Inducing cataract in postmortem pig eyes for cataract surgery training purposes.

We developed an easily reproducible cataract model for training purposes. Using the technique, cataract was induced in postmortem pig eyes after 9 seconds in a microwave oven. With this model, cataract surgery, including phacoemulsification and intraocular lens implantation, can be practiced successfully.

The effect of white light and UV-A on the green autofluorescence of the rabbit lens in vivo.

The part of the light spectrum which is responsible for an increase of lenticular green autofluorescence upon white light exposure was determined for the rabbit. The increase of autofluorescence as a function of the light energy was measured, to assess a possible threshold energy for lens alterations. Thirteen rabbits (Chinchilla Greys) were used. An area of 3 or 4.7 mm2 of the lens was exposed to light from a standard tungsten halogen lamp (250 W, lambda = 360-720 nm). Wavelength selection was performed with the use of light filters. The light dose was adjusted by varying the exposure time between 15 min and 180 min. The green lenticular autofluorescence (lambda exc = 420-490 nm, lambda fluor = 530-600 nm) was measured with a fluorophotometer. A significant increase of lenticular autofluorescence after exposure was observed only if the exposure light contained high wavelength UV-A (lambda = 360-400 nm; 0.8% of the total white light energy); additional white light (without UV-A; up to 13 kJ cm-2) did not have any effect on autofluorescence. The autofluorescence returned to pre-exposure values within 4 days. No lesions could be seen on slitlamp examination. The autofluorescence after exposure to UV-A increased linearly with the exposure energy from 13 J cm-2 (14 mW cm-2 for 15 min) up to 155 J cm-2. The increase was 2.0% of the pre-exposure value per J cm-2 and the correlation coefficient 0.94, P < 0.001. A threshold energy was not found.(ABSTRACT TRUNCATED AT 250 WORDS)

Early surgery for active infective endocarditis improves early and late results.

To investigate the timing of surgery in active infective endocarditis, the data of 54 patients, consecutively operated for this reason from September 1973 to May 1989, were analysed. Native valves were involved in 31 patients (57%): the aortic valve in 22, the mitral valve in 6, and both valves in 3 cases. Prosthetic valves were involved in 23 patients (43%): the aortic valve in 14, the mitral valve in 7, and both valves in 2 cases. There were no significant differences between involvement of native or prosthetic valves and mortality, morbidity, or consequences of morbidity. No significant correlation was found between causative microorganism and mortality, morbidity, or consequences of morbidity. The indication for operation was cardiac failure in 15 patients (28%), ongoing infection in 24 (44%) or a combination of these in 15 (28%). Major embolization occurred in 12 patients (22%) and affected women more than men (p = 0.05). Hospital mortality was 8 (15%). Morbidity involved 15 more patients; structural deterioration of the valve prosthesis occurred in 1 patient; nonstructural dysfunction of the valve prosthesis occurred 11 times in 10 patients; anticoagulation-related hemorrhage involved 2 patients (1 with nonstructural dysfunction of the valve prosthesis); endocarditis was diagnosed in 3 patients. The consequences of these morbid events concerned 14 patients; reoperations were done 9 times in 8 patients; mortality was valve related in 6 cases. Because 2 more patients died during the course of the study, total late mortality was 8. Probability of survival 5 years after operation was 72% (95% cl 56-83) and at 10 years 47% (95% cl 21-70).(ABSTRACT TRUNCATED AT 250 WORDS)

Oral transmucosal fentanyl citrate premedication in children.

The authors evaluated the safety and efficacy of four doses of oral transmucosal fentanyl citrate (OTFC) as a premedicant in 44 children about to undergo elective operations. The patients received 5-10, 10-15, 15-20, or 20-25 micrograms.kg-1 of OTFC in the holding area and had activity (sedation) scores, vital signs (including systolic and diastolic arterial blood pressures, heart, and respiratory rates), and pulse oximetry determined oxygen saturation measured before and at 15-min intervals after premedication until they were taken to the operating room. Cooperation during anesthetic induction, and quality and speed of recovery room emergence were measured and side effects noted. OTFC was readily accepted and provided significant (dose dependent) reductions in preoperative activity starting after 30 min. Onset of sedation was related to dose of OTFC but time to peak effect was not. Vital signs remained unchanged preoperatively in all groups but patients receiving 20-25 micrograms.kg-1 had oxygen saturations that were significantly lower than patients in the other groups 30 min after beginning OTFC consumption. Three of the 12 patients receiving the highest dose of OTFC experienced transient oxygen saturation less than 90% which, however, was easily treated by commands to take a breath. Anesthetic inductions were rated good or excellent in 80% of the patients and recovery times were similar irrespective of the OTFC dose. OTFC caused dose-independent preoperative pruritus in 90% or more of patients and pruritus (33%-70%), nausea (30%-58%), and vomiting (50%-83%) postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential expression of HLA-DR, DQ, and DP antigens in primary and metastatic melanoma.

Fifty-five primary and 33 metastatic surgically removed melanoma lesions were stained in indirect immunoperoxidase with anti HLA-DR, DQ, and DP monoclonal antibodies and with the monoclonal antibody CL203.4 to a 96-K melanoma associated antigen (MAA). The latter antigen may represent a marker to monitor susceptibility of melanoma cells to modulation by IFN-gamma, because it is highly susceptible to induction by IFN-gamma. In primary melanomas 44%, 29%, 10%, and 55% of the lesions tested were evidently stained by anti HLA-DR, DQ, DP, and 96-K MAA monoclonal antibodies, respectively. A statistically significant association (P less than 0.01) was demonstrated between the degree of intratumoral lymphocytic infiltrate and the expression of HLA-DR and HLA-DQ antigens. In addition, a high degree of concordance in the reactivity pattern of individual lesions stained for HLA-DR antigens and for the 96-K MAA was found. In metastases 64%, 33%, 47%, and 100% of the lesions tested were evidently stained by anti HLA-DR, DQ, DP, and 96-K MAA monoclonal antibodies, respectively. This study indicates that HLA-DR and HLA-DP antigens are expressed in a higher percentage of metastatic than of primary melanomas and that there is no marked difference in the expression of HLA-DQ antigens between primary and metastatic melanomas. The data suggest that the regulatory mechanisms which control the expression of HLA-DR and DP antigens in primary and metastatic melanoma lesions are different. Locally produced IFN-gamma may play a role in the regulation of HLA Class II antigens in primary melanomas.

Antagonism of postoperative opioid-induced respiratory depression: nalbuphine versus naloxone.

The authors compared naloxone and nalbuphine as antagonists of opioid-induced respiratory depression to determine the relative efficacies and safety of the two agents. In a double-blind, randomized fashion, 90 anesthetized patients received a mean dose of 25 micrograms/kg fentanyl during surgery. Inadequate spontaneous respirations at the end of anesthesia were treated with either naloxone 0.08 mg or nalbuphine 2.5 mg IV every 2 min while heart rate (HR), systolic and diastolic blood pressures (SBP, DBP), respiratory rate (RR), and tidal volume (TV) were measured at 2-min intervals. Arterial blood samples for analysis of PaCO2, PaO2, and pH were drawn when spontaneous ventilation resumed, and 30 and 60 min later. Narcotic antagonism and respiration were deemed adequate when TV was greater than or equal to 4 ml/kg and RR greater than or equal to 8 breaths/min. Heart rate, SBP, DBP, TV and RR were recorded, as were the occurrence of renarcotization (RR less than 8) and analgesic requirements every 5 min during the recovery room stay. Sixty of 90 patients required narcotic antagonism at the end of surgery. No patient required more than three doses (0.24 mg) of naloxone or four doses (10 mg) of nalbuphine. Both antagonists produced similar and moderate increases in SBP and HR while restoring adequate spontaneous ventilation. There were no significant differences in TV, RR, or arterial blood gases (ABGS) between the two groups after narcotic reversal.(ABSTRACT TRUNCATED AT 250 WORDS)