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Biomedical subjects

F Tost

Publications and source records attributed to F Tost.

At least 19 recordsLinked to original sources
PubMed2006

[Optical lamellar-penetrating keratoplasty with stem cell transplantation in high-risk cases].

BACKGROUND: Stem cells of the corneal epithelium are located mainly at the sclerocorneal limbus, and are essential for the maintenance of a healthy corneal surface. Limbal stem cell deficiency leads--depending on intensity and extension--to several corneal alterations. The appearance of limbal stem cell deficiency is chiefly concentrated on pemphigoids, Herpes relapses and alkali burns and represents the main part of high-risk keratoplasty. The different types of limbal stem cell deficiency (partial or total) are usually treated with several surgical techniques. Total limbal deficiency can be treated with limbal transplantation, either of the healthy eye (limbal autograft), or using material of another donor (limbal allograft). METHODS AND RESULTS: Lamellar-penetrating keratoplasty (L-P-KP) has been carried out in five patients. Unlike recent surgical techniques containing ring-shaped or circular transplantations, a stripe-like lamellar preparation was performed. L-P-KP involves a peripheral lamellar and a central penetrating keratoplasty combined with limbal stem cell transplantation. In four of six cases, the transplant has been successfully kept clear without the occurrence of corneal decompensation or ulceration. No major changes could be seen between pre- and postoperative visual acuity. The mean observation period was 24 months. DISCUSSION: L-P-KP offers a new surgical opportunity in the treatment of high-risk cases of limbal deficiency.

Adolescent↗
PubMed2006

[In vivo imaging of the conjunctival epithelium using confocal laser scanning microscopy].

BACKGROUND: In various ocular diseases, cytomorphological findings of the ocular surface are an essential component of clinical diagnostics. When evaluating the conjunctival epithelium, minimally invasive acquisition of biomaterial is necessary for lab and technical processing and in vitro histological examination. To examine corneal structures in vivo, confocal laser scanning microscopy is a successful standard method. Our aim was to employ in vivo confocal laser scanning microscopy also for examining the conjunctival epithelium. MATERIAL AND METHOD: Results were analyzed and compared with cytomorphological findings of impression cytology. Accordingly, the basic features of conjunctival in vivo examination using RLSM were described and defined. In vivo images were analyzed and compared with impression cytological slide preparations (n=110) of 23 healthy test persons. Examination was standardized. Finally, the confocal laser scan images were compared to the impression cytological patterns. RESULTS: Due to the distribution of reflectors (pixel brightness), diagnostic analysis of important morphological structures (cell nucleus, cytoplasm, nucleus/plasma relation) of the conjunctiva is possible. Secretory cells of the epithelium (goblet cells) can be easily recognized by their size. Highly reflective pixels depict cell walls or wide intercellular spaces with high contrast. CONCLUSIONS: The in vivo investigation of important anatomical and morphological structures of the conjunctival epithelium is possible using RLSM. The distribution pattern of goblet cell pixel brightness may correlate with various secretion contents or suggest distinct, recognizable, functional conditions (hypo- or hypersecretion).

Conjunctiva↗
PubMed2006

[Progress in geriatric care through telemedicine].

A constantly aging population leads to an increasing number of elderly patients. As a result, the treatment of chronic illnesses becomes a significant part of daily routine. Today's concepts in social services and healthcare require time consuming and barely cost-effective efforts for the special needs of geriatric care. The use of telemedicine offers a possible solution, because telemedical methods may help to realize improved monitoring systems for optimized and effective patient management. This report provides an overview of the scenarios and advantages of telemedicine in general. In addition, we provide information on practical experiences in a project on telemedical glaucoma management in Mecklenburg-Vorpommern.

Aged↗
PubMed2006

[Molecular genetic and histopathological examinations for genotype-phenotype analysis in patients with TGFBI-linked corneal dystrophy].

PURPOSE: Different missense mutations in the TGFBI gene cause granular (Groenouw CDGG1, Avellino CDA, Reis-Bücklers CDB1) and lattice (Type I; Biber-Haab-Dimmer; CDL1) corneal dystrophies and, in some reports, corneal dystrophy Thiel-Behnke (CDB2). We report on the mutation spectrum and the genotype-phenotype correlations on the basis of clinical and histopathological examinations of 13 German families with TGFBI-linked corneal dystrophies. METHODS: In 31 patients with different corneal dystrophies, DNA was extracted from leukocytes of the peripheral blood and mutation analysis was performed by direct sequencing of the TGFBI gene. Clinical and histopathological findings were compared with the molecular genetic findings for genotype-phenotype correlations. RESULTS: In 6 patients (2 families/one single person) with clinical and histopathological CDL1 we found a Missense mutation Arg124Cys and in 7 patients (3 families/one single person) with clinical and histopathological CDA we found a Missense mutation Arg124His in the exon 4 of the TGFBI gene. In 12 patients (4 families/2 single persons) with clinical and histopathological CDGG1 we found a Missense mutation Arg555Trypt in the codon 12 of the TGFBI gene. In all five patients (1 family/4 single persons) with clinical and histopathological CDB2 we could not find any mutation in the TGFBI gene. In one patient with exceptional clinical and histopathological findings we found a Missense mutation Ala546Asp, which was reported before only twice in connection with polymorphous corneal amyloidosis. CONCLUSIONS: In comparison of our clinical and histopathological findings and the molecular genetic results we found a strong genotype-phenotype correlation in patients with TGFBI-linked corneal dystrophies. Rare mutations can lead to exceptional clinical and histopathological findings which cannot be classified into the different groups of corneal dystrophies. In our patients with CDB2 we could not find any molecular genetic correlation to the TGFBI gene.

Adult↗
PubMed2006

[Digital patient record for remote monitoring of intraocular pressure, blood pressure and serum glucose].

BACKGROUND: At the University Eye Hospital of Greifswald, we have developed a digital patient record that allows close monitoring of glaucoma, diabetes and hypertension. The record stores contemporary, long-term profiles containing intraday variation and interaction of intraocular pressure, blood pressure and serum glucose levels even at night. METHODS: All patients are equipped with a home monitoring system. They subsequently transmit self-measurements via the "telemedical interface" to the server. Physicians use a web front-end to access electronic patient records; this provides a PDF export filter for printing. We intend to include a total number of 120 patients from Mecklenburg-Vorpommern who suffer from glaucoma possibly combined with hypertension/diabetes. This long-term investigation was designed as a randomised cross-over study in two groups. RESULTS: Especially for this project an electronic patient record was developed and implemented. The components of the home monitoring system were modified and connected to a custom-built "telemedical interface". To date the study includes 120 patients, 60 of whom constantly measure and transmit their values to the electronic patient record, while the others are treated without home monitoring. All self-measurements are presented in a tabular form. In addition, dynamically generated graphics provide a diagrammatic view of all values. On demand, a detailed protocol for every single measurement report allows a comprehensive evaluation of the quality of the self-measurements. Ocular perfusion pressure is calculated automatically from intraocular pressure and blood pressure. The presented system documents continuously all information that is relevant for treatment and provides fast access for all attending physicians. CONCLUSIONS: Central data collection and unlocalised access improve information exchange between involved physicians. Flexible measurement periods allow the detection of pressure spikes even at night. In addition, this may help to classify glaucoma (normal-pressure glaucoma) and its causal connection to blood pressure. The patients benefit from individualised therapy adaptation and early therapeutic intervention in case of critical parameters.

Blood Glucose Self-Monitoring↗
PubMed2005

[Corneal anomalies in murine trisomy 16].

BACKGROUND: The prevalence of human Down's syndrome is about 1:700. Investigations using animal models are therefore of clinical relevance for understanding its etiopathogenesis. No corneal changes have been reported with transgenic murine trisomy 16. METHODS: A total of 20 fetal mice (n=40 eyes) with experimentally induced trisomy 16 were investigated from day 18 of pregnancy in order to determine whether visible developmental disorders of the cornea occur. All specimen were investigated microscopically in serial sections. RESULTS: In addition to disturbances in systemic development, the transgenic mouse fetuses showed high rates of malformation of the eyes. Developmental and differentiation disorders of the corneal epithelial cell layers and structural disturbances of the corneal parenchyma were found. Our findings are the first demonstration of developmental disorders of the cornea in mouse fetuses with trisomy 16. These minor anomalies of the cornea could well have resulted in keratoconus if the animals had survived. CONCLUSIONS: Our findings in transgenic mouse fetuses with trisomy 16 correspond to the clinical pattern of Down's syndrome in humans. Disturbed development of lids and lenses have a high prevalence, whereas corneal hypoplasia is found less often.

Animals↗
PubMed2005

[Application of EMLA creme before upper lid blepharoplasty].

BACKGROUND: The injection of local anesthesia before upper lid blepharoplasty is perceived as unpleasant and painful by some patients. METHODS: In an intraindividual randomized prospective study, 14 patients undergoing upper lid blepharoplasty on both sides were examined. Before the operation the EMLA creme was put on one side. The pain sensibility was checked before and after using EMLA creme and during the infiltration of anesthesia and the operation. RESULTS: The sensitivity before putting on EMLA creme was equal in all patients on both sides. After application there was a distinct difference between the sides. During the infiltration of anesthesia 12 patients reported low and 2 patients medium pain on the treated side, while on the non-treated side 5 patients reported low, 4 patients medium, and 5 patients severe pain. CONCLUSIONS: Applying EMLA creme before an operation reduces the pain sensitivity during infiltration of anesthesia and during the operation.

Administration, Topical↗
PubMed2005

[Molecular genetic analysis of the BIGH3 gene in lattice type I (Biber-Haab-Dimmer) and granular type II (Avellino) corneal dystrophy: is indirect mutation analysis for hot spots recommended?].

BACKGROUND: Mutations of the BIGH3 gene were delineated as the underlying gene defect for corneal dystrophy Lattice Type I (CDL1) and corneal dystrophy Avellino type (CDA) in families with different regional provenance. Missense mutations in exon 4 with single base pair substitution which result in amino acid alterations Arg124Cys (CDL1) and ARG124His are described as hot spots. We report on histopathological and molecular genetic investigations in 2 German families and a single patient with CDL1 and CDA. METHOD: In 3 affected family members and 1 unaffected family member and in one single patient with CDL1 and in 3 affected family members and 1 unaffected family member of a family with CDA mutation analysis in exon 4 of BIGH3 gene by direct sequencing of genomic DNA from peripheral blood was performed. Histopathological examination of corneal tissue of both index patients was performed after penetrating keratoplasty. RESULTS: We revealed a heterozygous single base pair substitution 417C-->T in family A and patient B (CDL1) and a heterozygous single base pair substitution 418G-->A in family C (CDA). In all index patient's diagnosis was confirmed by histopathological examination of corneal tissue. The sequencing results were confirmed by restriction digestion with HpyCH4V (NEB; CDL1) restriction endonuclease site and AvaII (NEB; CDA) restriction endonuclease site. The heterozygous 417C-->T transition in family A and patient B alters the amino acid sequence from Arg124Cys while the heterozygous 418G-->A transition in family C alters the amino acid sequence from Arg124His in the keratoepithelin. COMMENT: Codon 124 of the BIGH3 gene appears as a mutation hot spot also in German families with CDL1 and CDA. Indirect mutation analysis with restriction digestion is suggested as first step investigation in families with relevant corneal dystrophies. Direct sequencing of all exons is recommended as a second step if there are no results in restriction digestion.

Adult↗
PubMed2005

[Minimally invasive endoscopic surgery of the lacrimal drainage system--two case reports].

BACKGROUND: Dacryoendoscopy is a standard procedure to directly evaluate the lacrimal system. The existence and localisation of dacryostenosis and mucosal changes as well as rare diseases in the drainage system, such as intracanalicular foreign bodies or dacryoliths, can be reliably detected and treated by minimally invasive endoscopic surgery. HISTORY AND SIGNS: A patient treated by canaliclulodacryozystorhinostomy with silicone tube intubation 5 years ago had a long symptom-free period but now shows tearing (epiphora) and occasional mucous secretion. During endoscopy residues of a silicone tube coated with a biofilm could be removed over the lacrimal canaliculus and then tested for microbiological contamination. A second patient with tearing, light mucous secretion and positive nasolacrimal duct irrigation was initially diagnosed with a tear-film disorder. Dacryoendoscopy showed a dacryolith in the saccus lacrimalis. This was consequently fragmented using a microdrill system and fully removed through the nasolacrimal duct as well as the lacrimal canaliculus. CONCLUSIONS: Endoscopy of the proximal and distal lacrimal system allows the assessment of intracanalicular structures and a reliable detection or exclusion of disorders in the draining system. This method is of great diagnostic importance as symptoms are frequently non-specific and the causes are multiple. Through endoscopy in combination with the use of a microdrill system the lacrimal system can be reopened and adequately reconstructed.

Adult↗
PubMed2003

[Schnyder's crystalline corneal dystrophy. Further narrowing of the linkage interval at chromosome 1p34.1-p36?].

BACKGROUND: Schnyder's crystalline corneal dystrophy (SCCD) is a rare autosomal dominant disease and can occur in association with hyperlipoproteinemia. The disease has been mapped to chromosome 1p34.1-p36. CASE REPORT: We report on a 66-year-old woman and her son with Schnyder's crystalline corneal dystrophy. The mother had type IV hyperlipoproteinemia and hypercholesterolemia while her son had hypercholesterolemia with elevated LDL-cholesterol. Analysis of microsatellite markers within the candidate interval of 1p34.1-p36 showed that the affected son and his unaffected brother had inherited different alleles only for the proximal marker D1S228 from their affected mother. CONCLUSIONS: The haplotype analysis suggests that either recombination has occurred, which would allow the candidate interval to be narrowed down, or alternatively, the SCCD in the reported family is not linked to chromosome 1, which would be a first indication of genetic heterogeneity in this disease. To reduce the risk of cardiovascular disease, hyperlipidemia should always be excluded in patients with Schnyder's crystalline corneal dystrophy.

Adult↗
PubMed2003

[Imaging the lacrimal canaliculus with 20-MHz ultrasonography: a normal diagnosis (Part 1)].

INTRODUCTION: High-frequency ultrasonography is used in ophthalmology with probes at 20, 30 and 50 MHz. The latter are used particularly for examining the anterior segments of the eye. The physical and acoustic parameters of the 20-MHz probes present an ideal compromise between resolution and penetration depth for examination of the lacrimal passages. These probes can be adapted to the I3 ultrasound diagnostic device, offering a clear financial advantage. MATERIAL AND METHODS: During the ultrasound examination, the patient is in the supine position with the head back and turned away from the eye to be examined. For proper transmission, enough gel must be applied, so that the 20-MHz probe can easily navigate on the surface to be scanned. If there is no inflammation, Healon can be applied in the canal so that it is dilated and easier to visualize. RESULTS: In all patients, we were able to visualize the canaliculi in the main cross-sections with the ultrasound. The edge of the eyelid, the lacrimal caruncle, and the medial palpebral ligament can serve as landmarks in the search for the canaliculi. CONCLUSION: The 20-MHz probes are better adapted to visualizing the presaccular lacrimal passages than conventional 10-MHz probes and the 50-MHz biomicroscope, thus enhancing the spectrum of imaging methods.

Equipment Design↗
PubMed2003

[High-frequency ultrasonography applied to disorders of the lacrimal canaliculi (Part 2)].

INTRODUCTION: Thirty patients presenting disorders of the lacrimal passages were examined using high-frequency ultrasonography in the hopes that this diagnostic tool would provide better image resolution and better reproduction quality than conventional 8- to 10-MHz ultrasound examination. MATERIAL AND METHODS: To carry out this examination, we were able to combine a 20-MHz ultrasound probe to the I3 ultrasound diagnostic device. The patient was then positioned and the interior palpebral angle was filled with methylcellulose. RESULTS: In all patients, we succeeded in detecting the course and diameter of the lacrimal passages with better images than those provided by conventional ultrasound. We found that chronic canaliculitis was an important clinical domain for the 20-MHz ultrasound. Diagnosis is made easily and decisive information is provided. In all patients with this disorder (n=5), widening of the lacrimal passages, development of a diverticulum, and the presence of drusen concretions were observed. CONCLUSION: In our opinion, the use of high-frequency sonography as a noninvasive diagnostic technique is advised in cases of lacrimal passage disorders and is valuable in detecting chronic canaliculitis.

Humans↗
PubMed2002

[20-MHz ultrasound of pre-saccular lacrimal ducts].

BACKGROUND: In clinical practice, ultrasound examination of the lacrimal drainage system is not able to represent the lacrimal canaliculi with a high quality but the high-resolution ultrasound with 20 MHz transducer is a better possibility to get images of the lacrimal canaliculi. PATIENTS AND METHODS: A total of 20 patients suffering from diseases of the lacrimal drainage system were examined ultrasonographically. Detection and localisation of the lacrimal canaliculi was made by a 20 MHz sector scanner in combination with the ultrasound diagnostic system I. After patient positioning, the high-resolution ultrasound investigation was done via immersion connection (methylcellulose). Instillation of viscoelastic substances (e.g. Healon) was necessary to detect the lacrimal canaliculi. RESULTS: In all investigated patients, the high-resolution ultrasound (transducer frequency of 20 MHz) allowed reproducible images of the lacrimal drainage system. Without viscoelastic substances, a good echographic visualisation of canaliculi structures was obtained from patients with chronic canaliculitis or dislocated punctum plugs. In chronic canaliculitis the ultrasonic images showed an ectatic canaliculus (diverticulum) and high-reflective structures (concrements). CONCLUSION: The high-resolution ultrasound (transducer frequency of 20 MHz) seems to be well suited for investigations of the lacrimal drainage system. In comparison with ultrasound biomicroscopy the resolution is lower but the depth of penetration is higher. The use of 20 MHz ultrasonic examination can be helpful in the clinical diagnostic of chronic canaliculitis.

Chronic Disease↗
PubMed2000

[20 MHz ultrasound diagnosis in chronic canaliculitis].

BACKGROUND: High frequency sonography is used with a medium frequency of 50 to 100 MHz for non-invasive examination of the anterior eye segment. 20-MHz probes are considered to be a cost-efficient alternative, with a lower resolution and a higher penetration depth. We examined the value of the 20-MHz probe in diagnosing chronic canaliculitis. CASE REPORT: A 50-year-old woman was evaluated for a chronic canaliculitis. A pathognomonic sign of the chronic canaliculitis was the detection of concrements by high-resolution ultrasound. Grains measuring 1-2 mm in diameter could be shown in an ecstatic canaliculus with 20-MHz sonography. The high-resolution sonography showed the extent of the ectasia of the canaliculus and was therefore useful in planing the operative strategy. CONCLUSION: The spectrum of possibilities in diagnosing chronic canaliculitis is broadened with this diagnostic tool. Specially when characteristic symptoms are missing, the 20-MHz probe may be useful in diagnosing patients with chronic canaliculitis.

Actinomycosis↗
PubMed2000

Clinical diagnosis of chronic canaliculitis by 20-MHz ultrasound.

The practical value of high-resolution ultrasound (transducer frequency of 20 MHz) in the study of the lacrimal canaliculi has been proven. It can also be used in the clinical diagnosis of chronic canaliculitis. If the classic symptoms are absent, the clinical diagnosis is often inaccurate, and treatment is insufficient. Representative images of normal cases and of chronic canaliculitis illustrate the potential of high-resolution ultrasound. In our patient, 20-MHz scanner images revealed pathological findings which were invisible during slitlamp examination. Ultrasonic images of chronic canaliculitis showed ectasia of the canaliculus and sulfur grains. High-resolution ultrasonic examination of the lacrimal drainage system demonstrated that the 20-MHz scanner used was able to show concrements (sulfur grains), measuring 1-2 mm in diameter. Such more reflective structures (like sulfur grains) are a pathognomonic sign of chronic canaliculitis. Our report confirms the efficiency of 20-MHz sonography in the diagnosis of canaliculitis without any side effects.

Adult↗
PubMed1999

[Postoperative complications of Toti DCR (dacryocystorhinostomy. An indication for canalicular surgery].

UNLABELLED: Failures with external DCR have also been attributed to canalicular occlusion. Since 1976 we have documented all patients with surgical reconstruction of occluded canaliculi. The indication, different surgical methods of choice and functional prognosis were evaluated. PATIENTS AND METHODS: From 1976 to 1997 we have treated 272 cases. The surgical technique canaliculodacryocystorhinostomy (n = 132) was performed in 45%. Thirty operations (11%) of occluded lacrimal canaliculi due to external DCR were done. The patients ranged in age from 2 to 79 years. We examined all 29 patients (10 male, 19 female) with 30 operations (1 patient was operated on in both eyes). RESULTS: The surgical procedure was performed after an interval of 1 month to 24 years (average 4 years). Seven times a second external DCR was done. Special causes of canalicular obstruction were severe previous soft tissue and bone trauma (4 patients) and congenital defects (3 patients). Canaliculorhinostomy was performed 15 times, canaliculodacryocystorhinostomy 14 times and conjunctivorhinostomy once. Fifteen operations had good functional results (without any symptoms). Five patients had good irrigation, but a prolonged fluorescein dye disappearance test. There were 10 failures with complete closure of the canaliculi. CONCLUSION: If failure with external DCR is caused by canalicular occlusion, the microsurgical technique has a possible success rate for long-term results of about 50%. Before hand, however, all prophylactic measures have to be taken to avoid this postoperative failure.

Adolescent↗