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Biomedical subjects

K Pollack

Publications and source records attributed to K Pollack.

7 recordsLinked to original sources
PubMed2005

[Best's disease with normal EOG. Case report of familial macular dystrophy].

Best's disease is an autosomal dominant disorder with incomplete penetrance and variable expression. A typical characteristic of Best's disease is a pathological EOG. We describe four members of a family with bilateral, subfoveal vitelliform lesions. The EOG was normal in all cases. Genetic analysis of the oldest son indicated a heterozygotic mutation Ala234Val in the VMD2 gene, so-called bestrophin gene, which is associated with Best's disease. Molecular genetic analysis also found Best's disease with a normal EOG. A normal EOG cannot exclude Best's disease. The family members should receive genetic consultation and if wished analysis of the VMD2 gene.

Adult↗
PubMed2005

[Applanation tonometry in "normal" patients and patients after LASIK].

BACKGROUND: Until now it was thought that morphological parameters of the eye such as corneal thickness, corneal curvature and axial length do not affect tonometry results. However, the aim of this study was to find out whether there actually is an influence of these parameters on applanation tonometry. PATIENTS AND METHOD: In this prospective study we examined 125 eyes of 125 normal patients with a corneal thickness of 568.8 +/- 43.79 microm, a corneal curvature of 7.72 +/- 0.27 mm and an axial length of 23.62 +/- 2.05 mm. Before performing a phacoemulsification, the anterior chamber was temporarily punctured. With a closed system the intraocular pressure (IOP) was manometrically set at 20, 35 and 50 mmHg using an H (2)O column. The IOP was then measured with a Perkins tonometer. With these patients we compared 102 eyes that had undergone LASIK due to a myopia of 6.3 +/- 2.17 D. Before and 6 months after surgery, IOD, k-values and central corneal thickness of these patients were measured. RESULTS: At all set pressure levels there was a highly significant correlation of measured IOP and corneal thickness. At all set pressure levels the measured IOP significantly depended on corneal thickness (r(2) = 0.78 - 0.83). After LASIK, IOP was reduced from 16.5 +/- 2.1 to 12.9 +/- 1.9 mmHg. There was a significant correlation between IOP and corneal curvature as well as corneal thickness (r(2) = 0.631; P < 0.001). The biomechanical characteristics of the cornea are changed so that the measured IOP has to be corrected by an additional 0.75 mmHg. CONCLUSION: Since corneal thickness does affect Goldmann applanation tonometry we recommend to use the "Dresden Correction Table" (Tab. ) to achieve the real IOP. Pressure measurements after LASIK are inaccurate because of a change in corneal biomechanics, corneal thickness and curvature and they should be corrected as follows: IOP (real) = IOP (measured) + (540 - CCT)/71 + (43 - K-value)/2.7 + 0.75 mmHg.

Aged↗
PubMed1993

Heterogeneous Dolichos biflorus lectin binding to a subset of rat alveolar macrophages in normal and fibrotic lung tissue.

The distribution of Dolichos biflorus lectin in the rat lung and during fibrosis after irradiation was investigated by lectin histochemical and electron microscopical techniques and double immunofluorescence labelling with the monoclonal antibodies RM-1 and ED-1. The results indicate a selective reaction of Dolichos biflorus lectin with a subpopulation of alveolar macrophages. No binding of the lectin was detectable in ED-1-positive macrophages but strong staining occurred in a part of the RM-1-positive cell population. In fibrotic lung specimens an increased number of Dolichos biflorus lectin-positive macrophages was found in which focally ED-1 reactive and RM-1 negative cells appeared. The finding of changing lectin binding pattern in a radiation-induced lung model emphasizes the suitability of the Dolichos biflorus lectin as a marker of macrophage activation or functional specialization.

Animals↗
PubMed1991

Algorithms for Bayesian background-subtracted Fourier darkfield imaging.

Formal consideration of prior information on the Fourier amplitude of background contrast in an image, using the same Bayesian principles of statistical inference which underlie thermodynamics, allows one to subtract background without favoring only selected parts of frequency space. Without the bias in frequency space which causes periodicity bleeding and mars literal interpretation of Fourier-filtered images, the shape transform of aperiodic objects can be left intact. Algorithms for Bayesian background subtraction from one- and two-dimensional images are presented which further consider, in ad hoc fashion, one's uncertainty about background amplitude. The results help explain the reported success of Fourier truncation, and indicate that Bayesian background-subtracted images can minimize root-mean-square image error, as well as periodicity bleeding, in comparison to Fourier-filtered and Fourier-truncated alternatives.

Algorithms↗
PubMed1990

Vision characteristics of individuals identified as Irlen Filter candidates.

Individuals with "scotopic sensitivity syndrome" have been reported to have visual symptoms including eye strain, headaches, blurred vision, double vision and words moving on the page. This study was designed to investigate Irlen's claims that these symptoms are unrelated to vision anomalies. She suggests that the use of Irlen tinted lenses/filters relieves these symptoms and results in improved reading performance. Thirty nine subjects (age 10-49) were recruited by advertising for a study of Irlen Filters/Lenses. Before the Irlen screening all subjects received an optometric examination. The results of this study demonstrate that 95 percent of the subjects identified as candidates for Irlen Filters did have significant and readily identifiable vision anomalies. Fifty seven percent of the subjects had received vision care within the past year, yet testing revealed that 90 percent of these subjects had significant vision problems that had not been corrected.

Accommodation, Ocular↗
PubMed1976

Immunologic assessment of regional lymph node histology in relation to survival in head and neck carcinoma.

Histologic material from 84 cases of squamous cell carcinoma of head and neck regions was studied by double blind retrospective analysis. Sections of lymph nodes draining the tumors were examined microscopically to assess the morphologic pattern of response. Patients whose lymph nodes demonstrated active immunologic responses in the form of expanded inner cortices or increased numbers of germinal centers had 5-year survival rates significantly greater than those patients whose regional lymph nodes showed an unstimulated pattern. None of the patients whose lymph nodes showed the depleted pattern survived 5 years. These correlations were independent of the stage or grade of the tumor. Metastases occurred much more frequently in patients having regional nodes showing an unstimulated or depleted pattern than in those whose regional nodes showed evidence of immunologic activity. The data support the concept of a relationship between immunologic activity, progression of neoplasia, and survival. Morphologic assessment of immunologic activity in lymph nodes draining malignant tumors appear to be of significant value in the predicting survival.

Carcinoma, Squamous Cell↗