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1.
Phys Chem Chem Phys ; 25(21): 15008-15014, 2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-37211947

RESUMO

In this work, we employed the back-propagation neural network (BPNN) for predicting the energetics of different sodium adsorption phases on the VS2 monolayer generated via ab initio random structure searching (AIRSS). Two key adsorption features were identified as inputs: the average Na-Na distance and a defined adsorption feature marker that indicates the number of nearest-neighbor pairs within a sodium cluster. Using the stoichiometric structure Na0.5VS2 as the test system, we first generated 50 random sensible structures via AIRSS and optimized them via density functional theory (DFT) calculations to obtain the sodium binding energy per atom. From these, 30 were utilized to train 3000 BPNNs with varying numbers of neurons and types of activation functions. The remaining 20 were employed to verify the generalization of the best identified BPNN model for the considered Na0.5VS2 system. The calculated mean absolute error for the predicted sodium binding energy per atom is smaller than 0.1 eV. This suggests that the identified BPNN model was able to predict the sodium binding energy per atom on VS2 with outstanding accuracy. Our results demonstrated that with the assistance of BPNN, it is possible to perform AIRSS with hundreds of random sensible structures without relying solely on DFT calculations. The uniqueness of this method lies on the utilization of a very large number of BPNN models to be trained by a relatively small number of structures. This is particularly very useful for large systems wherein the data come from DFT calculations, which is computationally expensive. Moreover, with the assistance of machine learning, the theoretical estimation of important metal-ion battery metrics such as specific energy capacity and open circuit voltage via AIRSS could be made more accurate and reliable.

2.
Clin Infect Dis ; 75(8): 1449-1452, 2022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-35243486

RESUMO

In Staphylococcus aureus bacteremia, mortality rates in randomized controlled trials (RCTs) are consistently lower than observational studies. Stringent eligibility criteria and omission of early deaths in RCTs contribute to this mortality gap. Clinicians should acknowledge the possibility of a lower treatment effect when applying RCT results to bedside care.


Assuntos
Bacteriemia , Infecções Estafilocócicas , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus
3.
J Craniofac Surg ; 30(2): e117-e119, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30507888

RESUMO

The paramedian forehead flap is a workhorse flap for reconstructing the nose and periorbital regions. Many variants are described including an islanded flap. However, eyebrow reconstruction is not usually performed with these flaps. The authors describe a patient suffering from postburn scarring medial to the left eye, including loss of the left eyebrow. He underwent a single-stage transfer of the paramedian forehead flap. The flap incorporated scalp hair, which restored the missing eyebrow hair after transfer. The donor defect closed primarily. The paramedian forehead flap is amenable to customization by including a segment of hair-bearing scalp to concomitantly reconstruct the nasal dorsum and eyebrow.


Assuntos
Cicatriz , Sobrancelhas/patologia , Face/cirurgia , Cabelo/transplante , Procedimentos de Cirurgia Plástica/métodos , Rinoplastia/métodos , Couro Cabeludo/transplante , Retalhos Cirúrgicos , Adulto , Queimaduras/complicações , Cicatriz/diagnóstico , Cicatriz/etiologia , Cicatriz/cirurgia , Traumatismos Faciais/etiologia , Traumatismos Faciais/cirurgia , Testa/cirurgia , Humanos , Masculino , Nariz/cirurgia
4.
Sensors (Basel) ; 19(22)2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31698678

RESUMO

The present methods of diagnosing depression are entirely dependent on self-report ratings or clinical interviews. Those traditional methods are subjective, where the individual may or may not be answering genuinely to questions. In this paper, the data has been collected using self-report ratings and also using electronic smartwatches. This study aims to develop a weighted average ensemble machine learning model to predict major depressive disorder (MDD) with superior accuracy. The data has been pre-processed and the essential features have been selected using a correlation-based feature selection method. With the selected features, machine learning approaches such as Logistic Regression, Random Forest, and the proposed Weighted Average Ensemble Model are applied. Further, for assessing the performance of the proposed model, the Area under the Receiver Optimization Characteristic Curves has been used. The results demonstrate that the proposed Weighted Average Ensemble model performs with better accuracy than the Logistic Regression and the Random Forest approaches.


Assuntos
Transtorno Depressivo Maior/diagnóstico , Adulto , Feminino , Humanos , Modelos Logísticos , Aprendizado de Máquina , Masculino , Máquina de Vetores de Suporte
6.
Indian J Otolaryngol Head Neck Surg ; 76(5): 4667-4672, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39376284

RESUMO

Introduction: Stapling-assisted closure of pharyngeal mucosa during total laryngectomy was described in 1973.Few authors have demonstrated that this technique provides a faster and more reliable pharyngeal closure with ashorter operative period. However, the simultaneous placement of tracheoesophageal prostheses is quitechallenging and affects the patient's speech rehabilitation. Aim: We are reporting our novel concurrent tracheoesophageal prosthesis insertion technique in stapler-assistedtotal laryngectomy. Methods: A patient with locally advanced laryngeal cancer underwent total laryngectomy with stapler-assistedcloser and concurrent primary tracheoesophageal prosthesis. In a closed stapler-assisted reconstruction of theneopharynx, an inflate folye ballon was utilised to identify the ideal TEP puncture site. Results: The immediate postop course was uneventful, and the patient acquired fluent alaryngeal speech after thespeech rehabilitation. Conclusion: Our novel technique of concurrent tracheoesophageal prosthesis insertion in stapler-assisted totallaryngectomy is practically simple and shortens the operative time.

7.
Fertil Steril ; 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39048020

RESUMO

OBJECTIVE: To compare the effect of a fully undisturbed culture strategy over a sequential one on embryo in vitro development and clinical outcomes in intracytoplasmic sperm injection (ICSI) cycles. DESIGN: Retrospective cohort study. SETTING: University-affiliated private IVF center. PATIENT(S): This study included 4,564 ICSI cycles performed over 5 years, including autologous and oocyte donation treatments with extended embryo culture until blastocyst in one of the two defined culture strategies. INTERVENTION(S): Embryo cohorts were cultured in one of two culture systems: a fully undisturbed culture, including an incubator with integrated time-lapse technology, a one-step culture medium and embryo selection assisted by semi-automatic tools on the basis of embryo morphokinetics, or a sequential culture, using a conventional benchtop incubator, sequential media and traditional morphological evaluation under optical microscope. The effect of the culture strategies on embryo development and clinical outcomes was quantified by generalized estimated equations, controlling for possible confounders through the inverse probability of the treatment weighting method. MAIN OUTCOME MEASURE(S): Weighted odds ratios (ORs) and 95% confidence intervals (CIs) for live birth rate after fresh single embryo transfer and the cumulative live birth rate. In addition, blastocyst development and morphology and other intermediate outcomes were also assessed. RESULT(S): A significant positive association was found between the employment of undisturbed embryo culture and higher live birth rate in the first embryo transfer in both autologous (OR, 1.617; 95% CI, 1.074-2.435) and oocyte donation cycles (OR, 1.316; 95% CI, 1.036-1.672). Cumulative live birth rate after 1-year follow-up was also positively associated with the undisturbed culture strategy in oocyte donation cycles (OR, 1.5; 95% CI, 1.179-1.909), but not in autologous cycles (OR, 1.051; 95% CI, 0.777-1.423). Similarly, blastocyst rate, good morphology blastocyst rate, and utilization rate were positively associated with the employment of undisturbed culture in oocyte donation cycles, but not in autologous cycles. CONCLUSION(S): These findings imply that a culture system combining integrated time-lapse incubators with a one-step culture medium may enhance the success rates of patients undergoing ICSI treatment by increasing the production of higher quality blastocysts and improving embryo selection while streamlining laboratory procedures and workflow.

9.
J Plast Reconstr Aesthet Surg ; 85: 235-241, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37527572

RESUMO

INTRODUCTION: In patients undergoing either robotic neck dissection or no neck dissection, the neck recipient vessels for the free flaps remain unexposed. Intraoral vessels have been successfully used as microvascular recipients but their use in intraoral malignancies is uncommon. We describe our initial experience of using intraoral recipients in 30 patients with oral cavity malignancies. METHODS: For this retrospective observational study, the hospital records of all patients who underwent microvascular reconstruction using intraoral recipient vessels over a 14-month period at a tertiary care hospital in India were studied. Patient demographics, disease profile, details of oncosurgical resection, reconstructive procedure details, and postoperative recovery data were analyzed. RESULTS: Intraoral anastomosis was successfully performed in 30 patients. The average patient was middle-aged (mean age 54 years) and male (26/30). Location of the postexcision defect was the buccal mucosa in 16/30 and the tongue in 12/30 patients. Anterolateral thigh flap (ALT) was used in 28/30 patients. Recipient vessels were facial vessels in 24/30 patients and lingual vessels in 6/30 patients. Venous anastomotic coupler was used in 27/30 patients. Three patients underwent re-exploration for flap congestion with loss of flap in 2/30 patients. CONCLUSION: The intraoral approach offers consistent vascular anatomy and can be performed without any external incision and oro-cervical tunneling. Being technically challenging, it has an initial learning phase. Adequate mouth opening and preservation of recipient vessels during excision and neck dissection are important prerequisites. This approach can offer a scarless reconstruction, which can improve the psycho-social rehabilitation of the patients.


Assuntos
Retalhos de Tecido Biológico , Neoplasias Bucais , Procedimentos de Cirurgia Plástica , Pessoa de Meia-Idade , Humanos , Masculino , Centros de Atenção Terciária , Estudos Retrospectivos , Neoplasias Bucais/cirurgia , Retalhos de Tecido Biológico/irrigação sanguínea , Anastomose Cirúrgica/métodos
10.
JAMA Netw Open ; 6(1): e2253301, 2023 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-36705921

RESUMO

Importance: Randomized clinical trials (RCTs) on COVID-19 are increasingly being posted as preprints before publication in a scientific, peer-reviewed journal. Objective: To assess time to journal publication for COVID-19 RCT preprints and to compare differences between pairs of preprints and corresponding journal articles. Evidence Review: This systematic review used a meta-epidemiologic approach to conduct a literature search using the World Health Organization COVID-19 database and Embase to identify preprints published between January 1 and December 31, 2021. This review included RCTs with human participants and research questions regarding the treatment or prevention of COVID-19. For each preprint, a literature search was done to locate the corresponding journal article. Two independent reviewers read the full text, extracted data, and assessed risk of bias using the Cochrane Risk of Bias 2 tool. Time to publication was analyzed using a Cox proportional hazards regression model. Differences between preprint and journal article pairs in terms of outcomes, analyses, results, or conclusions were described. Statistical analysis was performed on October 17, 2022. Findings: This study included 152 preprints. As of October 1, 2022, 119 of 152 preprints (78.3%) had been published in journals. The median time to publication was 186 days (range, 17-407 days). In a multivariable model, larger sample size and low risk of bias were associated with journal publication. With a sample size of less than 200 as the reference, sample sizes of 201 to 1000 and greater than 1000 had hazard ratios (HRs) of 1.23 (95% CI, 0.80-1.91) and 2.19 (95% CI, 1.36-3.53) for publication, respectively. With high risk of bias as the reference, medium-risk articles with some concerns for bias had an HR of 1.77 (95% CI, 1.02-3.09); those with a low risk of bias had an HR of 3.01 (95% CI, 1.71-5.30). Of the 119 published preprints, there were differences in terms of outcomes, analyses, results, or conclusions in 65 studies (54.6%). The main conclusion in the preprint contradicted the conclusion in the journal article for 2 studies (1.7%). Conclusions and Relevance: These findings suggest that there is a substantial time lag from preprint posting to journal publication. Preprints with smaller sample sizes and high risk of bias were less likely to be published. Finally, although differences in terms of outcomes, analyses, results, or conclusions were observed for preprint and journal article pairs in most studies, the main conclusion remained consistent for the majority of studies.


Assuntos
COVID-19 , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Viés , Projetos de Pesquisa , Tamanho da Amostra
11.
Int J Infect Dis ; 122: 405-411, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35728748

RESUMO

OBJECTIVES: Staphylococcus aureus bacteremia (SAB) is a common infection worldwide. We compared SAB mortality in low- and middle-income countries (LMIC) versus high-income countries (HIC) in a meta-analysis. METHODS: We searched MEDLINE, Embase, and Cochrane Database of Systematic Reviews from 1991-2021 and included observational, single-country studies on patients with positive blood cultures for S. aureus. The main outcome was the proportion of patients with SAB who died in the hospital. A generalized linear mixed random-effects model was used to pool estimates, and a meta-regression was used to adjust for study-level characteristics. RESULTS: A total of 332 studies involving 517,671 patients in 39 countries were included. No study was conducted in a low-income country. Only 33 (10%) studies were performed in middle-income countries (MIC), which described 6,216 patients. The pooled in-hospital mortality was 32.4% (95% confidence interval [CI] 27.2%-38.2%, T2 = 0.3063) in MIC and 22.3% (95% CI 20.1%-24.6%, T2 = 0.3257) in HIC. In a meta-regression model, MIC had higher in-hospital mortality (adjusted odds ratio 1.37, 95% CI 1.11-1.71; P = 0.0042) than HIC. CONCLUSION: In SAB studies, LMIC are poorly represented. In-hospital mortality was significantly higher in MIC than in HIC. Research should be conducted in LMIC to characterize differences in care processes driving the mortality gap.


Assuntos
Bacteriemia , Infecções Estafilocócicas , Humanos , Razão de Chances , Staphylococcus aureus
12.
Clin Microbiol Infect ; 28(8): 1076-1084, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35339678

RESUMO

BACKGROUND: Precise estimates of mortality in Staphylococcus aureus bacteraemia (SAB) are important to convey prognosis and guide the design of interventional studies. OBJECTIVES: We performed a systematic review and meta-analysis to estimate all-cause mortality in SAB and explore mortality change over time. DATA SOURCES: The MEDLINE and Embase databases, as well as the Cochrane Database of Systematic Reviews, were searched from January 1, 1991 to May 7, 2021. STUDY ELIGIBILITY CRITERIA: Human observational studies on patients with S. aureus bloodstream infection were included. PARTICIPANTS: The study analyzed data of patients with a positive blood culture for S. aureus. METHODS: Two independent reviewers extracted study data and assessed risk of bias using the Newcastle-Ottawa Scale. A generalized, linear, mixed random effects model was used to pool estimates. RESULTS: A total of 341 studies were included, describing a total of 536,791 patients. From 2011 onward, the estimated mortality was 10.4% (95% CI, 9.0%-12.1%) at 7 days, 13.3% (95% CI, 11.1%-15.8%) at 2 weeks, 18.1% (95% CI, 16.3%-20.0%) at 1 month, 27.0% (95% CI, 21.5%-33.3%) at 3 months, and 30.2% (95% CI, 22.4%-39.3%) at 1 year. In a meta-regression model of 1-month mortality, methicillin-resistant S. aureus had a higher mortality rate (adjusted OR (aOR): 1.04; 95% CI, 1.02-1.06 per 10% increase in methicillin-resistant S. aureus proportion). Compared with prior to 2001, more recent time periods had a lower mortality rate (aOR: 0.88; 95% CI, 0.75-1.03 for 2001-2010; aOR: 0.82; 95% CI, 0.69-0.97 for 2011 onward). CONCLUSIONS: SAB mortality has decreased over the last 3 decades. However, more than one in four patients will die within 3 months, and continuous improvement in care remains necessary.


Assuntos
Bacteriemia , Staphylococcus aureus Resistente à Meticilina , Sepse , Infecções Estafilocócicas , Antibacterianos/uso terapêutico , Bacteriemia/microbiologia , Humanos , Sepse/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus
13.
Open Forum Infect Dis ; 9(5): ofac096, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35415199

RESUMO

Background: Deaths following Staphylococcus aureus bacteremia (SAB) may be related or unrelated to the infection. In SAB therapeutics research, the length of follow-up should be optimized to capture most attributable deaths and minimize nonattributable deaths. We performed a secondary analysis of a systematic review to describe attributable mortality in SAB over time. Methods: We systematically searched Medline, Embase, and Cochrane Database of Systematic Reviews from 1 January 1991 to 7 May 2021 for human observational studies of SAB. To be included in this secondary analysis, the study must have reported attributable mortality. Two reviewers extracted study data and assessed risk of bias independently. Pooling of study estimates was not performed due to heterogeneity in the definition of attributable deaths. Results: Twenty-four observational cohort studies were included. The median proportion of all-cause deaths that were attributable to SAB was 77% (interquartile range [IQR], 72%-89%) at 1 month and 62% (IQR, 58%-75%) at 3 months. At 1 year, this proportion was 57% in 1 study. In 2 studies that described the rate of increase in mortality over time, 2-week follow-up captured 68 of 79 (86%) and 48 of 57 (84%) attributable deaths that occurred by 3 months. By comparison, 1-month follow-up captured 54 of 57 (95%) and 56 of 60 (93%) attributable deaths that occurred by 3 months in 2 studies. Conclusions: The proportion of deaths that are attributable to SAB decreases as follow-up lengthens. Follow-up duration between 1 and 3 months seems optimal if evaluating processes of care that impact SAB mortality. Clinical Trials Registration: PROSPERO CRD42021253891.

14.
Hand (N Y) ; 16(2): 230-234, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-31155937

RESUMO

Background: The management of combined defects of the dorsum of the hand and the thumb can be quite challenging. The conventional teaching has been to use more than 1 flap for such discontinuous defects of the hand. Methods: We present a novel technique to provide a reliable skin cover to a concomitant second defect over thumb, which otherwise would require an additional flap, by recruiting the excess skin available after closure of the primary flap donor site of the hypogastric flap being used for the defect on the dorsum of hand. We report a case series of 5 patients wherein this technique has been used successfully. Results: The modified technique was able to successfully manage the concomitant defects of the dorsum of hand and the thumb in 1 stage. Conclusions: We find this innovation can help cover 2 separate defects on dorsum of hand and the thumb in 1 stage by utilizing just 1 flap instead of the conventional method of raising 2 flaps for such defects.


Assuntos
Retalhos Cirúrgicos , Polegar , Mãos , Humanos , Pele , Polegar/cirurgia
16.
Can J Cardiol ; 36(4): 577-583, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32220387

RESUMO

BACKGROUND: Machine learning (ML) encompasses a wide variety of methods by which artificial intelligence learns to perform tasks when exposed to data. Although detection of myocardial infarction has been facilitated with introduction of troponins, the diagnosis of acute coronary syndromes (ACS) without myocardial damage (without elevation of serum troponin) remains subjective, and its accuracy remains highly dependent on clinical skills of the health care professionals. Application of a ML algorithm may expedite management of ACS for either early discharge or early initiation of ACS management. We aim to summarize the published studies of ML for diagnosis of ACS. METHODS: We searched electronic databases, including PubMed, Embase, and Web of Science from inception up to January 13, 2019, for studies that evaluated ML algorithms for the diagnosis of ACS in patients presenting with chest pain. We then used random-effects bivariate meta-analysis models to summarize the studies. RESULTS: We retained 9 studies that evaluated ML in a total of 6292 patients. The prevalence of ACS in the evaluated cohorts ranged from relatively rare (7%) to common (57%). The pooled sensitivity and specificity were 0.95 and 0.90, respectively. The positive predictive values ranged from 0.64 to 1.0, and the negative predictive values ranged from 0.91 to 1.0. The positive and negative likelihood ratios ranged from 1.6 to 33.0 and 0.01 to 0.13, respectively. CONCLUSIONS: The excellent sensitivity, negative likelihood ratio, and negative predictive values suggest that ML may be useful as an initial triage tool for ruling out ACS.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Aprendizado de Máquina , Inteligência Artificial , Humanos
17.
Zootaxa ; 4706(3): zootaxa.4706.3.1, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-32230528

RESUMO

We compared the species names in the Reptile Database, a dedicated taxonomy database, with those in the NCBI taxonomy database, which provides the taxonomic backbone for the GenBank sequence database. About 67% of the known ~11,000 reptile species are represented with at least one DNA sequence and a binary species name in GenBank. However, a common problem arises through the submission of preliminary species names (such as "Pelomedusa sp. A CK-2014") to GenBank and thus the NCBI taxonomy. These names cannot be assigned to any accepted species names and thus create a disconnect between DNA sequences and species. While these names of unknown taxonomic meaning sometimes get updated, often they remain in GenBank which now contains sequences from ~1,300 such "putative" reptile species tagged by informal names (~15% of its reptile names). We estimate that NCBI/GenBank probably contain tens of thousands of such "disconnected" entries. We encourage sequence submitters to update informal species names after they have been published, otherwise the disconnect will cause increasing confusion and possibly misleading taxonomic conclusions.


Assuntos
Bases de Dados Genéticas , Bases de Dados de Ácidos Nucleicos , Répteis/genética , Animais , DNA
18.
Endocrine ; 66(2): 166-177, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31502211

RESUMO

PURPOSE: Gigantomastia refers to pathological breast enlargement usually occurring in the peripubertal or peripartum period. Idiopathic gigantomastia, however, is a rare entity with hypotheses citing local expression of hormones and growth factors in causing this disease, none of which have been systemically analysed. The purpose of this study was to delve deeper into the mechanistic pathways causing this condition. METHODS: Herein, we describe three patients of idiopathic gigantomastia, all of whom had had normal puberty and uneventful pregnancies. Further, one of the patients had postmenopausal gigantomastia which is extremely rare, with only four cases described in the literature. Serum markers of autoimmunity, incriminated hormones and growth factors analysed, were normal in all the cases. Breast tissue specimens were subjected to histopathological examination and immunohistochemistry for ER, PR and Her-2-Neu. Quantitative immunofluorescence for aromatase, IGF2, EGFR, TGF-ß, PDGFR-α, ß, IGF1 and PTHrP was also performed. RESULTS: Of these, the tissue expression of aromatase, IGF2, EGFR, TGF-ß, PDGFR-α and ß were found to be upregulated, whereas IGF1 and PTHrP were comparable to normal breast. CONCLUSION: This observation that paracrine overexpression of these factors is responsible for the pathogenesis of apparently idiopathic gigantomastia may have therapeutic ramifications in the future for patients with this debilitating condition.


Assuntos
Mama/anormalidades , Mama/metabolismo , Hipertrofia/metabolismo , Receptores ErbB/metabolismo , Feminino , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Fator de Crescimento Insulin-Like II/metabolismo , Proteína Relacionada ao Hormônio Paratireóideo/metabolismo , Fator de Crescimento Transformador beta/metabolismo
19.
JPEN J Parenter Enteral Nutr ; 41(7): 1240-1244, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-26290495

RESUMO

BACKGROUND: Parenteral nutrition (PN) via a central venous catheter is routinely used for surgical patients without a functioning gastrointestinal tract. Complications of PN can be metabolic and thrombotic. Blindness is a rare and unexpected complication. CASE: A young female patient with postcorrosive pyloric stenosis was started on PN through an indwelling central venous catheter. On the sixth day of PN, the patient reported sudden painless bilateral complete loss of vision. Examination revealed bilateral normal-sized pupils with normal pupillary reaction. There was complete bilateral absence of visual acuity with no perception of light. Fundus examination was normal. Magnetic resonance imaging revealed an acute infarct in the left occipital lobe, left corpus callosum, and posteromedial aspect of the left thalamus. No cardiac source of the thrombus could be identified. After supportive treatment, the vision started improving after 3 days; recovery was 95% after 10 days. A feeding jejunostomy was performed urgently under local anesthesia, and 1 month of enteral nutrition was administered. One month after the event, the patient's vision returned to normal. Definitive surgery in the form of antrectomy with Billroth II reconstruction was performed 8 weeks later. CONCLUSION: Blindness secondary to central venous catheterization is very rare; possible mechanisms are venous thrombosis with paradoxical emboli, air emboli, or accidental arterial puncture. Clinicians must exercise caution while using PN. A high index of suspicion is required to diagnose and treat unexpected complications.


Assuntos
Cegueira/etiologia , Cateterismo Venoso Central/efeitos adversos , Cateteres Venosos Centrais/efeitos adversos , Embolia Intracraniana/etiologia , Nutrição Parenteral Total/efeitos adversos , Trombose Venosa/etiologia , Adolescente , Cegueira/diagnóstico , Feminino , Humanos , Embolia Intracraniana/diagnóstico , Trombose Venosa/diagnóstico
20.
Int J Neural Syst ; 15(1-2): 55-70, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15912583

RESUMO

Recent experimental studies of hetero-synaptic interactions in various systems have shown the role of signaling in the plasticity, challenging the conventional understanding of Hebb's rule. It has also been found that activity plays a major role in plasticity, with neurotrophins acting as molecular signals translating activity into structural changes. Furthermore, role of synaptic efficacy in biasing the outcome of competition has also been revealed recently. Motivated by these experimental findings we present a model for the development of simple cell receptive field structure based on the competitive hetero-synaptic interactions for neurotrophins combined with cooperative hetero-synaptic interactions in the spatial domain. We find that with proper balance in competition and cooperation, the inputs from two populations (ON/OFF) of LGN cells segregate starting from the homogeneous state. We obtain segregated ON and OFF regions in simple cell receptive field. Our modeling study supports the experimental findings, suggesting the role of synaptic efficacy and the role of spatial signaling. We find that using this model we obtain simple cell RF, even for positively correlated activity of ON/OFF cells. We also compare different mechanism of finding the response of cortical cell and study their possible role in the sharpening of orientation selectivity. We find that degree of selectivity improvement in individual cells varies from case to case depending upon the structure of RF field and type of sharpening mechanism.


Assuntos
Modelos Neurológicos , Plasticidade Neuronal/fisiologia , Neurônios/fisiologia , Orientação/fisiologia , Sinapses/fisiologia , Percepção Visual/fisiologia , Animais , Humanos , Córtex Visual/citologia , Córtex Visual/fisiologia
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