Evaluation of the Reveal® rapid AST system to assess the susceptibility of Pseudomonas aeruginosa from blood cultures.

This study was set up to assess the performance of the Reveal® rapid AST system to determine the drug susceptibility of Pseudomonas aeruginosa strains directly from blood cultures. Two hundred fully sequenced clinical P. aeruginosa strains were selected for the evaluation, of which 26.5% (n = 53) produced transferable ß-lactamases, and 2.0 to 33.0% had susceptibility levels close to the EUCAST 2021 breakpoints of 11 commonly used antipseudomonal antibiotics. The Reveal® AST system was run with a commercial MIC microplate designed for fast-growing Gram-negative bacilli (Microscan Neg MDR MIC 1), and was compared to the manually operated GN6F MIC microdilution panel from Thermo Fisher, as a comparator method. The Reveal® AST system provided MIC results for the 11 antipseudomonal antibiotics tested within a mean time to result of 6 h 22 min. By comparison with the GN6F panel, the overall rates of categorical agreement (CA), very major errors (VME), major errors (ME), and minor errors (mE for meropenem only) were 96.1%, 1.6%, 4.2%, and 0.6%, respectively. The Specific Reveal® AST system appears to be a reliable and fast technology to determine the susceptibility of P. aeruginosa to antibiotics, including those with resistance levels near categorical breakpoints, directly from blood cultures.

A feminist phenomenological approach to the analysis of body maps: Childhood trauma and anorexia nervosa.

Body mapping is an arts-based research technique that uses a life-sized outline of the participant's body and symbols that visually represent their lived experiences. In this article, we describe the methods of body mapping and analytic techniques used in a research inquiry exploring how child abuse influenced the embodied processes in anorexia. We aim to contribute to methodological research practice in anorexia using a method that can potentially add value in other areas of ED research or be adapted for treatment settings. Our research findings suggest that body mapping can add value to the interview method and extend the range of methods for researchers interested in interrogating the hard-to-reach subjective embodied processes.

Effect of a combination of butorphanol and detomidine on endoscopic assessment of laryngeal function in Thoroughbred yearlings.

BACKGROUND: To the authors' knowledge, the effect of a combination of butorphanol tartrate and detomidine hydrochloride on the laryngeal function and symmetry of the arytenoid cartilages in young Thoroughbred horses has not been examined. Therefore, this study aimed to examine the effects of administration of butorphanol and detomidine on left-to-right rima glottidis ratio (L:R RGR), cross-sectional area of the rima glottidis (CSARG) and grade of laryngeal function of Thoroughbred yearlings examined endoscopically at rest. METHODS: Forty-six Thoroughbred yearlings underwent laryngeal video endoscopy, at rest, before and after sedation with butorphanol and detomidine. Three clinicians assigned grades of laryngeal function after reviewing the video recordings. The L:R RGR and CSARG were measured at the point of arytenoid cartilages' maximal abduction. Student's t-test was used to compare the L:R RGR and CSARG. Cohen's kappa (κ) was used to compare the intra- and interobserver agreements. Spearman's rank order was used to assess agreement between CSARG and grade of laryngeal function. RESULTS: Sedation had no effect on L:R RGR and CSARG. Mean intraobserver agreement of grade of laryngeal function of unsedated yearlings was 93.1%, and that of sedated yearlings was 92.9%. Mean interobserver agreement of grade of laryngeal function of unsedated yearlings was 92.8%, and that of sedated yearlings was 92.7%. Correlation between CSARG and laryngeal function grade was significant for both groups (p < 0.001). CONCLUSION: Sedating Thoroughbred yearlings with detomidine and butorphanol, before endoscopically examining the larynx, did not significantly affect the grade of laryngeal function.

Color constancy and color term knowledge are positively related during early childhood.

The ability to keep perception constant despite environmental changes of illumination, viewing angle, or distance is a key feature of perception. Here, we investigated how "perceptual constancy" relates to language learning by investigating the relationship between color constancy and color term knowledge in 3- and 4-year-old children. We used a novel method to test color constancy where children are required to match colored stimuli under different illuminations. We found a positive relationship between color constancy and color term knowledge; children who knew more color words also had better color constancy. The relationship remained even when accounting for the effect of age and ability to discriminate colors. The findings have implications for understanding the development of perceptual constancy, language learning, and the link between perceptual processing and cognitive development.

Associations of force plate and body-mounted inertial sensor measurements for identification of hind limb lameness in horses.

OBJECTIVE: To investigate associations between inertial sensor and stationary force plate measurements of hind limb lameness in horses. ANIMALS: 21 adult horses with no lameness or with mild hind limb lameness. PROCEDURES: Horses were instrumented with inertial sensors and evaluated for lameness with a stationary force plate while trotting in a straight line. Inertial sensor-derived measurements of maximum and minimum pelvic height differences between right and left halves of the stride were compared with vertical and horizontal ground reaction forces (GRFs). Stepwise linear regression was performed to investigate the strength of association between inertial sensor measurements of hind limb lameness and amplitude, impulse, and time indices of important events in the vertical and horizontal GRF patterns. RESULTS: Difference in minimum pelvic position was moderately (Ra(2) = 0.60) associated with the difference in peak vertical GRF but had little association with any horizontal GRF measurements. Difference in maximum pelvic position was strongly (Ra(2) = 0.77) associated with a transfer of vertical to horizontal ground reaction impulse in the second half of the stance but was not associated with difference in peak vertical GRF. CONCLUSIONS AND CLINICAL RELEVANCE: Inertial sensor-derived measurements of asymmetric pelvic fall (difference in minimum pelvic position) indicated a decrease in vertical GRF, but similar measurements of asymmetric pelvis rise (difference in maximum pelvic position) indicated a transfer of vertical to horizontal force impulse in the second half of the stance. Evaluation of both pelvic rise and fall may be important when assessing hind limb lameness in horses.

A randomized controlled trial of in-patient treatment for anorexia nervosa in medically unstable adolescents.

BACKGROUND: Anorexia nervosa (AN) is a serious disorder incurring high costs due to hospitalization. International treatments vary, with prolonged hospitalizations in Europe and shorter hospitalizations in the USA. Uncontrolled studies suggest that longer initial hospitalizations that normalize weight produce better outcomes and fewer admissions than shorter hospitalizations with lower discharge weights. This study aimed to compare the effectiveness of hospitalization for weight restoration (WR) to medical stabilization (MS) in adolescent AN. METHOD: We performed a randomized controlled trial (RCT) with 82 adolescents, aged 12-18 years, with a DSM-IV diagnosis of AN and medical instability, admitted to two pediatric units in Australia. Participants were randomized to shorter hospitalization for MS or longer hospitalization for WR to 90% expected body weight (EBW) for gender, age and height, both followed by 20 sessions of out-patient, manualized family-based treatment (FBT). RESULTS: The primary outcome was the number of hospital days, following initial admission, at the 12-month follow-up. Secondary outcomes were the total number of hospital days used up to 12 months and full remission, defined as healthy weight (>95% EBW) and a global Eating Disorder Examination (EDE) score within 1 standard deviation (s.d.) of published means. There was no significant difference between groups in hospital days following initial admission. There were significantly more total hospital days used and post-protocol FBT sessions in the WR group. There were no moderators of primary outcome but participants with higher eating psychopathology and compulsive features reported better clinical outcomes in the MS group. CONCLUSIONS: Outcomes are similar with hospitalizations for MS or WR when combined with FBT. Cost savings would result from combining shorter hospitalization with FBT.

Current approaches to managing fear of cancer recurrence; a descriptive survey of psychosocial and clinical health professionals.

OBJECTIVE: Fear of cancer recurrence (FCR) is common amongst cancer survivors and help with this problem is the most frequently reported unmet need in this population. This study investigated how FCR is perceived and managed by clinical health professionals (medical and nursing staff) and psychosocial professionals in oncology settings. METHODS: Clinical health professionals and psychosocial professionals in oncology settings received emailed invitations from their professional organisation to participate in an online survey. RESULTS: Data from 77 clinical health professionals and 64 psychosocial professionals indicate that FCR is perceived as common and challenging to manage. Thirty-one percent of psychosocial professionals estimated FCR is present in >50% of cancer survivors seen in their practise. Only a minority (21%) of clinical staff reported always referring patients with high levels of FCR to psychosocial support. Strategies for managing FCR differed considerably amongst psychosocial professionals, and most reported that aspects of acceptance and commitment therapy and/or cognitive behaviour therapy were helpful. Greater than 99% of participants were interested in training to help patients manage FCR. CONCLUSIONS: Fear of cancer recurrence is commonly identified in oncology settings and a common focus of discussion in follow-up care. However, patients with high levels of FCR are not routinely referred to psychosocial staff, and barriers to referral to psychosocial care should be investigated. The diversity of approaches reported by psychosocial professionals suggests lack of consensus regarding management of FCR, indicating that the development effective, theoretical-based intervention and evidence-based intervention for FCR is a matter of priority.

Intranasal administration of insulin-like growth factor-1 protects against lipopolysaccharide-induced injury in the developing rat brain.

Our previous studies show that insulin-like growth factor-1 (IGF-1) can either protect against or increase lipopolysaccharide (LPS)-induced damage in the developing brain, depending on the dose, when it is co-administered with LPS through intracerebral injection. To further explore effects of IGF-1 on central inflammation associated brain injury, IGF-1 was administered through intranasal infusion in the current study. Postnatal day 5 (P5) rats were exposed to LPS at a dose of 1 µg/g body weight or sterile saline through intracerebral injection. Recombinant human insulin-like growth factor-1 (rhIGF-1) at a dose of 50 µg/pup or vehicle was administered intranasally 1 or 2 h after the LPS injection. Neonatal LPS exposure resulted in oligodendrocyte (OL) and white matter injury in the P6 or P21 rat brain. The damages include dilatation of lateral ventricles, pyknotic cell death, loss of OL progenitor cells and mature OLs in the cingulum area, and impairment of myelination at the corpus callosum area. Neurological dysfunctions were observed in juvenile rats with neonatal LPS exposure. Intranasal IGF-1 treatment at either 1 or 2 h after LPS exposure significantly attenuated LPS-induced brain injury and improved some behavioral deficits. Intranasal IGF-1 treatment also reduced infiltration of polymorphonuclear (PMN) leukocytes and activation of microglia in the rat brain 24 h after LPS exposure, but it did not prevent the elevation in concentrations of interleukin-1ß (IL-1ß) and tumor necrosis factor alpha (TNFα) in the LPS-exposed rat brain during the first 24 h. This is an indication that direct anti-inflammation might not be the primary mechanism for the protection of IGF-1, and other mechanisms, such as anti-apoptotic effects, are likely involved in its protective effects.

Dexamethasone pre-treatment protects brain against hypoxic-ischemic injury partially through up-regulation of vascular endothelial growth factor A in neonatal rats.

Dexamethasone (Dex) provides neuroprotection against subsequent hypoxia ischemia (HI) in newborn rats, but the mechanism of this neuroprotection is not well understood. It is known that vascular endothelial growth factor A (VEGF) has neuroprotective effects. The objective of this study was to evaluate the role of the VEGF signaling pathway in the Dex-induced neuroprotection in newborn rats. Seven-day-old rat pups had the right carotid artery permanently ligated followed by 140 or 160 min of hypoxia (8% oxygen). Rat pups received two i.p. injections of either saline or Dex (0.25 mg/kg) at 24 and 4 h before HI exposure. To quantify the effects of a glucocorticoid receptor (GR) blocker, on postnatal day (PD) 6 and 15 min prior to Dex treatment rat pups received s.c. vehicle or RU486 (GR blocker, 60 mg/kg). After 24 h at PD 7, all rat pups had HI as described earlier. To quantify the effects of a VEGFR 2 blocker, at 24 h after Dex/Veh treatment (PD7), SU5416, a VEGFR 2 inhibitor or vehicle was injected intracerebroventricularly in the right hemisphere at 30 min before and 2 h after HI. Dex pre-treatment reduced brain injury and enhanced the HI-induced brain VEGF protein while a GR blocker inhibited these effects. Treatment with VEGFR 2 blocker decreased Dex-induced neuroprotection also. Dex pre-treatment enhanced the HI-induced increase in mRNA expression of VEGF splice variants and decreased the HI-induced reduction of Akt phosphorylation. Additionally, it also decreased HI-induced increase of caspase-3 activity and DNA fragments in neonatal rat brain. We conclude that Dex provides robust neuroprotection against subsequent HI in newborn rats via GR likely with the partial involvement of VEGF signaling pathway.

Interleukin-1beta-induced brain injury and neurobehavioral dysfunctions in juvenile rats can be attenuated by alpha-phenyl-n-tert-butyl-nitrone.

Our previous study showed that perinatal exposure to interleukin-1beta (IL-1beta), an inflammatory cytokine, induces acute injury to developing white matter in the neonatal rat brain, and alpha-phenyl-n-tert-butyl-nitrone (PBN), a free radical scavenger and antioxidant, protects against IL-1beta-induced acute brain injury. The objective of the present study was to further examine whether perinatal exposure to IL-1beta resulted in persistent brain damage and neurological disabilities, and whether PBN offers lasting protection. Intracerebral injection of IL-1beta (1 microg/kg) was performed in postnatal day 5 (P5) Sprague-Dawley rat pups and PBN (100 mg/kg) or saline was administered intraperitoneally 5 min after IL-1beta injection. Perinatal IL-1beta exposure significantly affected neurobehavioral functions in juvenile rats. Although some neurobehavioral deficits such as performance in negative geotaxis, cliff avoidance, beam walking, and locomotion were spontaneously reversible, sustained deficits such as poor performance in the vibrissa-elicited forelimb-placing test, the pole test, the passive avoidance task, and the elevated plus-maze task were still observable at P21. Perinatal IL-1beta exposure resulted in persistent brain damage including enlargement of ventricles, loss of mature oligodendrocytes, impaired myelination as indicated by the decrease in myelin basic protein immunostaining, axonal and dendritic injury, and loss of hippocampal CA1 neurons and tyrosine hydroxylase positive neurons in the substantia nigra and ventral tegmental areas of the rat brain. Treatments with PBN provided lasting protection against the IL-1beta-induced brain injury and improved the associated neurological dysfunctions in juvenile rats, suggesting that prompt treatments for brain injury induced by perinatal infection/inflammation might have important long-term consequences.

Lipopolysaccharide-activated microglia induce death of oligodendrocyte progenitor cells and impede their development.

Damage to oligodendrocyte (OL) progenitor cells (OPCs) and hypomyelination are two hallmark features of periventricular leukomalacia (PVL), the most common form of brain damage in premature infants. Clinical and animal studies have linked the incidence of PVL to maternal infection/inflammation, and activated microglia have been proposed to play a central role. However, the precise mechanism of how activated microglia adversely affects the survival and development of OPCs is still not clear. Here we demonstrate that lipopolysaccharide (LPS)-activated microglia are deleterious to OPCs, that is, impeding OL lineage progression, reducing the production of myelin basic protein (MBP), and mediating OPC death. We further demonstrate that LPS-activated microglia mediate OPC death by two distinct mechanisms in a time-dependent manner. The early phase of cell damage occurs within 24 h after LPS treatment, which is mediated by nitric oxide (NO)-dependent oxidative damage and is prevented by N(G)-nitro-l-arginine methyl ester (l-NAME), a general inhibitor of nitric oxide synthase. The delayed cell death is evident at 48 h after LPS treatment, is mediated by cytokines, and is prevented by blocking the activity of tumor necrosis factor-alpha (TNF-alpha) and pro-nerve growth factor (proNGF), but not by l-NAME. Furthermore, microglia-derived insulin-like growth factor-1 (IGF-1) and ciliary neurotrophic factor (CNTF) were significantly suppressed by LPS, and exogenous IGF-1 and CNTF synergistically protected OLs from death induced by LPS-treated microglia conditioned medium, indicating that a deficiency in trophic support may also be involved in OL death. Our finding that LPS-activated microglia not only induce two waves of cell death but also greatly impair OL development may shed some light on the mechanisms underlying selective white matter damage and hypomyelination in PVL.

Dexamethasone induces neurodegeneration but also up-regulates vascular endothelial growth factor A in neonatal rat brains.

The use of dexamethasone (Dex) in premature infants to prevent and/or treat bronchopulmonary dysplasia can adversely affect early neurodevelopment and probably result in loss of cerebral volume. Vascular endothelial growth factor A (VEGF), specifically VEGF(164) isoform has neurotrophic, neuroprotective and neurogenesis enhancing effects. Previous studies have demonstrated that Dex usually down-regulates VEGF. In the present study we investigated the effect of Dex on brain growth and VEGF in the neonatal rat brain. The pups in each litter were divided into the vehicle (n=84) or Dex-treated (n=98) groups. Rat pups in the Dex group received one of three different regimens of i.p. Dex which included tapering doses on postnatal days 3-6 (0.5, 0.25, 0.125 and 0.06 mg/kg, respectively), or repeated doses of 0.5 or 1 mg/kg/day on postnatal days 4-6 or single dose of 0.031, 0.06, 0.125, 0.25 or 0.5 mg/kg on postnatal day 6. The total VEGF protein and mRNA expression of the three main VEGF splice variants (VEGF(120), VEGF(164), and VEGF(188)) were measured in the rat pup brain using enzyme-linked immunosorbent assay and real-time reverse transcription polymerase chain reaction, respectively. Treatment with Dex significantly decreased the gain of body and brain weight. The tapering and repeated doses of Dex significantly increased caspase-3 activity, VEGF protein and the expression of mRNA of VEGF(164) and VEGF(188) splice variants but the single dose did not. We conclude that Dex is neurodegenerative in the developing brain but also increases VEGF which may play a neurotrophic and neuroprotective role.

Assessment of the implementation of a national patient safety alert to reduce wrong site surgery.

BACKGROUND: In 2005, guidance on how to prevent wrong site surgery in the form of a national safety alert was issued to all NHS hospital trusts in England and Wales by the National Patient Safety Agency. OBJECTIVE: To investigate the response to the alert among clinicians in England and Wales 12-15 months after it had been issued. METHODS: A before-after study, using telephone/face-to-face interviews with consultant surgeons and senior nurses in ophthalmology, orthopaedics and urology in 11 NHS hospitals in England & Wales in the year prior to the alert and 12-15 months after. The interviews were coded and analysed thematically. RESULTS: The study revealed marked heterogeneity in organisational processes in response to a national alert. There was a significant change in surgeons' self-reported practice, with only 48% of surgeons routinely marking patients prior to the alert and 85% after (p<0.001). However, inter-specialty differences remained and change in practice was not always matched by change in attitude. Compliance with the detailed recommendations about how marking should be carried out was inconsistent. There were unintended consequences in terms of greater bureaucracy and concerns about diffusion of responsibility and hastily performed marking to enable release of patients from wards. CONCLUSION: The alert was effective in promoting presurgical marking and encouraging awareness of safety issues in relation to correct site surgery. However, care should be taken to monitor unintended consequences and whether change is sustained. Greater flexibility for local adaptation coupled with better design and early testing of safety alerts prior to national dissemination may facilitate more sustainable changes in practice.

Alpha-Phenyl-n-tert-butyl-nitrone attenuates lipopolysaccharide-induced neuronal injury in the neonatal rat brain.

Although white matter damage is a fundamental neuropathological feature of periventricular leukomalacia (PVL), the motor and cognitive deficits observed later in infants with PVL indicate the possible involvement of cerebral neuronal dysfunction. Using a previously developed rat model of white matter injury induced by cerebral lipopolysaccharide (LPS) injection, we investigated whether LPS exposure also results in neuronal injury in the neonatal brain and whether alpha-phenyl-n-tert-butyl-nitrone (PBN), an antioxidant, offers protection against LPS-induced neuronal injury. A stereotactic intracerebral injection of LPS (1 mg/kg) was performed in Sprague-Dawley rats (postnatal day 5) and control rats were injected with sterile saline. LPS exposure resulted in axonal and neuronal injury in the cerebral cortex as indicated by elevated expression of beta-amyloid precursor protein, altered axonal length and width, and increased size of cortical neuronal nuclei. LPS exposure also caused loss of tyrosine hydroxylase positive neurons in the substantia nigra and the ventral tegmental areas of the rat brain. Treatments with PBN (100 mg/kg) significantly reduced LPS-induced neuronal and axonal damage. The protection of PBN was associated with an attenuation of oxidative stress induced by LPS as indicated by the reduced number of 4-hydroxynonenal, malondialdehyde or nitrotyrosine positive cells in the cortical area following LPS exposure, and with the reduction in microglial activation stimulated by LPS. The finding that an inflammatory environment may cause both white matter and neuronal injury in the neonatal brain supports the possible anatomical correlate for the intellectual deficits and the other cortical and deep gray neuronal dysfunctions associated with PVL. The protection of PBN may indicate the potential usefulness of antioxidants for treatment of these neuronal dysfunctions.

Quality of care in diabetic patients attending routine primary care clinics compared with those attending GP specialist clinics.

AIM: To determine the impact on clinical outcomes of specialist diabetes clinics compared with routine primary care clinics. METHODS: Observational study measuring clinical performance (process/outcome measures) in the primary care sector. A cohort of patients attending specialist diabetes clinics was compared with a control cohort of patients attending routine primary care clinics. RESULTS: Patients seen in specialist diabetes clinics had a significantly higher HbA1c than patients in routine primary care clinics (mean difference 0.58%; P < 0.001) but there was no significant difference in rate of improvement with visits compared with primary care clinics. In contrast, patients seen in the routine primary care clinics had significantly higher cholesterol levels (mean difference 0.24 mmol/l; P < 0.001) compared with patients in specialist diabetes clinics and their improvement was significantly greater over time (mean difference 0.14 mmol/l per visit compared with 0.10 mmol/l; P < 0.006). Patients in routine primary care clinics also had significantly higher diastolic blood pressure (mean difference 1.6 mmHg; P < 0.007) but there was no difference in improvement with time compared with specialist diabetes clinics. Uptake of podiatry and retinal screening was significantly lower in patients attending routine primary care clinics, but this difference disappeared with time, with significant increases in uptake in the primary care clinic group. Weight increased in both groups significantly with time, but more so in the specialist clinic patients (mean increase 0.18 kg per visit more compared with routine clinic primary care patients; P < 0.001). CONCLUSIONS: This study provides evidence that the provision of primary care services for patients with diabetes, whether traditional general practitioner clinics or diabetes clinics run by general practitioners with special interests, is effective in reducing HbA1c, cholesterol and blood pressure. However, the same provision of care was unable to prevent increasing weight or creatinine over time. No evidence was found that patients in specialist clinics do better than patients in routine primary care clinics.

Role of interleukin-6 in lipopolysaccharide-induced brain injury and behavioral dysfunction in neonatal rats.

There are increasing data in support of the hypothesis that inflammatory cytokines are involved in neonatal white matter damage. Despite extensive study of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta, the role of interleukin-6 in the development of white matter damage is largely unknown. In the present study, the role(s) of interleukin-6 in mediating lipopolysaccharide-induced brain injury and behavioral changes was investigated by the intracerebral injection of lipopolysaccharide with interleukin-6 neutralizing antibody in the 5-day-old rat brain. Brain injury was examined in brain sections at postnatal day 8 and postnatal day 21. Behavioral tests including righting reflex, wire hanging maneuver, cliff avoidance, locomotor activity, gait analysis, responses in the elevated plus-maze and passive avoidance were performed from postnatal day 3 to postnatal day 21. Changes in astroglia, microglia and oligodendrocytes were studied using immunohistochemistry in the postnatal day 21 rat brain. Our results show that interleukin-6 antibody attenuated lipopolysaccharide-induced brain lateral ventricle dilation and improved neurobehavioral performance. Interleukin-6 antibody also suppressed lipopolysaccharide-induced astrogliosis and microglial activation, and increased the number of oligodendrocytes in white matter. However, no changes of tumor necrosis factor-alpha and interleukin-1beta were detected. In contrast, no histopathological changes and glial activation were observed in rats injected with only interleukin-6. The present study indicates that the contribution to brain injury by interleukin-6 depends on its interaction with other lipopolysaccharide-induced agents and not on interleukin-6 alone.

Antilisterial activity of grape juice and grape extracts derived from Vitis vinifera variety Ribier.

Grape juice and skin and seed extracts of Vitis vinifera var. Ribier black table grapes were found to be highly inhibitory towards Listeria monocytogenes. This grape juice was also active against all other Listeria species tested but not against Bacillus cereus, Salmonella Menston, Escherichia coli, Staphylococcus aureus or Yersinia enterocolitica. Fractionation of the extracts showed that the antilisterial activity was strongest in the polymeric phenolic fractions. Two different types of active compounds were identified: the red-pigmented polymeric phenolics from juice and skin showed pH-dependent antilisterial activity, while the unpigmented polymeric phenolics from the seed showed antilisterial activity which was independent of pH.

Minocycline alleviates hypoxic-ischemic injury to developing oligodendrocytes in the neonatal rat brain.

The role of minocycline in preventing white matter injury, in particular the injury to developing oligodendrocytes was examined in a neonatal rat model of hypoxia-ischemia. Hypoxia-ischemia was achieved through bilateral carotid artery occlusion followed by exposure to hypoxia (8% oxygen) for 15 min in postnatal day 4 Sprague-Dawley rats. A sham operation was performed in control rats. Minocycline (45 mg/kg) or normal phosphate-buffered saline was administered intraperitoneally 12 h before and immediately after bilateral carotid artery occlusion+hypoxia and then every 24 h for 3 days. Nissl staining revealed pyknotic cells in the white matter area of the rat brain 1 and 5 days after hypoxia-ischemia. Hypoxia-ischemia insult also resulted in apoptotic oligodendrocyte cell death, loss of O4+ and O1+ oligodendrocyte immunoreactivity, and hypomyelination as indicated by decreased myelin basic protein immunostaining and by loss of mature oligodendrocytes in the rat brain. Minocycline significantly attenuated hypoxia-ischemia-induced brain injury. The protective effect of minocycline was associated with suppression of hypoxia-ischemia-induced microglial activation as indicated by the decreased number of activated microglia, which were also interleukin-1beta and inducible nitric oxide synthase expressing cells. The protective effect of minocycline was also linked with reduction in hypoxia-ischemia-induced oxidative and nitrosative stress as indicated by 4-hydroxynonenal and nitrotyrosine positive oligodendrocytes, respectively. The reduction in hypoxia-ischemia-induced oxidative stress was also evidenced by the decreases in the content of 8-isoprostane in the minocycline-treated hypoxia-ischemia rat brain as compared with that in the vehicle-treated hypoxia-ischemia rat brain. The overall results suggest that reduction in microglial activation may protect developing oligodendrocytes in the neonatal brain from hypoxia-ischemia injury.

Minocycline attenuates lipopolysaccharide-induced white matter injury in the neonatal rat brain.

Our previous studies have shown that intracerebral administration of endotoxin, lipopolysaccharide (LPS), induces selective white matter injury and hypomyelination in the neonatal rat brain and that the LPS-induced brain injury is associated with activation of microglia. To test the hypothesis that inhibition of microglial activation may protect against LPS-induced white matter injury, we examined roles of minocycline, a putative suppressor of microglial activation, on LPS-induced brain injury in the neonatal rat. A stereotactic intracerebral injection of LPS (1 mg/kg) was performed in postnatal day 5 Sprague-Dawley rats and control rats were injected with sterile saline. Minocycline (45 mg/kg) was administered intraperitoneally 12 h before and immediately after LPS injection and then every 24 h for 3 days. Inflammatory responses, activation of microglia and brain injury were examined 1 and 3 days after LPS injection. LPS injection resulted in brain injury in selective brain areas, including bilateral ventricular enlargement, cell death at the sub- and periventricular areas, loss of O4+ and O1+ oligodendrocyte (OL) immunoreactivity and hypomyelination, as indicated by decreased myelin basic protein immunostaining, in the neonatal rat brain. Minocycline administration significantly attenuated LPS-induced brain injury in these rat brains. The protective effect of minocycline was associated with suppressed microglial activation as indicated by the decreased number of activated microglial cells following LPS stimulation and with consequently decreased elevation of interleukin 1beta and tumor necrosis factor-alpha concentrations induced by LPS and a reduced number of inducible nitric oxide synthase expressing cells. Protection of minocycline was also linked with the reduction in LPS-induced oxidative stress, as indicated by 4-hydroxynonenal positive OLs. The overall results suggest that reduction in microglial activation may protect the neonatal brain from LPS-induced white matter injury and inhibition of microglial activation might be an effective approach for the therapeutic treatment of infection-induced white matter injury.