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Biomedical subjects

J N Bloom

Publications and source records attributed to J N Bloom.

18 recordsLinked to original sources
PubMed1992

A laboratory evaluation of the Kowa laser flare-cell meter for the study of uveitis.

The Kowa FC-1000 laser flare-cell meter (LFCM) has been described as an instrument which will objectively quantify inflammation of the anterior chamber of the eye. We evaluated the LFCM using the intravenous endotoxin-induced uveitis (EIU) rabbit model of ocular inflammation. In vitro flare and cell calibration measurements utilizing bovine serum albumin (BSA) and latex particles, respectively, were also performed. A linear relationship between the flare measurements and BSA concentrations was noted. In addition, the time course of the LFCM flare count in EIU was comparable to previously published fluorophotometric data. However, the LFCM reported cells in the anterior chamber of the EIU rabbits despite negative cytology and histology results. The LFCM also recorded cells in BSA solutions which contained neither cells nor latex particles. Our results suggest that although the LFCM may be useful for evaluating flare, its cell measurements are not accurate in cases of severe uveitis.

Animals↗
PubMed1991

A magnetic resonance imaging study of the upshoot-downshoot phenomenon of Duane's retraction syndrome.

Patients with Duane's retraction syndrome may have an associated upshoot or downshoot of the involved eye in adduction. This vertical movement has been attributed to the lateral rectus muscle slipping over or under the globe and acting as an elevator or depressor, respectively ("bridle-effect"). We used magnetic resonance imaging to investigate this phenomenon in two patients, one with an overshoot and the other with an undershoot. Minimal vertical displacement of the lateral rectus muscle in relation to the orbit was noted both on upshoot and downshoot. The bridle-effect theory must be modified to account for this finding.

Adult↗
PubMed1990

Serum neopterin levels following intravenous endotoxin administration to normal humans.

Endotoxin was administered intravenously to five normal subjects. Measurement of serum neopterin levels demonstrated no significant change from baseline during the first 6 h after endotoxin administration, but were elevated two to four-fold at 24 h. In the three subjects in whom it was measured, a two-fold rise of the mean serum neopterin levels persisted at 48 h. The acute inflammatory events initiated by endotoxin administration to normal humans result in a delayed, but sustained, rise in serum neopterin levels which persists well after the acute phase response has subsided.

Acute-Phase Reaction↗
PubMed1989

Intravenous fluorescein interference with clinical laboratory tests.

The results of laboratory tests performed after fluorescein angiography may be erroneous because of interference by intravenous fluorescein. We investigated this potential interference in four adults at intervals of five minutes, three hours, six hours, and 12 hours after fluorescein injection. We used a panel of serum and urine chemistry tests on seven commonly used instruments. A significant change in the reported concentration of a serum or urine analyte was defined as a result beyond +/- 3 coefficients of variation of the preinjection baseline value for the test on a specific instrument. The determinations of creatinine, total protein, cortisol, digoxin, quinidine, and thyroxine in serum were affected by intravenous fluorescein. The urine tests were unaltered. The physician must be aware of the problem of interpreting clinical chemistry results after fluorescein angiography.

Adult↗
PubMed1988

The diagnosis of cytomegalovirus retinitis.

Immunosuppressed patients are at risk for developing cytomegalovirus retinitis. This disorder is the most common cause of vision loss in patients with the acquired immunodeficiency syndrome (AIDS). Cytomegalovirus retinitis is probably the result of hematogenous spread of the virus to the retina after systemic reactivation of a latent cytomegalovirus infection. Although the ophthalmic infection may initially be asymptomatic, the retinal necrosis it produces may result in both loss of visual field and decreased visual acuity. Routine screening of these patients is required for early diagnosis. The retinitis is detected with ophthalmoscopy as either a perivascular yellow-white retinal lesion frequently associated with retinal hemorrhage or as a focal white granular infiltrate, often without hemorrhage. Both lesions enlarge in a progressively expanding "brushfire" pattern. The diagnosis of cytomegalovirus retinitis, as well as the evaluation of its response to therapy, is determined primarily by clinical criteria. Serial retinal photography is an objective method to assess the changing appearance of these lesions. Ganciclovir and foscarnet are investigational antiviral drugs that appear to be effective in treating cytomegalovirus retinitis. However, maintenance therapy with these medications is required after initial treatment because the disease often relapses. The combined expertise of the internist and the ophthalmologist is needed to diagnose and treat these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Uveitis complicating autoimmune chronic active hepatitis.

A patient with autoimmune hepatitis B surface antigen-negative chronic active hepatitis (CAH) developed uveitis during the course of her disease. The occurrence of this eye disorder provides additional support for an autoimmune pathogenesis for CAH. Clinicians should be alert to the association of uveitis with CAH, so that patients at risk may be examined for this potentially serious ocular disease.

Autoimmune Diseases↗
PubMed1977

Herpes simplex retinitis and encephalitis in an adult.

A 17-year-old girl developed a viral encephalitis that was followed by massive exudative retinal detachments in both eyes. A diagnosis of herpes simplex encephalitis and retinitis was made as a result of finding rising herpes simplex viral titers. An examination of the patient's cell-mediated immune system showed it to be grossly intact.

Adolescent↗
PubMed1976

Fluorophotometry and the rate of aqueous flow in man. I. Instrumentation and normal values.

A new objective fluorophotometer, based on a previous model but with changes in electronic circuitry, was designed and built. The fluorometric method was applied to 38 normal eyes to obtain the aqueous outflow rate and fluorescein decay constant. Aqueous outflow rate has a direct correlation with the anterior chamber depth and an inverse correlation with age. The aqueous flow rate is higher in whites than in blacks, but in our sample, mean pressure was lower in whites. Acetazolamide decreases the aqueous flow rate and the fluorescein constant; the mean decrease in 10 eyes of 5 patients was approximately 38% and 22%, respectively. Fluorophotometry gives a higher value for the aqueous outflow rate than that calculated by tonography.

Acetazolamide↗
PubMed1976

Fluorophotometry and the rate of aqueous flow in man. II. Primary open angle glaucoma.

By fluorophotometry, the aqueous outflow rates of 38 eyes of 22 patients with definite or suspected primary open angle glaucoma, who were not receiving therapy, were determined. Although the values obtained do not differ from normal, the factors that modify or control the flow rate are different in normal and glaucomatous eyes. The flow rate decreases as the pressure increases in the glaucomatous group but not in the normal group. The flow rate increases with anterior chamber depth and decreases with age in the normal group but not in the glaucomatous group. The fluorescein decay constant is a measure of the movement of fluorescein from the cornea to the aqueous. This constant increases as the pressure increases in the glaucomatous group but not in the normal group.

Black or African American↗
PubMedDate not supplied

Orbital pseudotumor in the differential diagnosis of pediatric uveitis.

Pediatric orbital pseudotumor may be associated with iritis, unlike the adult form of this disorder. However, orbital pseudotumor is seldom considered in the differential diagnosis of childhood uveitis. We report two cases of children with uveitis who were ultimately diagnosed as having orbital pseudotumor. No proptosis was noted in either child. For those pediatric patients with a persistent or recurrent uveitis and a previous negative diagnostic workup, the possibility of an orbital pseudotumor should be considered and ultrasonography, magnetic resonance imaging, and/or computed tomography performed.

Child↗
PubMedDate not supplied

Serum antiocular antibodies in patients with juvenile rheumatoid arthritis.

Although the uveitis associated with juvenile rheumatoid arthritis (JRA) is presumed to have an autoimmune etiology, its pathogenesis is unknown. We utilized immunohistochemical techniques to detect the presence of serum antibodies directed against ocular tissues in these patients. The staining patterns of serum from patients with JRA, with and without uveitis, were compared with normal controls. Antibodies directed against epitopes in iris and ciliary body basement membranes, lens epithelium and fibers, Bruch's membrane, and iris and retinal blood vessels were observed in the sera of several individuals. These staining patterns were statistically more frequent among the pauciarticular and polyarticular JRA patients, with and without uveitis, than either the systemic JRA or normal populations. These results demonstrate the presence of antiocular antibodies in the sera of JRA patients, with and without uveitis. Whether those nonuveitic JRA patients with antiocular antibodies will develop uveitis is unknown at this time.

Adolescent↗
PubMedDate not supplied

Ocular pursuit movement assessment by magnetic resonance imaging.

We describe a new technique for generating cinematic magnetic resonance images. This method produces more physiological imaging of extraocular muscles than our previous method. In addition, this technique provides more comfort for the study subject and results in less head movement artifact.

Humans↗