Damian Valencia

Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111).

Tacrolimus-associated diabetic ketoacidosis: a case report and literature review

Post-transplant diabetes mellitus is a well-established adverse effect of calcineurin inhibitors, such as tacrolimus and cyclosporine. Failure to identify and manage this side effect in a timely manner could lead to life-threatening complications like diabetic ketoacidosis (DKA). To the best of our knowledge, this is the seventh published case of an uncommon but severe, and potentially fatal, adverse effect from tacrolimus after renal transplantation. The purpose of this case report is to add to the scant body of literature on tacrolimus-induced diabetes following renal transplantation.

Pasteurella multocida pneumonia in an immunocompetent patient: Case report and systematic review of literature

Pasteurella multocida infection is most commonly associated with the immunocompromised, mostly in the form of soft-tissue infection, although other sites of infection are still possible and have been reported in the immunocompetent. We report a case of an immunocompetent male with a history of exposure to carrier organisms without portal of entry who developed P. multocida pneumonia with bacteremia. We undertook a focused review of literature of previously reported cases of P. multocida pneumonia in patients with chronic obstructive pulmonary disease. This literature review supports the use of penicillins as the first line of treatment over macrolides. Considering the high mortality rates with P. multocida bacteremia, it is important for clinicians to maintain a high level of suspicion for this organism in any patient with a history of carrier species exposure.

Leuconostoc species endocarditis in an intravenous drug user

Infective endocarditis is a potentially lethal infection, which predominantly affects the atrioventricular valves. Rapid identification and management is critical to reduce morbidity and mortality in this patient population. Herein, we present a case of a 24-year-old man with Leuconostoc species infective endocarditis of the aortic valve. Disease course was complicated by several septic emboli to the brain, central retinal artery, and spleen. This case serves to remind clinicians that Leuconostoc species, which are typically not pathogenic to human species, can cause infective endocarditis in individuals with a history of intravenous drug use. <Learning objective: It is crucial that clinicians maintain a high index of suspicion in high-risk patients for infective endocarditis with Leuconostoc species, especially in the setting of positive blood cultures with group viridans streptococcus resistant to penicillin. Although cases of penicillin resistant group viridans streptococci have been reported, it is not common and merits further review. Leuconostoc is a Gram-positive ovoid cocci that is intrinsically vancomycin-resistant and is typically non-pathogenic to the human species.>.

Updates on the Role of Imaging in Cardiac Sarcoidosis

Purpose of reviewThe non-specific symptom profile and subclinical nature of disease along with variable region of cardiac involvement in systemic sarcoidosis make the diagnosis particularly challenging. The yield of endomyocardial biopsy, a gold standard for diagnosis, is not high unless coupled with additional imaging modalities to detect regional involvement. This review is focused on highlighting the major recent advances in imaging modalities and diagnosis of cardiac sarcoidosis.Recent findingsThere has been much interest and increasing research focused on developing newer and improved imaging modalities to establish diagnosis. CMR and 18F- FDG-PET are now considered imaging modalities of choice in most centers worldwide, but the data comparing both methodologies head-to-head is limited. Nevertheless, novel radiotracers (i.e. 68Ga-DOTANOC, 18F-Flurpiridaz, 13N-Ammonia) and hybrid combination PET/CMR imaging are coming to spotlight with improved sensitivity and specificity for earlier detection of myocardial sarcoid.SummaryAs CMR and PET are showing increased utilization in cardiac sarcoidosis, 201Th-SPECT, 99mTc MDP SPECT, 67Ga Scintigraphy, and 82Rb PET are falling out of favor. Newer imaging modalities, radionuclide tracers, and hybrid PET/CMR combinations have been promising in better detecting cardiac sarcoidosis and are currently being evaluated in larger trials.

Recurrent Cellulitis in a Patient with Papillomatosis Cutis Lymphostatica

Author(s): Pak, Stella; Markovic, John-Phillip; Yatsynovich, Yan; Tope, Ethan; Valencia, Damian

Transformation of hashimoto thyroiditis to Graves’ disease

Hashimoto’s thyroiditis and Graves’ disease are thyroid-specific autoimmune disorders with distinct pathological mechanism. Clinical presentation and histopathological features also vary greatly in these disorders. Sequential conversation from Hashimoto’s thyroiditis (HT) to Graves’ disease (GD) has been rarely reported throughout the world. Herein, we report a woman with history of HT, who then developed GD requiring total thyroidectomy. By reporting this case, we hope to raise awareness about this phenomenon among clinicians and illustrate the potential mechanisms behind such change. Improving recognition and identification of this potential conversation between HT and GD would allow clinicians to expeditiously implement appropriate treatment, increasing the quality of care. Correspondence to: Stella Pak, MD, Department of Medicine, Kettering Medical Center, Kettering, 3535 Southern Blvd, Kettering, OH 45429, USA, Tel. (937) 395-8997; Fax: (937) 395-8399; E-mail: Stella.Pak@ketteringhealth.org

Cerebral amyloidosis angiopathy related inflammation as a cause of erratic driving in elderly

Received: October 20, 2017; Accepted: October 31, 2017; Published: November 03, 2017 Figure 1. Computerized tomography of brain demonstrating a shift of midline structures by 6.4 mm to the left, leading to mass effect upon the right lateral ventricles. Cerebral amyloid angiopathy is a well-known clinicopathology prevalent in the elderly population. This disease is characterized by β-amyloid deposits in the vessels supplying blood to the cerebral cortex and the leptomeninges [1]. A rare complication of this disease is cerebral amyloid angiopathy-related inflammation (CAA-ri), which is a reversible encephalopathy caused by inflammation and edema [2]. Common clinical presentations of this complication are headaches, focal neurological deficit, and seizure [1]. Herein, we present a case of a patient who presented with an abrupt onset of driving impairment due to CAA-ri.

Ticking Bomb: Asymptomatic Mirizzi Syndrome

Mirizzi syndrome, also known as extrinsic biliary compression syndrome, is a rare clinical entity in which the common bile duct is obstructed by compression by the impaction of one or more gallstones in the cystic duct or gallbladder infundibulum. This case illustrates an absolutely asymptomatic presentation of Mirizzi syndrome in a 62-year-old, otherwise healthy, woman. Mirizzi syndrome was treated with preemptive laparotomy cholecystectomy. The present case is exemplary for careful evaluation with the proper index of suspicion in establishment of preoperative diagnosis as well as prompt treatment prior to development of complications.

Melena as Initial Presentation of Adenocarcinoma in Pancreatic Tail

Melena associated with gastric varices, in the setting of possible obstructing pancreatic adenocarcinoma, has been poorly documented as an initial presenting sign for pancreatic malignancy. Considering the late presentation of patients with pancreatic malignancy, it is important to consider all potential presenting symptoms for the early detection and treatment of pancreatic malignancy. Below, we present a patient with no history of liver pathology, who presents with melena and gastric varices, likely relating to portal hypertension in the setting of an obstructing pancreatic malignancy.