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Biomedical subjects

H Gerding

Publications and source records attributed to H Gerding.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Rhegmatogenous retinal detachments. Seasonal variation and incidence].

UNLABELLED: Seasonal variations in the relative incidence of rhegmatogenous retinal detachment were reported as a trend in several studies on the database of relatively limited cohort sizes. PATIENTS AND METHODS: An analysis on this topic was performed with a long-term database. A total of 3073 files of patients with rhegmatogenous retinal detachment, covering 11 years of observation, were reviewed for this study. Patients with signs of long-standing detachment or other predisposing diseases were excluded, so that a basic study population of 2314 patients remained for the analysis. RESULTS: The averaged seasonal incidence of rhegmatogenous detachments revealed a significant (P < 0.005) mid-summer peak (n in July = 228) and a winter trough (mean of December-January = 161; difference = 36%). Phase and curve fitting of the seasonal variations in the number of retina detachment cases was similar to the seasonal variation of the astronomic duration of the day (P < 0.001). The relation was closer compared to the average duration of light exposure per day calculated from behavioural data and the astronomic length of light phase (P < 0.0002). CONCLUSION: This long-time study revealed a close correlation of the relative seasonal incidence of retinal detachment and the seasonal variation of light hours per day. So far, this observations cannot be explained pathogenetically. Two basic hypotheses ought to be investigated further: (1) The influence of light on the generation of toxic oxygen radicals and the subsequent destruction of the vitreous and (2) possible light-induced changes in vitreoretinal adhesion.

Adult↗
PubMed1997

Cluster headache after orbital exenteration.

A 37-year-old man developed an ipsilateral headache which fulfilled the criteria for cluster headache after orbital extenteration because of a traumatic lesion of the bulb. The headache could be treated successfully by drugs usually applied in the therapy of cluster headache. Six similar cases of cluster headache after orbital exenteration could be identified in the literature suggesting that the eye itself is not necessarily part of the pathogenesis of cluster headache. We hypothesize that orbital exenteration can cause cluster headache by lesions of sympathetic structures. Possibly, these mechanisms are similar to those of sympathetic reflex dystrophy (Sudeck-Leriche syndrome) causing pain of the limbs.

Adult↗
PubMed1996

[Complications of preventive cryoretinopexy in retinal foramina and degeneration in 1,000 eyes].

INTRODUCTION: Prophylactic treatment of full-thickness retinal breaks is widely accepted. The side effects and benefits of prophylactic treatment, however, have to be considered critically. The complication rates of prophylactic procedures must be compared. The aim of our study was to find out the complication rate of cryopexy in prophylactic retinal surgery. PATIENTS: Retrospectively we analyzed 1000 eyes of 746 patients who were prophylactically treated by cryopexy for different reasons. We included eyes with round holes, horse shoe tears and peripheral degenerations. Follow-up time ranged from 6 months to 7 years (average 30 months). RESULTS: Further surgical treatment was necessary in 3.4% of the patients (1.8% had a second cryopexy, 0.1% needed laser coagulation, and in 1.5% a subsequent scleral buckling procedure was necessary. In 17.6% of these cases (0.6% of all cases) the retinal detachment occurred in the periphery of the primary cryopexy after more than 1 year. In all our patients we did not find postoperative macular pucker or cystoid macular edema. CONCLUSIONS: The complication rate of cryopexy performed for the treatment of retinal holes and degeneration is low. This method has to be regarded as a therapeutic tool in the prophylactic treatment of (dangerous) retinal areas.

Adolescent↗
PubMed1995

[Unilateral tucking and advancement of the inferior oblique muscle for treatment of A-pattern strabismus].

PATIENTS: The clinical results of the unilateral tucking and advancement of the inferior oblique base on the retrospective data of 81 patients. METHOD: Tucking and advancement of the inferior oblique was used in A-pattern strabismus, which showed a marked hypofunction of the inferior oblique in relation to hyperfunction of the superior oblique. RESULTS: The unilateral tucking and advancement of the inferior oblique improves the incomitance as well as the elevating deficiency in adduction. The effect of the operation relative to incomitance depends on its preoperative state. With increasing A-pattern strabismus has an increased effect of the advancement and tucking is revealed. CONCLUSION: Unilateral tucking and advancement of the inferior oblique is not a routine procedure in the treatment of A-pattern strabismus, but it is possible to improve the incomitance and the elevating deficiency in adduction.

Adolescent↗
PubMed1995

[Treatment guidelines in various stages of senile retinoschisis].

BACKGROUND: Concerning the indications, progression in course and the possible complications, the different methods of treatment in cases of retinoschisis in its different expressions were examined. A staging of senile retinoschisis is presented. PATIENTS: Patients' natural course, prophylactic treatment against expansion and treatment of retinal detachment were examined. RESULTS: The lateral and central barrier of laser or cryo around the schisis is contradictory since a progression in direction to the macula is the result. Three of such cases could be found. In 6 of 52 cases with prophylactic treatment of an outer layer defect with cryo the result was a schisis detachment. In all these cases a retinal reattachment was performed with the Custodis procedure. The final anatomic result of 95 treated schisis retinal detachments was a 98% success. The symptomatic or progressive cases had a little less favourable outcome. CONCLUSIONS: The only indication for treatment of a schisis at present is the symptomatic or progressive schisis detachment with threatening of the macula. Lateral or central barring of a schisis or treatment of the borders of an outer layer retinal break should be avoided. The rate of reattachment and the functional results are better than in the group of rhegmatogenous retinal detachments including the 50.5% schisis retinal detachments without symptoms.

Adult↗
PubMed1995

[Aniseikonia reduces binocular summation in the VECP].

The binocular summation effect of human VECP (increase in amplitude from about 4.0 microV to about 5.4 microV) was proved and optimized in 32 subjects. Stimulus parameters: TV steady-state pattern reversal (7.0 Hz); pattern size 1 degree; stimulus contrast 5% (higher stimulus contrasts reduced considerably the selectivity of the binocular summation effect); 96 sweeps averaging (Nicolet Compaq Four); position of electrodes: 10% and 30% above Protuberantia occipitalis externa of nasioninion distance. Aniseikonia of 7 to 52% was generated by means of small Galilei telescopes. Because of comparatively large interindividual variance within the series of subjects, no decrease in binocular VECP amplitude could be demonstrated at an aniseikonia less than 52%. On one woman subject, a significant reduction in amplitude (5% level) at 14%, 26% and 52% aniseikonia was apparent, but not at 7%. Thus, for this subject, it was possible to correlate the results with the clinically known limits of toleration for aniseikonia. This result was confirmed by more than 60% of the subjects in the test group.

Adult↗
PubMed1994

[Effect of biopterin on the electroretinogram of Long-Evans rats].

Tetrahydrobiopterin (BH4) is an important cofactor in the synthesis of the leading intraretinal catecholamine derivate dopamine. According to Iuvone et al., retinal BH4-tyrosine affinity and dopamine synthesis are influenced by environmental light intensities. So far, no data are available about the in vivo effect of BH4 concentrations on the functional parameters of the retina. ERG recordings were performed after BH4 had been administered for 3 days (10 micrograms and 500 micrograms/day IP). After high-dose application a significant ERG effect was observed in a-, b-amplitudes and latencies, respectively. This is the first observation that BH4 has an in vivo effect on the functional parameters of the retina and is consistent with previous results on retinal dopamine action. This result supports the hypothesis that pterin metabolism plays an important role in the adaptive processes of the retina. It may be discussed as a model for the so far unexplained adaptation of neurons.

Animals↗
PubMed1994

[Distribution of the frequency of various Mendelian modes of inheritance in families with retinopathia pigmentosa. Results of an evaluation of the RP register of the Munster University Ophthalmology Clinic].

International studies on the relative distribution of various genetic types of retinitis pigmentosa (RP) have revealed major regional differences, especially for x-recessive (1-24%) and autosomal dominant inheritance (3-39%). At present there are no data available concerning the population genetics of RP in Germany. We performed a study on the clinical findings and genetic classification of patients with tapetoretinal dystrophies based on a population of 702 German patients examined in our hospital between 1977 and 1990. Data were eligible on 603 of these patients for the standardized final study protocol. 78% (n = 473/603) of the study group patients were classified as typical non-syndrome RP cases. Second was Usher's syndrome (9.5% of all patients) and third choroideremia (2.3% of all patients). In 250 of the enrolled families with RP the reconstruction of pedigrees was sufficiently complete for a definite genetic characterization. The relative incidence of families with the different patterns of inheritance was: (1) single cases: 48.4%; (2) autosomal dominant: 25.2%; (3) autosomal recessive: 16.4%; (4) x-linked recessive: 10.0%.

Adolescent↗
PubMed1994

[Retinopathia praematurorum: risks and critical timing].

Two prospective studies were performed to characterize the retinopathy of prematurity (ROP) risk in preterms further. In the first study the gradual relationship between birth weight, gestational age and duration of oxygen therapy and the incidence of ROP was evaluated. A total of 487 preterms were enrolled in this survey. Seventeen percent (67 babies) of 389 surviving children presented clinical signs of acute ROP. Among the analyzed risk factors "gestational" age provided the best correlation with the manifestation of acute ROP. According to the nonlinear regression model the risk of acute ROP can approximately be calculated as: R = 2(39-SSW).0.5 (R = relative risk of ROP in %). The second study focused on the relationship between individual risk factors and the age at stage III onset. The mean age of the first ROP stage III diagnosis was 66 days after birth at an average gestational age (post-menstrual age) of 37.0 weeks. Multifactorial analysis clearly demonstrated that birth weight was most informative among the tested set of parameters concerning the age at onset of ROP stage III. Best fitted linear regression of this relation was: LAT = 100-BW.34 (LAT = age at onset of ROP III expressed as postnatal days; BW birthweight measured in kg). It is suggested to take this approximation into account for the timing of ROP screening.

Birth Weight↗
PubMed1993

Ocular findings in Walker-Warburg syndrome.

Ocular symptoms are frequently observed in Walker-Warburg (WWS) and associated syndromes. The majority of patients present with malformations of the anterior segment and severe retinal dysplasia. We report on the findings in a female patient with WWS who died at the age of 9 months. Major ocular findings were: severe iridocorneal malformation, a membrane-like structure of the lens and funnel-shaped retinal dysplasia. The retina presented various grades of differentiation with rosettes and atypical sequences of cells, e.g. ganglion cells intermingled between granular layers. The anterior part of the retina presented as a primitive homogeneous layer with a cell-free space that might be interpreted as the primary optic ventricle. This finding suggests that we are dealing with a primary dysplastic non-attachment rather than a real detachment of the retina in WWS. The malformation of the anterior segment was not typical of the Peters' anomaly, as usually described in WWS, but of Rieger's syndrome.

Abnormalities, Multiple↗
PubMed1993

Ocular findings in a family with autosomal dominant retinitis pigmentosa and a frameshift mutation altering the carboxyl terminal sequence of rhodopsin.

A family is described in which an 8 base pair deletion (nucleotides 5252-5259, codons 341-343) of the rhodopsin gene cosegregates with autosomal dominant retinitis pigmentosa (adRP). The deletion results in a shift in the reading frame, causing a rhodopsin molecule extended by one residue and substantially altered at the carboxyl terminus. Phenotypic expression is relatively mild. In affected members, night blindness did not occur before the age of 16, and late onset of visual field loss was consistently reported. Even older individuals (59 and 76 years) had preserved central islands in the visual field; a younger female patient had normal visual fields until the age of 34. ERG and psychophysical tests showed well preserved cone function at stages of virtually abolished rod function. Phenotypic differences and similarities between this form of adRP and others associated with mutations at the carboxyl terminus of the rhodopsin molecule are discussed. The cause of RP by mutations in this region remains to be clarified.

Adult↗
PubMed1993

Neopterin in patients with choroidal melanoma.

Neopterin excretion in urine and the serum concentrations of neopterin were compared in 101 patients with a malignant melanoma of the choroid and in a matched group of healthy volunteers. The majority of cases (n = 99) presented an untreated (n = 20) or treated and either partially (n = 33) or completely regressed (n = 47) melanoma of stage I-III without signs of extraocular manifestation at the time of analyses. The incidence of elevated neopterin concentrations in all melanoma patients beyond the upper limit (mean + 2 S.D. of healthy controls) was 16% for both serum and urine. In patients with critical events, for example orbital infiltration or delayed metastatic disease during the subsequent follow-up period (at least 14 months), the neopterin concentrations were at the higher end of distribution. One patient with verified metastatic disease at the time of analysis presented extremely elevated neopterin concentrations in serum (82.3 nmol/l) and urine (1608 mumol/mol creatinine). It seems that the results of neopterin analyses are informative as a prognostic factor for the follow-up of patients with a malignant melanoma of the choroid.

Aged↗
PubMed1993

[Incontinentia pigmenti in a male infant].

Bloch-Sulzberger incontinentia pigmenti (IP) is a rare X-linked neuroectodermal syndrome. Over 97% of the patients are female. We report on a male baby who developed blisters in linear groups or bands shortly after birth. When the child was 3 months old the blisters were followed by verrucous papules, which cleared after 1 year leaving areas of brownish grey hyperpigmentation. In addition to the skin involvement, our patient showed central motor dysfunction on the right side of the body and also dental and ocular anomalies. Both parents were in good health. Chromosome analysis yielded a normal karyotype (46, XY). The genes for coagulation factor VIII and biglycan in the Xq28 region were not deleted. The presence of the disease in this male infant may be due to an early somatic mutation or a half-chromatid mutation. A further possibility is mosaic expression of an unstable premutation. This model offers a good explanation for the reports in the literature of transmission of the disease from mother to son.

Diagnosis, Differential↗
PubMed1993

Is there a relationship between cytarabine pharmacokinetics and keratitis?--A case report.

While on therapy for acute myeloid leukemia, a 15-year-old girl developed extensive punctate keratitis of both eyes following high-dose cytarabine therapy (HD-Ara-C). Pharmacokinetic monitoring showed an increase of the Ara-C plasma levels up to twice the steady-state level within 10 minutes after discontinuation of the Ara-C infusion. Calculations of Ara-C plasma half-life, plasma clearance and volume of distribution were within the expected range. Owing to the short half-life of Ara-C in blood due to rapid deamination, varying infusion velocities will result in markedly varying plasma levels. Higher peak plasma levels lead to proportionally higher diffusion into compartments like tears, aqueous humor and cerebrospinal fluid. In compartments which lack noteworthy deaminase activity, dose intensity will be much more enhanced than in plasma. Peak plasma levels, therefore, may be associated with multifold local toxicity without concurrent increase of hematological toxicity. Especially when the drug is given in small volumes of infusion, these considerations should be taken into account. Precise control of infusion parameters and application of artificial tears for dilution of the Ara-C concentration on the corneal surface should be part of keratitis prophylaxis.

Adolescent↗