Publications by authors named "Kevin Hewitt"

Background And Aims: Hepatic steatosis (HS), particularly macrovesicular steatosis (MaS), influences transplant outcomes. Accurate assessment of MaS is crucial for graft selection. While traditional assessment methods have limitations, non-invasive spectroscopic techniques like Raman and reflectance spectroscopy offer promise.

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This study explores a combined strategy of Raman and reflectance spectroscopy for quantifying liver fat content and fat droplet size, crucial in assessing donor livers. By using Monte Carlo simulations and experimental setups with oil-in-water phantoms, our findings indicate that Raman scattering can solely differentiate between varying fat contents. At the same time, reflectance intensity is influenced by both fat content and oil droplet size, with a more pronounced sensitivity to fat droplet size.

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During liver procurement, surgeons mostly rely on their subjective visual inspection of the liver to assess the degree of fatty infiltration, for which misclassification is common. We developed a Raman system, which consists of a 1064 nm laser, a handheld probe, optical filters, photodiodes, and a lock-in amplifier for real-time assessment of liver fat contents. The system performs consistently in normal and strong ambient light, and the excitation incident light penetrates at least 1 mm into duck fat phantoms and duck liver samples.

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To develop a treatment modality for triple-negative breast cancer, we investigated the efficacy of a bifunctional theranostic nanoprobes (BN) during Photodynamic Therapy (PDT) on human breast carcinoma and normal human cells. The BN is a 21 nm gold nanoparticles functionalized with Chlorin e6 (Ce6) and Epidermal Growth Factor (EGF). Attachment to gold nanoparticle stabilizes Ce6 while EGF acts as a cancer cell targeting agent.

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Purpose: Patients with a history of a bone marrow transplant (BMT) have a higher risk of infectious complications because of an immunocompromised state. It has been shown that giving timely antibiotics in 1 hour or less from presentation to the emergency department (ED) decreases morbidity and mortality in this patient population. We hypothesize that a quality improvement (QI) process, termed BMT Fever, will improve timely administration of antibiotics for this population presenting to the ED.

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Thromboembolism is a known phenomenon in patients with Coronavirus disease 2019 (COVID-19). Recent investigations have revealed that a significant proportion of those hospitalized with severe COVID-19 demonstrate clinical and laboratory markers compatible with hypercoagulability, which is differentiated from disseminated intravascular coagulation (DIC), termed COVID-associated coagulopathy. Additionally, there is increasing concern for development of acute ischemic stroke because of this hypercoagulable state.

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Pineal glioblastoma is an exceedingly rare potential etiology for a pineal region mass. The presentation, imaging appearance, and changes in treatment have been documented in a select number of cases since its first description in 1954. Through these cases, changes in treatment have shown to improve outcomes in select patients, some of which have had survival times over two or three years.

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In this paper, we report a successful combination of stimulated Raman spectroscopy (SRS) and surface-enhanced Raman scattering (SERS) using cw laser sources and gold/silica nanoparticles with embedded reporter molecules. We describe the preparation method for our gold/silica nanoparticles as well as the effect of probe wavelength, pump and probe power, polarization and sample concentration on the cwSESRS signal. Altogether, a stable ~12 orders of magnitude enhancement in the stimulated Raman signal is achieved because of the amplification of both pump and probe beams, leading to the detection of pico-molar nanoparticle concentrations, comparable to those of SERS.

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Spontaneous intracranial hypotension (SIH) associated with cerebrospinal fluid leak classically presents with postural headache. It is most commonly caused by the spontaneous dehiscence of a meningeal diverticulum or as a consequence of dural tears. The association between connective tissue disease and SIH is well known.

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We report a case of a ventriculoperitoneal shunt incidentally found within the stomach while the patient was undergoing a percutaneous endoscopic gastrostomy (PEG) tube placement. Among the complications of ventriculoperitoneal shunt placement, bowel perforation is rare a complication found in 0.01%-0.

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We describe the case of a previously healthy 33year-old male pilot recently arrived to the United States from Africa. The patient presented to our ED febrile and disoriented, with projectile coffee-ground emesis. He was later found to have severe malaria and cerebral parasitemia.

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Multimodal analgesia is common practice in the postoperative setting, but the utility of adjunctive analgesia in the emergency department (ED) is less understood. The primary objective of this study was to analyze ED prescriber ordering habits for adjunct nonopioid pain medication for opioid-naïve patients who require intravenous (IV) morphine or hydromorphone for acute pain. Secondary objectives were to assess initial and total opioid consumption in morphine equivalent units (MEU), pain scores, and ED length of stay (LOS) between groups.

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Nanotechnology offers a targeted approach to both imaging and treatment of cancer, the leading cause of death worldwide. Previous studies have found that nanoparticles with a wide variety of coatings initiate an immune response leading to sequestration in the liver and spleen. In an effort to find a nanoparticle platform which does not elicit an immune response, we created 43 nm and 44 nm of gold and silver nanoparticles coated with biomolecules normally produced by the body, α-lipoic acid and the epidermal growth factor (EGF), and have used mass spectroscopy to determine their biodistribution in mouse models, 24 h after tail vein injection.

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Due to the shortage of healthy donor organs, steatotic livers are commonly used for transplantation, placing patients at higher risk for graft dysfunction and lower survival rates. Raman Spectroscopy is a technique which has shown the ability to rapidly detect the vibration state of C-H bonds in triglycerides. The aim of this study is to determine whether conventional Raman spectroscopy can reliably detect and quantify fat in an animal model of liver steatosis.

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Although all emergency physicians are familiar with catastrophic causes of free intraperitoneal air, we describe the case of a healthy 26-year-old woman who presented to our emergency department (ED) with a nonsurgical and previously unreported cause of pneumoperitoneum. The patient presented to our ED with complaints of shoulder and neck pain several hours after having undergone FemVue ultrasonography (Femasys, Suwanee, GA) for infertility evaluation. The technique uses an air and saline solution mixture injected into the uterine cavity to assess for tubal patency and uterine cavity morphology.

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Collagen fibrils are the main constituent of the extracellular matrix surrounding eukaryotic cells. Although the assembly and structure of collagen fibrils is well characterized, very little appears to be known about one of the key determinants of their biological function-namely, the physico-chemical properties of their surface. One way to obtain surface-sensitive structural and chemical data is to take advantage of the near-field nature of surface- and tip-enhanced Raman spectroscopy.

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