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Biomedical subjects

S E Brooks

Publications and source records attributed to S E Brooks.

At least 37 records · Page 2Linked to original sources
PubMed1998

Telemedicine diagnosis of eye disorders by direct ophthalmoscopy. A pilot study.

OBJECTIVE: To report a pilot study of telemedical direct ophthalmoscopy in the diagnosis of acquired immune deficiency syndrome (AIDS)-related retinopathy in a human immunodeficiency virus (HIV)-positive population and in the diagnosis of glaucoma, cataract, and retinopathy in a diabetic population. DESIGN: Prospective comparative case series. PARTICIPANTS: Seventeen HIV-positive and 20 diabetic patients. METHODS: A direct ophthalmoscope custom-fitted with a digital microcamera capable of transmitting images from any of 61 sites within the Georgia Statewide Telemedicine Program was used by a nonophthalmologist to examine 34 eyes of 17 HIV-positive patients and 39 eyes of 20 patients with diabetes. Fundus images were transmitted in real-time to a reviewing ophthalmologist. An in-person, comprehensive examination including indirect ophthalmoscopy, was performed by a second ophthalmologist. Telemedical examination was compared to the in-person comprehensive examination. RESULTS: For the HIV study, 21 eyes did not show HIV retinopathy (noninfectious retinopathy with cotton-wool spots) by in-person examination. Telemedical examination correctly identified 20 of these eyes as disease-free (specificity = 95%). HIV retinopathy was present in 12 of the 34 eyes by in-person evaluation with telemedical examination correctly diagnosing 10 of these eyes (sensitivity = 83%). One eye with dense cataract and retinal detachment was unable to be evaluated ophthalmoscopically by either in-person or telemedical examination. Telemedical and in-person assessments for HIV retinopathy were identical in 100% of eyes without cataract. Disagreement in diagnosis between telemedical and in-person examination was associated with cataract (P < 0.0007). For the diabetes study, because of an inadequate image, telemedical examination was unable to classify 46% and 36% of eyes for glaucoma and diabetic retinopathy, respectively. Inability to make a telemedical determination for glaucoma (P < 0.011), nonproliferative (P < 0.064) and proliferative (P < 0.064) diabetic retinopathy was associated with cataract. Of the eyes that were able to be assessed by telemedical examination for diabetic retinopathy (n = 25), glaucoma (n = 21), and cataract (n = 39), the accuracy was poor (sensitivity = 29%, 50%, and 41%, respectively). Telemedical examination for diabetic retinopathy and glaucoma was more likely to agree with in-person examination in eyes without cataract as compared to eyes with cataract (not statistically significant). CONCLUSION: Telemedical direct ophthalmoscopic, real-time fundus imaging may provide a valuable means for providing ophthalmic consultation to the primary care physician in younger patients without lens or media opacity, but is inadequate for eyes with any degree of lens or media opacity.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Quantitative forced ductions in an animal model--characterization of passive forces.

PURPOSE: Our purpose was to characterize the passive tissue forces involved in ocular rotation in a controlled animal model and to evaluate the influence of manual versus mechanized ductions, repeated measurements, speed of rotation, and the influence of the nondepolarizing muscle relaxant mivacurium. METHODS: Forced ductions were performed under general anesthesia on 20 eyes of 10 pigs, with or without mivacurium, with use of a highly sensitive force gauge attached to the eye by a traction suture. The eye was moved either manually or at constant speed with a motorized platform. Eyes were rotated a total of 8 mm from their resting position under anesthesia. The force-displacement relationship was analyzed and compared between groups. RESULTS: A linear (elastic) relationship between force and displacement was noted, with a slope of 0.4 g per degree with use of the mechanized technique. Neither speed of rotation, use of mivacurium, nor repeated ductions significantly influenced the shape or slope of the relationship. Hysteresis averaged 2 to 4 g. Measurements performed with use of the motorized platform showed significantly improved reliability over those made manually. CONCLUSIONS: The passive length-tension data correlate well with data reported by others in humans. Within a wide range of eye movement, this force is elastic in nature. For relatively low angular velocities, such as might be produced in smooth pursuit, the passive forces do not change appreciably with changes in velocity. The nondepolarizing muscle relaxant mivacurium has no effect on accurate performance of passive forced ductions under general anesthesia. Studies collecting quantitative data on passive orbital forces should be performed, when feasible, with an automated duction and recording apparatus.

Anesthesia, General↗
PubMed1998

Restricted ocular motility after orbital trauma--studies with an animal model.

OBJECTIVE: Our purpose was to develop a quantitative model of restricted ocular motility (fat adherence syndrome) in the pig orbit to facilitate research into pathogenesis and treatment. METHODS: Twenty eyes of 10 pigs were used in an attempt to create a fibrous adhesion between either the inferior rectus or the medial rectus muscle and the adjacent periorbita. Quantitative forced ductions were performed preoperatively and 6 weeks postoperatively with an electronic force gauge. RESULTS: Forced ductions displayed a linear relationship to displacement over the range tested, both preoperatively and postoperatively. Although increased resistance to forced ductions was produced in 10 of the 20 (50%) eyes, the average changes were not statistically significant. The absolute change in force (Postoperative--Preoperative) was linearly related to the amount of ocular rotation. Reproducibility of measurements was markedly improved by the use of a motorized forced duction apparatus compared with manual rotation. CONCLUSIONS: The results from this study, and those from previous work, suggest that the classic fat adherence syndrome is an uncommon event, even after significant soft tissue injury in the orbit. Further studies are needed to more completely define the risk factors and pathogenesis of the fat adherence syndrome and the suitability of the pig orbit as a model.

Adipose Tissue↗
PubMed1998

Modulation of VEGF production by pH and glucose in retinal Müller cells.

PURPOSE: To investigate the influence of pH and glucose concentration, both of which represent significant biochemical variables in tissue ischemia, on the production of VEGF protein by retinal Müller cells and C6 glioma cells, under normoxic and hypoxic conditions. METHODS: Rat retinal Müller cells and C6 glioma cells grown in tissue culture monolayers were studied. The effect of pH (range 7.0-8.0) and glucose concentration (0.6-25 mmol/L) on VEGF protein production, under both normoxic and hypoxic conditions, were evaluated by ELISA analysis of the conditioned media. Establishment of significant cell hypoxia was verified by measurement of lactate release into the conditioned media. RESULTS: Hypoxia caused a 7.9-fold increase in VEGF production in C6 cells at 24 h, and a 3.4-fold increase in Müller cells after 48 h. Under hypoxic conditions, VEGF protein production was increased further by increasing pH and increasing glucose, and decreased by low pH and low glucose. Varying the glucose concentration or pH of the medium did not result in significant induction of VEGF protein production by either cell type under normoxic conditions. CONCLUSIONS: Both glucose and pH significantly affected VEGF production induced by low oxygen. However, neither exerted a measurable stimulatory effect on VEGF production in normoxic conditions. Coexisting hypoxia and acidosis or hypoglycemia, as might occur in severe tissue ischemia, may render glial cells incapable of effectively upregulating VEGF synthesis, while alkalosis or hyperglycemia may augment hypoxia-induced VEGF production.

Animals↗
PubMed1998

Periorbital vasculitis complicating Kawasaki syndrome in an infant.

Periorbital vasculitis is a previously unreported complication of Kawasaki syndrome (KS). We describe an infant with severe KS refractory to initial management with salicylate and intravenous immunoglobulin (IVIG). Retreatment with IVIG and high-dose pulsed steroids was required for persistent fever and inflammatory manifestations. Despite aggressive medical therapy, a large left coronary artery aneurysm developed. After apparent complete KS remission, acute periorbital vasculitis developed in the left upper eyelid and orbit, requiring operative intervention for diagnosis and high-dose pulsed steroids for therapy. The significance of this previously unreported ophthalmic complication of KS is reviewed, along with a discussion of the role of steroids in KS manifestations refractory to IVIG.

Eyelid Diseases↗
PubMed1998

Kinetics of fluid delivery from methylcellulose sponges.

PURPOSE: The authors quantitatively evaluate the kinetics of fluid transfer from microsurgical sponges in a laboratory model to understand the kinetics of mitomycin C (MMC) delivery. METHODS: The amount of fluid transferred from soaked methylcellulose (Weck-cel, Weck Inc., Durham, NC, U.S.A.) sponges to small pieces of hydrated or dry filter paper used to simulate episcleral tissue and Tenon fascia was measured as a function of time, sponge size, hydration status of the filter paper, and technique of sponge application. RESULTS: The time course of fluid delivery from methylcellulose sponges to filter paper was nonlinear and characterized by a rapid delivery phase over the first 15 to 30 seconds, followed by a slow phase extending to at least 5 minutes. Sponge size and baseline hydration of the paper significantly influenced the rate and amount of fluid delivered, as did replacing the sponge every minute with a new sponge. CONCLUSION: The transfer of fluid from a microsurgical sponge displays nonlinear kinetics, with the majority of delivery occurring in the first 15 to 30 seconds. Sponge size, hydration of the recipient tissue, and technique of sponge application are significant variables influencing the amount of fluid, and therefore mitomycin C, delivered.

Antibiotics, Antineoplastic↗
PubMed1997

Retinal pigment epithelium abnormalities in mice with adenomatous polyposis coli gene disruption.

OBJECTIVE: To examine eyes from mice with targeted adenomatous polyposis coli (APC) gene disruption to determine if retinal pigment epithelium (RPE) abnormalities replicate the human counterpart. METHODS: Thirty-two eyes from 16 mice heterozygous for APC gene disruption (chain-termination mutation in codon 1638 of exon 15) and 12 control eyes were examined by light microscopy. RESULTS: Fifteen of 32 eyes from 12 of 16 APC-disrupted mice demonstrated abnormalities of the RPE and retina. The RPE abnormalities included RPE coloboma, unifocal and multifocal RPE hypertrophy, RPE hyperplasia, and RPE duplication with invasion in the areas of outer and inner segments. Retinal abnormalities included outer nuclear layer duplication and outer nuclear layer atrophy. There were no RPE and retinal abnormalities seen in the control eyes. CONCLUSIONS: This study is consistent with the hypothesis that the APC gene is critical in the regulation of RPE proliferation and development. These findings also demonstrate that mutation of the APC gene in codon 1638, a location beyond the previously described critical region for human RPE abnormalities, leads to perturbation in the mouse RPE and retina. Further study of this murine model and the APC/RPE relationship may provide insight into regulatory mechanisms for RPE proliferation.

Adenomatous Polyposis Coli↗
PubMed1997

Detection and localization of steel intraocular foreign bodies using computed tomography. A comparison of helical and conventional axial scanning.

PURPOSE: To compare the sensitivity and specificity of detection, and accuracy of localization, of small steel intraocular and episcleral foreign bodies, using conventional axial and helical computed tomographic scanning in an experimental model. METHODS: Small steel foreign bodies ranging in size from 0.048 to 0.179 mm3 were placed in intraocular and episcleral locations in eye bank eyes mounted in the orbits of a human skull and scanned using helical and conventional axial techniques. Helical scanning was performed using 1-mm and 3-mm thick sections. Conventional axial scanning was performed using 3-mm thick sections. Images were reviewed by masked observers to determine sensitivity, specificity, and accuracy of localization for each imaging method. RESULTS: Steel foreign bodies as small as 0.048 mm3 were detectable with each scanning protocol. Although the helical scans appeared to provide higher levels of sensitivity compared to conventional axial scanning, the difference in outcome between the scan types was not statistically significant. Sensitivity was dependent on the size of the foreign body and ranged from 45% to 65% for the smaller ones (< 0.06 mm3) to 100% for the larger ones (> 0.06 mm3). Multiplanar reformatting of images was helpful in achieving optimal accuracy. CONCLUSION: In an experimental model of steel intraocular foreign body, helical computed tomographic scanning provided images of high quality similar to that of conventional axial scanning.

Cadaver↗
PubMed1997

Scanning electron microscopy of the jejunum in children with protein-energy malnutrition.

Samples of jejunum from seven children dying from severe oedematous malnutrition were fixed with intralumenal glutaraldehyde in combination with external immersion, using a rapid autopsy protocol. Selected areas were post-fixed in osmium tetroxide, dehydrated with an ethanol series and critical point dried. After mounting on aluminium stubs, specimens were sputter-coated with a thin layer of gold and palladium. Scanning electron microscopy showed patterns ranging from subtotal villous atrophy, through partial villous atrophy with low ridges, to longer, taller ridges with cerebriform convolutions. In one case, villous height had been interpreted as normal on light microscopy. The scanning electron microscope revealed that the mucosa in this case was composed of ridges and leaf forms. Processing for scanning electron microscopy is simple. The specimens can be viewed and photographed in a relatively short time. In addition, the three-dimensional record provides clarification of ambiguities which often arise from routine histological sections.

Child, Preschool↗
PubMed1997

A review of screening and early detection of endometrial cancer and use of risk assessment.

Although the majority of patients with endometrial cancer have a good prognosis, subgroups of individuals are at risk of more aggressive disease. Early detection programs should target individuals who have the highest risk of advanced disease, high-risk histology, and poorly differentiated tumors. This will afford the greatest improvement in survival. Screening of the general population is not cost-effective and indeed may incur iatrogenic morbidity. Recent data also suggest that routine screening of patients receiving tamoxifen citrate may not be indicated. This area is still being investigated. While screening is not appropriate for the general population, a strategy of early evaluation of postmenopausal bleeding with judicious use of endometrial biopsy is important for the early detection of endometrial cancer. Ultrasound is most effective in excluding pathology in symptomatic patients whose biopsy specimen is nondiagnostic. Fractional dilation and curettage is reserved for patients with abnormal vaginal bleeding who cannot undergo office biopsy or who experience persistent symptoms.

Biopsy, Needle↗
PubMed1996

Thickened endometrial stripe and/or endometrial fluid as a marker of pathology: fact or fancy?

OBJECTIVE: To evaluate the implication of a thickened endometrial stripe (ES) and endometrial fluid (EF) in postmenopausal women. METHODS: Between 1991 and 1995, 897 consecutive postmenopausal patients underwent pelvic ultrasound at our institution. Clinical and ultrasound data were reviewed for the 624 patients in whom a comprehensive evaluation of the uterus and adnexae was performed. Of this study group, 495 had normal ES thickness. Nine patients with a thickened ES were excluded due to immediate hysterectomy or history of cervical cancer. This resulted in 120 subjects comprising the group with EF, or a thickened ES > or = 5 mm for patients not on hormone replacement therapy (HR-) and > or = 8 mm in patients receiving hormone replacement therapy (HR+)]. Symptoms were defined as bleeding. Statistical analysis was performed by use of Fisher's exact test. RESULTS: 184/ 495 patients with normal ES thickness underwent biopsy. In this group, 7 cases of simple hyperplasia, 4 cases of atypical hyperplasia (AH), and 4 cases of endometrial cancer (CA) were detected. All of these subjects who were found to have either AH or CA were symptomatic. Of the subjects with a thickened ES, 54 had symptoms and 66 were asymptomatic with 51/54 and 52/66 undergoing endometrial sampling, respectively. Initial sampling in the symptomatic group with thickened ES revealed 7 cases of simple hyperplasia and 2 cases of AH. There were 6 cases of simple hyperplasia in the asymptomatic group (P = NS). Initial biopsy results were either negative or nondiagnostic in 42 symptomatic patients and 46 asymptomatic patients with 40/42 and 19/46 undergoing repeat sampling, respectively. Repeat sampling further identified 9 cases of endometrial hyperplasia or cancer in the symptomatic group while in the asymptomatic group, 2 cases of simple hyperplasia were detected. For symptomatic and asymptomatic patients, analysis of combined initial and second biopsies performed within 1 year was undertaken. This combined analysis revealed a significantly greater rate of detection of endometrial hyperplasia or carcinoma in the symptomatic group vs the asymptomatic group (P = 0.0229, Fishers exact test, [Mantel-Haenszel odds ratio 3.094, confidence interval 0.4799-25.7]). Indeed, the observed detection of hyperplasia or cancer doubled in the symptomatic group, increasing from 9 to 18%, but did not increase significantly in the asymptomatic group. A subpopulation of 21 patients with a thickened ES were HR+ and underwent biopsy, while 72 patients with a thickened ES who were HR- underwent biopsy. 43% of HR+ patients manifested endometrial hyperplasia vs 8% in the HR- group (P = 0.0022). Endometrial fluid was present in 23 patients. The one patient with EF who was determined to have endometrial hyperplasia also had a thickened ES, was symptomatic and HR+. CONCLUSIONS: In the absence of symptoms, repeat sampling is not warranted in patients with a thickened ES and negative findings at initial abnormal biopsy. The presence of symptoms with a thickened ES warrants further diagnostic evaluation to determine an etiology. There was an association with hyperplasia in patients with a thickened ES who were HR+.

Adult↗
PubMed1996

Inflammatory opacities of the vitreous in rifabutin-associated uveitis.

PURPOSE: To describe rifabutin-associated uveitis with opacities in the inferior and posterior vitreous in three patients with acquired immunodeficiency syndrome. METHOD: Case reports of the three patients are presented. RESULTS: The patients, who were being treated with rifabutin and fluconazole, developed anterior and posterior uveitis. The posterior uveitis was characterized by white-yellow inflammatory opacities located in the inferior and posterior vitreous. Discontinuation of rifabutin and the start of topical corticosteroid therapy resulted in improvement of the uveitis and visual acuity. CONCLUSION: Recognition of rifabutin-associated uveitis with opacities in the inferior and posterior vitreous may prevent unnecessary invasive diagnostic and therapeutic procedures.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Anisometropia and binocularity.

PURPOSE: To determine the effects of experimentally induced anisometropia on binocular function in healthy adults as a means of assessing the potentially detrimental effects of uncorrected anisometropia on binocular development in childhood. METHODS: Nineteen adults with normal binocularity, ranging in age from 26 to 59 years, were studied. Unilateral myopia, hyperopia, or astigmatism (at 90 degrees or 45 degrees) was induced in each subject using trial lenses. Sensory status then was assessed by measuring stereoacuity, Worth four-dot fusion, and Bagolini lens response. RESULTS: All subjects showed a decline in binocular function with increasing levels of anisometropia. Foveal suppression was evident on the Worth four-dot test, and increased in proportion to the anisometropia. Stereoacuity was similarly degraded by the induced anisometropia, with some subjects showing significant loss of stereoacuity with as little as 1 diopter of spherical anisometropia. Bagolini lens responses were binocular in almost all patients, although occasional abnormalities were found. CONCLUSIONS: Relatively low degrees of anisometropia may cause significant abnormalities in high-grade binocular visual functions in adults. The potential effects of uncorrected anisometropia on binocularity in children require further investigation, but should be considered in developing guidelines for the empiric correction of refractive errors.

Adult↗
PubMed1995

Cytotoxicity of antitumor platinum complexes with L-buthionine-(R,S)-sulfoximine and/or etanidazole in human carcinoma cell lines sensitive and resistant to cisplatin.

Human 2008 ovarian carcinoma cells and the C13 CDDP-resistant subline and human MCF-7 breast carcinoma cells and the MCF-7/CDDP CDDP-resistant subline were exposed to L-buthionine-(S,R)-sulfoximine (50 microM) for 48 h prior to and during exposure for 1 h to the antitumor platinum complexes, cis-diamminedichloroplatinum(II), carboplatin or D,L-tetraplatin and/or to etanidazole (1 mM) for 2 h prior to and during exposure for 1 to the antitumor platinum complexes. These modulators alone did not significantly alter the cytotoxicity of CDDP toward either parental line. A twofold enhancement in cytotoxicity was observed with carboplatin in the 2008 cells and with D,L-tetraplatin in both parental lines with the single modulators. The modulator combination (buthionine sulfoximine/etanidazole) was very effective along with D,L-tetraplatin in both the MCF-7 parent and MCF-7/CDDP cell lines where at the higher platinum complex concentrations there was 1.5 to 3 logs increased killing of cells by the drug plus the modulators compared with the drug alone. Similarly, when C13 cells were exposed to CDDP (100 microM) or D,L-tetraplatin (100 microM) along with buthionine sulfoximine and etanidazole there was a 2-log increase in cell killing compared with exposure to the platinum complex alone. Treatment of each of the four cell lines with buthionine sulfoximine decreased both the non-protein and total sulfhydryl content of the cells. Treatment with the combination of modulators did not produce a further decrease in cellular sulfhydryl content compared with buthionine sulfoximine alone. The total sulfhydryl content in MCF-7 cells and 2008 cells exposed to buthionine sulfoximine and etanidazole was 58% and 31% of normal and the total sulfhydryl content of MCF-7/CDDP cells and C13 cells treated the same way was 54% and 23% of normal, respectively. DNA alkaline elution was used to assess the impact of exposure to the modulators, buthionine sulfoximine and etanidazole, alone and in combination on the cross linking of DNA by the antitumor platinum complexes in the MCF-7 and MCF-7/CDDP cell lines. Overall, the increases in DNA cross linking factors were greater in the MCF-7 cells than in the MCF-7/CDDP cells. These results indicate a possible clinical potential for this modulator combination.

Antimetabolites, Antineoplastic↗
PubMed1995

Age-specific incidence of cancer in Kingston and St. Andrew, Jamaica, 1988-1992.

During the period 1988-1992, a total of 4,030 malignant neoplasms were recorded in Kingston and St. Andrew, Jamaica. These comprised 1,829 in males and 2,201 in females. Histological confirmation was obtained in 83.4%. The crude incidence rate for males was 128.5, and 136.2 for females. The age-standardized rates (ASR) were 179.9 for males and 166.1 for females. Age-specific rates by site, sex and age are tabulated. Attention is drawn to increased incidence for cancers of prostate, larynx, bronchus and non-Hodgkin's lymphoma in males. There was also an increase in female breast cancer (crude rate 36.0; ASR 47.1). Invasive cervix cancer has shown no significant change in incidence. Neoplasms of the body of the uterus have increased (crude rate 7.6; ASR 9.5). The rise in cancer of breast and body of uterus suggests that the influence of exogenous oestrogens should be considered.

Adolescent↗