Spoilage microflora in fresh chicken breast stored at 4 °C : influence of packaging methods

Chicken breasts with skin were packaged either in air, under vacuum or in modified atmospheres of (i) 30% CO₂/70% N₂ and (ii) 70% CO₂/30% N₂. After 3, 7, 14 and 21 days of storage at 4 °C, the samples were evaluated for spoilage microbial growth, odour and overall aspect. As expected, pseudomonads grew well in air or under vacuum, but growth was suppressed in both types of modified atmosphere packaging (MAP). However, growth of lactobacilli, Enterobacteriaceae and Brochothrix thermosphacta was not inhibited in MAPs. Modified atmosphere packaging (ii) extended shelf-life up to 21 days compared to 5 days for air-packed samples.     

Ectopic Pregnancy: A Review of 113 Selected Cases

One hundred and thirteen selected cases of ectopic pregnancy were analyzed to clarify the diagnostic and therapeutic factors. The incidence of this condition was higher in “ward” patients and in the Negro. Salpingitis was the commonest etiological factor. The common symptoms were pain, a missed period, vaginal bleeding, faintness, nausea and vomiting, and shoulder pain. The common signs were abdominal tenderness, a positive “chandelier sign”, rebound tenderness, a pelvic mass and pallor. Fertility of the women in this series was equal to that of women in the general population of the same age group. The frog (pregnancy) test was the only significant laboratory test. Colpocentesis proved very helpful, whereas dilatation and curettage did not. Conservative operation, consisting of salpingectomy plus a uterine wedge, was recommended for tubal pregnancy and was performed in 107 patients. The ovary was removed only if involved. Interstitial pregnancies were treated by removal of the corneal portion of the uterus and by salpingectomy, rather than hysterectomy; this procedure was successful in four out of four patients. Incidental appendectomy is not recommended.     

Protection against β‐amyloid neurotoxicity by a non‐toxic endogenous N‐terminal β‐amyloid fragment and its active hexapeptide core sequence

High levels (μM) of beta amyloid (Aβ) oligomers are known to trigger neurotoxic effects, leading to synaptic impairment, behavioral deficits, and apoptotic cell death. The hydrophobic C‐terminal domain of Aβ, together with sequences critical for oligomer formation, is essential for this neurotoxicity. However, Aβ at low levels (pM‐nM) has been shown to function as a positive neuromodulator and this activity resides in the hydrophilic N‐terminal domain of Aβ. An N‐terminal Aβ fragment (1–15/16), found in cerebrospinal fluid, was also shown to be a highly active neuromodulator and to reverse Aβ‐induced impairments of long‐term potentiation. Here, we show the impact of this N‐terminal Aβ fragment and a shorter hexapeptide core sequence in the Aβ fragment (Aβcore: 10–15) to protect or reverse Aβ‐induced neuronal toxicity, fear memory deficits and apoptotic death. The neuroprotective effects of the N‐terminal Aβ fragment and Aβcore on Aβ‐induced changes in mitochondrial function, oxidative stress, and apoptotic neuronal death were demonstrated via mitochondrial membrane potential, live reactive oxygen species, DNA fragmentation and cell survival assays using a model neuroblastoma cell line (differentiated NG108‐15) and mouse hippocampal neuron cultures. The protective action of the N‐terminal Aβ fragment and Aβcore against spatial memory processing deficits in amyloid precursor protein/PSEN1 (5XFAD) mice was demonstrated in contextual fear conditioning. Stabilized derivatives of the N‐terminal Aβcore were also shown to be fully protective against Aβ‐triggered oxidative stress. Together, these findings indicate an endogenous neuroprotective role for the N‐terminal Aβ fragment, while active stabilized N‐terminal Aβcore derivatives offer the potential for therapeutic application.

     

Characterization of a CC49-based single-chain fragment-beta-lactamase fusion protein for antibody-directed enzyme prodrug therapy (ADEPT)

CC49 is a clinically validated antibody with specificity for TAG-72, a carbohydrate epitope that is overexpressed and exposed on the cell surface in a large fraction of solid malignancies. We constructed a single-chain fragment (scFv) based on CC49 and fused it to beta-lactamase (BLA). Following optimization of the scFv domain by combinatorial consensus mutagenesis (CCM) for increased expression and stability, we characterized the protein variant for binding, in vivo pharmacokinetics (PK), and antitumor efficacy. The fusion protein TAB2.5 possessed a similar binding specificity relative to the parent antibody CC49. TAB2.5 also showed prolonged retention (T(1/2) = 36.9 h) in tumor-bearing mice with tumor/plasma ratios of up to 1000. Preliminary evaluation of TAB2.5, in combination with a novel prodrug, GC-Mel, resulted in significant efficacy in a colorectal xenograft tumor model and supports the utility of the protein as an agent for tumor-selective prodrug activation.     

Survival of Salmonella hadar after washing disinfection of minimally processed spinach

Washing disinfection with chlorine is widely used to reduce the initial microbiological load during the preparation of minimally processed vegetables. The effects of initial concentration of chlorine, time and the liquid volume:produce weight ratio on the reduction of Salmonella counts on inoculated spinach were evaluated using response surface methodology. Initial chlorine concentration, time and the interaction between them had a significant effect on reduction of Salmonella populations. However, the liquid volume:produce weight ratio did not have significant effects. The highest Salmonella reduction was around 1.2-1.4 log at 125 ppm during 8 min regardless of the water:produce ratio. According to the results, chlorination reduced Salmonella hadar population, but the complete elimination from the produce was not achieved.     

Small-Conductance Ca2+-Activated Potassium Type 2 Channels Regulate the Formation of Contextual Fear Memory

Small-conductance, Ca²⁺ activated K⁺ channels (SK channels) are expressed at high levels in brain regions responsible for learning and memory. In the current study we characterized the contribution of SK2 channels to synaptic plasticity and to different phases of hippocampal memory formation. Selective SK2 antisense-treatment facilitated basal synaptic transmission and theta-burst induced LTP in hippocampal brain slices. Using the selective SK2 antagonist Lei-Dab⁷ or SK2 antisense probes, we found that hippocampal SK2 channels are critical during two different time windows: 1) blockade of SK2 channels before the training impaired fear memory, whereas, 2) blockade of SK2 channels immediately after the training enhanced contextual fear memory. We provided the evidence that the post-training cleavage of the SK2 channels was responsible for the observed bidirectional effect of SK2 channel blockade on memory consolidation. Thus, Lei-Dab⁷-injection before training impaired the C-terminal cleavage of SK2 channels, while Lei-Dab⁷ given immediately after training facilitated the C-terminal cleavage. Application of the synthetic peptide comprising a leucine-zipper domain of the C-terminal fragment to Jurkat cells impaired SK2 channel-mediated currents, indicating that the endogenously cleaved fragment might exert its effects on memory formation by blocking SK2 channel-mediated currents. Our present findings suggest that SK2 channel proteins contribute to synaptic plasticity and memory not only as ion channels but also by additionally generating a SK2 C-terminal fragment, involved in both processes. The modulation of fear memory by down-regulating SK2 C-terminal cleavage might have applicability in the treatment of anxiety disorders in which fear conditioning is enhanced.