Biomedical subjects
Publications and source records attributed to M Schulzer.
The effects of 0.5% Thymoxamine on intraocular pressure and anterior chamber depth were studied in 20 non-glaucomatous eyes. Miosis occurred in all of the eyes but was not accompanied by a shallowing of the anterior chamber or reduction in the intraocular pressure. The significance of the findings is discussed.
Twenty-four eyes of 20 patients with chronic open angle glaucoma who had a trabeculectomy were studied retrospectively. Trabeculectomy resulted in a significant lowering of mean intraocular pressures and improvement of pressure control for the group. Progression of visual field defects occurred in all 24 eyes preoperatively, while postoperatively, the fields of 14 eyes showed no change, but the other ten showed further progression. A comparison of the pressures of the eyes showing continued progression after surgery with the eyes showing no further progression revealed no significant difference in the mean preoperative or postoperative pressure or the mean pressure reduction after surgery. Measurements of the quality of the control, however, showed that the quality of pressure control was significantly better in the eyes that did not show progression of field loss postoperatively. Careful postoperative follow-up observation of the visual field remains necessary even after successful surgical pressure reduction.
The duration of intraocular pressure reduction by Ocusert Pilocarpine was found to be 10 days for P20 and 12 days for P40. Ocusert Pilocarpine reduced visual acuity and anterior chamber depth less than the aqueous pilocarpine drops.
Eighteen unilaterally affected acute angle-closure glaucoma patients were seen a period of time after the acute episode, and 11 unilateral chronic angle-closure patients were seen while under control. Visual fields, optic nerve heads, and vision were assessed using the normal eye as a control. Nerve fiber bundle defects were seen in seven of the acute and nine of the chronic angle-closure cases. None of the acute, but five of the chronic angle-closure patients, showed asymmetry of cupping, while pallor was seen in seven of the acute and nine of the chronic patients. No significant difference in reduction of vision was seen between the two groups. The duration of pressure is a possible reason for cupping in glaucoma.
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A study of the duration of intraocular pressure reduction of Ocusert P 20 and P 40 revealed that both agents were active in this regard at the end of a week. The side effects of this new mode of medication were less than with conventional Pilocarpine drops.
Simultaneous stereophotography achieves reproducible records of the optic cup topography. The clinical usefulness of sterophotographs remains unknown. This study compares the optic cup evaluation from contact lens examination with the evaluation from stereophotograph examination. Both methods of examination were used by each of 2 examiners to record their estimates of 12 parameters describing the optic cup topograhy. One eye of each of 50 patients was studied. In only 3 of the parameters studied were there statistically significant differences between the 2 methods of examination. Simultaneous stereophotography achieves a permanent record of the optic disc which is reproducible, objective and convenient. This method provides an excellent tool for following optic cup configuration.
A study of the Dioptron automatic refraction machine reveals a good reproducibility of the results obtained by the machine. In a comparison with retinoscopy and subjective refraction, the spherical components were well correlated while the cylindrical power was less well related. The rejection rate of the machine was high and its usefulness in refraction is discussed.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
PURPOSE: This study was done to produce enhanced fetal biometry charts and graphs presenting percentile values as a function of fetal age. METHODS: The relationships between the ultrasound measurements of 10 fetal parameters and menstrual age were determined by a cross-sectional study. Data were obtained from 508 to 790 fetuses. Anatomic structures were scanned and measured 3 times during 1 routine sonographic examination. The study group consisted of 1,396 Caucasian women who had normal singleton fetuses with confirmation of menstrual dates by sonography before 14 weeks and for whom complete pregnancy outcome information was available. For each of the 10 parameters, percentile curves were derived for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles. RESULTS: Ready-to-use fetal measurement charts and graphs are presented in a format giving the percentile values as a function of fetal age. There were no significant differences between male and female fetuses. CONCLUSIONS: These fetal biometry charts and graphs, obtained from a North American Caucasian population, enhance previously published data.
Variations have been observed in the measurement of fetal femoral diaphysis length by ultrasound. This in vitro study examines the effect of depth, the angle of the bone relative to the axis of the sound beam, the machine, and the observer on the precision of measurement. Using analysis of variance techniques, it demonstrates that three of these factors (depth, angle, and machine) have significant effects. Depth-associated variations were less than one millimeter and are probably not of clinical importance. However, the variations due to changes in angle are highly significant (P = less than 0.001) and may be controlled by obtaining the measurement with the femur perpendicular to the sound beam. Errors due to variation between machines were also highly significant (P = less than 0.001). When determining serial growth patterns, the errors due to variations between machines can be controlled by using the same machine for each examination. The variation between machines is also an important factor to consider when choosing a curve for reference purposes.
In diseases such as the Parkinson dementia complex of Guam (PDC) or Alzheimer's disease, susceptible neurons develop intracellular tangles (iNFTs) and then die, leaving behind extracellular tangles (eNFTs). We performed counts of healthy neurons, iNFTs, and eNFTs in the hippocampus of Guamanian Chamorros who were neurologically normal or who suffered from PDC. The total of surviving and dead neurons in the CA4 region was remarkably constant from case to case, indicating that eNFTs are not phagocytosed. Since cases of recent PDC showed only marginal tangle formation in CA4, we concluded that tangle development in CA4 commenced close to the onset of the disease. Based on this assumption, as well as the further assumption that the average rate of tangle development and the average lifetime of a tangled neuron do not alter as the disease progresses, we derived equations to determine the average lifetime of tangled neurons. The results varied from 0.13 years for the most rapidly progressing case to 7.98 years for the most slowly developing case. The average for 8 cases was 2.51 years.
The dopa analogue 6-fluorodopa (6-FD) used with positron emission tomography (PET) allows in vivo visualization of dopamine and its metabolites in nigrostriatal nerve endings. We have now found abnormal 6-FD scans in four subjects exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). None had parkinsonism. The results suggest subclinical damage to the nigrostriatal pathway. This is the first direct evidence that dopaminergic impairment can exist without clinical deficits. Here we discuss this finding in the context of the hypothesis that Parkinson's disease may stem from clinically silent damage to the substantia nigra, followed by slow attrition of neurones in this region because of its particular vulnerability to cell loss as a normal consequence of ageing.