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Biomedical subjects

J Funk

Publications and source records attributed to J Funk.

At least 91 records · Page 5Linked to original sources
PubMed1990

Increase of neuroretinal rim area after surgical intraocular pressure reduction.

The Optic Nerve Head Analyzer was used to measure the optic disc structure of 18 eyes (13 adult glaucoma patients) before and after surgical intraocular pressure reduction. Neuroretinal rim area markedly increased (from +0.15 mm2 to +0.45 mm2) in eight eyes, but changed either very little (less than +/- 0.1 mm2) or not at all in the remaining 10 eyes. The mean increase was from 0.75 +/- 0.26 mm2 to 0.92 +/- 0.36 mm2. The increased neuroretinal rim area found at this time remained in all eyes reexamined 1 to 3 years after surgery. Our data support previous findings that glaucomatous disc cupping may be reversed even in adult eyes, perhaps as the result of adequate pressure reduction.

Adult↗
PubMed1990

[Normal values of various papillary parameters and correlation to papillary size].

The Optic Nerve Head Analyzer was used to study the disc parameters--neuroretinal rim area and cup/disc ratio--in 194 eyes of 122 healthy subjects. Both neuroretinal rim area (1.35 +/- 0.35 mm2) and cup/disc ratio (0.5 +/- 0.18) showed a large interindividual variability, i.e., very small values for the neuroretinal rim and very large values in the cup/disc ratio are not only found in glaucomatous but even in healthy eyes. Due to the great variability of disc parameters, a single examination using the Optic Nerve Head Analyzer will presumably not be sufficient to decide whether an individual disc is glaucomatous or normal. Early recognition of glaucoma by means of computerized disc analysis will therefore require follow-up examinations. In accordance with other investigators, we found a highly significant correlation between the neuroretinal rim area and the corresponding disc size (p less than 0.001), i.e., a large disc normally has a large neuroretinal rim. In addition, we also found a significant correlation between the cup/disc ratio and the corresponding disc size (p less than 0.001), i.e., even the relative value of the cup/disc ratio is not independent of disc size. A large disc normally has a large cup/disc ratio. Correlation studies between disc parameters and disc size cannot determine whether the neuroretinal rim area or the cup/disc ratio gives more information about an optic disc. Both parameters, neuroretinal rim area and cup/disc ratio, however, are of equal value concerning the recognition of glaucoma by means of computerized disc analysis, because early diagnosis of glaucoma with this new technique presupposes intraindividual follow-up examinations.

Adolescent↗
PubMed1989

Child abuse disposition: concurrences and differences between a hospital team, child protection agency and the court.

Ninety-six children admitted to a pediatric ward for maltreatment are described statistically using variables characterizing the child, the family and the type of abuse. Recommendations of the hospital's child protection team in 81 cases are compared to those of the county childrens Services Board and the court. Multiple regression analysis is used to identify which variables influenced the decisions of these three agencies.

Adolescent↗
PubMed1989

Correlation between neuroretinal rim area and age in normal subjects.

The Rodenstock Optic Nerve Head Analyzer was used to study the age distribution of the neuroretinal rim area in 194 eyes of 122 normal subjects aged 7-84 years. No significant linear correlation was found between neuroretinal rim area and age. Linear regression analysis of the neuroretinal rim area in the temporal disc quadrant as a function of age led to the following equation: y = 0.00029x + 0.245; r = 0.052. Linear regression analysis of the neuroretinal rim area in the total disc as a function of age led to the following equation: y = 0.001x + 1.314; r = 0.0053. The 99% confidence limits of the regression slope ranged from -0.0025 to + 0.0045 (temporal disc quadrant) and from -0.00077 to + 0.0013 (total disc), respectively. A nonlinear correlation between neuroretinal rim area and age is very unlikely. Using the Mann-Whitney U-test, no statistically significant difference between the smallest (group of subjects aged 7-19 years) and the largest mean neuroretinal rim area (group of subjects aged 30-39 years) was detectable. From our data we conclude that there are no age-related changes in the neuroretinal rim area as measured with the Optic Nerve Head Analyzer. Changes in the neuroretinal rim area during follow-up examinations of glaucoma suspects may therefore be interpreted as an important sign of early glaucomatous damage. This confirms our previous suggestion that follow-up examinations of the optic disc structure with the Rodenstock Optic Nerve Head Analyzer are useful to confirm the diagnosis of glaucoma, even at a stage where a visual field loss cannot yet be detected by routine perimetry.

Adolescent↗
PubMed1989

[Changes in the temporal neuroretinal border area of the papilla following pressure-reducing surgery].

The Optic Nerve Head Analyzer (Rodenstock München, FRG) was used to investigate the optic disc structure of 9 eyes before and after surgical reduction of intraocular pressure (IOP). Four out of 9 eyes showed a marked increase of their temporal neuroretinal rim area after surgery (between 140% and 400%). The observed increase of neuroretinal rim area was still present after more than one year, although it was less pronounced. Five eyes did not show changes of the neuroretinal rim area of their optic discs. A further evaluation regarding IOP and visual field of the 9 eyes examined lead to the following results: 1) There is no correlation between increase of neuroretinal rim area and extent of IOP reduction, i.e. some eyes showed an increase of neuroretinal rim area with only slight IOP reduction whereas others with more pronounced IOP reduction did not show an increase of neuroretinal rim area. 2) All eyes showing an increase of neuroretinal rim area after surgical IOP reduction had normal visual fields an a mean sensitivity of more than 24.5 dB within the central part of the G 1-program of the Octopus perimeter. 3) All eyes without increase of the neuroretinal rim area after surgical IOP reduction had visual field defects and a mean sensitivity of less than 19 dB within the central part of the G 1-program. According to these data we suppose that occurrance of increase of neuroretinal rim area after glaucoma surgery depends mainly on the stage of glaucoma (as determined by visual field testing) and that it is not clearly correlated to the amount of IOP reduction.

Follow-Up Studies↗
PubMed1988

Neuroretinal rim area and visual field in glaucoma.

The correlation between visual field and neuroretinal rim area of the optic disc was studied in 70 eyes of 44 patients with suspected or definite glaucoma. Visual field analysis was performed by automated perimetry with the Octopus 2000R, using the program G1; the neuroretinal rim area of the disc was measured by the "Optic Nerve Head Analyzer." All eyes with a glaucomatous loss within the central sector of the visual field showed a significantly reduced neuroretinal rim area in the corresponding, i.e., the temporal quadrant of the disc. The reverse conclusion, however, was not valid: If there is a significantly reduced neuroretinal rim area in the temporal quadrant of the optic disc, one cannot predict the presence or absence of visual field loss. Actually, both high and low values are found in the neuroretinal rim area even if no visual field loss is detectable by the Octopus G1 program. There are two clinical consequences based on this result: (1) follow-up examinations of the disc structure that show increasing loss of the neuroretinal rim area may establish the diagnosis of glaucoma even at a stage where no visual field loss can be detected. Therefore, analysis of the disc structure may be more sensitive than analysis of the visual field, especially in patients who only show elevated intraocular pressure and no other signs of glaucoma. (2) If there is already a definite visual field loss due to glaucoma, the effect of antiglaucomatous therapy should be monitored by visual field analysis rather than by analysis of the optic nerve head.

Evaluation Studies as Topic↗
PubMed1984

Action of botulinum A toxin and tetanus toxin on synaptic transmission.

Intracellular recordings of the spontaneous activity from mammalian spinal cord neurons in culture demonstrated different sensitivities of excitatory and inhibitory synaptic transmission for the action of tetanus toxin (Tetx) and botulinum toxin type A (Botx). The effects of Tetx and Botx on spontaneous and nerve-evoked transmitter release were compared under identical experimental conditions in experiments on in vitro poisoned mouse diaphragms. At 37 degrees C completely paralyzed endplates are characterized by a very low frequency of spontaneous miniature endplate potentials (m.e.p.p.s) and by a 100% failure to evoke endplate potentials (e.p.p.s) in response to single nerve stimuli. Striking differences in the action of both toxins have been observed when the very low transmitter release probabilities of paralyzed nerve-muscle preparations were increased by tetanic nerve stimulation and/or application of potent K+-channel blockers and/or by reduction of temperature to 25 degrees C. While Botx did not change the short latency between nerve impulse and postsynaptic response, Tetx produced a temporal dispersion of the quantal release suggesting that the toxins act at different sites in the chain of events that result in transmitter release. To find further evidence to support the different actions of the toxins the spontaneous transmitter release was studied in more detail. Tetx blocked preferentially the release of so-called large mode m.e.p.p.s without affecting the frequency of the small mode ones. In contrast, Botx strongly inhibited both the small and large mode m.e.p.p.s.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1982

Temperature-induced vertical shift of proteins in membranes.

Thermotropic changes in the transverse order of microsomal membranes isolated from Tetrahymena are revealed by low-angle X-ray diffraction. These are correlated with the lateral order of the membrane lipids by wide-angle X-ray diffraction. Upon lowering the temperature from 28 degrees C to 2 degrees C, the Bragg period of the membrane stack reveals an abrupt increase of approximately 3.1 nm at approximately 19 degrees C, which is reversible upon reheating to 28 degrees C. This is coupled with an alteration in the electron density profile, revealing a shift of mass from the hydrophobic core towards one of the two hydrophilic surfaces. Between 35 degrees C and 0 degrees C, the membrane lipids undergo a broad, thermotropic "two-stage" liquid crystalline in equilibrium crystalline phase separation with a "breakpoint" at approximately 18 degrees C. This breakpoint signals an abrupt lipid redistribution, presumably due to a change in the composition of the two coexisting liquid crystalline and crystalline lipid phases. We conclude: (1) the temperature-induced mass shift reflects a shift in the transverse partition of proteins in membranes; (2) this is triggered by an abrupt lipid redistribution occurring during a broad liquid crystalline in equilibrium crystalline phase separation.

Fatty Acids↗
PubMed1982

Thermotropic 'two-stage' liquid crystalline equilibrium crystalline lipid phase separation in microsomal membranes.

The effect of temperature on native microsomal membrane vesicles isolated from Tetrahymena is investigated by wide angle X-ray diffraction. A 4.2 reflection, typical for lipids in the crystalline state, can be recorded in the temperature range between 0 degree C and 35 degrees C. Quantitative evaluation of this reflection reveals a broad thermotropic 'two-stage' liquid crystalline equilibrium crystalline lipid phase separation with a 'breakpoint' at approx. 18 degrees C. This 'breakpoint' coincides with the emergency of lipid-protein segregations in endomembranes of intact Tetrahymena cells as previously visualized by freeze-etch electron microscopy.

Animals↗
PubMed1981

Evaluation of the electron density profile of the frog rod outer segment disc-membrane in vivo using x-ray diffraction.

The structure of the rod outer segment disc-membrane in vivo was studied by X-ray low-angle scattering. The experiments were made on frogs under narcosis. Diffraction patterns corresponding to a resolution of 1.5 nm could be obtained from the membrane stacks of the rod outer segment discs. For the analysis of the measured diffraction pattern a new special computer procedure was elaborated. Among other generalizations of the theory, it was taken into account that the electron densities in the inter- and intra-disc spaces differ from the mean electron density of the whole stack. The consideration of this possibility, together with an exact experimental measurement of the isotrope background scattering, led to a mathematically unique solution. The calculated electron density profile apparently is a distinct asymmetric bilayer. The electron density of the side of the membrane which is in contact with the disc lumen is higher than the electron density on the side in contact with the cytoplasm. Therefore, a localization of rhodopsin or of other high molecular proteins mainly on the cytoplasmatic edge of the membrane can be excluded for the rod outer segment discs in vivo.

Animals↗
PubMedDate not supplied

[Application of a dynamic pedicle screw system (DYNESYS) for lumbar segmental degenerations - comparison of clinical and radiological results for different indications].

AIM: Evaluation of the efficacy of a dynamic stabilizing system for different indications using medium-term clinical and radiological parameters. METHODS: Out of a total of 70 evaluated patients, 35 showed initial disc degeneration and disc herniation (group 1). In this group, additional nucleotomy was performed. Group 2 included 22 patients with initial osteochondrosis and facet joint osteoarthritis. 13 patients suffered from progressive segment degeneration or degenerative spondylolisthesis (group 3). Clinical evaluation was performed preoperatively, three months postoperatively and at follow-up (33 months). Examinations included subjective and objective measures using the Oswestry Index and VAS as well as radiographs and MRI. RESULTS: Oswestry Index and VAS improved significantly in groups 1 and 2 and remained improved until follow-up. Group 3 showed no significant changes. The evaluation of radiographs and MRI of groups 1 and 2 revealed no progression of the degeneration either at the operated segments or at the adjacent segments. In group 3, 9 cases of progressive degeneration of the operated segments and 3 cases of adjacent segment degeneration were found. Out of 5 implant-associated complications 4 were observed in group 3. CONCLUSION: Dynesys is able to compensate initial morphological changes and to prevent progression of segment degeneration. The system seems not to be indicated for treating marked deformities or if osseous decompression needs to be performed.

Adult↗
PubMedDate not supplied

Chronic postoperative endophthalmitis caused by Propionibacterium acnes.

Persistent intraocular inflammation after cataract surgery with intraocular lens implantation is acquiring importance. Frequently, chronic uveitis or the "toxic lens syndrome" have to be differentiated from bacterial infection. This report describes five cases with chronic postoperative endophthalmitis where the anaerobic bacterium Propionibacterium acnes was found to be the causative organism. Adequate anaerobic culture media and proper sampling from the area around the lens haptics are the most important requirements for the detection of P. acnes.

Cataract Extraction↗
PubMedDate not supplied

Recurrent herpetic keratitis during topical acyclovir application.

Dendritic herpetic keratitis developed in a 49-year-old patient during topical acyclovir treatment. A positive herpes simplex culture was obtained. After acyclovir was replaced by trifluorothymidine and interferon, the dendritic lesion disappeared and herpes simplex culture became negative. Six months later a carcinoma of the larynx was diagnosed. The acyclovir-resistant herpetic keratitis may be associated with the carcinoma because resistant herpes simplex virus strains are predominantly described in patients suffering from immune deficiency.

Acyclovir↗
PubMedDate not supplied

Is the blind spot enlarged in early glaucoma?

PURPOSE: We investigated whether the blind spot is larger in early "preperimetric" glaucoma with already deeply excavated optic discs than in normal persons. METHODS: We examined eight eyes of five patients with definite glaucomatous optic disc cupping but normal visual fields. Ten eyes of five normal healthy volunteers, with normal central excavation, served as controls. With SLO-perimetry we measured the differential light sensitivity 0.5-1.0 degrees outside the disc margins, "within" the center (Goldmann V stimulus) and along the horizontal meridian of the optic discs. Optic disc topography was documented with the Heidelberg Retina Tomograph (HRT). RESULTS: Differential light sensitivities adjacent to the optic discs did not differ in the two groups (normal 8.3dB, early glaucoma 8.4dB). Goldmann IV stimuli presented on the horizontal meridian of optic discs with glaucomatous cupping were seen up to 0.7 degrees centrally (i.e., towards the center) of the disc margin. In the control group this distance was significantly greater (1.3 degrees). The light differential thresholds with stimulus presentation in the disc center (Goldmann V) were significantly higher in the glaucoma group (0+/-2.8dB) than in the normal controls (6.6+/-1.3dB), though disc size was the same in both groups. CONCLUSIONS: Blind spots of normal discs seem to be smaller than those of deeply excavated discs in eyes with early glaucoma, possibly because there is more light scattering by the normal disc surface towards the adjacent functioning retina.

Adaptation, Ocular↗