Pre-pubertal exposure of cytarabine-induced testicular atrophy,impaired spermatogenesis and germ cell DNA damage in SD rats

Context: Cytarabine (Ara-C) is an effective chemotherapeutic drug for the treatment of acute leukaemias. It inhibits the DNA synthesis and repair, thereby causes cytotoxicity in the proliferating cells.

Objective: This study was aimed to investigate the effects of pre-pubertal exposure of Ara-C on testesticular development in juvenile SD rats and their function at puberty.

Materials and methods: Ara-C was injected at the doses of 50, 100 and 200?mg/kg/day from postnatal day (PND) 29–42 (14 days) by intraperitoneal (i.p.) route. Half of the animals were sacrificed on PND 43 and remaining on PND 70. End points of the evaluation included gross pathological examination, histomorphometric analysis, sperm count and sperm head morphology, cell proliferation and DNA damage as well as apoptosis analysis.

Results: Ara-C treatment significantly decreased food and water intake, weight gain, testes and epididymis weight and increased histological alterations in the seminiferous tubule. Furthermore, Ara-C treatment significantly decreased the PCNA-positive cells and sperm count in a dose-dependent manner. Ara-C treatment also increased the DNA damage and apoptosis in testes and sperm as evident from the comet and TUNEL assays results.

Discussion: The present study results clearly indicated that Ara-C treatment impaired spermatogenesis and adversely affects the testicular development and its function in rats by reducing the germ cell proliferation and the inducing DNA damage and apoptosis.     

Unraveling the cytotoxic potential of Temozolomide loaded into PLGA nanoparticles

Background

Nanotechnology has received great attention since a decade for the treatment of different varieties of cancer. However, there is a limited data available on the cytotoxic potential of Temozolomide (TMZ) formulations. In the current research work, an attempt has been made to understand the anti-metastatic effect of the drug after loading into PLGA nanoparticles against C6 glioma cells.Nanoparticles were prepared using solvent diffusion method and were characterized for size and morphology. Diffusion of the drug from the nanoparticles was studied by dialysis method. The designed nanoparticles were also assessed for cellular uptake using confocal microscopy and flow cytometry.

Results

PLGA nanoparticles caused a sustained release of the drug and showed a higher cellular uptake. The drug formulations also affected the cellular proliferation and motility.

Conclusion

PLGA coated nanoparticles prolong the activity of the loaded drug while retaining the anti-metastatic activity.     

Tumor-Targeted Responsive Nanoparticle-Based Systems for Magnetic Resonance Imaging and Therapy

Purpose

Design and synthesis of a tumor responsive nanoparticle-based system for imaging and treatment of various cancers.

Methods

Manganese oxide nanoparticles (Mn₃O₄ NPs) were synthesized and modified with LHRH targeting peptide or anti-melanoma antibodies (cancer targeting moieties) and a MMP2 cleavable peptide (a possible chemotactic factor). Nanostructured lipid carriers (NLCs) were used to entrap the BRAF inhibitor, vemurafenib, and enhance cytotoxicity of the drug. Size distribution, stability, drug entrapment, cytotoxicity and genotoxicity of synthesized nanoparticles were studied in vitro. Enhancement of MRI signal by nanoparticles and their body distribution were examined in vivo on mouse models of melanoma, ovarian and lung cancers.

Results

Uniform, stable cancer-targeted nanoparticles (PEGylated water-soluble Mn₃O₄ NPs and NLCs) were synthesized. No signs of cyto-,genotoxicity and DNA damage were detected for nanoparticles that do not contain an anticancer drug. Entrapment of vemurafenib into nanoparticles significantly enhanced drug toxicity in cancer cells with targeted V600E mutation. The developed nanoparticles containing LHRH and MMP2 peptides showed preferential accumulation in primary and metastatic tumors increasing the MRI signal in mice with melanoma, lung and ovarian cancers.

Conclusions

The proposed nanoparticle-based systems provide the foundation for building an integrated MRI diagnostic and therapeutic approach for various types of cancer.     

Coupled cell-free synthesis, segregation, and core glycosylation of a secretory protein

mRNA from rat mammary glands 13-15 days post partum was translated in a wheat germ cell-free system either in the absence or in the presence of ribosome-denuded membranes prepared from isolated rough microsomes of dog pancreas. Newly synthesized alpha-lactalbumin was identified by immunoprecipitation with a monospecific rabbit antiserum against rat alpha-lactalbumin and was characterized by partial amino-terminal sequence determination and by lectin affinity chromatography. In the absence of membranes a presumably unglycosylated form of alpha-lactalbumin was synthesized that bound neither to concanavalin A-Sepharose nor to Ricinus communis lectin-agarose and that contained an amino-terminal signal peptide region comprising 19 amino acid residues. In the presence of membranes a processed form was synthesized that lacked the signal peptide portion and that had an amino-terminal sequence identical to that of mature alpha-lactalbumin. Furthermore, this processed form was found to be segregated, presumably within the microsomal vesicles, because it was resistant to post-translational proteolysis. It was also found to be glycosylated, and because it bound to concanavalin A-Sepharose, from which it could be eluted specifically by alpha-methyl mannoside, but not to R. communis lectin-agarose, it was presumably core-glycosylated. Processing, segregation, and core glycosylation were observed to proceed only when membranes were present during translation and not when they were added after translation.     

Expert insights: The potential role of the gut microbiome-bile acid-brain axis in the development and progression of Alzheimer's disease and hepatic encephalopathy

Recent epidemiological and molecular studies have linked the disruption of cholesterol homeostasis to increased risk for developing Alzheimer's disease (AD). Emerging evidence also suggests that brain cholesterol accumulation contributes to the progression of hepatic encephalopathy (HE) via bile acid (BA)-mediated effects on the farnesoid X receptor. In this perspective paper, we reviewed several recently published studies that suggested a role for the gut microbiota transformation of BAs as a factor in AD and HE development/progression. We hypothesize that in addition to cholesterol elimination pathways, alteration of the gut microbiota and subsequent changes in both the serum and brain BA profiles are mechanistically involved in the development of both AD and HE, and thus, are a potential target for the prevention and treatment of the two diseases. Our understanding of the microbiome-BAs-brain axis in central nervous system disease is still evolving, and critical questions regarding the emerging links among central, peripheral, and intestinal metabolic failures contributing to brain health and disease during aging have yet to be addressed.     

Clinically detectable copy number variations in a Canadian catchment population of schizophrenia

Copy number variation (CNV) is a highly topical area of research in schizophrenia, but the clinical relevance is uncertain and the translation to clinical practice is under-studied. There is a paucity of research involving truly community-based samples of schizophrenia and widely available laboratory techniques. Our objective was to determine the prevalence of clinically detectable CNVs in a community sample of schizophrenia, while mimicking typical clinical practice conditions. We used a brief clinical screening protocol for developmental features in adults with schizophrenia for identifying individuals with 22q11.2 deletions and karyotypically detectable chromosomal anomalies in 204 consecutive patients with schizophrenia from a single Canadian catchment area. Twenty-seven (13.2%) subjects met clinical criteria for a possible syndrome, and 26 of these individuals received clinical genetic testing. Five of these, representing 2.5% of the total sample (95% CI: 0.3%-4.6%), including two of ten patients with mental retardation, had clinically detectable anomalies: two 22q11.2 deletions (1.0%), one 47, XYY, and two other novel CNVs - an 8p23.3-p23.1 deletion and a de novo 19p13.3-p13.2 duplication. The results support the utility of screening and genetic testing to identify genetic syndromes in adults with schizophrenia in clinical practice. Identifying large, rare CNVs (particularly 22q11.2 deletions) can lead to significant changes in management, follow-up, and genetic counselling that are helpful to the patient, family, and clinicians.