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Biomedical subjects

S R Carter

Publications and source records attributed to S R Carter.

At least 73 records · Page 4Linked to original sources
PubMed1996

Silicone frontalis slings for the correction of blepharoptosis: indications and efficacy.

PURPOSE: To determine the efficacy of silicone rod frontalis sling ptosis repair in selected patients. METHODS: The authors retrospectively studied 35 consecutive patients who underwent silicone sling ptosis repairs in 6 lids at the University of California, San Francisco. RESULTS: Preoperative diagnoses included congenital ptosis causing developmental delay or possible amblyopia in children younger than 3 years of age, chronic progressive external ophthalmoplegia, third-nerve palsy, myasthenia gravis, and ocular restriction secondary to glaucoma filtering valves. With a mean follow-up of 22 months, good-to excellent final lid height was achieved in all 61 lids. Recurrence of the ptosis occurred in four lids (7%), requiring replacement of the silicone rod in two lids and revision of the original sling in two lids to reach the final lid height. Chronic exposure keratopathy without corneal infection occurred postoperatively in 9 (15%) of 61 eyes, all in patients with an inadequate or absent Bell phenomenon. Chronic corneal problems did not develop in any of the children. Extrusion of the sling with or without infection occurred in three foreheads (5%) in two patients younger than 15 years of age. CONCLUSION: Silicone rod is an effective material for use in frontalis suspension in treating severe ptosis with poor levator function. Children younger than 3 years of age with congenital ptosis and developmental delay or possible amblyopia can undergo silicone frontalis suspension to achieve good visual results. The elasticity and ease of adjustment of the silicone rod are ideal characteristics for a suspensory material used to correct severe ptosis associated with a minimal or absent Bell phenomenon, such as in chronic progressive external ophthalmoplegia, myasthenia gravis, or third-nerve palsy.

Adolescent↗
PubMed1996

The total cost of hip-joint replacement; a model for purchasers.

A computer-based model is used to investigate the total cost of primary total hip-joint replacement. The model takes into account the probability of prosthesis failure, death and re-revision. The results emphasize the importance of age at insertion, demonstrating that the expected life-span of the patient has a major influence on the total cost for a given prosthesis. The discussion considers the idea of a 'lifetime care package' to encapsulate the concept of quality when considering the purchasing of total hip replacements. If it is assumed that a primary replacement episode costs 3500 pounds and revision surgery costs twice as much, then the additional premium on the best implant currently available would be 630 pounds. The premium payable on the same patient using the worst design would be 3080 pounds. This difference reflects the importance of quality in total hip replacement surgery.

Adult↗
PubMed1996

The outcome and functional results of diaphyseal endoprostheses after tumour excision.

Improvement in the life expectancy of patients with primary bone tumours has led to increased emphasis on limb salvage and preservation of function. Between 1979 and 1994 we used custom-made endoprostheses in 18 patients to reconstruct diaphyseal defects after excision of primary bone tumours. The mean age at operation was 26 years (9 to 64) and the median follow-up 65 months (6 to 188). Fifteen patients have survived and are free from local or metastatic disease. Local recurrence developed in one patient. Using the modified Enneking functional scoring system, 77% of the patients achieved 80% or more of their premorbid functional capability. Mechanical loosening, limb shortening and secondary osteoarthritis were the main complications. There were no infections. We conclude that diaphyseal endoprostheses offer a good clinical and functional outcome in the lower limb.

Adolescent↗
PubMed1996

The surgical treatment and outcome of pathological fractures in localised osteosarcoma.

We reviewed the surgical treatment and oncological results of 40 patients with pathological fractures from localised osteosarcoma of the long bones to determine the outcome of limb salvage in their management. All had had adjuvant chemotherapy. There were 26 males and 14 females with a median age at diagnosis of 18 years (2 to 46) and a median follow-up of 55 months (8 to 175). We performed limb salvage in 27 patients and amputation in 13. The margins of resection were radical in five patients, wide in 26, marginal in six, wide but contaminated in two and intralesional in one. Local recurrence developed in 19% of those treated by limb salvage and in none of those who had an amputation. The cumulative five-year survival of all the patients was 57% and in those treated by limb salvage or amputation it was 64% and 47%, respectively (p > 0.05). Limb-sparing surgery with adequate margins of excision can be achieved in many patients with pathological fractures from primary osteosarcoma without compromising survival, but the risk of local recurrence is significant.

Adolescent↗
PubMed1995

Assessment of cocaine-like discriminative stimulus effects of dopamine D3 receptor ligands.

The highly selective dopamine D3 receptor ligand, (+)-PD 128907 4aR10bR-(+)-trans-3,4,4a,10b-tetrahydro-4-n-propyl-2H5H[4,3- b]-1,4- oxazin-9-ol), and other dopamine D3 receptor ligands, (+/-)-7-hydroxy-2-(N,N-di-n-propylamino)tetralin and (+)-7-hydroxy-2-(N,N-di-n-propylamino)tetralin, substituted for the discriminative stimulus effects of cocaine in rats, an animal model of subjective effects in humans. Substitution only occurred at doses that markedly decreased responding. These results suggest that dopamine D3 receptors may be involved in the subjective effects of cocaine, and therefore may be a target for the discovery of treatments for cocaine dependence.

Animals↗
PubMed1995

Treatment of facial palsies with external eyelid weights.

PURPOSE: Because ocular exposure is a major complication of facial paralysis, an external gold eyelid load weight was evaluated for effectiveness in the treatment of this problem. METHODS: We prospectively studied 12 patients with unilateral facial paralysis who were treated with the external eyelid weights. Follow-up examinations included corneal exposure, amount of artificial tear usage, patient comfort, and complications associated with the weights. Treatment end points were the patient's decision to undergo a canthoplasty or placement of an implanted weight or resolution of the facial paresis to better than House's grade IV/VI. RESULTS: Of the 12 patients studied, ten had decreased corneal exposure on the affected side, with a coincident decrease in artificial tear drop use and increased comfort. One patient had no improvement in a corneal defect, and one was unable to apply the weight. Five patients had some difficulty in positioning the weight, which was related to upper eyelid dermatochalasis in four of the five. Only two weights were lost in over two years of total wearing time. CONCLUSIONS: External eyelid weights are useful in the treatment of ocular exposure associated with facial paralysis. The weights decreased corneal exposure, decreased reliance on artificial tear drops, and increased patient comfort. The weights were helpful as a trial before implantation of eyelid weights and as a longer-term treatment for ocular exposure in patients with temporary facial paralysis. Loose upper eyelid skin may limit their usefulness in some patients.

Adult↗
PubMed1995

Macular changes in pseudotumor cerebri before and after optic nerve sheath fenestration.

PURPOSES: Macular abnormalities such as chorioretinal striae, pigmentary disturbances, exudates, and subretinal hemorrhage or scar can occur in patients with pseudotumor cerebri. The purpose of this study is to determine the potential resolution of the macular abnormalities after optic nerve sheath fenestration, as well as the visual significance of these changes. METHODS: The authors retrospectively compared the preoperative and postoperative examinations of seven patients with pseudotumor cerebri-associated macular changes who underwent unilateral optic nerve sheath fenestration. RESULTS: Preoperatively, visual acuity was worse than 20/25 in two patients with macular exudates and in one with a subretinal scar. Chorioretinal striae and pigment mottling did not appear to decrease visual acuity. With a mean postoperative follow-up of 14 months, the patients with exudates had improvement in visual acuity and clearing of the exudates, unlike the patient with the subretinal scar. Chorioretinal striae, pigment mottling, and the subretinal scar did not resolve with surgery. CONCLUSIONS: This study suggests that chorioretinal striae and pigment mottling in the setting of pseudotumor cerebri, unlike exudates and subretinal scars, do not have a significant effect on visual acuity. After optic nerve sheath fenestration, only macular exudates decreased. Therefore, the persistence of striae, pigment mottling, and macular scars, in the face of resolved papilledema and improved visual fields, does not indicate failure of the optic nerve sheath fenestration.

Adult↗
PubMed1995

Paediatric surgical oncology. 3--Bone tumours.

Bone tumours are rare--they represent less than 1% of all malignancies but about 6% in the paediatric population. Early diagnosis, chemotherapy and limb salvage surgery can result in 60% cure rates with a near normal functional outcome. Surgery plays a major part in the management of these tumours, and is technologically as well as surgically exacting.

Adolescent↗
PubMed1994

Purification and active-site characterization of equine plasma amine oxidase.

An improved purification scheme for an amine oxidase from equine plasma (EPAO), a nonruminant source, is described and the protein's active-site is characterized. EPAO is dimeric and contains one Type-2 Cu(II) ion per monomer. The EPAO Cu(II) site is spectroscopically very similar to the Cu(II) sites in other amine oxidases. Unlike the extensively investigated nonruminant amine oxidase from porcine plasma, EPAO does not display half-of-the-sites reactivity; titrations with p-nitrophenylhydrazine and phenylhydrazine indicate two active cofactors per dimer. This cofactor is determined to be the same as that of other copper-containing amine oxidases, 6-hydroxydopa quinone (topa quinone). Upon anaerobic reduction with substrate at ambient temperature, the EPR spectrum of EPAO exhibits a sharp signal at g congruent to 2, attributable to the topa semiquinone. Equine plasma amine oxidase possesses novel in vitro substrate specificity; while other mammalian amine oxidases oxidize norepinephrine only slowly or not at all, EPAO displays significant activity toward this biogenic amine.

Amine Oxidase (Copper-Containing)↗
PubMed1994

The value of computed tomographic measurements in osteosarcoma as a predictor of response to adjuvant chemotherapy.

The response to pre-operative adjuvant chemotherapy was assessed with computed tomography (CT) in 41 osteosarcomas of the long bones of the lower limb. Measurements were made of cross-sectional tumour areas and volumes on both the pre- and post-chemotherapy CT examinations. Changes in these measurements were compared with the percentage necrosis determined from examination of the tumour histology from the excised specimen in 39 cases. An increase in the relative size of the tumour (expressed as a ratio of the pretreatment volume) showed a statistically significant correlation with a poor tumour response as judged by the degree of tumour necrosis. Further analysis of the results showed that quantitative assessment of tumour response by CT is able to identify cases with poor response to therapy (negative predictive value = 0.9). This is, however, only achieved with a low specificity (0.5-0.6). These findings are in agreement with other studies of tumour volume changes using MR imaging.

Adolescent↗
PubMed1993

The retrograde tracer Fluoro-Gold interferes with the infectivity of herpes simplex virus.

Fluoro-Gold has been used previously to identify those trigeminal ganglion cells that innervate the central cornea. To examine the effects of Fluoro-Gold treatment on infection and spread of HSV in vivo, we measured the number of plaque forming units recovered from trigeminal ganglia 3 or 5 days after corneal scratch and inoculation with Fluoro-Gold and HSV. Treatment with Fluoro-Gold reduced the amount of virus recovered after retrograde transport 63% at 3 days and 28% at 5 days after inoculation. When we examined trigeminal ganglion sections from animals treated with HSV and Fluoro-Gold, we found the number of neurons double labeled with antibodies that recognize HSV and Fluoro-Gold was only 13% of all Fluoro-Gold labeled neurons. This was significantly fewer cells that we had anticipated, on the basis of double labeling experiments with wheat germ agglutinin combined with Fluoro-Gold. The effects of varying doses of the retrograde tracer, Fluoro-Gold on Herpes simplex virus (type 1) (HSV) infectivity were also assayed in vitro using a standard viral plaque assay. At 1 x 10(-3) mg/ml Fluoro-Gold there was no effect on the number of plaque forming units. At 5 x 10(-1) mg/ml the number of plaques was reduced about 67%. We conclude that Fluoro-Gold interferes with productive HSV infection in vivo and in vitro after retrograde transport of HSV by neurons.

Animals↗
PubMed1993

Designer hips.

Explore the source record for details and available documents.

Budgets↗
PubMed1993

Fatigue fracture of the sacrum in a child.

Fatigue fractures involving the sacrum are extremely rare, and to our knowledge no occurrence of such a fracture in a child has been reported in the English-language literature. These fractures may mimic primary bone tumours or infection, and it is important to make an accurate diagnosis so that unnecessary biopsy can be avoided. We report a fatigue fracture of the sacrum in an 11-year-old child following prolonged aerobic exercise.

Child↗
PubMed1992

Sensitive stereospecific assay of warfarin in plasma: reversed-phase high-performance liquid chromatographic separation using diastereoisomeric esters of (-)-(1S,2R,4R)-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]-hept-5- ene-2-carboxylic acid.

A stereospecific reversed-phase high-performance liquid chromatographic (HPLC) assay for warfarin in plasma has been developed. The assay involves a rapid, simple clean-up procedure which separates warfarin from plasma constituents and warfarin metabolites. Warfarin enantiomers were assayed as their (-)-(1S,2R,4R)-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene -2- carboxylic acid diastereoisomeric esters by reversed-phase HPLC. Excellent resolution of the diastereoisomers was achieved in less than 10 min. Sensitivity of the assay was approximately 5-10 ng/ml for each isomer.

Bridged Bicyclo Compounds↗
PubMed1992

Computed tomographic appearances of the pelvis following hindquarter amputation.

Bilateral and midline symmetry of the normal pelvic anatomy is an aid to the interpretation of computed tomographic (CT) examinations. Following hindquarter amputation (HQA) or partial hemipelvectomy (PHP) the normal anatomical relationships are disturbed. The CT examinations of 15 patients who had undergone either an HQA or a PHP for an advanced musculoskeletal malignancy are reviewed. The new "normal" anatomy revealed displacement of the bladder and small bowel to the side of surgery in one third of patients, more commonly in the PHP cases. There were varying degrees of wasting of the ipsilateral musculature, gluteus maximus muscle flap, erector spinae and psoas muscles, etc., because of partial denervation and disruption of their origin or insertion. Recurrent tumour was identified in eight of 10 cases in which it was clinically suspected prior to the CT examination. Invariably the recurrence arose within the muscle flap at the resection margin. Bone involvement by direct tumour spread was present in three cases. Pitfalls in differentiating recurrent tumour from scar tissue are discussed.

Adult↗
PubMed1992

A quantitative assay of retrograde transported HSV in the trigeminal ganglion.

The relationship between the dose of Herpes simplex virus type 1 (HSV) inoculated in the cornea and the amount of actively replicating virus recovered from mouse trigeminal ganglion cells 5 d after corneal scratch and inoculation was investigated with a tissue culture plaque assay. A dose response curve of productive viral replication was obtained. The estimated dose of HSV that produces half-maximal recovery of virus within the ganglion was 9.15 x 10(3) plaque forming units per eye, and the maximal amount of HSV recovered was 1.34 x 10(4) pfu per ganglion. This definition of infectivity as a function of dose will be useful for studying the effects of potential inhibitors of the binding, uptake, and transport of HSV by productively or latently infected trigeminal neurons.

Animals↗