Biomedical subjects

Vijay Anand

Publications and source records attributed to Vijay Anand.

12 recordsLinked to original sources

PubMed2005

Does head extension and flexion increase postural instability in elderly subjects when visual information is kept constant?

The present study determined the effects of flexing and extending the head on the postural stability and mean anterior-posterior (A-P) center of mass (CM) position during upright stance in the elderly. To ensure visual input to stability was not a confounding variable, visual information was kept as constant as possible for all head positions. Twelve healthy elderly subjects (72.3 +/- 4.7 years) were asked to stand stationary on a single force-platform. Postural stability (assessed using the rms A-P excursion of the center of pressure (CP)) was determined for standing with the head erect, and with the head flexed and extended. The vestibular contribution to postural stability becomes increasingly important under challenging conditions, so to highlight the effects of vestibular system input, measurements of postural stability under conditions where visual and somatosensory inputs were disrupted were included. Changes in the mean A-P CM position when tilting the head were assessed by determining changes in the mean A-P location of the CP from standing with the head erect. Compared to standing with the head erect and looking straight ahead, postural stability was reduced when the head was flexed or extended (P < 0.01). Changes in mean A-P CM position were only significant when standing with the head flexed (P < 0.05). This suggests that increases in postural instability with the head tilted from the erect position may be in part due to mechanical perturbation rather than solely vestibular disruption.

Aged↗

PubMed2005

Computer-assisted surgical navigation in revision endoscopic sinus surgery.

The anatomical variations of surgical landmarks associated with revision endoscopic sinus surgery (ESS) represent a significant challenge even to the most experienced surgeon. Multiple studies have demonstrated higher rates of both minor and major complications associated with revision cases. In the past decade, the availability of multiple computer-assisted surgical navigation systems has resulted in its widespread adoption as a tool in ESS.Computer-aided surgery (CAS) allows for triplanar anatomic localization, which may improve spatial orientation and help avoid trauma to vital structures, namely the orbit and anterior skull base.Theoretically, this would result in a lower rate of complications and a more complete surgical exploration. Future advances in CAS involve real-time computer-assisted surgical navigation using an operating room-based CT, C-arm, or MRI unit.

Endoscopy↗

PubMed2004

Expression, purification, and characterization of BsSco, an accessory protein involved in the assembly of cytochrome c oxidase in Bacillus subtilis.

The studies described here were performed to characterize further the plasma membrane associated protein BsSco, which is the product of the gene ypmQ, in Bacillus subtilis. BsSco is a member of the Sco family of proteins found in the inner mitochondrial membrane of yeast and humans and implicated as an accessory protein in the assembly of the Cu(A) site of cytochrome c oxidase. We have cloned the gene expressing BsSco, placed a six-histidine tag on its C-terminus, and over-expressed this protein in B. subtilis. Recombinant BsSco with the his-tag has been purified from Triton X-100-solubilized plasma membranes by nickel metal affinity chromatography. Mass spectral analysis of the purified protein is consistent with processing of BsSco by signal peptidase II removing an N-terminal putative transmembrane sequence to leave an acyl-glyceryl moiety at cysteine residue 19. Antibodies, raised against purified, recombinant BsSco, were used to characterize the timing of the level of native BsSco in batch cultures of wild-type B. subtilis. There is a marked lag in the level of native BsSco, but it does appear prior to cytochrome c oxidase, which is expressed in late stage growth. This work supports a role for BsSco in the assembly of the Cu(A) site of cytochrome c oxidase and its functional relationship to the Sco proteins found in eukaryotic cells.

Bacillus subtilis↗

PubMed2004

Fluconazole nasal spray in the treatment of allergic fungal sinusitis: a pilot study.

The authors describe a prospective pilot study designed to investigate the use of topical nasal antifungal spray in addition to systemic steroids and itraconazole in the treatment of allergic fungal sinusitis. Sixteen patients with a history of allergic fungal sinusitis were given fluconazole nasal spray and followed for 3 months. Stabilization or improvement of disease without significant side effects was observed in 12 of the 16 patients who were treated with this protocol. These results indicate that topical fluconazole application may help patients with allergic fungal sinusitis; however, a larger multicenter study with longer patient follow-up is required to validate these initial findings.

Administration, Topical↗

PubMed2003

A role for apolipoprotein(a) in protection of the low-density lipoprotein component of lipoprotein(a) from copper-mediated oxidation.

Low-density lipoprotein (LDL) oxidation is stimulated by copper. Addition of a recombinant form of apolipoprotein(a) (apo(a); the distinguishing protein component of lipoprotein(a)) containing 17 plasminogen kringle IV-like domains (17K r-apo(a)) protects LDL against oxidation by copper. Protection is specific to apo(a) and is not achieved by plasminogen or serum albumin. When Cu(2+) is added to 17K r-apo(a), its intrinsic fluorescence is quenched in a concentration-dependent and saturable manner. Quenching is unchanged whether performed aerobically or anaerobically and is reversible by ethylenediaminetetraacetate, suggesting that it is due to equilibrium binding of Cu(2+) and not to oxidative destruction of tryptophan residues. The fluorescence change exhibits a sigmoid dependence on copper concentration, and time courses of quenching are complex. At copper concentrations below 10 microM there is little quenching, whereas above 10 microM quenching proceeds immediately as a double-exponential decay. The affinity and kinetics of copper binding to 17K r-apo(a) are diminished in the presence of the lysine analogue epsilon -aminocaproic acid. We propose that copper binding to the kringle domains of 17K is mediated by a His-X-His sequence that is located about 5A from the closest tryptophan residue of the lysine binding pocket. Copper binding may account for the natural resistance to copper-mediated oxidation of lipoprotein(a) relative to LDL that has been previously reported and for the protection afforded by apo(a) from copper-mediated oxidation of LDL that we describe in the present study.

Apolipoproteins A↗

PubMed2003

Postural stability in the elderly during sensory perturbations and dual tasking: the influence of refractive blur.

PURPOSE: To determine the influence of refractive blur on postural stability during somatosensory and vestibular system perturbation and dual tasking. METHODS: Fifteen healthy, elderly subjects (mean age, 71 +/- 5 years), who had no history of falls and had normal vision, were recruited. Postural stability during standing was assessed using a force platform, and was determined as the root mean square (RMS) of the center of pressure (COP) signal in the anterior-posterior (A-P) and medial-lateral directions collected over a 30-second period. Data were collected under normal standing conditions and with somatosensory and vestibular system perturbations. Measurements were repeated with an additional physical and/or cognitive task. Postural stability was measured under conditions of binocular refractive blur of 0, 1, 2, 4, and 8 D and with eyes closed. The data were analyzed with a population-averaged linear model. RESULTS: The greatest increases in postural instability were due to disruptions of the somatosensory and vestibular systems. Increasing refractive blur caused increasing postural instability, and its effect was greater when the input from the other sensory systems was disrupted. Performing an additional cognitive and physical task increased A-P RMS COP further. All these detrimental effects on postural stability were cumulative. CONCLUSIONS: The findings highlight the multifactorial nature of postural stability and indicate why the elderly, many of whom have poor vision and musculoskeletal and central nervous system degeneration, are at greater risk of falling. The findings also highlight that standing instability in both normal and perturbed conditions was significantly increased with refractive blur. Correcting visual impairment caused by uncorrected refractive error could be a useful intervention strategy to help prevent falls and fall-related injuries in the elderly.

Aged↗

PubMed2003

Postural stability changes in the elderly with cataract simulation and refractive blur.

PURPOSE: To determine the influence of cataractous and refractive blur on postural stability and limb-load asymmetry (LLA) and to establish how postural stability changes with the spatial frequency and contrast of the visual stimulus. METHODS: Thirteen elderly subjects (mean age, 70.76 +/- 4.14 [SD] years) with no history of falls and normal vision were recruited. Postural stability was determined as the root mean square [RMS] of the center of pressure (COP) signal in the anterior-posterior (A-P) and medial-lateral directions and LLA was determined as the ratio of the average body weight placed on the more-loaded limb to the less-loaded limb, recorded during a 30-second period. Data were collected under normal standing conditions and with somatosensory system input disrupted. Measurements were repeated with four visual targets with high (8 cyc/deg) or low (2 cyc/deg) spatial frequency and high (Weber contrast, approximately 95%) or low (Weber contrast, approximately 25%) contrast. Postural stability was measured under conditions of binocular refractive blur of 0, 1, 2, 4, and 8 D and with cataract simulation. The data were analyzed in a population-averaged linear model. RESULTS: The cataract simulation caused significant increases in postural instability equivalent to that caused by 8-D blur conditions, and its effect was greater when the input from the somatosensory system was disrupted. High spatial frequency targets increased postural instability. Refractive blur, cataract simulation, or eye closure had no effect on LLA. CONCLUSIONS: Findings indicate that cataractous and refractive blur increase postural instability, and show why the elderly, many of whom have poor vision along with musculoskeletal and central nervous system degeneration, are at greater risk of falling. Findings also highlight that changes in contrast sensitivity rather than resolution changes are responsible for increasing postural instability. Providing low spatial frequency information in certain environments may be useful in maintaining postural stability. Correcting visual impairment caused by uncorrected refractive error and cataracts could be a useful intervention strategy to help prevent falls and fall-related injuries in the elderly.

Aged↗

PubMed2002

The effect of refractive blur on postural stability.

The effect of refractive blur upon postural stability was investigated under three conditions: normal standing, standing with input from the somatosensory system disrupted and standing with input from the somatosensory and vestibular systems disrupted. Standing stability was assessed using the centre of pressure (COP) signal from force plate data in four young subjects (mean 23.9+/-3.1 years) and five repeated sets of measurements were taken. The subjects looked straight ahead at a horizontal and vertical square wave pattern of 2.5 cycles (degree)(-1). Under each of the three test conditions, standing stability was measured with the optimal refractive correction and under binocular blur levels of 0, + 1, + 2, + 4, and + 8 D and with eyes closed. In the normal standing condition, dioptric blur had only a mild effect on postural stability. However refractive blur produced large increases in postural instability when input from one or both of the other two sensory systems were disrupted. We hypothesized that dioptric blur would have an even great effect on postural stability if the visual target used was of higher spatial frequency. This was confirmed by repeated measurements on one subject using a target of 8 cycles (degree)(-1). The study highlights the possible importance of an optimal correction to postural stability, particular in situations (or people) where input from the somatosensory and/or vestibular systems are disrupted, and where the visual surrounds are of high spatial frequency.

Adult↗

PubMed2002

Incidence of chronic hyperostotic rhinosinusitis in patients undergoing primary sinus surgery compared to revision surgery.

HYPOTHESIS: The incidence of chronic hyperostotic rhinosinusitis has been underreported due to poor recognition of the disease process. The surgical management of chronic hyperostotic rhinosinusitis with prolonged pre and post-operative antibiotic therapy can alter clinical course of the disease process. STUDY DESIGN: A prospective study of 40 patients based at two teaching tertiary care institutions. MATERIAL AND METHODS: CT scans of twenty patients (ten undergoing primary sinus surgery and ten undergoing revision sinus surgery) were randomly selected from each institution and reviewed by an independent radiologist for evidence of hyperostosis and compared to original reading of the CT scans. RESULTS: The finding of sinus hyperostosis is rarely reported by the radiologist on the sinus CT scan where the focus is always on mucosal disease. The incidence of sinus hyperostosis is higher, in patients undergoing revision sinus surgery than patients undergoing primary sinus surgery. CONCLUSION: Sinus hyperostosis is not an uncommon finding in chronic refractory sinusitis which may require long term intravenous antibiotic therapy in conjunction with surgery to provide symptomatic relief.

Adult↗

PubMed2002

Applications of the diode laser in otolaryngology.

We undertook a study to determine the usefulness and effectiveness of a relatively new, portable 980-nm wavelength diode laser with a fiberoptic delivery system. We tested the laser in several clinical situations, both in the operating room and in the office. We used it while performing 14 turbinate reduction procedures, one nasal polypectomy, one ablation of an oral papilloma, and one photocoagulation of nasal telangiectasias. Our preliminary findings indicate that the use of this laser was helpful in alleviating nasal congestion in the patients with turbinate dysfunction and in controlling epistaxis in the patient with telangiectasias. It was also effective in treating the polyp and papilloma patients. We did not experience any intra- or postoperative complications. The laser's flexible fiber delivery system is compatible with hollow instruments, allows for coaxial vision, and is ideally suited for intranasal use. Its portability and functional diversity make it an attractive alternative to the conventional carbon dioxide, argon, and neodimium:yttrium-aluminumgarnet lasers.

Humans↗

PubMedDate not supplied

Outcome of computer-assisted sinus surgery: a 5-year study.

BACKGROUND: The aim of this work was to study the outcome and rate of complications in a cohort of patients who underwent computer-assisted surgery (CAS). A retrospective study was performed of all patients undergoing CAS at a tertiary care teaching hospital over a 5-year period. METHODS: All patients who underwent computer-assisted sinus surgery with at least 1 year of follow-up were included in the study. Charts were reviewed for indication of CAS, incidence of major complications, and need for revision surgery after CAS. RESULTS: A total of 120 patients underwent CAS in the 5-year period. Ten patients were lost to follow-up and were not included in the analysis. Indications for the use of CAS were revision surgery in 85 patients, sphenoid sinus disease in 12 patients, isolated frontal sinus disease in 4 patients, combined sphenoid and frontal disease in 2 patients, and cerebrospinal fluid leak (CSF) leak in 7 patients. The mean postoperative follow-up was 2.6 years. There were no major complications. Fifteen (16.5%) patients required revision surgery: 10 patients required revision endoscopic sinus surgery (1-5 revisions using CAS), 3 patients required an external open procedure, and 3 patients required revision CSF leak closure (one patient required both revision sinus surgery and an external procedure). There were no cases of major intra- or postoperative bleeding, central nervous system damage, CSF leak, or orbital trauma in this study. CONCLUSION: CAS helps in avoiding trauma to the orbit and anterior skull base and has a low incidence of major complications. The need for revision surgery may occur in patients with frontal sinus disease, nasal polyposis, or recurrent CSF leak.

Adult↗

PubMedDate not supplied

Intravenous antibiotics for refractory rhinosinusitis in nonsurgical patients: preliminary findings of a prospective study.

BACKGROUND: Some patients with persistent chronic sinusitis have either had unsuccessful surgery or have simply refused surgery. In nonsurgical candidates, when oral antibiotics and traditional therapy are unsuccessful, home intravenous (i.v.) antibiotics present an effective alternative. METHODS: Forty-five patients were assessed before treatment using a semiquantitative scoring system and visual analog scales to measure major and minor symptoms of rhinosinusitis. Computed tomography (CT) scans were assessed using the Lund-MacKay staging system; nasal endoscopic findings were documented. Seven patients had nasal endoscopy and CT results. Medical diseases known to be associated with rhinosinusitis were documented. Endoscopic-guided culture and sensitivities were obtained. After successful insertion and radiological placement confirmation, home i.v. antibiotics were administered via a peripherally inserted central catheter line. Antibiotic choice was based on the culture and sensitivity reports. Treatment continued for 6 weeks; subsequent cultures were obtained at weeks 3, 6, and 9. Nasal endoscopy was performed, and rhinosinusitis symptoms were assessed at weeks 3, 6, and 9. Follow-up CT scans were obtained at week 12 in a subset of patients. RESULTS: Significant improvement in symptom analysis was seen in patients receiving home i.v. antibiotics when previous oral antibiotic treatment and/or surgery had failed. CONCLUSION: Home i.v. antibiotics provide an excellent alternative to surgery for patients who have either had unsuccessful surgery or who have refused surgery.

Anti-Bacterial Agents↗