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Biomedical subjects

R S Wagner

Publications and source records attributed to R S Wagner.

At least 55 records · Page 3Linked to original sources
PubMed1977

PH-dependent drug release from certain commercial tablets.

A dissolution-dialysis profile for each of several brands of nitrofurantoin, hydrochlorothiazide and sulfisoxazole tablets was developed at three pH levels. The study used a two-compartment diffusion cell with a semipermeable cellophane membrane. Nitrofuratoin tablets were tested at pH values of 7.2, 4.7 and 1.2; sulfisoxazole tablets at 7.2, 5.5 and less than 1. Studies with hydrochlorothiazide tablets were terminated because the pH of the dissolution medium had no effect of practical significance on dissolution or dialysis rates. The dissolution rates of the nitrofurantoin and sulfisoxazole tablets were highly brand-individualized and complex. The effects of pH upon a particular formulation were unpredictable. The results suggest that dissolution testing at one fixed pH, as commonly practiced, may be insufficient for some products. This pH-dependent release characteristic may not correspond to a change in bioavailability in all cases, but it represents a potential problem which should be considered by the formulator.

Biological Availability↗
PubMedDate not supplied

Ocular torticollis.

Torticollis can arise from nonocular (usually musculoskeletal) and ocular conditions. Abnormal head position for ocular reasons is usually assumed in order to maintain binocularity and/or to optimize visual acuity. A variety of conditions may be responsible. The sensory organ of position sense, the labyrinth, lies within the inner ear and it relates to eye movement in both a dynamic and static fashion. The Bielschowsky head tilt test is based on the functioning of the otolithic apparatus and is the primary test in evaluating abnormal head position. Treatment is usually surgical, with extent and location dependent upon on the underlying cause. While corrective surgery has usually been done on an elective basis for cosmetic purposes, there is evidence that uncorrected torticollis can cause musculoskeletal problems. This review describes the physiological bases for ocular torticollis and the diagnosis and treatment of its various underlying causes.

Apraxias↗
PubMedDate not supplied

Congenital esotropia.

Congenital esotropia represents the most common type of strabismus. Its pathogenesis, however, remains uncertain. It is typically characterized as a large angle, constant esotropia with onset during the first six months of life. Associated clinical findings include normal refractive errors for age, amblyopia, dissociated vertical deviation, inferior oblique muscle overaction and nystagmus. It must be distinguished from Duane's retraction syndrome, Moebius syndrome, nystagmus blockage syndrome, and early onset accommodative esotropia, as well as other causes of esotropia in infancy. The surgical management may involve recession of both medial recti muscles, unilateral recession of a medial rectus muscle and a resection of a lateral rectus muscle or three or four muscle surgery.

Botulinum Toxins↗
PubMedDate not supplied

Duane's retraction syndrome.

Duane's retraction syndrome (DRS) has been a recognized clinical entity for nearly a century. It is a clinically well described ocular disorder consisting of retraction of the globe with narrowing of the lid fissure in attempted adduction, frequent abduction deficiency with variable limitation to adduction, and upshoot and/or downshoot of the affected eye on adduction. Among strabismus patients the incidence of DRS is probably not more than 5%. Most cases are sporadic, but familial cases have been estimated at 10% by most authors. Numerous theories concerning the etiology and pathogenesis of DRS have been proposed, including agenesis of the abducens nucleus, but the majority of investigators concur that the characteristic findings are best explained by a paradoxical innervation of the lateral rectus muscle, which subsequently causes a cocontraction of the horizontal rectus muscles. The frequent association of DRS with other congenital anomalies suggests a teratogenic event occurring between the fourth to eighth week of gestation as an etiological factor. In this review historical aspects and theories of the syndrome are studied and statistical data are compiled and analyzed. Clinical features, differential diagnoses and variants of the syndrome are examined. Testing and treatment objectives are discussed.

Duane Retraction Syndrome↗
PubMedDate not supplied

Results of a survey of children with acute bacterial conjunctivitis treated with trimethoprim-polymyxin B ophthalmic solution.

Acute conjunctivitis, one of the most frequently seen eye diseases in infants and children, is associated with a shorter duration of clinical disease when antimicrobial agents are used. Although viruses often are implicated as causative agents, Haemophilus influenzae and Streptococcus pneumoniae are the most commonly isolated bacterial pathogens. Empiric therapy of acute conjunctivitis therefore should include agents with both gram-positive and gram-negative antimicrobial activity. Trimethoprim-polymyxin B is a broad-spectrum antimicrobial agent available as an ophthalmic solution. We conducted a patient outcomes study to evaluate the subjective response to treatment with trimethoprim-polymyxin B of children with presumed acute bacterial conjunctivitis. Questionnaires were distributed to more than 100 pediatricians who assessed outcome measures in 472 children with acute bacterial conjunctivitis for whom they prescribed trimethoprim-polymyxin B. The parameters evaluated were clinical outcome, overall efficacy, and comfort provided by the medication regimen. The physicians reported that 95% of the infected eyes were cured or improved within 7 days. In addition, the overall efficacy trimethoprim-polymyxin B was rated as excellent or good in 76% and 20% of cases, respectively. With regard to patient comfort, patients or their caregivers reported that patients were very comfortable or moderately comfortable in 62% and 27% of cases, respectively. Four adverse events were reported; all were transient and of mild-to-moderate intensity. The survey results support clinical research findings on the comparative efficacy and safety of trimethoprim-polymyxin B ophthalmic solution compared with other ophthalmic antimicrobial agents. The pediatricians in our survey who prescribed trimethoprim-polymyxin B ophthalmic solution for children with presumed acute bacterial conjunctivitis reported that this medication was effective and well tolerated.

Acute Disease↗
PubMedDate not supplied

Long-term results: botulinum for sixth nerve palsy.

Eight patients with intracranial malignancies or vascular lesions and sixth nerve palsies were treated with botulinum toxin chemodenervation of the antagonist medial rectus muscle. Primary deviation ranged from 20 to 75 prism diopters (pd) of esotropia. Six were treated acutely (within 3 months of onset) and two, which demonstrated partial recovery of lateral rectus function but with residual esotropia and diplopia, were treated after 6 months. After a mean follow-up of 20.6 months, seven were diplopia-free with excellent rotations. Five had complete resolution of the esotropia and diplopia, with near complete recovery of abduction. One had 6 pd residual esotropia, while another, whose sixth nerve had been resected, required a modified Jensen procedure, resulting in full rotations. The single case of bilateral sixth nerve palsy had a functional improvement but was lost to follow-up. One patient had a vertical strabismus induced with the injection and had a gradual return of the esotropia.

Abducens Nerve↗
PubMedDate not supplied

Anterior segment ischemia and retinal detachment after vertical rectus muscle surgery.

PURPOSE: The authors describe the clinical course of a woman who developed two complications following vertical strabismus repair: anterior segment ischemia (ASI) and retinal detachment. METHODS: A 62 year-old woman is described. She presented with new onset proptosis and left hypertropia with significant diplopia in all fields of gaze. This presentation, her 15 year history of thyroid disease, and preoperative computed tomography (CT) of the orbits were consistent with Graves' ophthalmopathy. Vertical strabismus repair was carried out by recessing the left superior rectus muscle and resecting the left inferior rectus muscle. RESULTS: The diplopia was eliminated. The patient developed significant postoperative ASI and iatrogenic rhegmatogenous retinal detachment in the left eye due to unsuspected globe perforation. She was treated with systemic corticosteroids and radial scleral buckling. CONCLUSIONS: Severe ASI following strabismus surgery is a well recognized complication, with age, thyroid ophthalmopathy, and manipulation of the vertical rectus muscles as risk factors. The retinal detachment soon after strabismus surgery was difficult to detect, possibly due to diminished visualization of the posterior segment as a result of ASI.

Anterior Eye Segment↗