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Biomedical subjects

M N Luxenberg

Publications and source records attributed to M N Luxenberg.

At least 19 recordsLinked to original sources
PubMed1995

Computer-simulated eye surgery. A novel teaching method for residents and practitioners.

PURPOSE: To describe an eye surgery simulator that uses a computerized graphic display to allow ophthalmic surgeons of all experience levels to enhance their surgical skills. METHODS: The eye surgery simulation environment consists of a high-speed computer graphics workstation, a stereo operating system, a wrist rest, and a position tracking stylus connected to force feedback motors. The surgeon views computer-generated images of the eye and surgical instruments through the stereo operating system and controls the position and orientation of the chosen surgical instrument by moving the stylus. During the simulated instrument-tissue interactions, three feedback motors generate component force feedback along three orthogonal axes connected by thin rigid bars to the tip of the stylus. RESULTS: The current proof-of-concept system provides a method for rapid learning experiences in a living eye simulation. Procedures can be recorded for playback and analysis, as well as for examination of techniques from different viewpoints (e.g., from inside the eye). Four simulated surgical instruments are available for use (scalpel, forceps, scissors, and phacoemulsifier). CONCLUSION: Eye surgery simulation offers both beginning and experienced ophthalmic surgeons an opportunity to learn new techniques and skills and achieve a satisfactory level of proficiency before use of that procedure in the operating room. When fully developed, this system should shorten the learning curve for new surgeons (i.e., residents) and offer an opportunity for practice before doing a difficult case or development of new techniques by experienced surgeons. The goal of replacement of current standard training methods for surgeons awaits further refinement and adjustment of the model.

Computer Simulation↗
PubMed1990

Cisplatin-based chemotherapy in advanced basal and squamous cell carcinomas of the skin: results in 28 patients including 13 patients receiving multimodality therapy.

This study reports the results of cisplatin (CDDP)-based chemotherapy (CT) as sole therapy and as neoadjuvant (NA) therapy in 28 consecutive patients (pts) with advanced basal cell (BC) and squamous cell (SC) cancers of the skin. CT in 24 pts consisted of CDDP 75 mgm/m2 and doxorubicin (Dox) 50 mg/m2 intravenously (IV) every 3 weeks with Dox being omitted in four pts due to severe preexisting cardiac disease. Thirteen of the 28 pts received CT in the NA setting, five before surgery and eight before radiation therapy (RT). Response rates to CT were complete remission (CR) in eight of 28 (28%) pts, partial remission (PR) in 11 of 28 (40%) for an overall response rate of 68%. Thirteen pts received a second treatment modality with five of 13 pts having a CR to CT alone before the second modality and seven converting to CR postsecond modality for a total CR rate of 12 of 13 (92%) in the multimodality group. Duration of responses in the CT-only group ranged from 4 to 82 months; however, only two patients remain in remission in this group. Of the twelve CRs from the multimodality therapy group, 11 of 12 (91%) pts remain in CR with duration of response ranging from 3 to 81 months. Toxicities were manageable, with no toxic deaths and only five pts stopped CT secondary to side effects. This study suggests the combination of CDDP and Dox is highly effective in BC and SC cancers of the skin and by itself can produce long unmaintained remissions, but when combined with a second modality of therapy, it is capable of producing not only long unmaintained CRs but probable cures in the majority of pts.

Aged↗
PubMed1988

Topical indomethacin and prostaglandins in normal and aphakic rabbit eyes.

Lenses were removed from rabbit eyes using an extracapsular technique. Animals were in three groups; no treatment (NT), post-treatment (PT) and pre- and post-treatment (PPT). Treatment consisted of 2% topical indomethacin given three times a day after surgery, except for the PPT group that received 3 drops on the day prior to surgery and drops at 3 hours and 1 hour before surgery. Prostaglandin levels in ocular tissues and fluids were determined at 7, 14 and 21 days post-surgery. Indomethacin decreased prostaglandin formation in most ocular tissues, and was more effective in the PPT group than in the PT group. The data indicate that topical indomethacin suppresses prostaglandin formation from ocular tissues, and that local prostaglandin release from retina and choroid can provide locally high prostaglandin concentrations, regardless of their source, after lensectomy.

Administration, Topical↗
PubMed1986

Chemotherapy of basal cell and squamous cell carcinoma of the eyelids and periorbital tissues.

Eight patients, aged 62 to 85 years, with nine instances of histologically proven basal cell carcinoma (BCC) or squamous cell carcinoma (SCC) involving the eyelids and periorbital tissues, were treated with systemic and/or local (iontophoresis) chemotherapy using cisplatin (Platinol) and doxorubicin (Adriamycin). All patients had either refused surgery, would have required extensive procedures, or had medical problems contraindicating surgery. Systemic chemotherapy induced a complete or partial remission in eight of nine lesions. No patient has required maintenance chemotherapy and no significant toxic side effects were encountered. The length of follow-up ranged from 2 to 50 months. Iontophoretic therapy with cisplatin was used to treat five small foci of new, recurrent or persistent tumor(s) in three of these patients and resulted in a partial response in all five lesions. Systemic or local chemotherapy offers an alternative to current standard forms of treatment for BCC and SCC in selected cases.

Aged↗
PubMed1985

Chemotherapy of eyelid and peritorbital tumors.

Eight patients with nine histologically proven BCC or SCC involving the eyelids and periorbital tissues were treated with systemic and/or local (iontophoresis) chemotherapy using cisplatin and doxorubicin. All patients had either refused surgery, would have required extensive procedures, or had medical problems contraindicating surgery. Systemic chemotherapy induced a CR or PR in eight of nine lesions. No patient has required maintenance chemotherapy and no significant toxic side effects were encountered. The length of follow-up ranges from 2 to 50 months. Iontophoretic therapy with cisplatin was used to treat five small foci of new, recurrent or persistent tumor(s) in three of these patients, and resulted in a partial response in all five lesions. Systemic or local chemotherapy offers an alternative to current standard forms of treatment for BCC and SCC in selected cases.

Aged↗
PubMed1983

Penetration of topical indomethacin into phakic and aphakic rabbit eyes.

The penetration of indomethacin labeled with radioactive carbon (14C) into all ocular tissues and fluids was determined at various intervals in both phakic and aphakic rabbit eyes after either single or multiple (every 12 hours for three days) topical application (50 microL) regimens. More indomethacin was found in the vitreous of aphakic eyes compared with phakic eyes after single- or multiple-drop administration. Retinal and choroidal indomethacin concentrations were equal in both phakic and aphakic eyes after either drug regimen and are much greater than those of the vitreous. A pathway other than diffusion through the vitreous exists for the drug to reach these tissues. The concentration of indomethacin reaching the retina and choroid is not sufficient to inhibit prostaglandin formation locally. The concentrations of indomethacin are high enough to inhibit the biotransformation of prostaglandin precursor only in the anterior segment.

Administration, Topical↗
PubMed1983

Present and future training of foreign ophthalmologists in the USA. Perspective of Association of University Professors of Ophthalmology.

A questionnaire entitled "Present and Future Training of Ophthalmologists in the USA" was sent to members of the Association of University Professors of Ophthalmology. Data obtained from the questionnaire indicate that: the complex regulations pertaining to training foreign medical graduates (FMGs) in the USA are often not fully understood by the chairmen, most programs are willing to accept but do not actively recruit FMGs, there are a number of obstacles encountered in selecting and training FMGs, and most resident and fellowship positions are filled by US graduates.

Education, Medical, Graduate↗
PubMed1982

Endophthalmitis after strabismus surgery.

We treated two cases of endophthalmitis caused by strabismus surgery. In one patient, a scleral perforation was recognized during surgery and treated with cryopexy. In the other, a scleral perforation was suspected but never confirmed. Despite intensive antibiotic and corticosteroid therapy, visual acuity decreased to light perception in Case 1 and to counting fingers in Case 2. The second eye was enucleated eight years later after it had become blind and painful.

Adolescent↗
PubMed1981

The value, limitations, and applications of nuclear dacryocystography.

Nuclear dacryocystography is simple, relatively harmless method of evaluating patients suspected of having abnormalities of the nasolacrimal drainage system. A group of normal saline containing approximately 100 muCi of 99mTc-pertechnetate is placed on the conjunctiva near the lateral canthus, and serial scintigrams are obtained as the pertechnetate flows along the tear strips, through the nasolacrimal drainage system, into the nasal fossa. By using a pinhole collimator with a very small aperture (1mm), the canaliculi, the nasolacrimal sac, and the nasolacrimal duct are readily visualized. When flow is impaired, the site of obstruction can often be identified. Contrast dacryocystography provides similar information but requires the injection of contrast material directly into a canaliculus. Nuclear dacryocystography provides good functional assessment of nasolacrimal drainage but has serious shortcomings in defining pathologic anatomy. Contrast dacryocystography outlines the anatomy well but often misses minor obstructions. The two studies are complementary and together provide an effective means of evaluating the nasolacrimal drainage system.

Ethiodized Oil↗
PubMed1979

Consequences of eyelid squeezing on intraocular pressure.

We investigated the effect of a forcible eyelid squeeze (two-second squeeze and two-second rest) over one minute, on intraocular pressure in volunteer groups of normal volunteers, ocular hypertensive and glaucoma patients, and those with a family history of glaucoma. The normal volunteers fell into two groups: responders and nonresonders, with the responders showing about a 2-mm Hg decrease and the nonresponders a small increase in intraocular pressure. It was possible to arrange the groups into an order dependent upon the change in intraocular pressure induced by eyelid squeezing; normal responders (-1.98 mm Hg), family history of glaucoma (-0.48 mm Hg), ocular hypertensive patients (-0.07 mm Hg), normal nonresponders (+ 0.04 mm Hg) and glaucoma patients (taking medication) (+ 0.25 mm Hg). Correlation of disease entity with other ocular factors such as intraocular pressure and total outflow facility was poor.

Adolescent↗
PubMed1979

An experimental approach to the study of intraocular Toxocara canis.

An experimental study of nematode endophthalmitis due to T canis and review of the literature has been presented. Six owl monkeys were infected either by nasogastric tube using embryonated T canis eggs or by carotid or intravitreal injection of second stage larvae. The clinical manifestations, especially ocular, were observed and various diagnostic tests performed. Only minimal or no intraocular changes were seen after systemic infection but significant abnormalities such as retinal hemorrhages and venous dilation were noted after intravitreal infection. Motile larvae were observed in the lenses of three eyes and in the vitreous of five eyes and, probably a sixth, after intravitreal injection. The intensity and timing of the intraocular reaction seemed to correlate with the infecting dose and apparent disappearance of larvae from the eye. Pathologic confirmation of larvae in the lens was obtained in one eye. A marked inflammatory reaction occurred in eyes receiving intraocular infection but none was seen in eyes with only systemic infectin. Various laboratory and serologic studies were performed, including the ELISA test, which were used to evaluate systemic as well as intraocular responses to infection with T canis. The two monkeys infected by nasogastric tube gave a positive ELISA response in the serum but intraocular fluids gave a negative response in all monkeys including those infected syst:mically and/or intraocularly. Problems in the understanding of clinical aspects of the disease, laboratory diagnosis and treatment are discussed. The need for future experimental studies is emphasized.

Adult↗