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排序方式: 共有260条查询结果,搜索用时 15 毫秒
91.
Merida M. Grant David White Jennifer Hadley Nathan Hutcheson Richard Shelton Karthik Sreenivasan Gopikrishna Deshpande 《Human brain mapping》2014,35(9):4815-4826
Objective: Early life trauma (ELT) is a significant risk factor for the onset of depression. Emerging findings indicate ELT is associated with enhanced amygdala reactivity to aversive stimuli in never‐depressed healthy controls as well as those with acute depression but may be absent in non‐ELT exposed depressed. The precise mechanism mediating these differences in amygdala reactivity remains unclear. Method: The authors used Granger causality methods to evaluate task‐based directional connectivity between medial or lateral prefrontal cortex (PFC) and amygdala in 20 unmedicated patients with current major depressive disorder (MDD) and 19 healthy matched controls while participants engaged in an affective variant of the flanker task comparing response to sad and neutral faces. These data were correlated with childhood trauma history. Results: Exposure to ELT was associated with failure of inhibition within the MDD group based on medial PFC–amygdala connectivity. In contrast, non‐ELT exposed MDD was associated with a negative causal pathway from medial prefrontal cortex to amygdala, despite reduced dorsolateral PFC input in comparison to healthy controls. Neither MDD group demonstrated significant lateral PFC–amygdala connectivity in comparison to healthy controls. Conclusions: Failure of the circuit implicated in emotion regulation was associated with a significant history of ELT but not with MDD more broadly. Non‐ELT related depression was associated with intact regulation of emotion despite the absence of difference in severity of illness. These findings indicate opposing system‐level differences within depression relative to ELT are expressed as differential amygdala reactivity. Hum Brain Mapp 35:4815–4826, 2014. © 2014 Wiley Periodicals, Inc . 相似文献
92.
Anil K Jain Ravi Sreenivasan R Mukunth Ish Kumar Dhammi 《Indian Journal of Orthopaedics》2014,48(2):136-144
Spine of the child has unique anatomy and growth potential to grow to adult size. Tuberculosis (TB) spine results in bone loss as well as disturbed growth potential, hence spinal deformities may progress as the child grows. The growth potential is also disturbed when the disease focus is surgically intervened. Surgery is indicated for complications such as deformity, neurological deficit, instability, huge abscess, diagnostic dilemma and in suspected drug resistance to mycobacterium tuberculosis. The child on antitubercular treatment needs to be periodically evaluated for weight gain and drug dosages need to be adjusted accordingly. The severe progressive kyphotic deformity should be surgically corrected. Mild to moderate cases should be followed up until maturity to observe progression/improvement of spinal deformity. The surgical correction of kyphotic deformity in active disease is less hazardous than in a healed kyphosis. The internal kyphectomy by extra pleural approach allows adequate removal of internal salient in paraplegic patients with healed kyphotic deformity. 相似文献
93.
Md. Ibrarullah S. Sankar K. Sreenivasan S. R. K. Gavini 《The Indian journal of surgery》2015,77(2):92-98
The clinical presentation, management and outcome of all patients with bile duct injury who presented to our tertiary care centre at various stages after cholecystectomy were analyzed. The patients were categorized into three groups: group A–patients in whom the injury was detected during cholecystectomy, group B–patients who presented within 2 weeks of cholecystectomy and group C–patients who presented after 2 weeks of cholecystectomy. Our team acted as rescue surgeons and performed ‘on-table’ repair for injuries occurring in another unit or in another hospital. Strasberg classification of bile duct injury was followed. In group A, partial and complete transections were managed by repair over T-tube and high hepaticojejunostomy, respectively. Patients in group B underwent endoscopic retrograde cholangiogram and/or magnetic resonance cholangiogram to evaluate the biliary tree. Those with intact common bile duct underwent endoscopic papillotomy and stenting in addition to drainage of intra-abdominal collection when present. For those with complete transection, early repair was considered if there was no sepsis. In presence of intra-abdominal sepsis an attempt was made to create controlled external biliary fistula. This was followed by hepatico jejunostomy at least after 3 months. Group C patients underwent hepaticojejunostomy at least 6 weeks after the injury. The outcome was graded into three categories: grade A–no clinical symptoms, normal LFT; grade B–no clinical symptoms, mild derangement of LFT or occasional episodes of pain or fever; grade C–pain, cholangitis and abnormal LFT; grade D–surgical revision or dilatation required. Fifty nine patients were included in the study and the distribution was group A–six patients, group B–33 patients and group C–20 patients. In group A, one patient with complete transection of the right hepatic duct (type C) and partial injury to left hepatic duct (LHD) underwent right hepaticojejunostomy and repair of the LHD over stent. Two patients with type D and three patients with type E 2 injury underwent repair over T-tube and hepaticojejunostomy, respectively. In group B, all except one of the 18 patients with type A injury underwent endoscopic papillotomy and stenting. The bile leak subsided at a mean interval of 8 days in all, except one patient who died of fulminant sepsis. Of the 15 patients with type E injury, five underwent hepaticojejunostomy after a minimum gap of 3 months. Early repair was considered in 10 patients. Twenty patients in group C underwent hepaticojejunostomy. In a mean follow-up of 40 months, the outcome was grade A in 54 patients, grade B in three patients (one from each of the three groups) and grade D in one patient (group C). The latter patient with a type E3 injury developed recurrent stricture and cholangitis necessitating percutaneous transhepatic dilatation. The high success rate of bile duct repair in the present study can be attributed to the appropriate timing, meticulous technique and the tertiary care experience. 相似文献
94.
Transformation of Actinobacillus actinomycetemcomitans by electroporation, utilizing constructed shuttle plasmids. 总被引:1,自引:3,他引:1
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Actinobacillus actinomycetemcomitans, a periodontal pathogen, has been strongly implicated in human periodontal disease. Advances in the molecular analysis of A. actinomycetemcomitans virulence factors have been limited due to the unavailability of systems for genetic transfer, transposon mutagenesis, and gene complementation. Slow progress can be traced almost exclusively to the lack of gene vector systems and methods for the introduction of DNA into A. actinomycetemcomitans. An electrotransformation system that allowed at least five strains of A. actinomycetemcomitans to be transformed with stable shuttle plasmids which efficiently replicated in both Escherichia coli and A. actinomycetemcomitans was developed. One plasmid, a potential shuttle vector designated pDL282, is 5.7 kb in size, has several unique restriction enzyme sites, and codes for resistance to spectinomycin and ampicillin. E. coli and A. actinomycetemcomitans were transformed with equal efficiencies of approximately 10(5) transformants per micrograms of DNA. Similar transformation efficiencies were obtained whether the plasmid DNA was isolated from A. actinomycetemcomitans or E. coli. In addition, frozen competent cells of A. actinomycetemcomitans yielded comparable efficiencies of transformation. Restriction enzyme analysis of pDL282 isolated after transformation confirmed the presence of intact donor plasmids. A plasmid isolated from A. pleuropneumoniae was also capable of transforming some isolates of A. actinomycetemcomitans, although generally at a lower frequency. The availability of these shuttle plasmids and an efficient transformation procedure should significantly facilitate the molecular analysis of virulence factors of A. actinomycetemcomitans. 相似文献
95.
Azadeh Sabetghadam Surash Ramanathan Sreenivasan Sasidharan Sharif Mahsufi Mansor 《Journal of ethnopharmacology》2013
Ethnopharmacological relevance
Mitragyna speciosa is a popular medicinal plant in Southeast Asia which is commonly used for its morphine-like effects. Although the analgesic properties of Mitragyna speciosa and its ability to ameliorate withdrawal signs after abrupt cessation of opioid abuse are well known, information about the long-term safety of the plant's active compounds is lacking. In this work, we evaluated the effects of sub-chronic exposure to mitragynine, the principal alkaloid of Mitragyna speciosa leaves in rats. Materials and methods: Male and female Sprague-Dawley rats received three doses of mitragynine (1, 10, 100 mg/kg, p.o) for 28 days respectively. Food intake and relative body weight were measured during the experiment. After completion of drug treatment biochemical, hematological, and histological analyses were performed.Results
No mortality was observed in any of the treatment groups. The groups of rats treated with the lower and intermediate doses showed no toxic effects during the study. However, the relative body weight of the group of female rats treated with the 100 mg/kg dose was decreased significantly. Food intake also tended to decrease in the same group. Only relative liver weight increased after treatment with the high dose of mitragynine (100 mg/ kg) in both the male and female treatment groups of rats. Biochemical and hematological parameters were also altered especially in high dose treatment group which corresponds to the histopathological changes.Conclusions
The study demonstrated that mitragynine is relatively safe at lower sub-chronic doses (1–10 mg/kg) but exhibited toxicity at a highest dose (sub-chronic 28 days: 100 mg/kg). This was confirmed by liver, kidney, and brain histopathological changes, as well as hematological and biochemical changes. 相似文献96.
Between February and March 1981 an epidemic of hepatitis occurred in Kolhapur City, Maharashtra State, India. Approximately 1200 cases of jaundice were reported; more than 300 patients were hospitalized and three died. The epidemiological investigations showed a distinct concentration of cases in municipal ward E of the city. Investigations of the ward E water supply system disclosed gross contamination of raw water with sewage at source. The serological studies revealed that the aetiological agent responsible for this epidemic was neither hepatitis A virus nor hepatitis B virus but was likely to have been due to a non-A, non-B hepatitis virus. 相似文献
97.
Karen Clarke Nicole Adler Deepak Agrawal Dimpal Bhakta Suchita Shah Sata Sarguni Singh Arjun Gupta Amit Pahwa Emily Pherson Alexander Sun Frank Volpicelli Aditya Sreenivasan Hyung J Cho 《Journal of hospital medicine》2021,16(7):417-423
Proton pump inhibitors (PPIs) are among the most commonly used medications in the world; however, these drugs carry the risk of patient harm, including acute and chronic kidney disease, Clostridium difficile infection, hypomagnesemia, and fractures. In the hospital setting, PPIs are overused for stress ulcer prophylaxis and gastrointestinal bleeding, and PPI use often continues after discharge. Numerous multifaceted interventions have demonstrated safe and effective reduction of PPI use in the inpatient setting. This narrative review and the resulting implementation guide summarize published interventions to reduce inappropriate PPI use and provide a strategy for quality improvement teams. 相似文献
98.
Masih Rahmati Kevin DeSimone Clayton E. Curtis Kartik K. Sreenivasan 《The Journal of neuroscience》2020,40(49):9487
Theoretically, working memory (WM) representations are encoded by population activity of neurons with distributed tuning across the stored feature. Here, we leverage computational neuroimaging approaches to map the topographic organization of human superior colliculus (SC) and model how population activity in SC encodes WM representations. We first modeled receptive field properties of voxels in SC, deriving a detailed topographic organization resembling that of the primate SC. Neural activity within human (5 male and 1 female) SC persisted throughout a retention interval of several types of modified memory-guided saccade tasks. Assuming an underlying neural architecture of the SC based on its retinotopic organization, we used an encoding model to show that the pattern of activity in human SC represents locations stored in WM. Our tasks and models allowed us to dissociate the locations of visual targets and the motor metrics of memory-guided saccades from the spatial locations stored in WM, thus confirming that human SC represents true WM information. These data have several important implications. They add the SC to a growing number of cortical and subcortical brain areas that form distributed networks supporting WM functions. Moreover, they specify a clear neural mechanism by which topographically organized SC encodes WM representations.SIGNIFICANCE STATEMENT Using computational neuroimaging approaches, we mapped the topographic organization of human superior colliculus (SC) and modeled how population activity in SC encodes working memory (WM) representations, rather than simpler visual or motor properties that have been traditionally associated with the laminar maps in the primate SC. Together, these data both position the human SC into a distributed network of brain areas supporting WM and elucidate the neural mechanisms by which the SC supports WM. 相似文献
99.
In this paper, a time series complexity analysis of dense array electroencephalogram signals is carried out using the recently introduced Sample Entropy (SampEn) measure. This statistic quantifies the regularity in signals recorded from systems that can vary from the purely deterministic to purely stochastic realm. The present analysis is conducted with an objective of gaining insight into complexity variations related to changing brain dynamics for EEG recorded from the three cases of passive, eyes closed condition, a mental arithmetic task and the same mental task carried out after a physical exertion task. It is observed that the statistic is a robust quantifier of complexity suited for short physiological signals such as the EEG and it points to the specific brain regions that exhibit lowered complexity during the mental task state as compared to a passive, relaxed state. In the case of mental tasks carried out before and after the performance of a physical exercise, the statistic can detect the variations brought in by the intermediate fatigue inducing exercise period. This enhances its utility in detecting subtle changes in the brain state that can find wider scope for applications in EEG based brain studies. 相似文献
100.