that the motor-contracted structure is stable and robust to nonlinear forcing. Unique features of the nonlinear response include increased mechanical stiffness, memory and heterogeneity, coupled with suppressed filament bending following motor-driven restructuring. Our results shed important new light onto the interplay between viscoelasticity and non-equilibrium dynamics in active polymer composites such as the cytoskeleton

A case of inflammatory pseudotumour of the gallbladder presenting as a big mass of uncertain behavior

Background: Inflammatory pseudotumour has been used to describe an inflammatory or fibrosing tumoral process of an undetermined cause that may involve a variety of organ systems, including the lungs, spleen, liver, lymph nodes, pancreas and extrahepatic bile duct with potential for recurrence and persistent local growth. In this article, we report a patient with a big mass of uncertain nature and behavior.Case presentationA 60-year-old woman presented with a 1-week history of abdominal pain, fever and jaundice. Six months before she had had right upper quadrant pain that was interpreted as biliary colic. A contrast-enhanced CT scan showed a big mass of soft tissue with diffuse infiltration of the gallbladder, displacement of the transverse colon, hepatic flexure and duodenum. For diagnostic distinction between a chronic inflammatory disease or a neoplasm, exploratory laparotomy was required. Intraoperative exploration disclosed a big mass of hard texture involving the gallbladder, with multiple concrements, hepatoduodenal ligament, right and transverse mesocolon, stomach and duodenum.Cholecystectomy was performed, preserving adjacent organs with macroscopic desmoplastic reaction. Histopathologic examination of the gallbladder showed a spindle cell proliferation with diffuse chronic inflammatory infiltrate of lymphocytes, plasma cells and hyalinized fibrous stroma. No vascular invasion or cellular atypia were evident.ConclusionInflammatory pseudotumour is a rare condition and diagnostic distinction from a chronic inflammatory disease or other neoplasm is only possible by histopathologic examination. There is a limited number of case reports in the literature indicating tumor location in the gallbladder

Complementary paths to Chagas disease elimination: the impact of combining vector control with etiological treatment

Background. The World Health Organization's 2020 goals for Chagas disease are (1) interrupting vector-borne intradomiciliary transmission and (2) having all infected people under care in endemic countries. Insecticide spraying has proved efficacious for reaching the first goal, but active transmission remains in several regions. For the second, treatment has mostly been restricted to recently infected patients, who comprise only a small proportion of all infected individuals. Methods. We extended our previous dynamic transmission model to simulate a domestic Chagas disease transmission cycle and examined the effects of both vector control and etiological treatment on achieving the operational criterion proposed by the Pan American Health Organization for intradomiciliary, vectorial transmission interruption (ie, <2% seroprevalence in children <5 years of age). Results. Depending on endemicity, an antivectorial intervention that decreases vector density by 90% annually would achieve the transmission interruption criterion in 2-3 years (low endemicity) to >30 years (high endemicity). When this strategy is combined with annual etiological treatment in 10% of the infected human population, the seroprevalence criterion would be achieved, respectively, in 1 and 11 years. Conclusions. Combining highly effective vector control with etiological (trypanocidal) treatment in humans would substantially reduce time to transmission interruption as well as infection incidence and prevalence. However, the success of vector control may depend on prevailing vector species. It will be crucial to improve the coverage of screening programs, the performance of diagnostic tests, the proportion of people treated, and the efficacy of trypanocidal drugs. While screening and access can be incremented as part of strengthening the health systems response, improving diagnostics performance and drug efficacy will require further research

Importance of B4 medium in determining organomineralization potential of bacterial environmental isolates

B4 precipitation medium has been used as the preferred medium for studying mineral precipitation using bacterial strains in vitro since pioneer studies were performed by Boquet and coworkers in 1973. Using this medium, several authors have demonstrated that some environmental isolates were able to precipitate minerals, yet others did not. The main goal of the current study is to understand whether pH and buffer conditions would have a significant effect on mineral precipitation results for environmental isolates grown on B4. For this study, a total of 49 strains isolated from natural environments from Puerto Rico were grown on B4 plates, and their CaCO3 precipitation potential was investigated. Our findings revealed a strong correlation between a lack of CaCO3 precipitation and the acidification of the B4 plates by the colonies. The ability to precipitate CaCO3 could be restored by buffering the B4 medium to a pH of 8.2. Buffering capacity of the medium was proposed to be involved in CaCO3 precipitation: acid-base titrations conducted on the individual ingredients of B4 showed that yeast extract has a poor buffering capacity between pH 6.5?7.5. This pH range corresponds to the pH of B4 plates 6.87 (�±0.05)] prior to the inoculation. This might explain why B4 is such a good precipitation medium: a small variation in the H+/OH? balance during microbial growth and precipitation produces rapid changes in the pH of the medium. Finally, an amorphous matrix was distributed within 90% of the examined crystals generated on B4 medium by the environmental strains. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file.; B4 precipitation medium has been used as the preferred medium for studying mineral precipitation using bacterial strains in vitro since pioneer studies were performed by Boquet and coworkers in 1973. Using this medium, several authors have demonstrated that some environmental isolates were able to precipitate minerals, yet others did not. The main goal of the current study is to understand whether pH and buffer conditions would have a significant effect on mineral precipitation results for environmental isolates grown on B4. For this study, a total of 49 strains isolated from natural environments from Puerto Rico were grown on B4 plates, and their CaCO3 precipitation potential was investigated. Our findings revealed a strong correlation between a lack of CaCO3 precipitation and the acidification of the B4 plates by the colonies. The ability to precipitate CaCO3 could be restored by buffering the B4 medium to a pH of 8.2. Buffering capacity of the medium was proposed to be involved in CaCO3 precipitation: acid-base titrations conducted on the individual ingredients of B4 showed that yeast extract has a poor buffering capacity between pH 6.5?7.5. This pH range corresponds to the pH of B4 plates 6.87 (�±0.05)] prior to the inoculation. This might explain why B4 is such a good precipitation medium: a small variation in the H+/OH? balance during microbial growth and precipitation produces rapid changes in the pH of the medium. Finally, an amorphous matrix was distributed within 90% of the examined crystals generated on B4 medium by the environmental strains. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the free supplemental file

Preservation of Mouse Sperm by Convective Drying and Storing in 3-O-Methyl-D-Glucose

With the fast advancement in the genetics and bio-medical fields, the vast number of valuable transgenic and rare genetic mouse models need to be preserved. Preservation of mouse sperm by convective drying and subsequent storing at above freezing temperatures could dramatically reduce the cost and facilitate shipping. Mouse sperm were convectively dried under nitrogen gas in the Na-EGTA solution containing 100 mmol/L 3-O-methyl-D-glucose and stored in LiCl sorption jars (Relative Humidity, RH, 12%) at 4°C and 22°C for up to one year. The functionality of these sperm samples after storage was tested by intracytoplasmic injection into mouse oocytes. The percentages of blastocysts produced from sperm stored at 4°C for 1, 2, 3, 6, and 12 months were 62.6%, 53.4%, 39.6%, 33.3%, and 30.4%, respectively, while those stored at 22°C for 1, 2, and 3 months were 28.8%, 26.6%, and 12.2%, respectively. Transfer of 38 two- to four-cell embryos from sperm stored at 4°C for 1 year produced two live pups while 59 two- to four-cell embryos from sperm stored at 22°C for 3 months also produced two live pups. Although all the pups looked healthy at 3 weeks of age, normality of offspring produced using convectively dried sperm needs further investigation. The percentages of blastocyst from sperm stored in the higher relative humidity conditions of NaBr and MgCl2 jars and driest condition of P2O5 jars at 4°C and 22°C were all lower. A simple method of mouse sperm preservation is demonstrated. Three-O-methyl-D-glucose, a metabolically inactive derivative of glucose, offers significant protection for dried mouse sperm at above freezing temperatures without the need for poration of cell membrane

Flux norm approach to finite dimensional homogenization approximations with non-separated scales and high contrast

We consider divergence-form scalar elliptic equations and vectorial equations for elasticity with rough ($L^\infty(\Omega)$, $\Omega \subset \R^d$) coefficients $a(x)$ that, in particular, model media with non-separated scales and high contrast in material properties. We define the flux norm as the $L^2$ norm of the potential part of the fluxes of solutions, which is equivalent to the usual $H^1$-norm. We show that in the flux norm, the error associated with approximating, in a properly defined finite-dimensional space, the set of solutions of the aforementioned PDEs with rough coefficients is equal to the error associated with approximating the set of solutions of the same type of PDEs with smooth coefficients in a standard space (e.g., piecewise polynomial). We refer to this property as the {\it transfer property}. A simple application of this property is the construction of finite dimensional approximation spaces with errors independent of the regularity and contrast of the coefficients and with optimal and explicit convergence rates. This transfer property also provides an alternative to the global harmonic change of coordinates for the homogenization of elliptic operators that can be extended to elasticity equations. The proofs of these homogenization results are based on a new class of elliptic inequalities which play the same role in our approach as the div-curl lemma in classical homogenization.Comment: Accepted for publication in Archives for Rational Mechanics and Analysi