Biomedical subjects

Robert Sweet

Publications and source records attributed to Robert Sweet.

7 recordsLinked to original sources

PubMed2006

Mail-in crystallography program at Brookhaven National Laboratory's National Synchrotron Light Source.

For the last six years, the Macromolecular Crystallography Research Resource (PXRR) has been providing mail-in access to several beamlines at the National Synchrotron Light Source (NSLS) for X-ray diffraction. This program is available at no charge for academic users from the US and around the world. This service has fostered a new paradigm for collaborations between the local staff scientists and synchrotron users. It also accelerates the innovation of new productivity tools, which benefit users who come to NSLS beamlines as well as those who use the mail-in program.

Biomedical Research↗

PubMed2006

Factors affecting unanticipated hospital admission following otolaryngologic day surgery.

BACKGROUND: Day surgery constitutes an important part of modern otolaryngology practice. However, high rates of unplanned admissions remain an issue. OBJECTIVE: To determine the incidence, reasons, and predictive factors for unanticipated admission after ambulatory otolaryngologic surgery. METHODS: A retrospective review of all cases of unplanned admission following otolaryngology day surgery at a tertiary care centre over a 4-year period from 2000 to 2004. Data relating to patient demographics, physical status, surgical procedure, perioperative complications, and reasons for hospital admission were recorded. A case-control analysis of these parameters with nonadmitted day surgery patients was used for comparison. RESULTS: During the above period, 1106 patients underwent otolaryngologic day surgery, of whom 74 (6.7%) required admission. Fifty-seven percent of the patients were male, and the average age was 48.9 years. The three most common procedures with unplanned admission were open neck biopsy (27%), functional endoscopic sinus surgery (20.3%), and panendoscopy (16.2%). The reasons for admission could be divided into airway monitoring (37.7%), postoperative bleeding (28.6%), the need for supportive or pain management (19.5%), anesthetic complication (5.2%), cardiovascular complication (3.9%), clerical error (3.9%), and suspicion of a cerebrospinal fluid leak (1.3%). Risk factors for admission were determined to be an American Society of Anesthesiologists' class of 3 or greater, open neck surgical procedures, and a length of surgery of 60 minutes or greater. Minor factors included the use of general anesthesia, male gender, advanced age, and living far from a hospital. CONCLUSIONS: This study suggests strategies to reduce the rate of unplanned admission by means of careful preoperative assessment and planning, patient selection, careful scheduling of higher-risk patients, and appropriate postoperative observation and management.

Adolescent↗

PubMed2004

Apert syndrome and hearing loss with ear anomalies: a case report and literature review.

Acrocephalosyndactyly Type I, or Apert syndrome is a congenital disorder characterized by craniosynostosis and syndactyly. When hearing loss occurs, it is usually bilateral and conductive, often attributable to congenital stapes fixation. In determining treatment, the risk of gusher with stapedectomy becomes an important consideration. We present an adult with Apert syndrome and hearing loss, with particular emphasis on a progressive conductive component in one ear. Surgical exploration failed to reveal any definite middle ear abnormality and no stapedectomy was performed. A theory on the pathogenesis of the conductive loss in our patient follows a brief review of the literature on gusher in patients with ear malformations.

Acrocephalosyndactylia↗

PubMed2004

The role of the middle fossa approach in the management of traumatic facial paralysis.

There are several controversial aspects to the management of traumatic facial paralysis. One of these involves the precise nature of surgical intervention once the decision to operate has been made. Between June 1, 1984, and June 30, 1993, we surgically treated 220 cases of traumatic facial paralysis with good cochlear reserve by decompressing the tympanic and mastoid segments via a transmastoid approach followed by decompression of the geniculate ganglion and the distal half of the labyrinthine segment via a middle fossa approach. We discuss the results of surgery via the middle fossa approach, and we review the literature.

Adolescent↗

PubMed2003

Plasma and cerebrospinal fluid alpha1-antichymotrypsin levels in Alzheimer's disease: correlation with cognitive impairment.

alpha-1-Antichymotrypsin (ACT) is present in neuritic plaques in which it participates in the inflammatory cascade of Alzheimer's disease (AD). Reports of blood ACT levels in AD, and its usefulness as a disease biomarker, have been conflicting. In an effort to clarify this, we measured plasma ACT levels in 516 white subjects including 359 subjects with probable or possible AD, 44 subjects with other late-life dementias, and 113 nondemented people. Subjects with systemic inflammatory diseases or who were taking antiinflammatory medications were excluded. All patients underwent extensive medical and detailed neuropsychological examinations at the time their blood was drawn. We found that plasma ACT levels were elevated in AD patients compared with the control group (p = 0.01) and were associated with severity of AD dementia; there was a negative association with the Mattis Dementia Rating Scale (a global measure of cognition) and a positive association with the Clinical Dementia Rating Scale (a global functional assessment). These relationships remained significant after controlling for demographic and genetic variables. When AD subjects were stratified into subgroups by dementia severity, matched by age, education, and gender, increased serum ACT correlated with Clinical Dementia Rating Scale (p = 0.0041) or Mattis Dementia Rating Scale (p = 0.0031) scores. ACT measurements in cerebrospinal fluid from an additional 34 AD cases and 16 controls showed elevated levels (p = 0.02) in AD. There was a negative correlation (p = 0.037) between cerebrospinal fluid ACT levels and clinical severity as measured by the Mini-Mental State Examination. Our results demonstrate that peripheral ACT levels are elevated in AD, but not in dementias other than AD, and they increase with progression of AD dementia. Although not useful as a diagnostic biomarker, ACT may reflect disease severity and may be helpful as a within subject biomarker in interventions (particularly with antiinflammatory agents) directed at slowing or halting progression of disease.

Aged↗

PubMed2002

Fibroblast growth factor-10 is a mitogen for urothelial cells.

Fibroblast growth factor (FGF)-10 plays an important role in regulating growth, differentiation, and repair of the urothelium. This process occurs through a paracrine cascade originating in the mesenchyme (lamina propria) and targeting the epithelium (urothelium). In situ hybridization analysis demonstrated that (i) fibroblasts of the human lamina propria were the cell type that synthesized FGF-10 RNA and (ii) the FGF-10 gene is located at the 5p12-p13 locus of chromosome 5. Recombinant (r) preparations of human FGF-10 were found to induce proliferation of human urothelial cells in vitro and of transitional epithelium of wild-type and FGF7-null mice in vivo. Mechanistic studies with human cells indicated two modes of FGF-10 action: (i) translocation of rFGF-10 into urothelial cell nuclei and (ii) a signaling cascade that begins with the heparin-dependent phosphorylation of tyrosine residues of surface transmembrane receptors. The normal urothelial phenotype, that of quiescence, is proposed to be typified by negligible levels of FGF-10. During proliferative phases, levels of FGF-10 rise at the urothelial cell surface and/or within urothelial cell nuclei. An understanding of how FGF-10 works in conjunction with these other processes will lead to better management of many diseases of the bladder and urinary tract.

Amino Acid Sequence↗

PubMed2002

Simulation of bleeding in endoscopic procedures using virtual reality.

BACKGROUND AND PURPOSE: An image-based approach has been developed to represent bleeding in a simulator for transurethral resection of the prostate (TURP). Whereas previous groups attempted to simulate bleeding mathematically over tissue surfaces or in blood vessels, our approach focused on macroscopic visualization of bleeding in a fluid environment. The TURP is an ideal procedure for simulator-based training because of its importance as a skill to acquire as well as its long learning curve. The most challenging step in creating a realistic TURP simulator is simulated bleeding. MATERIALS AND METHODS: We took an image-based approach in which we generated blood flow movies of bleeding vessels having different severity and position under variable fluid flow conditions and processed them to separate the blood flow from the background anatomy. We then organized the movies into a parametric database. During the running of the simulation, resection systematically triggers the playback of a blood flow movie (bleeding event). The movie is texture mapped onto a virtual surface that is positioned, oriented, morphed, composited, and looped into the virtual scene. RESULTS AND CONCLUSION: The technique produced an accurate depiction of bleeding vessels one would encounter during a TURP. The image changes readily according to the fluid flow state.

Blood Loss, Surgical↗