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Biomedical subjects

J D Brandt

Publications and source records attributed to J D Brandt.

16 recordsLinked to original sources
PubMed1997

Group dynamics in forensic pretrial decision-making.

This study examines how forensic evaluators' opinions that pertain to diagnosis, competency to stand trial, and criminal responsibility (Maryland's version of the not guilty by reason of insanity plea) are rendered at a state forensic hospital for defendants pleading not criminally responsible. Pretrial evaluations completed independently by a psychiatrist, a psychologist, and a social worker were presented at a forensic staff conference where psychiatrist and psychologists openly "voted" on diagnosis, competency to stand trial, and criminal responsibility. These results were then sent to the court. The purpose of this study was to assess the clinicians' level of agreement and the role that conformity played in the decision-making process. A sample of twenty court-ordered pretrial evaluations of defendants examined at the hospital between March and June 1991, with evaluators' opinions generated by a secret ballot, were compared with a matched control group from an earlier time, when opinions were generated by open ballot. The study was designed to compare the opinions of forensic evaluators in the issues of diagnosis, competency to stand trial, and criminal responsibility between the two samples. The defendants in the experimental group and the control group were matched on the basis of age, race, sex, and offense. It was hypothesized that with secret ballot voting there would be a greater disparity of agreement regarding diagnosis, competency to stand trial, and criminal responsibility opinions compared with the open method of voting. However, the results of this study did not support that hypothesis. There was little disparity on forensic opinions rated either by secret or open voting.

Adolescent↗
PubMed1997

Effects of dexamethasone on sodium-potassium-chloride cotransport in trabecular meshwork cells.

PURPOSE: Previous studies in the authors' laboratory have shown that bovine and human trabecular meshwork (TM) cells possess a robust sodium-potassium-chloride (Na-K-Cl) cotransport system that functions in regulating intracellular volume and may play a central role in modulating outflow facility across the TM. Dexamethasone, which can induce ocular hypertension, has been found to increase resistance to aqueous outflow across the TM. The current study was conducted to investigate the hypothesis that alteration of TM cell Na-K-Cl cotransport function, regulation, or both may be an underlying factor in steroid-induced glaucoma. To this end, the authors evaluated the effects of dexamethasone treatment of TM cells on Na-K-Cl cotransport activity and cotransporter protein expression. METHODS: Cultured bovine and human TM cell monolayers were exposed to dexamethasone (10(-9) to 10(-6) M) for varying times, then evaluated for Na-K-Cl cotransport activity or harvested for cellular membrane proteins. Cotransport activity was assessed as bumetanide-sensitive K influx. Cotransport protein expression was evaluated by Western blot analysis of cellular proteins using a monoclonal antibody to the human colonic T84 epithelial cell Na-K-Cl cotransporter. RESULTS: The authors found that 24- and 48-hour exposures of human and bovine TM cells to dexamethasone stimulates Na-K-Cl cotransport activity (10(-8) to 10(-6) M dexamethasone in human cells; 10(-8) and 10(-7) M in bovine cells). The authors also found that dexamethasone (10(-8) M) stimulates Na-K-Cl cotransport activity of TM cells with exposure times as early as 12 hours and up to 5 days. In addition, the authors found that the level of Na-K-Cl cotransport protein expressed in TM cells is modulated by dexamethasone. When bovine or human TM cells are exposed to 10(-8) or 10(-6) M dexamethasone for 2 to 5 days, cotransporter protein expression is increased. With longer exposures, however, cotransporter protein levels decrease below control levels. Finally, the authors found that TM cells exposed to dexamethasone become unresponsive to regulation by hypertonicity and vasopressin. CONCLUSIONS: The authors' findings suggest that dexamethasone may be exerting its effect, at least in part, through altering Na-K-Cl cotransport function and regulation in TM cells.

Animals↗
PubMed1995

Short-wavelength automated perimetry in low-, medium-, and high-risk ocular hypertensive eyes. Initial baseline results.

OBJECTIVE: To examine the relationship between the prevalence of short-wavelength sensitivity losses in the central 30 degrees visual field and risk factors for development of glaucomatous visual field loss in ocular hypertension. DESIGN: A modified Humphrey Field Analyzer was used to perform standard automated perimetry and short-wavelength automated perimetry (SWAP), which is a technique that isolates the activity of short-wavelength-sensitive ("blue") mechanisms. In addition, an assessment of the risk of developing glaucomatous visual field loss was determined, based on a validated model that utilized intraocular pressure, a family history of glaucoma, age, and the vertical cup-to-disc ratio. PATIENTS: Both eyes of 232 ocular hypertensive patients were examined and compared with results from an age-matched control group of normal subjects. Both ocular hypertensive patients and normal subjects had to have normal visual fields on standard automated perimetry, good visual acuity, and no evidence of other ocular or neurologic disease or surgery. Intraocular pressure in the ocular hypertensive patients was 21 mm Hg or greater OU (without medication), and it was less than 20 mm Hg OU in normal control subjects. RESULTS: Less than 10% of the low-risk ocular hypertensive eyes had a SWAP deficit, as compared with 20% of the moderate-risk and 33% of the high-risk ocular hypertensive eyes. Intraocular pressure and a family history of glaucoma showed no meaningful relationship with the prevalence of SWAP deficits, but both age and the vertical cup-to-disc ratio demonstrated a strong association with the SWAP abnormalities. CONCLUSIONS: The SWAP results that were found in the ocular hypertensive eyes were associated with other risk factors that have been reported to be predictive of the development of glaucomatous visual field loss, especially the vertical cup-to-disc ratio and age. These findings support the notion that the SWAP deficits represent early glaucomatous damage and may be related to early changes that occur at the optic nerve head.

Adult↗
PubMed1995

Clinical experience with the Baerveldt glaucoma drainage implant.

PURPOSE: To assess clinical outcomes in patients who were treated with the Baerveldt glaucoma drainage implant. METHODS: The authors performed a retrospective multicenter study of 100 patients (103 eyes) with medically uncontrollable glaucomas who underwent a one-stage implantation with either the 200-, 250-, 350-, or 500-mm2 Baerveldt implant. The authors defined surgical success as 5 mmHg less than intraocular pressure less than 22 mmHg without additional glaucoma surgery and without loss of light perception. RESULTS: With a mean follow-up of 13.6 +/- 0.9 months (range, 4-37 months), 74 eyes (71.8%) had successful outcomes. Cumulative life-table success rates were 90.3% at 3 months (n = 103), 72.6% at 6 months (n = 84), and 60.3% at 24 months (n = 34). Intraocular pressure (IOP) was reduced from a mean of 38.5 +/- 1.4 mmHg with 2.2 +/- 0.1 antiglaucoma medications to 15.1 +/- 0.8 mmHg (P < 0.0005) with 0.5 +/- 0.1 antiglaucoma medications (P < 0.0005). Visual acuity was improved or remained within one line of the preoperative visual acuity in 90 eyes (87.4%). Complications occurred in 74 eyes (71.8%). A significant portion of these complications (45%) was transient, resolving without any intervention. Only 8% were serious sight-threatening complications. The most common complications included shallow anterior chamber or hypotony (32%), choroidal effusion or hemorrhage (20.4%), corneal decompensation or edema (17.5%), hyphema (14.1%), and tube obstruction (12.6%). CONCLUSION: The Baerveldt implant is effective in lowering the IOP in patients with intractable glaucomas. Hypotony and other complications are common, which also have been reported in other nonvalved glaucoma drainage implants. However, the majority of these complications did not affect surgical outcome.

Adolescent↗
PubMed1995

Na-K-Cl cotransport regulates intracellular volume and monolayer permeability of trabecular meshwork cells.

The trabecular meshwork (TM) of the eye plays a critical role in modulating intraocular pressure (IOP) through regulation of aqueous humor outflow, although the underlying mechanisms remain unknown. Ethacrynic acid, an agent known to inhibit Na-K-Cl cotransport of a number of cell types, recently has been reported to increase aqueous outflow and lower IOP through an unknown effect on the TM. In vascular endothelial cells and a variety of other cell types, the Na-K-Cl cotransporter functions to regulate intracellular volume. The present study was conducted to evaluate TM cells for the presence of Na-K-Cl cotransport activity and to test the hypothesis that modulation of cotransport activity alters intracellular volume and, consequently, permeability of the TM. We demonstrate here that bovine and human TM cells exhibit robust Na-K-Cl cotransport activity that is inhibited by bumetanide and by ethacrynic acid. Our studies also show that TM cell Na-K-Cl cotransport is modulated by a variety of hormones and neurotransmitters. Inhibition of the cotransporter either by bumetanide, ethacrynic acid, or inhibitory hormones reduces TM intracellular volume, whereas stimulatory hormones increase cell volume. In addition, shrinkage of the cells by hypertonic media stimulates cotransport activity and initiates a subsequent regulatory volume increase. Permeability of TM cell monolayers, assessed as transmonolayer flux of [14C]sucrose, is increased by hypertonicity-induced cell shrinkage and by bumetanide. These findings suggest that Na-K-Cl cotransport of TM cells is of central importance to regulation of intracellular volume and TM permeability. Defects of Na-K-Cl cotransport may underlie the pathophysiology of glaucoma.

Animals↗
PubMed1993

Blue-on-yellow perimetry can predict the development of glaucomatous visual field loss.

OBJECTIVE: The purpose of this investigation was to determine whether blue-on-yellow (B/Y) perimetry is capable of predicting the onset and location of impending glaucomatous visual field loss in patients with ocular hypertension. DESIGN: A Humphrey Field Analyzer (Humphrey Instruments, San Leandro, Calif) was modified to perform B/Y perimetry to isolate and measure the sensitivity of short-wavelength-sensitive mechanisms. Participants were tested annually with standard white-on-white (W/W) and B/Y automated perimetry for a period of 5 years. PATIENTS: The study population consisted of 38 patients with ocular hypertension and 62 age-matched normal control subjects. RESULTS: Initially, all 76 ocular hypertensive eyes had normal W/W automated perimetry results, with 67 eyes having normal and nine eyes having abnormal B/Y test results. Five years later, five of the nine ocular hypertensive eyes with initial B/Y abnormal results developed glaucomatous visual field loss measured by standard W/W automated perimetry, while none of the 67 ocular hypertensive eyes with initially normal B/Y results developed abnormal W/W perimetry results. CONCLUSIONS: Blue-on-yellow perimetry deficits are an early indicator of glaucomatous damage and are predictive of impending glaucomatous visual field loss for standard W/W automated perimetry. To our knowledge, this is the first prospective, long-term longitudinal study that demonstrates the ability to predict the onset of glaucomatous visual field loss in patients with ocular hypertension on the basis of psychophysical testing.

Adult↗
PubMed1993

Progression of early glaucomatous visual field loss as detected by blue-on-yellow and standard white-on-white automated perimetry.

OBJECTIVE: To determine whether blue-on-yellow perimetry reveals progression of glaucomatous damage before it is evident with standard white-on-white perimetry. DESIGN: A Humphrey field analyzer (Humphrey Instruments, San Leandro, Calif) was modified to perform blue-on-yellow perimetry to isolate and measure the sensitivity of short wavelength-sensitive mechanisms. Participants were tested annually with standard white-on-white automated perimetry and blue-on-yellow automated perimetry for 5 years. PATIENTS: Sixteen patients with early glaucomatous visual field loss in one or both eyes and 62 age-matched normal control subjects. RESULTS: At baseline, 25 (78.1%) of the 32 eyes exhibited larger deficits with blue-on-yellow perimetry, five (15.6%) had equivalent loss with both tests, and two (6.3%) had larger deficits with standard white-on-white perimetry. Seven (21.9%) of the 32 eyes demonstrated evidence of progressive visual field loss with standard white-on-white perimetry in 5 years, while the other 25 eyes (78.1%) were relatively stable. Deficits with blue-on-yellow perimetry were twice as large as deficits with white-on-white perimetry in the stable group and were three to four times as large in the group with progressive field loss. CONCLUSIONS: Blue-on-yellow perimetry is effective in predicting which patients with early glaucomatous visual field loss are most likely to have progressive loss. The rate of progressive loss is greater with blue-on-yellow perimetry than with standard white-on-white perimetry.

Adult↗
PubMed1993

Patch grafts of dehydrated cadaveric dura mater for tube-shunt glaucoma surgery.

Human donor sclera is commonly used in glaucoma surgery with a tube-shunt (eg, Molteno, Baerveldt, Shocket, Krupin-Denver) to cover the external portion of the silicone tube and prevent its erosion through the overlying conjunctiva. Common problems with this technique include immune-mediated melting of the graft and the potential for infectious disease transmission by the grafted material. A case is presented of a patient in whom a low-grade iridocyclitis was associated with the gradual melting of a scleral patch graft; the scleral patch was then replaced with commercially available, dehydrated human dura mater. The practical and theoretical advantages of cadaveric human dura mater in tube-shunt glaucoma surgery are discussed.

Dehydration↗
PubMed1992

The effect of trabeculectomy on corneal topography.

Trabeculectomy is increasingly being performed earlier in the treatment of primary open-angle glaucoma (POAG). Surgically-induced alterations in corneal curvature resulting from filtering surgery may have a significant impact on patients, especially younger ones, whose vision may already be compromised by visual-field loss. Using data obtained by computer-assisted topographic analysis performed preoperatively and at 12 weeks postoperatively, we longitudinally studied the corneal surface changes induced by primary trabeculectomy in eight eyes undergoing surgery for POAG or normal-tension glaucoma. Additional data collected included refraction, keratometry, axial length, intraocular pressure, and pachometry. Five of eight eyes developed 1.50 to 2.50 diopters of steepening in the 90-degree meridian. One patient developed flattening in the 180-degree meridian without vertical steepening. Two patients had little change in the central optical zone. Of the six eyes with induced with-the-rule astigmatism, keratometry was less sensitive than topographic analysis in detecting the changes induced by trabeculectomy. Our data indicate that changes in corneal curvature are induced by filtering surgery, but may be undetectable without topographic analysis.

Astigmatism↗
PubMed1991

Conjunctival impression cytology in patients with glaucoma using long-term topical medication.

Increasing evidence indicates that long-term use of topically administered medications can induce changes in the conjunctiva and ocular surface. We used the technique of conjunctival impression cytology to evaluate the conjunctival changes that develop with long-term use of topically administered antiglaucoma medications. Patients with glaucoma who were on a stable regimen of one, two, or three topically administered medications were recruited for study; glaucoma suspects who were not using topically administered medications served as controls. Eyes with clinical or historical evidence of external eye disease or conjunctival surgery were excluded. Impression cytology specimens, collected from the bulbar and palpebral conjunctiva, were coded and subsequently graded by a masked observer. We examined specimens from 72 eyes by using this technique. Aggregate scores for the bulbar conjunctiva were compiled, using a previously described grading system with a range of 0 (normal) to 3 (diffuse, severe metaplasia). The results show statistically significant degrees of conjunctival metaplasia associated with the number of glaucoma medications used. These results suggest that the long-term use of antiglaucoma medications induces changes in the conjunctival surface. These changes may be related to the medications themselves, the preservatives in the commercial preparations, or the duration of topical treatment. The clinical relevance of these changes remains unknown.

Administration, Topical↗
PubMed1987

Adrenergic stimulation of ciliary process epithelium causes surface membrane internalization.

An ultrastructural change induced in the nonpigmented epithelium (NPE) of the ciliary processes by adrenergic stimulation in the albino rabbit was studied. Thirty min after topical treatment with 2% isoproterenol, an extensive intracellular membranous network, previously reported to be smooth endoplasmic reticulum, was revealed by electron microscopy. It was postulated that this network originated from the plasma membrane. Using cationized ferritin (CF) as an ultrastructural tracer, freshly isolated anterior segments were incubated in buffer containing 10(-5) M isoproterenol and 0.2% CF. As early as 10 min, and for at least 30 min, the isoproterenol-treated NPE cells contained a membranous network that was morphologically similar to that which occurs in vivo. CF particles were present within the network, indicating that the membranous network had originated at the cell surface. This labeling was prevented by pretreatment with the beta-adrenergic antagonist timolol maleate. In both treated and control ciliary processes, CF was present in the ciliary canals between the NPE and the underlying pigmented epithelium after 10 min incubation. This suggests that the NPE is able to transport CF from its basilar to apical surface. These experiments imply that the NPE is able to internalize rapidly large amounts of plasma membrane in response to adrenergic stimulation. This response may be part of the mechanism of adrenergic receptor desensitization, alteration of aqueous humor production, or another adrenergic response.

Administration, Topical↗
PubMedDate not supplied

Ophthalmology's botanical heritage.

Many of today's important ophthalmic pharmaceuticals have a rich ethnobotanical history. Solanaceous plants, the source of atropine, have contributed to medical therapy since the beginning of Western civilization. The botanical source of physostigmine played a pivotal role as an ordeal poison in the culture of Old Calabar, West Africa. Native peoples of Amazonia treasured plants containing pilocarpine as panaceas because of their impressive diaphoretic effect. Nineteenth century scientists examining these plants because of their folkloric reputations discovered their active compounds and documented their physiological effects. Ophthalmologists such as Argyll Robertson, Laqueur, and Weber built upon this research to bring these pharmaceuticals into therapeutic use. The ongoing loss of the world's tropical rain forests threatens to destroy a vast storehouse of untested biological compounds.

Glaucoma↗