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Biomedical subjects

A C Ho

Publications and source records attributed to A C Ho.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cogan's syndrome with refractory abdominal aortitis and mesenteric vasculitis.

Cogan's syndrome is a rare multisystem disease characterized by ocular inflammation, vestibuloauditory dysfunction, and vasculitis. We report a 26-year-old Caucasian woman who died from Cogan's syndrome. Her case illustrates that patients with Cogan's syndrome can have abdominal aortitis and mesenteric vasculitis, and that the vasculitis can be refractory to methotrexate, cyclophosphamide, cyclosporine, and chlorambucil.

Adult↗
PubMed1998

The local addition of tenoxicam reduces the incidence of low back pain after lumbar epidural anesthesia.

BACKGROUND: Postepidural backache is a common postoperative complaint after lumbar epidural anesthesia. Useful interventions to decrease the incidence of postepidural backache would be helpful. METHODS: We performed a prospective, randomized, double-blind study to compare the effect of local addition of tenoxicam on the incidence of postepidural backache after nonobstetric surgery. One thousand unpremedicated ASA physical status I or II patients scheduled for hemorrhoidectomy were assigned randomly to tenoxicam or control groups. Patients in the control group received 25 ml lidocaine, 2%, with epinephrine 1:200,000 epidurally and 4 ml lidocaine, 1%, for local skin infiltration. Patients in the tenoxicam group received 25 ml lidocaine, 2%, with epinephrine 1:200,000 epidurally and 4 ml lidocaine, 1%, with tenoxicam (2 mg) 1:2,000 for local skin infiltration. Patients were interviewed at 24, 48, and 72 h postoperatively using a standard visual analog scale for evaluation of postepidural backache. A patient was considered to have postepidural backache when the postoperative visual analog scale score was higher than the preoperative score. RESULTS: The incidence of postepidural backache in patients in the control group for the 3 days were 22.8%, 17.4%, and 9.2%, all of which were significantly more frequent than observed in the patients in the tenoxicam group (6.8%, 4.0%, and 1.2%, P < 0.01). There was a significant association between backache and multiple attempts at epidural needle insertion. CONCLUSION: In summary, the local addition of tenoxicam reduced the incidence and severity of postepidural backache.

Adolescent↗
PubMed1998

Softened endothracheal tube reduces the incidence and severity of epistaxis following nasotracheal intubation.

BACKGROUND: Many complications were reported to be related with nasotracheal intubation. Various chemical or mechanical techniques have been proposed to decrease hemorrhage and trauma associated with nasotracheal intubation but the results remain controversial. We conducted a prospective, randomized, single-blind study to elucidate the effect of an endotracheal tube softened with warm water before use on the incidence and severity of epistaxis following nasotracheal intubation. METHODS: Sixty-two healthy, (ASA class I or II) patients scheduled for elective surgery were randomly assigned into two groups. Patients in the treatment group were intubated with a softened endotracheal tube made possible by heating it in warm water while those in the control group were intubated with unsoftened (intact) tube. Epistaxis was evaluated immediately after intubation and its severity was graded as none, mild, moderate and severe. The use of Magill forceps and postoperative nasal morbidity were also recorded. RESULTS: The total incidence of epistaxis in the "unsoftened" group was significantly higher than that of "softened" group (76.7% vs. 43.8%, P = 0.0002). The severity of nasal hemorrhage was also significantly lightened in the "softened" group. No technical difficulty was encountered in intubation with a softened endotracheal tube by prewarming. The morbidity referable to nasal intubation, however, did not differ in both groups. CONCLUSIONS: In conclusion, our study shows that using an endotracheal tube softened by warm water could reduce the incidence and severity of epistaxis during the act of nasotracheal intubation. It is an effective way and worth a try.

Adolescent↗
PubMed1998

Foveolar choroidal blood flow in age-related macular degeneration.

PURPOSE: To compare measurements of the foveolar choroidal blood circulation in subjects with nonexudative, age-related macular degeneration (AMD) with those of control subjects. METHODS: Laser Doppler flowmetry was used to assess relative choroidal blood velocity (ChBVel), volume (ChBVol), and flow (ChBFlow) in the center of the fovea. Measurements were obtained in 20 eyes of 20 subjects with 10 or more large drusen, visual acuity of 20/32 or better, and no evidence of choroidal neovascularization. Findings obtained in these subjects were compared with those of 10 eyes of 10 age- and blood pressure-matched control subjects with no large drusen. Foveolar choroidal blood flow measurements were obtained by asking the study participants to fixate on a probing laser beam. RESULTS: No significant differences in average age, blood pressure, or intraocular pressure were observed between subjects with AMD and control subjects. In subjects with AMD, average ChBVol was 0.24 +/- 0.08 (+/- 1 SD) arbitrary units (AU); this value was 33% lower than that of control subjects (0.36 +/- 0.11 AU; two-tailed, independent Student's t-test, P = 0.005). Average ChBVel, conversely, was not significantly different from normal (0.44 +/- 0.07 AU) in subjects with AMD (0.44 +/- 0.10 AU). Average ChBFlow in subjects with AMD (8.7 +/- 3.1 AU) was 37% lower than that of control subjects (13.7 +/- 3.5 AU) (P = 0.0005). Average blood flow pulsatility was 6% higher in subjects with AMD (0.71 +/- 0.15) than in control subjects (0.66 +/- 0.14), but this difference was not statistically significant (P = 0.42). CONCLUSIONS: Average ChBFlow in the nonexudative stages of AMD is lower than that of age-matched controls, and the effect is caused mainly by a decrease in ChBVol. Further studies are needed to elucidate whether decreased ChBFlow plays a role in the development of choroidal neovascularization, and whether ChBFlow measurements may help identify subjects with AMD at risk for developing choroidal neovascularization.

Aged↗
PubMed1998

Airway compression by a biplane pediatric transesophageal echocardiography probe: case report.

Transesophageal echocardiography (TEE) has been extensively used in cardiac surgery to assess cardiac function and anatomical relationships in both adults and children. Newer monitoring devices, despite being labeled "noninvasive", often present significant risks. Physicians should be cautious with the use of TEE in infants and small children, recognizing that oversized probes may inadvertently compress vital structures, resulting in airway or vascular compromise. If severe compression of the airway or vascular structures occurs, TEE monitoring may need to be discontinued. Although technological progress has yielded smaller ultrasonic probes, the TEE probe is significantly larger than most other devices placed in the esophagus. We present in this report a case of airway compression using a small-sized biplane pediatric TEE probe in a child undergoing Blalock-Taussig shunt surgery. Pediatric patients may be more at risk for airway obstruction because of the over-size of the probe-distended esophagus in relation to adjacent airway structures.

Airway Obstruction↗
PubMed1997

Absorption of irrigating fluid during transcervical resection of endometrium--a report of two cases.

It has been recognized for many years that the use of hypotonic solution for the irrigation of the bladder cavity during transurethral resection of the prostate (TURP) may result in hyponatremia and water intoxication due to rapid and excessive absorption of the solution from the exposed prostatic bed, the clinical manifestation of which is termed "TURP syndrome". A similar condition termed "female TURP syndrome" following hysteroscopic transcervical endometrial resection (TCR) has been reported. Since the frequency of TCR continues to increase the increased rate of "TCR syndrome" would come in its wake. Here, we present two cases who developed severe hyperglycemia and hyponatremia while underwent TCR with 10% dextrose in water as the irrigation fluid and the same time emphasize the potential risk of this complication.

Adult↗
PubMed1997

Propofol anesthesia in a patient with Isaacs syndrome--report of a case and literature review.

Isaacs syndrome is an unusual lower motor neuron disease characterized by myokymia (muscle twitching), muscular stiffness, and decreased tendon reflexes. We reported a patient who was affected with this rare disease, with manifestation of involuntary muscular contractions and required general anesthesia for bilateral tonsillectomies. Understanding the presentation and characterization of this unusual disease may be helpful in making choice of anesthetics or anesthetic techniques. Its possible mechanisms of action and its specific considerations in anesthesia in the literature are reviewed and discussed.

Adult↗
PubMed1995

Flow cytometric assessment of the cellular pharmacokinetics of fluorescent drugs.

Development of multidrug resistance (MDR) in cancer cells decrease net doxorubicin uptake as a result of either increased efflux, or decreased intracellular sequestration, or decreased membrane permeability. Kinetic parameters of drug uptake can distinguish among these forms of altered transport. Cellular uptake of fluorescent drugs was monitored by a flow cytometric assay using a rapid-injection system and analyzed with a three-compartment model in which rapid diffusion from extracellular fluid into the cell was followed by uptake into a nonexchangeable pool. In agreement with our recent studies of 14C-doxorubicin distribution (Dordal et al.: J Pharmacol Exp Ther 271:1286-1290, 1994), sequestration of doxorubicin was decreased 2.7-fold in P-glycoprotein-expressing SU-4R lymphoma cells compared to drug-sensitive SU-4 cells (14.0 +/- 4.8 vs. 5.0 +/- 0.9 nl s-1) without a change in membrane permeability or evidence of active efflux. In contrast, sequestration of the highly fluorescent dye rhodamine 123 was decreased 20-fold (17.1 +/- 8.3 vs. 0.9 +/- 0.8 nl s-1). Resistant cells were significantly less permeable to rhodamine than sensitive cells (3.8 +/- 1.2 vs. 10.2 +/- 2.6 x 10(5) cm2 s-1), and rhodamine efflux was increased by 24%. Thus, SU-4R cells exhibit multiple alterations that cause decreased intracellular drug concentrations, of which decreased sequestration is quantitatively the most significant.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Rapidly progressive optic disk neovascularization after diabetic papillopathy.

PURPOSE: To determine if diabetic papillopathy may be associated with optic disk neovascularization and visual loss. METHODS: We examined two young adults with bilateral diabetic papillopathy who had permanent loss of vision associated with rapidly progressive posterior segment neovascularization. RESULTS: Within three months both patients developed florid optic disk neovascularization. This neovascularization was slow to regress despite full panretinal photocoagulation. One patient developed a macular tractional retinal detachment. CONCLUSIONS: Diabetic papillopathy may be associated with rapid progression of diabetic retinopathy and, in particular, optic disk neovascularization. Patients should be monitored for this possibility.

Adolescent↗
PubMed1995

The natural history of idiopathic subfoveal choroidal neovascularization.

PURPOSE: To study the long-term natural history of idiopathic subfoveal choroidal neovascularization (CNV) in young patients. METHODS: A retrospective survey of 19 consecutive patients with idiopathic subfoveal CNV diagnosed in an urban eye hospital and a single practice. RESULTS: Twenty-three (26%) of 87 consecutive patients with idiopathic CNV demonstrated subfoveal CNV. Nineteen patients with subfoveal involvement were followed for a median of 87 months (range, 5-230 months). On initial examination, the median best-corrected Snellen visual acuity was 20/100 (range, 20/40-counting fingers); at final examination, the median visual acuity was 20/70 (range, 20/20-counting fingers). A total of 95% of patients had stable or significantly improved visual acuity, whereas only 5% had significant visual loss. Size of the CNV was the only variable associated with long-term final visual acuity. Lesions 1 disc area or smaller at the time of initial fluorescein angiography were more likely to be associated with a final visual acuity of 20/60 or better and less likely to be associated with a final visual acuity of 20/200 or worse (P = 0.038) as compared with larger lesions. These results were confirmed with multiple logistic regression analysis (P = 0.027). Fellow eyes remained unaffected during the follow-up period. CONCLUSIONS: The natural history of idiopathic subfoveal CNV is not necessarily associated with a profound loss of vision. Therapies for this type of subfoveal lesion must take into consideration the possibility of a favorable natural course.

Adult↗
PubMed1995

Elevation of maternal alpha-fetoprotein in systemic lupus erythematosus: a controlled study.

OBJECTIVE: To determine if maternal alpha fetoprotein (AFP) is elevated in lupus pregnancy and, if so, whether it is associated with treatment or outcome. METHODS: Maternal serum AFP values were obtained once during Weeks 16.3 to 31.7 in 54 pregnancies followed prospectively. AFP was measured by the Maryland State Health Department, who reported the AFP level and a corrected value, multiple of the median (AFP MOM), adjusted for weight, gestational age, and insulin dependent diabetes. Controls were 1001 consecutive samples measured by the same laboratory. RESULTS: AFP MOM was higher in lupus pregnancies (1.425 +/- 0.73 vs 1.169 +/- 0.50, p = 0.001), as were the unadjusted AFP levels (lupus 68.26 +/- 42.2, control 52.49 +/- 27.25, p = 0.001). Of lupus pregnancies 7.4 vs 2.6% of control pregnancies had an abnormal AFP MOM (p = 0.06). The 4 patients with abnormal AFP-MOM, using the 2.3 cutoff, were taking more prednisone (27.25 +/- 18.54 mg vs 10.85 +/- 12.29 mg, p = 0.02), were more likely to have delivered preterm (31.50 +/- 36.31 weeks, p = 0.02), and were more likely to have a high anticardiolipin (aCL) antibody during the pregnancy (p = 0.03). CONCLUSION: AFP is higher in lupus than in control pregnancies, without any increase in neural tube or other birth defects. An abnormal maternal serum AFP level is associated with higher prednisone dose, preterm delivery and aCL. Patients and obstetricians need to be aware that an elevated maternal AFP in lupus pregnancy is not necessarily due to a birth defect, and may be predictive of preterm delivery.

Adult↗
PubMed1994

A pilot study of indocyanine green videoangiography-guided laser photocoagulation of occult choroidal neovascularization in age-related macular degeneration.

PURPOSE: To evaluate the use of digital indocyanine green videoangiography in patients with clinical and fluorescein angiographic evidence of "occult" choroidal neovascularization in age-related macular degeneration and to investigate indocyanine green videoangiography-guided laser photocoagulation as a therapeutic approach. METHODS: Three hundred forty-seven consecutive patients with exudative age-related macular degeneration and symptoms and clinical manifestations of occult choroidal neovascularization were studied with indocyanine green videoangiography. Patients were selected for laser treatment, using conventional guidelines, when indocyanine green videoangiography demonstrated a well-delineated area of hyperfluorescence, presumed to be a focal area of choroidal neovascularization. RESULTS: Seventy-nine (23%) of 347 eyes were found to have a localized and definable lesion that was potentially amenable to laser photocoagulation therapy; 44 (56%) of these 79 treated eyes had complete resolution of their exudative manifestations. Visual acuity improvement was noted in 10 (13%) of 79 eyes, and stabilization of vision achieved in 42 eyes (53%). CONCLUSION: Laser photocoagulation treatment guided by indocyanine green videoangiography was shown to produce promising anatomical and visual improvement in a small number of patients with occult choroidal neovascularization secondary to age-related macular degeneration. This pilot study warrants further research to investigate the efficacy and safety of this form of treatment.

Aged↗
PubMed1994

A pilot study of digital indocyanine green videoangiography for recurrent occult choroidal neovascularization in age-related macular degeneration.

PURPOSE: Digital indocyanine green videoangiography (ICG-V) was used to study recurrent choroidal neovascularization (CNV) in patients with the clinical and fluorescein angiographic findings indicative of ill-defined, or recurrent occult, CNV (RO-CNV). The use of ICG-V-guided laser caphotocoagulation as an alternative form of treatment was also investigated when a well-delineated area of CNV was imaged with this technique. METHODS: A consecutive series of 66 patients were studied who presented with exudative age-related macular degeneration and symptoms and clinical manifestations of recurrent CNV in which fluorescein angiography did not reveal classic, or well-defined, neovascularization. Patients were selected for laser treatment based on conventional guidelines if ICG-V imaged a well-delineated area of recurrent CNV. RESULTS: Indocyanine green videoangiography showed late staining that was consistent with recurrent CNV in 64 (97%) of these 66 patients with RO-CNV. Twenty-nine (44%) of the 66 were eligible for laser treatment, and 18 (62%) of these 29 patients experienced successful anatomic and visual results, which were defined as resolution of the exudative manifestations and improvement or stabilization (+/- 1 line on a Snellen chart) of vision. CONCLUSIONS: This pilot study suggests that ICG-V is of value in imaging patients with RO-CNV after laser photocoagulation for CNV secondary to age-related macular degeneration. Laser treatment of RO-CNV with ICG-V guidance may be successful both anatomically and functionally in a promising number of these otherwise untreatable cases. Further studies are necessary to validate these preliminary findings.

Aged↗
PubMed1994

Color Doppler hemodynamics of giant cell arteritis.

OBJECTIVES: To determine quantitative and qualitative hemodynamic alterations within the ophthalmic, central retinal, and short posterior ciliary arteries in patients with giant cell arteritis (GCA) proved by biopsy specimen. DESIGN, PATIENTS, AND SETTING: A consecutive case series of patients with GCA referred to an urban eye hospital who were evaluated with color Doppler imaging that was used to analyze orbital blood flow velocities and vascular resistance in 22 consecutive patients with GCA compared with age and sex-matched controls. RESULTS: Patients with GCA all demonstrated significantly reduced central retinal and short posterior ciliary arterial mean flow velocities as well as significantly increased vascular resistance compared with matched controls. Ophthalmic artery mean flow velocity demonstrated marked variation depending on the anatomic location studied. Other color Doppler imaging characteristics of GCA included the following: ophthalmic artery aliasing (high velocity and turbulent flow at presumed focal vasculitic stenoses), reversal of flow within the ophthalmic artery, reduced and truncated time-velocity waveforms of the central retinal and short posterior ciliary arteries, and absolute deficits of flow within the central retinal and short posterior ciliary arteries. Aliasing of flow velocity within the ophthalmic artery (two patients) was associated with clinical progression of GCA. CONCLUSIONS: These data support the concept that quantitative and qualitative alterations in blood flow or pathophysiologic mechanisms of visual loss in GCA. This technique may be useful in the diagnosis and management of GCA since some of the color Doppler waveforms observed in GCA have not been seen in non-arteritic optic neuropathy. Treatment with corticosteroids often appears to stop the progression of these hemodynamic abnormalities but generally does not improve preexisting vascular abnormalities.

Aged↗
PubMed1994

Intraretinal leakage of indocyanine green dye.

PURPOSE: Indocyanine green (ICG) dye is known to remain selectively in and around choroidal neovascularization (CNV) associated with age-related macular degeneration, and is thought to be cleared from the overlying retinal circulation without leakage. This is the basis of ICG dye-enhanced laser photocoagulation. The authors have observed, however, leakage of ICG dye into cystoid spaces within the retinal and have determined the incidence, clinical features, and angiographic characteristics of this newly described phenomenon. METHODS: The digital ICG videoangiograms of 149 consecutive patients with exudative age-related macular degeneration and occult CNV were reviewed independently to determine the characteristics of intraretinal ICG dye leakage. RESULTS: Of the 149 patients with occult CNV, 16 (11%) demonstrated intraretinal leakage of ICG dye between 14 and 34 minutes (median = 20 minutes). The clinical features most commonly associated with this phenomenon are: subretinal fluid (88%), subretinal hemorrhage (88%), subretinal lipid (63%), and retinal pigment epithelial detachment (56%). CONCLUSIONS: Indocyanine green dye may not be as concentrated in and around CNV as previously reported. The delayed onset of its appearance within intraretinal cystoid spaces may suggest a diffusible choroidal source of leakage. Intraretinal ICG dye may be a relative contraindication for ICG dye-enhanced laser photocoagulation.

Aged↗