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Biomedical subjects

J Strobel

Publications and source records attributed to J Strobel.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Prognosis of postoperative endophthalmitis].

BACKGROUND: The outcome of 20 patients is summarized in a retrospective study to identify clinical findings that influence the long-term prognosis of postoperative endophthalmitis. PATIENTS: Between 1991 and 1997 a total of 20 patients with postoperative endophthalmitis were admitted. Median age was 80 years (range: 9-95), 11 patients were male, 9 female. Sixteen pars-plana vitrectomies, 2 anterior vitrectomies and 2 rinsings of the anterior chamber without vitrectomy were performed. Furthermore, all patients received intraocular and systemic antibiotic treatment. For microbiological investigation, specimens from vitreous, anterior chamber and conjunctiva were sent in. Long-term outcome was controlled for an average of 14 months after treatment of the endophthalmitis (range: 4-36 months). RESULTS: At the end of treatment, 40% of patients had a visual acuity of 0.4 or better, 80% had 1/20 or better. Patients with a preoperative visual acuity of at least hand movement had a better postoperative visual outcome than patients with only light perception. Visual acuity was better in patients with chronic endophthalmitis than in patients with acute or subacute endophthalmitis. In patients with chronic or subacute endophthalmitis, improvement of visual acuity was found some months after the operation more often than in patients with acute endophthalmitis. However, in 40% of cases with an acute onset, no improvement or even worsening of the visual acuity was documented. Best postoperative results were found after infection with Staphylococcus epidermidis and Propionibacterium acnes. CONCLUSION: Important prognostic factors of postoperative endophthalmitis are visual acuity, the onset of the endophthalmitis (acute, subacute or chronic) and the microbiological findings. At the time of surgery and antibiotic treatment, visual acuity should be at least hand motion to expect an improvement in the visual outcome.

Adolescent↗
PubMed2000

[Age-correlation of blood pressure induced myogenic autoregulation of human retinal arterioles in 40 volunteers].

PURPOSE: For the first time noninvasive measurement of the myogenic response of retinal arterioles is possible by the use of the Retinal-Vessel-Analyzer (RVA). This study investigates the influence of age on retinal autoregulation. PATIENTS AND METHODS: In 40 healthy volunteers continuous measurement of a retinal arteriole over a 9-min period was performed. After a 3-min baseline measurement isometric exercise caused a rise in blood pressure of 15-30 mm Hg. During the last 3 minutes recovery was documented. Volunteers were split into a group of 20 younger (18-34 yrs.) and 20 older subjects (35-57 yrs.). For statistical analysis the Mann-Whitney test was used. RESULTS: All volunteers showed a rise in blood pressure. Significant differences in the blood-pressure rise were followed by a myogenic response of 1% up to 10% vasoconstriction. An individual autoregulation-curve was defined with negative gradient. Significant differences between the younger and the older volunteers can be identified by this methodology. CONCLUSION: Age has a significant influence on the myogenic response in human retinal arterioles. Age should be considered as a factor in clinical studies on retinal autoregulation.

Adolescent↗
PubMed2000

[Autoregulation of retinal arterioles in patients with diabetes mellitus and normal probands].

BACKGROUND: Measurement of myogenic autoregulation of retinal arterioles was demonstrated by the use of the Retinal-Vessel-Analyzer (Carl Zeiss, Jena). The purpose of the presented study was to find a significant difference of this myogenic response in a group of healthy individuals vs. a group of patients with pathologic conditions. PATIENTS AND METHODS: As a group of patients with known pathology in microcirculation patients with type 1 diabetes were chosen. By isometric exercise an identical rise in mean arterial blood-pressure was provoked in 20 patients with type-1 diabetes and 20 matched healthy volunteers. The myogenic response of retinal arterioles was measured in both groups by the use of the Retinal-Vessel-Analyzer. The Wilcoxon test was used for statistical analysis within the two groups whereas both groups were compared with each other by the use of the Mann-Whitney test. RESULTS: Having the same age and same blood-pressure rise (p = 0.624) a significant better myogenic response was found in the healthy subjects vs. the diabetic group (p = 0.008). In the diabetic group no correlation was found between myogenic response and duration of diabetes (p = 0.982) or HbA1c values (p = 0.83). CONCLUSIONS: In this study significant loss of autoregulation in patients with type 1 diabetes is demonstrated. By the use of the Retinal-Vessel-Analyzer noninvasive testing of the function of autoregulation of retinal arterioles is possible. This method might prove to be of great value in early detection of diabetic vessel pathology.

Adolescent↗
PubMed1999

[Oxygen saturation of retinal vessels. Studies for measuring with polarized light].

UNLABELLED: The accuracy of the spectrometric measurement of the oxygen saturation in retinal vessels is limited by its signal-to-noise ratio. The aim of this study was to investigate the possibility of enhancement of the reflection signal by the use of polarized light. MATERIALS AND METHODS: The Jena ophthalmospectrometer was equipped with two polarizing filters: one in the illumination and the other in front of the detector. Reflection spectra of erythrocytes streaming through a cuvette in the focus of an artificial eye were recorded. The influence of the polarization on the reflection spectra was investigated by rotating the polarizer in front of the detector. Furthermore, the degree of polarization of the light reflected from retinal vessels in vivo was determined. RESULTS: The degree of polarization of the light reflected from the erythrocytes was 0.6-0.8, whereas the polarization of light reflected by a standard white reflectance target was virtually zero. CONCLUSION: Polarized light can be used for the reduction of error in retinal vessel oximetry.

Blood Flow Velocity↗
PubMed1999

[YAG laser capsulotomy in multifocal intraocular lenses].

INTRODUCTION: Multifocal intraocular lenses (MIOLs) have been implanted with good results for several years. Because the light is distributed between two or more focuses, there is slight light reduction for every picture. Capsular fibrosis can cause additional reduction of the amount of light to the retina. PATIENTS AND METHODS: A diffractive MIOL 811X from Pharmacia & Upjohn was implanted in 40 eyes of 40 patients. Within 1 year postoperatively, 13 patients underwent YAG Laser capsulotomy between the 4th and the 6th month. Before and after the YAG laser the visual acuity for distance and near vision was tested. In addition, a contrast test (Ginsburg test) was performed. RESULTS: Before YAG laser capsulotomy, the visual acuity for distance without correction was 0.5 (+/- 0.17) and near vision J 2.4 (+/- 1.4). After the YAG laser procedure, uncorrected visual acuity improved to 0.65 (+/- 0. 21) for distance and J 1 (+/- 0) for near vision. With the best distance correction the distance vision was 0.85 (+/- 0.18) and near vision was J 1.77 (+/- 0.89) before capsulotomy. After the YAG laser treatment, patients reached with best correction a visual acuity of 1.1 (+/- 0.24) at distance and J 1 (+/- 0) at near vision. The contrast equivalent acuity increased from 20/70 before the YAG laser treatment to 20/40 after ward. DISCUSSION: Patients with a MIOL feel early visual discomfort due to capsular fibrosis. In most cases the patients still have good visual acuity, but decreased contrast sensitivity. Early YAG laser capsulotomy increases the visual acuity and the contrast sensitivity significantly.

Aged↗
PubMed1999

Noninvasive measurement of the Bayliss effect in retinal autoregulation.

PURPOSE: The Bayliss effect describes the reaction of smooth muscle cells in the arterial wall to changes in blood pressure. A rise in mean arterial blood pressure (MAP) causes an autoregulatory myogenic vessel constriction by smooth muscle cells in the arterial wall. The responsiveness of retinal vessels to changes in MAP were analyzed using the Retinal Vessel Analyzer (RVA). METHODS: Continuous measurement of retinal arterial vessels was performed in 40 healthy volunteers (age 18-56 years.) over a 9-min period. After a 3-min baseline measurement (phase I), isometric exercise caused a rise in MAP over the next 3 min (phase II). During the last 3 min (phase III) recovery was observed. Blood pressure and ECG were documented simultaneously throughout the experiment. RESULTS: Exercise caused a significant rise of 22.8 (+/-6.0) mm Hg in MAP (phase II vs. phase I: P<0.001). Retinal arterioles showed 5.5% (+/-2.8%) vasoconstriction (P<0.001). During phase III vessel diameters returned to normal, with no difference from phase I (P = 0.179). CONCLUSION: Noninvasive measurement and quantitative analysis of the Bayliss effect in human retinal vessels by means of the RVA is possible. Analysis of retinal arterial autoregulation may provide valuable insight into pathologic conditions such as diabetic or hypertensive retinopathy.

Adolescent↗
PubMed1999

Identification of a cyclic nucleotide- and voltage-activated ion channel from insect antennae.

From an antennal cDNA library of Heliothis virescens a clone has been isolated encoding a polypeptide of 678 amino acids. Data base comparisons and primary structure analysis of the deduced protein sequence (HvCNG) indicated significant homology to cyclic nucleotide and voltage-activated ion channels including six putative membrane spanning domains, a putative cyclic nucleotide binding site, a pore region and a voltage-sensor motif. Heterologous expression of the cloned cDNA in Sf9 cells resulted in a polypeptide of the predicted molecular mass. Patch clamp analysis allowed to record the activity of the identified HvCNG channels; they were activated by cAMP but also by hyperpolarization. The channel displayed in potassium solution a conductance of 30 pS; the ion selectivity was calculated as PK/PNa approximately 3. Northern blot analysis revealed that the channel is highly expressed in the antennae; weaker signal were detected in heads and legs. In situ hybridization of tissue sections through the antennae showed a spatial distribution of reactive cells; they are located beneath sensillar hairs. Thus, a novel channel type has been identified which may play an important role in antennal cells.

Amino Acid Sequence↗
PubMed1999

In vivo measurement of the oxygen saturation of retinal vessels in healthy volunteers.

A new method for the spatially resolved measurement of the oxygen saturation of retinal vessels is described. Imaging spectrometry was used for both measurements of transmission and reflectance spectra of whole blood in cuvettes as well as for fundus reflectance spectra. A model was developed for the calculation of the oxygen saturation, valid in the wavelength range between 510 nm and 586 nm, in that the internal reflectance is constant and only the transmitted light depends on layer thickness and hematocrit. Altogether 265 measurements were performed in different number at 30 eyes. In each measurement, the oxygen saturation was simultaneously determined for 193 locations along a line of 1.5 mm at the fundus. The mean oxygen saturation in retinal arteries was (92.2 +/- 4.1)% and (57.9 +/- 9.9)% in retinal veins. The mean retinal arterio-venous difference of the oxygen saturation was (35.1 +/- 9.5)%. The venous oxygen saturation depended on distance from the optic disc. The measured mean of the arterio-venous difference of the oxygen saturation corresponded well to the value of the brain (34%). The utilization of oxygen in the temporal quadrants (inferior: 39.4 +/- 10.4%) is significantly (p = 0.05) higher than in the nasal quadrants (inferior: 31.3 +/- 6.7%).

Adolescent↗
PubMed1998

[Flare measurement and albuminuria in type I diabetics].

BACKGROUND: Chronic hyperglycaemia causes microangiopathy with manifestations in different organ systems. The purpose of this study was to investigate whether anterior chamber protein concentrations and albuminuria in patients with diabetes mellitus type 1 have any correlation. PATIENTS AND METHODS: 23 patients with type 1 diabetes were examined in both eyes by the use of the laser flare-cell meter (LFCM). After clinical exclusion of urinary tract infection urine-samples were taken on the examination-day. Patients were divided into two groups: group 1 consisted of 13 patients with albuminuria (8x microalbuminuria, 5x macroalbuminuria), group 2 comprised 10 controls with normal urine albumin concentrations. RESULTS: Both groups were identical according to age and gender. The flare values in the group with albuminuria were significantly elevated (10.7 +/- 7.1 counts/msec) in comparison to those of the control group (3.7 +/- 1.9 counts/msec)(p = 0.042). The duration of the diabetes was as well significantly different in both groups (7.9 +/- 6.9 yrs. vs. 23.9 +/- 13.4 yrs.)(p = 0.02). A correlation was found between albuminuria and flare values (r = 0.67; p = 0.003). CONCLUSIONS: Our results demonstrate a correlation between protein concentration in aqueous and albuminuria. In future flare measurements could possibly offer a non-invasive diagnosis of diabetic nephropathy.

Adult↗
PubMed1998

[Bilateral endogenous endophthalmitis].

BACKGROUND: The endogenous endophthalmitis is a septic-metastatic late complication of a generalized bacterial or fungal infection or an asymptomatic fungaemia. Aspergillus organisms are a rare cause of endophthalmitis. Aspergillus ocular manifestations have been mostly reported in connection with immunosuppression, severe diseases or drug abuse. PATIENT AND METHODS: A 51-year-old man underwent a kidney transplantation, an immunosuppressive therapy, and, in addition, treatments for some other generalized diseases. Endogenous endophthalmitis was diagnosed in both eyes at an interval of about eight weeks. The treatment included pars-plana-vitrectomy on both eyes. RESULTS: At first, an endogenous endophthalmitis was found in the right eye which was assumed to be induced by bacteria. About eight weeks later, however, an endogenous endophthalmitis was diagnosed in the left eye, also, which was caused by Aspergillus. The patient received an intensive medical care including operative, antibacterial and antimycotic treatments. The bacterial endophthalmitis in the right eye was healed, and the state of the left eye was found to be post-operatively stabilized. Unfortunately, the patient died of a septic shock in systemic Aspergillus infection. CONCLUSION: Endogenous endophthalmitis has a very poor prognosis. To our knowledge, the described medical history seems to be the first reported case of an endophthalmitis on both sides, apparently caused by bacteria in one eye and by fungi in the other one.

Aspergillosis↗
PubMed1998

Nonproliferative diabetic retinopathy-reflection spectra of the macula before and after laser photocoagulation.

This study examines the influence of diabetic and laser photocoagulation on the reflection spectra of the macula. In the investigation 43 patients with type II diabetes mellitus and 33 normals were included. It was shown that the optical density in diabetics is increased compared to normals. After laser photocoagulation the reflection spectra have changed, suggesting a decrease in optical density. It is proposed that the therapeutic effect of photocoagulation in diabetic retinopathy is related to an alteration in blood flow in the choroid.

Adult↗
PubMed1997

[Endogenous endophthalmitis in severe generalized diseases].

BACKGROUND: In spite of modern antibacterial, antimycotic and operative therapies, endogenous endophthalmitis connected with other severe diseases and an impaired state of health is an eye complication with a very poor prognosis. PATIENTS: The study presents observations about the progress of the endogenous endophthalmitis in five eyes of four patients. The age of the patients ranged from 58 to 71 years. The span between the appearance of the first eye symptoms and hospital treatment amounted to 1 week and 3 months. The general diseases have been diagnosed as endometrium cancer, colon cancer, corpus uteri cancer (with intestinal fistula) and pancreatic insufficiency (with subclavian catheter) as well as diabetes mellitus. RESULTS: In regard to the infections we analyzed (Candida albicans in 3 eyes, bacteria in 2 eyes), very intensive medical treatment was initiated, including antibacterial or antimycotic therapy (local, subconjunctival, intraocular and systemic) as well as pars plana vitrectomy and/or vitreous puncture. Nevertheless, by the end of the clinical attendance, the following statements were established: one-eye enucleation, one-eye evisceration, two eyes perception of light, one eye visual acuity 0.2. CONCLUSION: The patients should be immediately admitted to a hospital with a department for vitreous surgery. Only with this option is it possible to initiate adequate therapy.

Aged↗
PubMed1997

[Haptic position of iris-fixed posterior chamber lenses. Determination by ultrasound biomicroscopy].

UNLABELLED: In eyes lacking adequate posterior capsular support, fixation of posterior chamber intraocular lenses (IOL) by iris sutures has become one of the methods available. Ultrasound biomicroscopy (UBM) allows detection of the haptic position postoperatively and determination of its relationship to adjacent intraocular structures. METHODS: Thirteen patients with iris-sutured IOLs were examined pre- and postoperatively with UBM. The examination included locating the haptic and tracing the haptic to the position closest to other uveal structures. RESULTS: The position of all 26 haptics was determined. All haptics were in touch with the iris. In the 12-clock position 11 haptics did not touch other intraocular structures. In one case the haptic was located in the ciliary sulcus, and in another case it touched the ciliary body. In the 6-clock position two haptics were located in the sulcus region, and seven were located posterior to the ciliary processes. Four haptics did not touch any other intraocular structures. CONCLUSIONS: In most cases surgical placement of iris-fixed lenses is a blind procedure. UBM is an adequate method of determining the position of IOL haptics postoperatively.

Aged↗
PubMed1997

[Online measurement of retinal artery branches in type II diabetic patients. Initial clinical trials before and after laser coagulation].

UNLABELLED: By the use of a new online measuring system the effect of argon-laser coagulation in diabetics on the diameters of retinal arteries was measured. METHOD: The vessel diameter of retinal branch arteries were measured in patients with type-II diabetes before and after (0.5 h) argon-laser coagulation. Ten patients without previous laser treatment were included in this study. Measurements were taken in all four quadrants by the use of a new automatic online measuring system. RESULTS: The new technique allowed measurements to be made within an acceptable period of time and with little strain on patients. After argon-laser coagulation 56.7% of retinal arteries showed a significant vasodilation. No significant changes in vessel diameter were found in 18.9% of these arteries, whereas 24.3% showed significant vasoconstriction. CONCLUSION: The new online measuring system is able to measure the effects of photocoagulation on an individual basis with a noninvasive technique. The first findings presented here confirm previous studies of larger groups, with a considerable reduction in efforts required.

Aged↗