Library study of the effect of nutrition on healing

Thesis (M.S.)--Boston Universit

Molecular markers to characterize the hermaphroditic reproductive system of the planarian Schmidtea mediterranea

<p>Abstract</p> <p>Background</p> <p>The freshwater planarian <it>Schmidtea mediterranea </it>exhibits two distinct reproductive modes. Individuals of the sexual strain are cross-fertilizing hermaphrodites with reproductive organs that develop post-embryonically. By contrast, individuals of the asexual strain reproduce exclusively by transverse fission and fail to develop reproductive organs. These different reproductive strains are associated with distinct karyotypes, making <it>S. mediterranea </it>a useful model for studying germline development and sexual differentiation.</p> <p>Results</p> <p>To identify genes expressed differentially between these strains, we performed microarray analyses and identified >800 genes that were upregulated in the sexual planarian. From these, we characterized 24 genes by fluorescent <it>in situ </it>hybridization (FISH), revealing their expression in male germ cells or accessory reproductive organs. To identify additional markers of the planarian reproductive system, we also used immuno- and fluorescent lectin staining, identifying several antibodies and lectins that labeled structures associated with reproductive organs.</p> <p>Conclusions</p> <p>Collectively, these cell-type specific markers will enable future efforts to characterize genes that are important for reproductive development in the planarian.</p

Dramatic Intracerebral Hemorrhagic Presentations of Reversible Cerebral Vasoconstriction Syndrome: Three Cases and a Literature Review

Reversible cerebral vasoconstriction syndrome (RCVS) refers to a number of disorders characterized by severe and sudden-onset (“thunderclap”) headaches and angiographic features of reversible, segmental, multifocal vasoconstriction of cerebral arteries. Although RCVS generally resolves without significant sequelae, a rare and possibly underrecognized hemorrhagic presentation has a worse potential course. We report three cases of hemorrhagic RCVS and review the literature. Three females (42, 54, and 33 years old, resp.) presented with severe headache, neurological deficits, and dramatic intracerebral hemorrhage (ICH). Patient 1 presented comatose with a 9 × 4 × 6.6 cm left deep intraparenchymal hemorrhage (IPH) and 1 cm midline shift. She underwent emergent surgical intervention. Patient 2 had a 3.3 × 1.5 cm left superior frontal IPH that enlarged to 4 × 2.5 cm within 12 hours with worsening headache and neurological deficits. She was successfully managed nonoperatively. Patient 3, after uncomplicated pregnancy and delivery, presented with a 1.5 cm left superior parietal IPH on postpartum day 7. Two days later, she acutely developed right hemiplegia. Repeat CT demonstrated a new 3.3 × 1.7 cm left frontal IPH. She was also successfully managed nonoperatively. Many diverse conditions are grouped within the category of RCVS. Dramatic ICH remains a rare and possibly underrecognized presenting feature. Prompt diagnosis and management are essential for obtaining the best outcome

An analysis of social interaction between novice older adults when learning gesture-based skills through simple digital games

This paper reports three exploratory empirical studies with older adults that had little or no prior experience with interactive technologies. The participants were introduced to interactive technology by playing games on touchscreens, playing in pairs with the assistance of a mentor. We focus on two principle aspects, the peer-to-peer interaction during these sessions, and the role of the mentor in progressing the sessions. In the case of peer-to-peer interaction we looked for ways in which players supported each other during interaction to assess the role of peer interaction in this context. In the case of mentoring, we examined the efficacy of a minimalist approach where verbal encouragement, suggestions or (in the last resort) intervention are used to provide support to learners. The sessions showed that learners typically could play and learn basic manipulations independently after initial help and guidance from mentors. We also found that peer interaction, both in verbal and non-verbal communication and cooperative action was broadly a positive influence within sessions, suggesting that there is significant value in building confidence as well as in learning

Expression of miR-200c corresponds with increased reactive oxygen species and hypoxia markers after transient focal ischemia in mice

Embolic stroke results in a necrotic core of cells destined to die, but also a peri-ischemic, watershed penumbral region of potentially salvageable brain tissue. Approaches to effectively differentiate between the ischemic and peri-ischemic zones is critical for novel therapeutic discovery to improve outcomes in survivors of stroke. MicroRNAs are a class of small non-coding RNAs regulating gene translation that have region- and cell-specific expression and responses to ischemia. We have previously reported that global inhibition of cerebral microRNA200c after experimental stroke in mice is protective, however delineating the post-stroke sub-regional and celltype specific patterns of post-stroke miR-200c expression are necessary to minimize off-target effects and advance translational application. Here, we detail a novel protocol to visualize regional miR-200c expression after experimental stroke, complexed with visualization of regional ischemia and markers of oxidative stress in an experimental stroke model in mice. In the present study we demonstrate that the fluorescent hypoxia indicator pimonidazole hydrochloride, the reactive-oxygen-species marker 8-hydroxy-deoxyguanosine, neuronal marker MAP2 and NeuN, and the reactive astrocyte marker GFAP can be effectively complexed to determine regional differences in ischemic injury as early as 30 min post-reperfusion after experimental stroke, and can be effectively used to distinguish ischemic core from surrounding penumbral and unaffected regions for targeted therapy. This multi-dimensional post-stroke immunofluorescent imaging protocol enables a greater degree of subregional mechanistic investigation, with the ultimate goal of developing more effective post-stroke pharmaceutical therapy.Peer reviewe

ATR-mediated phosphorylation of DNA polymerase η is needed for efficient recovery from UV damage

DNA polymerase η (polη) belongs to the Y-family of DNA polymerases and facilitates translesion synthesis past UV damage. We show that, after UV irradiation, polη becomes phosphorylated at Ser601 by the ataxia-telangiectasia mutated and Rad3-related (ATR) kinase. DNA damage–induced phosphorylation of polη depends on its physical interaction with Rad18 but is independent of PCNA monoubiquitination. It requires the ubiquitin-binding domain of polη but not its PCNA-interacting motif. ATR-dependent phosphorylation of polη is necessary to restore normal survival and postreplication repair after ultraviolet irradiation in xeroderma pigmentosum variant fibroblasts, and is involved in the checkpoint response to UV damage. Taken together, our results provide evidence for a link between DNA damage–induced checkpoint activation and translesion synthesis in mammalian cells

Faster adjustment of O-2 delivery does not affect Vo(2) on-kinetics in isolated in situ canine muscle

The mechanism(s) limiting muscle O2 uptake (V\u307O2) kinetics was investigated in isolated canine gastrocnemius muscles (n = 7) during transitions from rest to 3 min of electrically stimulated isometric tetanic contractions (200-ms trains, 50 Hz; 1 contraction/2 s; 60-70% of peak V\u307O2). Two conditions were mainly compared: 1) spontaneous adjustment of blood flow (Q\u307) [control, spontaneous Q\u307 (C Spont)]; and 2) pump-perfused Q\u307, adjusted ~15 s before contractions at a constant level corresponding to the steady-state value during contractions in C Spont [faster adjustment of O2 delivery (Fast O2 Delivery)]. During Fast O2 Delivery, 1-2 ml/min of 10-2 M adenosine were infused intra-arterially to prevent inordinate pressure increases with the elevated Q\u307. The purpose of the study was to determine whether a faster adjustment of O2 delivery would affect V\u307O2 kinetics. Q\u307 was measured continuously; arterial (Ca(O2)) and popliteal venous (CV(O2)) O2 contents were determined at rest and at 5- to 7-s intervals during contractions; O2 delivery was calculated as Q\u307 \ub7 Ca(O2), and V\u307O2 was calculated as Q\u307 \ub7 arteriovenous O2 content difference. Times to reach 63% of the difference between baseline and steady-state V\u307O2 during contractions were 23.8 \ub1 2.0 (SE) s in C Spont and 21.8 \ub1 0.9 s in Fast O2 Delivery (not significant). In the present experimental model, elimination of any delay in O2 delivery during the rest-to-contraction transition did not affect muscle V\u307O2 kinetics, which suggests that this kinetics was mainly set by an intrinsic inertia of oxidative metabolism

Bioenergetics of contracting skeletal muscle after partial reduction of blood flow

The purpose of this study was to examine the bioenergetics and regulation of O2 uptake (V\u307O2) and force production in contracting muscle when blood flow was moderately reduced during a steady-state contractile period. Canine gastrocnemius muscle (n = 5) was isolated, and 3-min stimulation periods of isometric, tetanic contractions were elicited sequentially at rates of 0.25, 0.33, and 0.5 contractions/s (Hz) immediately followed by a reduction of blood flow [ischemic (I) condition] to 46 \ub1 3% of the value obtained at 0.5 Hz with normal blood flow. The V\u307O2 of the contracting muscle was significantly (P < 0.05) reduced during the I condition [6.5 \ub1 0.8 (SE) ml \ub7 100 g-1 \ub7 min-1] compared with the same stimulation frequency with normal flow (11.2 \ub1 1.5 ml \ub7 100 g-1 \ub7 min- 1), as was the tension-time index (79 \ub1 12 vs. 123 \ub1 22 N \ub7 g-1 \ub7 min-1, respectively). The ratio of V\u307O2 to tension-time index remained constant throughout all contraction periods. Muscle phosphocreatine concentration, ATP concentration, and lactate efflux were not significantly different during the I condition compared with the 0.5-Hz condition with normal blood flow. However, at comparable rates of V\u307O2 and tension-time index, muscle phosphocreatine concentration and ATP concentration were significantly less during the I condition compared with normal-flow conditions. These results demonstrate that, in this highly oxidative muscle, the normal balance of O2 supply to force output was maintained during moderate ischemia by downregulation of force production. In addition, 1) the minimal disruption in intracellular homeostasis after the initiation of ischemia was likely a result of steady-state metabolic conditions having already been activated, and 2) the difference in intracellular conditions at comparable rates of V\u307O2 and tension-time index between the normal flow and I condition may have been due to altered intracellular O2 tension