Low viscosity silicone with less shrinkage for brain slices

Plastination consists of replacing lipid and water with a curable polymer. This technique has numerous advantages, of which the production of non-toxic, inert, highly durable, dry, and easy maintenance and storage specimens stand out. Like all anatomical techniques, plastination also has disadvantages, and one of them is tissue shrinkage. The feasibility of using low viscosity domestic silicone (0,1Pa.s at 20°C) to plastinate brain slices was examined. Twenty humans, 10 millimeters (mm) brain slices were impregnated, ten slices each with two polymers [10 with domestic low viscosity polymer - P1 and 10 slices with Biodur® (0,45-0,6Pa.s at 20°C) S10]. Shrinkage was accessed by volume and area measurements. Volume shrinkage was significantly less in the slices impregnated with low viscosity domestic polymer, demonstrating the feasibility to plastinate brain slices with domestic low viscosity silicone polymer.

Progressive plasticity during colorectal cancer metastasis

Metastasis is the principal cause of cancer death, yet we lack an understanding of metastatic cell states, their relationship to primary tumor states, and the mechanisms by which they transition. In a cohort of biospecimen trios from same-patient normal colon, primary and metastatic colorectal cancer, we show that while primary tumors largely adopt LGR5 + intestinal stem-like states, metastases display progressive plasticity. Loss of intestinal cell states is accompanied by reprogramming into a highly conserved fetal progenitor state, followed by non-canonical differentiation into divergent squamous and neuroendocrine-like states, which is exacerbated by chemotherapy and associated with poor patient survival. Using matched patient-derived organoids, we demonstrate that metastatic cancer cells exhibit greater cell-autonomous multilineage differentiation potential in response to microenvironment cues than their intestinal lineage-restricted primary tumor counterparts. We identify PROX1 as a stabilizer of intestinal lineage in the fetal progenitor state, whose downregulation licenses non-canonical reprogramming.

Gamma-aminobutyric acid agonists for neuroleptic-induced tardive dyskinesia

BACKGROUND

Chronic antipsychotic drug treatment may cause tardive dyskinesia (TD), a long-term movement disorder. Gamma-aminobutyric acid (GABA) agonist drugs, which have intense sedative properties and may exacerbate psychotic symptoms, have been used to treat TD.

OBJECTIVES

To determine the effects of GABA agonist drugs (baclofen, gamma-vinyl-GABA, gamma-acetylenic-GABA, progabide, muscimol, sodium valproate and tetrahydroisoxazolopyridine (THIP)) for people with antipsychotic-induced tardive dyskinesia (TD) and schizophrenia or other chronic mental illnesses.

SEARCH STRATEGY

We updated the previous Cochrane review by searching the Cochrane Schizophrenia Group Register (September 2003). We searched references for further trial citations and, where possible, contacted authors.

SELECTION CRITERIA

Randomised controlled trials comparing use of non-benzodiazepine GABA agonist drugs with placebo or no intervention, involving people with schizophrenia or other chronic mental illnesses with signs of antipsychotic-induced TD.

DATA COLLECTION AND ANALYSIS

Working independently, we selected and critically appraised studies, extracted data and analysed on an intention-to-treat basis. Where possible and appropriate we calculated risk ratios (RR) and their 95% confidence intervals (CI) with the number needed to treat (NNT). For continuous data Weighted Mean Differences (WMD) were calculated.

MAIN RESULTS

We identified eight small poorly reported studies for inclusion. For the outcome of 'no clinically important improvement in tardive dyskinesia' GABA agonist drugs were not clearly better than placebo (n = 108, RR 0.83 CI 0.6 to 1.1). Deterioration in mental state was more likely to occur in people receiving GABA medication (n = 95, RR 2.47 CI 1.1 to 5.4), but this effect was influenced by the decision to assign a negative outcome to those who dropped out before the end of the study. A greater proportion of people allocated GABA medication may fail to complete the trial compared with those allocated placebo (20% versus 9%), but this difference was not statistically significant (n = 136, RR 1.99 CI 0.8 to 4.7). There is a suggestion of an increase in ataxia (loss of power of muscular coordination) for both baclofen and sodium valproate (n = 95, RR 3.26 CI 0.4 to 30.2), and in sedation (n = 113, RR 2.12 CI 0.8 to 5.4) compared with placebo, but this was not significant. Withdrawal of tetrahydroisoxazolopyridine (THIP) may cause seizures.

REVIEWERS' CONCLUSIONS

Evidence of the effects of baclofen, progabide, sodium valproate, or THIP for people with antipsychotic-induced TD is inconclusive and unconvincing. Any possible benefits are likely to be outweighed by the adverse effects associated with their use.

cis-acting elements involved in transcriptional regulation of the herpes simplex virus type 1 latency-associated promoter 1 (LAP1) in vitro and in vivo

Latency-associated promoter 1 (LAP1) of herpes simplex virus type 1 is required to generate a series of latency-associated transcripts (LATs) in sensory neurons of latently infected animals. Sequence analysis and DNA binding studies have suggested the existence of several cis-acting elements within LAP1 that are potentially important for promoter function, although their role in LAT gene expression during latency is largely unexplored. In this report, we present evidence that the LAP1 TATA box is essential for transcription initiation in vitro. A reduction in LAT synthesis measured by in situ hybridization and reverse transcription-PCR (RT-PCR) of rat brain tissue latently infected with a LAP1 TATA substitution virus demonstrated that this sequence was required for full LAP1 activity in vivo. Analysis of additional site-directed and 5'-deletion mutants of LAP1 by in vitro transcription-primer extension assays showed that upstream elements including the USF and cyclic AMP response element (CRE) site specifically contributed to LAP1 function and that sequences beginning at position -620 relative to the transcription start site were essential for full promoter activity. The combination of deleting USF, CRE, and TATA completely abolished LAT expression in the brain, identifying these as essential elements for the neuron-specific functioning of LAP1 during latency. Mutation of the transcription start site did not abolish transcription, suggesting the absence of an initiator element. However, one of the most exciting findings from this study is that the region downstream of the TATA box appears to contain a true enhancer that is not only essential for transcription, but also functional when positioned 1.6 kb downstream of the start site of transcription. It was concluded that (i) the TATA box was essential for full transcriptional activity from LAP1 both in vitro and in vivo, (ii) the USF element and CRE contribute to LAP1 function during latency in combination with the TATA element, (iii) multiple trans-acting factors besides the USF- and CRE-binding proteins were required for full promoter activity in vitro, and (iv) sequences downstream of the TATA box enhanced promoter activity in vitro.