Peripheral choroidal neovascularization.

Peripheral choroidal neovascularization can result in an elevated subretinal lesion which can simulate a choroidal tumor. We reviewed 8 eyes with 11 peripheral areas of subretinal fluid and exudate which were subsequently determined to be secondary to peripheral choroidal neovascularization. Previous reports of peripheral choroidal neovascularization have emphasized the hemorrhagic nature of these lesions which can simulate a choroidal melanoma.

Fluorescein labeling of tissue plasminogen activator for subretinal thrombolysis.

Purpose: To assess a technique that facilitated the use of tissue plasminogen activator in the dissolution and evacuation of subretinal blood.

Methods: Fluorescein dye was added to the tissue plasminogen activator solution before subretinal injection.

Results: Labeling tissue plasminogen activator solution with fluorescein made the solution easily visible, enhancing the ability of the surgeon to assess clot lavage, detect reflux into the vitreous cavity, and judge the extent of clot dissolution.

Vitrectomy for proliferative diabetic retinopathy with severe equatorial fibrovascular proliferation.

Purpose: We studied the surgical treatment and visual outcome in a consecutive series of eyes with an unusual syndrome of diabetic retinopathy and severe peripheral fibrovascular proliferation involving the equatorial and pre-equatorial fundus.

Methods: In a retrospective study of 276 eyes (245 patients) that underwent pars plana vitrectomy for diabetic retinopathy between November 1988 and February 1993, nine eyes of eight patients (3.3% of eyes and 3.

Laser photocoagulation of the choroid through experimental subretinal hemorrhage.

Objective: To study the differential abilities of diode infrared, krypton red, and argon blue-green laser energies to penetrate experimental subretinal hemorrhage and coagulate the underlying choroid.

Methods: Autologous, heparinized whole blood was injected beneath the neurosensory retina of pigmented rabbit eyes. After 30 to 60 minutes, confluent patches of moderate or severe diode, krypton, or argon laser burns were applied to adjacent healthy retina and continued into the region of the subretinal hematoma without varying the power setting or focal plane.

Acute posterior ophthalmomyiasis interna treated with photocoagulation.

Purpose/methods: We studied a patient with subretinal myiasis with pain and rapidly progressive visual loss and found that prompt photocoagulation resulted in marked visual improvement. A 16-year-old boy had subconjunctival hemorrhage and periocular pain associated with progressive visual loss of 6/200 over a four-day period.

Results/conclusions: A live maggot found crawling in the subretinal space was promptly photocoagulated with an argon green laser.

A comparison of surface doses for two immobilizing systems.

To achieve accurate and reproducible treatments, many types of immobilizing systems have been used. Two of these systems: Alpha Cradle and VacFix, conform around the patient to improve day-to-day treatment repositioning. The Alpha Cradle system has been in clinical use for several years.

Cross-Resistance to Bacillus thuringiensis Toxin CryIF in the Diamondback Moth (Plutella xylostella).

Selection with Bacillus thuringiensis subsp. kurstaki, which contains CryIA and CryII toxins, caused a >200-fold cross-resistance to CryIF toxin from B. thuringiensis subsp.

Reversal of resistance to Bacillus thuringiensis in Plutella xylostella.

Continued success of the most widely used biopesticide, Bacillus thuringiensis, is threatened by development of resistance in pests. Experiments with Plutella xylostella (diamondback moth), the first insect with field populations resistant to B. thuringiensis, revealed factors that promote reversal of resistance.

Recommendations for measurement of tray and wedge factors for high energy photons.

Transmission factors for beam modifers such as wedges and blocking trays in dosimetry calculations are very common, but various methods have been used in measuring these factors. A systematic study to measure these factors as a function of field size and point of measurement was carried out. The beam modifiers were a blocking tray and the standard wedges supplied with a cobalt-60 unit and a medical electron accelerator (6- and 18-MV x rays).

Idiopathic recurrent branch retinal arterial occlusion. Natural history and laboratory evaluation.

Purpose: To investigate the long-term visual and systemic prognosis of patients with idiopathic recurrent branch retinal artery occlusions, and to test recent hypotheses regarding possible causes of this syndrome.

Methods: The authors retrospectively reviewed the medical and photographic records of 16 eligible patients. Each of 15 living patients was interviewed by one of the authors, then underwent follow-up ophthalmic examination, formal visual field testing, and a battery of clinical laboratory tests.

Resistance to Toxins from Bacillus thuringiensis subsp. kurstaki Causes Minimal Cross-Resistance to B. thuringiensis subsp. aizawai in the Diamondback Moth (Lepidoptera: Plutellidae).

Repeated exposure in the field followed by laboratory selection produced 1,800- to >6,800-fold resistance to formulations of Bacillus thuringiensis subsp. kurstaki in larvae of the diamondback moth, Plutella xylostella. Four toxins from B.

Surface dose perturbation due to air gap between patient and bolus for electron beams.

The effect of air gaps under bolus material on the surface dose for electron beams is investigated. Dose measurements were performed for air gaps from 0.0 to 3.

Oviposition preference of the diamondback moth (Plutella xylostelld) unaffected by the presence of conspecific eggs orBacillus thuringiensis.

Neither toxins fromBacillus thuringiensis Berliner nor conspecific eggs deterred oviposition by the diamondback moth,Plutella xylostella (L.) (Lepidoptera: Plutellidae), in laboratory choice tests. The finding that toxins did not deter oviposition by moths from a susceptible line shows that oviposition preference and larval survival were not associated in this line.

Morbidity and mortality in pups from pet stores and private sources: 968 cases (1987-1988).

Morbidity (greater than or equal to 1 disease condition) for pups sold from 3 pet stores from January 1987 through December 1988 ranged from 54 to 68%. In 1 store, morbidity was higher for store pups, compared with pups originating from private parties, for such disease conditions as "kennel cough," diarrhea, and several species of gastrointestinal parasites. In-store mortality ranged from 5 to 9.

Tissue plasminogen activator thrombolysis during surgical evacuation of experimental subretinal hemorrhage.

To assess the role for intraoperative thrombolysis during surgical evacuation of massive subretinal hemorrhage, the authors studied the ability of tissue plasminogen activator (tPA) to facilitate removal of an experimental subretinal blood clot through a small drainage retinotomy. In rabbit eyes, a single subretinal injection of tissue plasminogen activator in concentrations of up to 250 micrograms/ml failed to produce significant (greater than 50%) clot dissolution during a 3-hour period. However, repetitive subretinal lavage and aspiration with tPA (50 micrograms/ml) resulted in progressive intraoperative clot dissolution in rabbits and allowed complete evacuation of blood through a small drainage retinotomy in 6 (100%) of 6 cat eyes.

Complete blood count indices in colorectal carcinoma.

Since carcinomas of the colon or rectum are associated with blood loss, we wondered if complete blood count data were suggestive of iron deficiency in cases of colorectal carcinoma. The mean corpuscular volume and especially the red blood cell distribution width are thought to be more sensitive to early iron deficiency than the hemoglobin value. These values were recorded from a series of 98 consecutive cases of colorectal carcinoma and compared with an age-matched control group consisting of patients with no history or clinical suspicion of malignant neoplasm.

Merger and medical staff: an approach to integration.

One of the most important aspects of a hospital merger is the impact on the medical staff. At University Hospital in British Columbia, which was established when two large general teaching hospitals merged, the comprehensive process to reorganize the medical staff structure was designed to account for this impact. Preliminary indications are that the process used was effective in creating a positive atmosphere and that the fundamental arrangements that resulted are conductive to future development.

Pars plana vitrectomy and direct diathermy for complications of multiple retinal angiomas.

A 16-year-old female had multiple retinal capillary angiomas, complicated by marked retinal and optic disc neovascularization, preretinal membranes, and retinal detachment in her right eye. Pars plana lensectomy, vitrectomy, fluid/gas exchange, direct transvitreal diathermy of the angiomas, endolaser scatter photocoagulation, and scleral buckling resulted in retinal reattachment and regression of the neovascularization. Although additional surgery was necessary for recurrent tractional retinal detachment, long-term retinal reattachment and stable vision was achieved following obliteration of all angiomas.

Photon beam attenuation for a patient support assembly during arc therapy for a medical linear accelerator.

Arc therapy is one of the treatment techniques for small, centrally located deep-seated tumors. However, care must be taken to remove any components that would interfere with the beam as the gantry rotates around the patient. One such component that may interfere with the beam is the patient support assembly (PSA) or treatment table.

Transpalpebral extrusion of a silicone sponge exoplant.

We report an unusual case of scleral buckle extrusion in a 63-year-old woman. A 5 mm silicone sponge exoplant eroded through Tenon's capsule, conjunctiva, and full-thickness upper eyelid, traversing the tarsal plate.

Electron beam effective source surface distances for a high energy linear accelerator.

The design of the Varian Clinac 1800 linear accelerator electron applicator system does not allow clearance for all head and neck patients to be treated at the standard calibration distance of 100 cm. Discrepancies have been found between dose calculations using the inverse square law for extended distances and their measured data. A 4 X 4 cm2 applicator at an energy of 9 MeV, for example, had dose differences of 13 and 23% at distances of 105 and 110 cm SSD.