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Biomedical subjects

J Funk

Publications and source records attributed to J Funk.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Improved reproducibility of computer-assisted structural analysis of the optic papilla].

Longitudinal monitoring of the optic disc structure by means of automated nervehead analysis (Optic Nerve Head Analyzer, ONHA) can facilitate the diagnosis of ongoing glaucoma. Until recently, however, longitudinal disc monitoring was complicated by considerable fluctuations of the results measured with the Optic Nerve Head Analyzer. Since March/1990 there is a new software version of the equipment (ONHA-plus). The determination of disc parameters using ONHA-plus proved to be significantly more reliable than the determination using the former ONHA: the mean fluctuation of the neuroretinal rim area measured on 18 normal eyes was 0.07 mm2 (ONHA-plus) compared to 0.094 mm2 (ONHA); the variation coefficient dropped from 7.9% (ONHA) to 4.6% (ONHA-plus). A further improvement of the reproducibility can be obtained by double examinations, because the mean examination time using ONHA-plus is about half as long as the examination time using ONHA. Moreover, ONHA-plus enables the recognition and elimination of unreliable results caused by poor image quality. Due to this increased reliability the ONHA-plus system is a considerably improved equipment for the clinical monitoring of glaucoma patients.

Glaucoma↗
PubMed1991

[Group G streptococci as pathogens of postoperative endophthalmitis].

We report an exceptional case of fulminant endophthalmitis after uncomplicated extracapsular cataract extraction with posterior chamber lens implantation. The first unusual finding was the causative organisms, group G streptococci. These organisms are commonly found as normal flora of the skin, pharynx and gastrointestinal tract. They are also well known as pathogens of neonatal sepsis, otitis media and pneumonia, but there are only three case reports describing a streptococcus G endophthalmitis. The second unusual finding was the delayed onset of the fulminant endophthalmitis, occurring later than 9 days after surgery. A retrospective analysis of 17 additional cases showed that endophthalmitis occurred either during the first 5 days after surgery or later than 35 days after surgery. If endophthalmitis developed shortly after surgery it progressed rapidly and with intense inflammation. The other cases showed more chronic inflammatory reaction. From the latter finding we conclude that long postoperative monitoring remains necessary even if at first no signs of intraocular inflammation are detectable.

Aged↗
PubMed1991

[Spontaneous bilateral lens resorption in a case of Hallermann-Streiff syndrome].

The Hallermann-Streiff-syndrome was first described in 1948 by Hallermann and in 1950 by Streiff. The most common features are dyscephalia, cataract, microphthalmia, dental anomalies, hypotrichosis, cutaneous atrophy, and nanism. Anomalies of the eye include cataract, microphthalmia, nystagm, strabism, blue sclera, fundus anomalies and combined anomalies of all segments of the eye. The frequency of cataract is about 90%. Spontaneous resorption of the lens is described in about 8%. We present a five year old girl showing the typical dyscephalia of the Hallermann-Streiff-syndrome (bird face). Her lenses were replaced by opaque membranes. These membranes presumably were remnants of the posterior lens capsule.

Aphakia↗
PubMed1991

[Automatic perimetry of the central visual field in diseases of the macula].

We developed a program for testing the central 12 degrees of the visual field with a spatial resolution of 1.6 degrees that was easy to operate. The program was designed for the Octopus computer-perimeter and created by means of the SARGON-utility. Our way of examining differed slightly from the standard Octopus procedure. We tested 16 normal eyes and 13 eyes of patients with various diseases of the central retina. Our normal values of differential threshold sensitivities were about 1.8 dB below the normal values of the Octopus system. Sensitivity and specificity of the program were nearly identical irrespective of using our normal values or the Octopus normal values for the calculation of the above mentioned parameters. Sensitivity was 84.6%, specificity 87.5%. The ability of the program to correctly localize retinal defects was shown. The program was designed for follow-up of patients having undergone paramacular lasercoagulation.

Adult↗
PubMed1991

Psoriasis induced by interferon-alpha.

Recombinant human interferon-alpha has been used in the treatment of several cancers, but there have been several reports that it may exacerbate psoriasis or trigger off its onset. We report four patients, three of whom first developed psoriasis and one who had an aggravation of the condition during treatment with interferon-alpha. Three of the patients had the carcinoid syndrome and one a renal carcinoma, and all were treated with interferon-alpha 2b or 2a (IFN-alpha 2b, 2a) with doses ranging from 1.5 x 10(6) U daily to 18 x 10(6) U three times weekly. In two of the patients there appeared to be a correlation between the severity of the psoriasis and the dosage of interferon.

Aged↗
PubMed1991

[Follow-up of patients suspected of glaucoma using computer-assisted analysis of the optic disk].

The Optic Nerve Head Analyzer was used for longitudinal monitoring of glaucoma suspects. Forty-one patients (76 eyes) were monitored for more than 12 months and 29 patients (51 eyes) for more than 18 months. A significant (p less than or equal to 0.06) decrease in the neuroretinal rim area was found in 8 of 51 eyes monitored greater than 18 months. Thirty-eight of 19 healthy subjects served as the control group. Only 1 of these 38 healthy eyes showed a significant decrease in the neuroretinal rim area (p = 0.04); this decrease is perhaps an artifact caused by the limited accuracy of the Optic Nerve Head Analyzer. From our data we conclude that longitudinal monitoring of patients for glaucoma by means of the Optic Nerve Head Analyzer is an adequate method of detecting ongoing glaucoma damage.

Adolescent↗
PubMed1990

[Computer-controlled analysis of the optic papilla with the Optic Nerve Head Analyzer: normal values and various age dependent papilla parameters].

The Rodenstock Optic Nerve Head Analyzer was used to study the disk parameters of 194 eyes of 122 healthy subjects. No age-related changes in the neuroretinal rim area or in the cup/disk ratio could be detected. Furthermore, no significant differences in the mean values of disk parameters were found when right eyes were compared with left eyes or when eyes of male and female subjects were compared. It was thus possible to base calculations of normal values for disk parameters on the entire sample of 194 eyes, irrespective of age and sex. It was also possible to determine the range of variation of these parameters. Statistical analysis of the data produced the following results: the smallest mean neuroretinal rim area is in the temporal disk quadrant; the largest is in the nasal disk quadrant. The mean neuroretinal rim area of the upper quadrant is almost as large as that of the lower quadrant. Consequently, the temporal quadrant has the largest cup/disk ratio, while the nasal quadrant has the smallest. The cup/disk ratios of the upper and lower quadrants are almost identical. The range of variation of all disk parameters was found to be considerable, i.e., the neuroretinal rim area of the whole disk, as well as that of each disk quadrant may be very small, not only in glaucomatous but even in normal eyes. Accordingly, the cup/disk ratio may be large even in normal eyes. Due to the broad range of interindividual variation of disk parameters, a single examination with the Optic Nerve Head Analyzer is not sufficient to distinguish normal from glaucomatous disks. Follow-up examinations are therefore required for early diagnosis of glaucoma, because the finding of a reduction in neuroretinal rim area during follow-up must be interpreted as an important sign of early glaucoma damage.

Adolescent↗
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↗