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Biomedical subjects

B K Ambati

Publications and source records attributed to B K Ambati.

11 recordsLinked to original sources
PubMed2001

Nonglaucomatous cupping of the optic disc.

Optic disc cupping is a consequence of myriad disorders. The anatomy and vasculature of the disc provide great insight into why, how, and when ODC occurs in various conditions. Approaches to distinguish glaucomatous from nonglaucomatous causes of ODC should rely on patient history, visual fields assessment, and funduscopic findings, as described. Cupping can be seen with neurological processes, including benign tumors, that are treatable. The clinician must remain vigilant to detect uncommon but potentially threatening forms of nonglaucomatous optic disc cupping.

Diagnosis, Differential↗
PubMed2000

A randomized, double-masked trial of topical ketorolac versus artificial tears for treatment of viral conjunctivitis.

OBJECTIVE: To determine if topical ketorolac 0.5% relieves the symptoms and signs of viral conjunctivitis better than artificial tears. DESIGN: Randomized, controlled trial. PARTICIPANTS: One hundred seventeen patients with a clinical diagnosis of viral conjunctivitis were randomized to the treatment group or control group. METHODS: Physicians and patients were masked to treatment. Patients in the treatment group received topical ketorolac 0.5% four times daily. Patients in the control group received artificial tears four times daily. Symptom and sign scores were recorded on the day of recruitment and at the time of a follow-up examination 3 to 4 days later. MAIN OUTCOME MEASURES: Change in six symptoms of conjunctivitis (overall discomfort, itching, foreign body sensation, tearing, redness, and lid swelling) and four signs of conjunctivitis (conjunctival injection, conjunctival chemosis, conjunctival mucus, and lid edema). Adverse effects were also studied. RESULTS: A total of 105 patients returned for their 3- to 4-day follow-up. Both the artificial tear and ketorolac groups showed improvement in all symptom scores at their 3- to 4-day follow-up visit. There was no statistically significant difference between the change in symptom scores between the treatment group and control group in any symptom category except redness. Patients in the control group were more likely to report improvement in redness than those in the treatment group, P = 0.012. There was no statistically significant difference between the change in sign scores between the treatment and control groups. Ketorolac 0.5% was more likely to produce stinging than artificial tears, 59.2% versus 18.8%, P < 0.001. CONCLUSIONS: Topical ketorolac 0.5% used four times daily is no better than artificial tears at relieving the symptoms or signs of viral conjunctivitis and produces more stinging than artificial tears.

Administration, Topical↗
PubMed2000

Periorbital and orbital cellulitis before and after the advent of Haemophilus influenzae type B vaccination.

OBJECTIVE: To evaluate the effect of the introduction of the Haemophilus influenzae B (Hib) vaccine (introduced first in 1985, then extended in 1990 to children at least 2 months of age) on the epidemiologic features of periorbital and orbital cellulitis. DESIGN: Retrospective, comparative case series. PARTICIPANTS: Three hundred fifteen pediatric inpatients. METHODS: Children at Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary with discharge diagnosis of periorbital or orbital cellulitis from 1980 through 1998 were reviewed. MAIN OUTCOME MEASURES: Case rate, culture-positive isolates, and associated conditions. RESULTS: A total of 297 cases of periorbital cellulitis and 18 cases of orbital cellulitis were reviewed. Before 1990, there were 27 cases of Hib-related cellulitis (11.7% of total in that period), whereas after 1990, there were only three (3.5% of total; P = 0.028). The number of cases per year was significantly lower after 1990 (21.2 +/- 10.4 vs. 8.7 +/- 3.9; P = 0.008), as were the number of positive culture isolates (for any organism) after 1990 (76 [33. 0%] vs. 9 [10.6%]; P < 0.001). The medical conditions most commonly associated with periorbital cellulitis were sinusitis (44 [14.5%]) and upper respiratory infections (73 [26.6%]). All cases of orbital cellulitis were associated with sinusitis. CONCLUSIONS: The introduction of the Hib vaccine coincided with a sharp decline not only in the number of periorbital and orbital cellulitis cases related to H. influenzae, but also in the annual case rate. These data are consistent with a facilitative role for H. influenzae in the development of cellulitis secondary to other pathogens. They also may support restriction of the spectrum of antibiotics used to manage these conditions.

Cellulitis↗
PubMed1997

Elevated gamma-aminobutyric acid, glutamate, and vascular endothelial growth factor levels in the vitreous of patients with proliferative diabetic retinopathy.

OBJECTIVE: To examine the relative levels of gamma-aminobutyric acid (GABA), glutamate, and vascular endothelial growth factor (VEGF) in the vitreous of nondiabetic and diabetic patients. METHODS: Undiluted vitreous samples were obtained from 22 patients with proliferative diabetic retinopathy (PDR) and 28 patients without diabetes who underwent pars plana vitrectomy. Simultaneous venous blood samples also were obtained. Amino acid concentrations were determined using sensitive high-performance liquid chromatography, and VEGF levels by quantitative enzyme-linked immunosorbent assay. Hemoglobin concentrations in the blood and vitreous were determined using spectrophotometry. RESULTS: The level of GABA in the vitreous of patients with PDR, 29.4 +/- 7.8 mumol/L, was significantly higher than in controls (18.4 +/- 5.5 mumol/L) (P = .004). The vitreous concentration of glutamate was higher in patients with PDR (24.7 +/- 14.0 mumol/L) compared with controls (9.1 +/- 5.1 mumol/L) (P < .001). Vitreous VEGF level was significantly higher in patients with PDR (1759 +/- 1721 pg/mL) compared with controls (27 +/- 65 pg/mL) (P < .001). There were moderately strong correlations between GABA and VEGF levels (r = 0.68) and glutamate and VEGF levels (r = 0.43). Elevated GABA, glutamate, and VEGF levels also correlated strongly with the presence of PDR. Correcting for possible introduction of these molecules by vitreous hemorrhage did not significantly alter these findings. CONCLUSIONS: Levels of glutamate potentially toxic to retinal ganglion cells are found in the vitreous of patients with PDR. Elevated vitreous GABA may reflect amacrine cell dysfunction and underlie electroretinographic oscillatory potential abnormalities seen in diabetic retinopathy. The correlations of glutamate and GABA levels with an elevated VEGF level provide biochemical support for ischemia-induced neovascularization in patients with PDR. These findings present opportunities for novel therapeutic modalities in the treatment of PDR.

Chromatography, High Pressure Liquid↗
PubMed1997

Dynamics of knowledge and attitudes about AIDS among the educated in southern India.

AIDS awareness and attitudes among an educated segment of the Indian population were assessed. The study population was a total of 433 students and faculty in colleges and universities, and research & technical staff of the Public Health Service. While most knew that sexual intercourse (96%) & injection drug use (85%) could transmit HIV, and that shaking hands (95%) & mosquitoes (86%) could not, 63% did not know that breastfeeding was a mode of transmission and 71% falsely believed that they could acquire HIV by donating blood. The only variable to correlate positively with knowledge was education. Knowledge about true and false modes of transmission constituted three distinct dimensions as determined by factor analysis. An overwhelming majority (90%) harboured at least one hostile view towards persons with AIDS. Knowledge and education independently correlated with decreased hostility. There was great concern about the impact of the disease: 85% believed that AIDS is a very serious problem in India and 93% favoured increased government spending on AIDS education. These results display high levels of knowledge (with some gaps), and widespread support for increased action.

Adolescent↗
PubMedDate not supplied

Outcomes of granulocyte colony-stimulating factor or granulocyte-macrophage colony-stimulating factor use in neutropenic patients infected with human immunodeficiency virus.

OBJECTIVE: To characterize the effects of granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) on clinical outcomes in neutropenic HIV-infected patients, by means of a retrospective cohort study at an urban teaching hospital. METHOD: Data were reviewed from all patients discharged between January 1, 1996, and August 31, 1997, with human immunodeficiency virus and neutropenia (absolute neutrophil count (ANC) <1000 cells/mL), with outcome measures of length of stay, infectious complications, and survival to discharge. RESULTS: Of the 228 discharged patients who met selection criteria, 71 had received G-CSF or GM-CSF; 157 controls had not. Cases had lower CD4+ cell counts (30 vs. 54 cells/mL; P = 0. 017) and lower nadir ANCs (372 vs. 579 cells/mL; P < 0.001). Granulocyte-CSF or GM-CSF usage was not associated with the frequency of site-related infections, fever, or sepsis (all P > 0. 20). No difference was found in duration of hospitalization (23 vs. 21 days; P > 0.20). In a logistic regression model for survival to discharge, higher nadir ANC and CSF use were independently associated with improved survival (P = 0.034 and P = 0.026, respectively). CONCLUSION: Use of G-CSF or GM-CSF was associated with improved survival to discharge among hospitalized HIV-infected patients with neutropenia.

AIDS-Related Opportunistic Infections↗