Tulio A. Valdez
Stanford University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Tulio A. Valdez.
Annals of Otology, Rhinology, and Laryngology | 2002
Tulio A. Valdez; Stanley M. Shapshay
Idiopathic subglottic stenosis (ISS) is a rare inflammatory process of unknown cause, usually limited to the subglottic region and the first 2 tracheal rings. We performed a retrospective analysis of our experience with a series of patients with this condition. The study involved retrospective review of the records of patients with ISS. A series of criteria that included patient clinical history, laboratory tests, flexible nasolaryngoscopic examination, and biopsies were used to establish a diagnosis. Symptoms, treatment, and outcome were examined. A total of 16 patients were identified; 14 were female (87.5%), and 2 were male. The mean follow-up time was 75.5 months. Fourteen patients required surgical treatment for respiratory compromise. Nine of these cases have been controlled effectively with endoscopic laser techniques. Endoscopic management failed in 5 patients, and 2 patients underwent laryngotracheal resection and reconstruction. Mitomycin-C was used in 6 patients as an adjuvant to endoscopic laser surgery. Patients in whom endoscopic treatment failed were noted to have thicker (>1 cm) and more complex stenoses. The diagnosis of ISS is a diagnosis of exclusion. A complete workup of the patient must be performed to rule out other causes of stenosis. Endoscopic laser surgery is a valid initial approach for thinner, noncomplicated lesions. Patients with thicker, complex lesions in whom endoscopic treatment fails are best managed with laryngotracheal resection and reconstruction. However, adjuvant use of mitomycin-C may prove beneficial in the treatment of these patients. Estrogen may play a role in the pathogenesis of ISS by altering the wound healing response.
Pediatrics | 2008
Julina Ongkasuwan; Tulio A. Valdez; Kristina G. Hulten; Edward O. Mason; Sheldon L. Kaplan
OBJECTIVE. We review the impact of pneumococcal conjugate vaccine on pneumococcal mastoiditis in children at Texas Childrens Hospital. METHODS. The medical charts (including the number of pneumococcal conjugate vaccine doses) for children with pneumococcal mastoiditis treated at Texas Childrens Hospital between January 1995 and June 2007 were reviewed retrospectively. Isolates were serotyped with the capsular swelling method. Pulsed-field gel electrophoresis was performed on the 19A isolates and multilocus sequence typing on selected 19A clones. RESULTS. Forty-one pneumococcal mastoiditis cases were identified, and 19A (n = 19) was the most common serotype. Before the introduction of pneumococcal conjugate vaccine (from 1995 to December 1999), 0 of 12 cases were 19A. Between April 2000 and October 2006, 15 cases of pneumococcal mastoiditis occurred, and 5 were 19A. Fourteen cases of pneumococcal mastoiditis occurred between November 2006 and June 2007, all of which were 19A. Mastoiditis caused by 19A isolates was more likely to present with subperiosteal abscess and was more likely to need intraoperative mastoidectomy than was mastoiditis caused by non-19A isolates. Multidrug resistance was also common among the 19A isolates; 13 (68%) of the 19A isolates were resistant to all antibiotics tested routinely. Pulsed-field gel electrophoresis analysis placed 14 (74%) of the 19 serotype 19A isolates into a highly related group; 12 isolates were classified as closely related, and 2 were possibly related. Multilocus sequence typing analysis placed the pulsed-field gel electrophoresis cluster isolates into clonal complex 271 (sequence types 320 and 1451). CONCLUSIONS. At Texas Childrens Hospital, 19A has become the predominant serotype causing pneumococcal mastoiditis, partly related to the emergence of multidrug-resistant clonal complex 271 strains. Subperiosteal abscesses and the need for mastoidectomy were more common in children with mastoiditis caused by serotype 19A isolates, compared with isolates of other serotypes.
Otolaryngology-Head and Neck Surgery | 1999
Tulio A. Valdez; Kathleen McMillan; Stanley M. Shapshay
OBJECTIVES: Microvascular targeting with the 585-nm pulsed dye laser (PDL) may provide a new form of therapy to control symptoms caused by recurrent respiratory papillomatosis (RRP). METHODS: Ten patients with RRP underwent 13 procedures under general anesthesia with the 585-nm PDL. A micromanipulator (11 procedures) and a flexible nasolaryngoscope (2 procedures) were used to deliver the laser pulses. Patients were followed postoperatively according to protocol. RESULTS: Clinical examination revealed regression of papillomas in all patients. Seven patients had complete regression after PDL surgery, and 2 patients had partial response to treatment. One patient was lost to follow-up. No complications were present during this prospective nonrandomized pilot study. CONCLUSION: Patients treated with PDL experienced regression of their papillomas. PDL may provide patients with RRP with an alternative treatment without the risks associated with CO2 laser surgery. This procedure also has potential to be delivered on an outpatient basis with flexible fiberoptic laryngoscopes.
Accounts of Chemical Research | 2017
Rishikesh Pandey; Santosh Kumar Paidi; Tulio A. Valdez; Chi Zhang; Nicolas Spegazzini; Ramachandra R. Dasari; Ishan Barman
The successful development of a noninvasive blood glucose sensor that can operate reliably over sustained periods of time has been a much sought after but elusive goal in diabetes management. Since diabetes has no well-established cure, control of elevated glucose levels is critical for avoiding severe secondary health complications in multiple organs including the retina, kidney and vasculature. While fingerstick testing continues to be the mainstay of blood glucose detection, advances in electrochemical sensing-based minimally invasive approaches have opened the door for alternate methods that would considerably improve the quality of life for people with diabetes. In the quest for better sensing approaches, optical technologies have surfaced as attractive candidates as researchers have sought to exploit the endogenous contrast of glucose, notably its absorption, scattering, and polarization properties. Vibrational spectroscopy, especially spontaneous Raman scattering, has exhibited substantial promise due to its exquisite molecular specificity and minimal interference of water in the spectral profiles acquired from the blood-tissue matrix. Yet, it has hitherto been challenging to leverage the Raman scattering signatures of glucose for prediction in all but the most basic studies and under the least demanding conditions. In this Account, we discuss the newly developed array of methodologies that address the key challenges in measuring blood glucose accurately using Raman spectroscopy and unlock new prospects for translation to sustained noninvasive measurements in people with diabetes. Owing to the weak intensity of spontaneous Raman scattering, recent research has focused on enhancement of signals from the blood constituents by designing novel excitation-collection geometries and tissue modulation methods while our attempts have led to the incorporation of nonimaging optical elements. Additionally, invoking mass transfer modeling into chemometric algorithms has not only addressed the physiological lag between the actual blood glucose and the measured interstitial fluid glucose values but also offered a powerful tool for predictive measurements of hypoglycemia. This framework has recently been extended to provide longitudinal tracking of glucose concentration without necessitating extensive a priori concentration information. These findings are advanced by the results of recent glucose tolerance studies in human subjects, which also hint at the need for designing nonlinear calibration models that can account for subject-to-subject variations in skin heterogeneity and hematocrit levels. Together, the emerging evidence underscores the promise of a blood withdrawal-free optical platform-featuring a combination of high-throughput Raman spectroscopic instrumentation and data analysis of subtle variations in spectral expression-for diabetes screening in the clinic and, ultimately, for personalized monitoring.
Scientific Reports | 2015
Rishikesh Pandey; Santosh Kumar Paidi; Jeon Woong Kang; Nicolas Spegazzini; Ramachandra R. Dasari; Tulio A. Valdez; Ishan Barman
Despite its widespread prevalence, middle ear pathology, especially the development of proliferative lesions, remains largely unexplored and poorly understood. Diagnostic evaluation is still predicated upon a high index of clinical suspicion on otoscopic examination of gross morphologic features. We report the first technique that has the potential to non-invasively identify two key lesions, namely cholesteatoma and myringosclerosis, by providing real-time information of differentially expressed molecules. In addition to revealing signatures consistent with the known pathobiology of these lesions, our observations provide the first evidence of the presence of carbonate- and silicate-substitutions in the calcium phosphate plaques found in myringosclerosis. Collectively, these results demonstrate the potential of Raman spectroscopy to not only provide new understanding of the etiology of these conditions by defining objective molecular markers but also aid in margin assessment to improve surgical outcome.
American Journal of Otolaryngology | 2009
Collin S. Karmody; Tulio A. Valdez; Urmen Desai; Nikolas H. Blevins
OBJECTIVE The study aimed to discuss the association between sensorineural hearing loss (SNHL) and inflammatory bowel disease (IBD). METHODS We reviewed cases of patients with known IBD seen in an otolaryngology practice with documentation of all otologic data including age of onset, family history of otologic problems, exposure to noise, audiometric findings, and so on. RESULTS Of 38 patients with a history of IBD, 22 had documented SNHL. Nineteen of these had no other identifiable etiology for their inner ear dysfunction. Fourteen of these patients had a diagnosis of ulcerative colitis and 5 had Crohn disease. Sixteen patients had bilateral SNHL, and 3 patients had unilateral SNHL. Only one patient had a lasting response of SNHL to medical treatment. CONCLUSION This review suggests that SNHL is an extraintestinal association of IBD. As IBD is considered to be a local or systemic immunopathy, the associated SNHL might also be an expression of systemic immune dysfunction.
International Journal of Pediatric Otorhinolaryngology | 2009
Shraddha Mukerji; Alex J. Osborn; Jess Roberts; Tulio A. Valdez
An infant initially diagnosed with a parotid hemangioma presented with stridor and thrombocytopenia. Diagnosis of Kaposiform hemangioendothelioma was confirmed with biopsy. The child succumbed to multi-system organ failure related to consumptive coagulopathy despite aggressive medical management. Kaposiform hemangioendothelioma is a rare head and neck tumor that may be mistaken for a hemangioma on preliminary diagnosis, which may lead to increased morbidity and mortality especially in the setting of Kasabach-Merritt phenomenon. A platelet count may provide an early and important clue to the possibility of coagulopathy; prompting physicians to look for a diagnosis other than a simple hemangioma.
International Journal of Pediatric Otorhinolaryngology | 2012
Corrie E. Roehm; Juan C. Salazar; Nathan Hagstrom; Tulio A. Valdez
OBJECTIVE Invasive rhinocerebral fungal infections are a difficult and often fatal problem in children with hematologic malignancies, with increasing reports of rare pathogens. We describe a case of congenital acute lymphoblastic leukemia (ALL) and invasive fungal rhinosinusitis involving Acremonium and Phoma species, not previously reported in invasive pediatric fungal rhinosinusitis, and review all published cases of human Phoma infections. METHODS A literature and institutional review for Phoma spp. was completed including patient demographics, infection site, immune status, treatment and outcome. RESULTS A female neonate with acute lymphoblastic leukemia presented with hyperleukocytosis and advanced invasive Phoma and Acremonium spp. rhinosinusitis. Despite aggressive medical and surgical therapy, the disease progressed to a rhinocerebral infection with a fatal outcome. Twenty cases of Phoma spp. were found in a complete literature search, including 6 females and 14 males from 18 months to 77 years old. Infections were superficial in fifteen patients and involved deeper tissue in five patients, with sites including cutaneous, subcutaneous and deep tissue sites (eye, lung, extremity deep tissue compartments). CONCLUSIONS This case highlights the risks and grave prognosis of fulminant invasive fungal rhinosinusitis in the context of congenital leukemia, and the potential for rare fungal species in neonates with immunosuppression.
Analytical Chemistry | 2014
Tulio A. Valdez; Rishikesh Pandey; Nicolas Spegazzini; Kaitlyn Longo; Corrie E. Roehm; Ramachandra R. Dasari; Ishan Barman
A common motif in otolaryngology is the lack of certainty regarding diagnosis for middle ear conditions, resulting in many patients being overtreated under the worst-case assumption. Although pneumatic otoscopy and adjunctive tests offer additional information, white light otoscopy has been the main tool for diagnosis of external auditory canal and middle ear pathologies for over a century. In middle ear pathologies, the inability to avail high-resolution structural and/or molecular imaging is particularly glaring, leading to a complicated and erratic decision analysis. Here, we propose a novel multiwavelength fluorescence-based video-rate imaging strategy that combines readily available optical elements and software components to create a novel otoscopic device. This modified otoscope enables low-cost, detailed and objective diagnosis of common middle ear pathological conditions. Using the detection of congenital cholesteatoma as a specific example, we demonstrate the feasibility of fluorescence imaging to differentiate this proliferative lesion from uninvolved middle ear tissue based on the characteristic autofluorescence signals. Availability of real-time, wide-field chemical information should enable more complete removal of cholesteatoma, allowing for better hearing preservation and substantially reducing the well-documented risks, costs and psychological effects of repeated surgical procedures.
Laryngoscope | 2001
Rahul K. Shah; Tulio A. Valdez; Zhi Wang; Stanley M. Shapshay
Objectives/Hypothesis This study examined the role of the pulsed‐dye laser (PDL) at 585 nm coupled with retinoic acid at therapeutic (5.0 mg/kg) and nontherapeutic (0.5 mg/kg) doses to delay the progression of cancer with a two‐hit approach. The existing vasculature is selectively targeted by the laser, whereas retinoic acid inhibits future angiogenesis.