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Biomedical subjects

C Erb

Publications and source records attributed to C Erb.

At least 19 recordsLinked to original sources
PubMed2006

[Intermittent ciliary block as a result of haemodialysis].

We report the case of a patient who experienced recurrent elevations of intraocular pressure during haemodialysis. We measured a rise in intraocular pressure of 10-12 mmHg after dialysis. The lens showed intumescence, and a ciliary block was detected by means of Orbscan II. Within 6 h findings had normalized. Changes in serum osmolarity due to haemodialysis may result in fluid shifts between different compartments. Decrease of serum osmolarity during dialysis may lead to lens swelling and thus cause a ciliary block. This may end with regression of the lens swelling.

Aged↗
PubMed2006

[Colour vision and acquired colour vision disturbances. Part I: basic aspects].

Colour vision is the most sensitive sensory ability of the human eye, making it possible to distinguish several million nuances of colour. The physiology of colour vision has meanwhile been researched in depth, including the genetic and biochemical principles. This knowledge has facilitated a better understanding of the results of clinical tests on colour vision. These clinical tests provide useful information on the aetiology of very different clinical pictures in ophthalmology and as such are important for the diagnosis of these diseases. Acquired colour vision deficiencies in patients with systemic vascular disease are early signs of dysfunctional microcirculation and play a role in the early diagnostic work-up. Part I of this review summarizes the basic principles of colour vision and its disturbances. Congenital and acquired colour vision disturbances are distinguished. The second part then describes the most commonly employed examination procedures to assess colour vision.

Color Perception↗
PubMed2006

[Intraocular pressure measurements with the Proview self-tonometer in comparison of Goldmann applanation tonometry in healthy and glaucomatous eyes].

BACKGROUND: The aim of this study was to compare the results of intraocular pressure (IOP) measurements obtained using the pressure phosphene tonometer Proview with those from Goldmann applanation tonometer (GAT) in normal and glaucomatous eyes. PATIENTS AND METHODS: The IOP in 150 eyes of 62 healthy volunteers and 88 patients with glaucoma or ocular hypertension was measured prospectively in a sitting position. After being trained to use the Proview device, Goldmann applanation tonometry was performed first. Then the patient took a reading with the Proview self-tonometer. RESULTS: For all investigated eyes the measurements with the Proview were on average 5.5 mmHg higher than those by GAT. Only 34 % of the readings from the two devices were within a difference range of +/- 3 mmHg. On comparing the group of glaucomatous patients with slight visual field defects with the group of healthy subjects and patients with ocular hypertension without visual field defects we determined almost the same mean difference between the Proview and GAT (mean difference in the group with visual field defects = 4.7 +/- 4.1 mmHg; without defects = 4.8 +/- 2.9 mmHg). CONCLUSIONS: The tonometer Proview did not show a close agreement to GAT. Therefore, the PPT does not offer an alternative method for measuring IOP. We do not recommend the Proview for self-tonometry at home or for clinical management of patients with glaucoma. Slight visual field defects seem to have no influence on intraocular pressure measurement with the self-tonometer.

Adolescent↗
PubMed2006

[Comparisons of manual and automatic refractometry with subjective results].

BACKGROUND: Refractometry is very important in everyday clinical practice. The aim of this study is to compare the precision of three objective methods of refractometry with subjective dioptometry (Phoropter). The objective methods with the smallest deviation to subjective refractometry results are evaluated. MATERIALS AND METHODS: The objective methods/instruments used were retinoscopy, Prism Refractometer PR 60 (Rodenstock) and Auto Refractometer RM-A 7000 (Topcon). The results of monocular dioptometry (sphere, cylinder and axis) of each objective method were compared to the results of the subjective method. The examination was carried out on 178 eyes, which were divided into 3 age-related groups: 6 - 12 years (103 eyes), 13 - 18 years (38 eyes) and older than 18 years (37 eyes). All measurements were made in cycloplegia. RESULTS: The smallest standard deviation of the measurement error was found for the Auto Refractometer RM-A 7000. Both the PR 60 and retinoscopy had a clearly higher standard deviation. Furthermore, the RM-A 7000 showed in three and retinoscopy in four of the nine comparisons a significant bias in the measurement error. CONCLUSIONS: The Auto Refractometer provides measurements with the smallest deviation compared to the subjective method. Here it has to be taken into account that the measurements for the sphere have an average deviation of + 0.2 dpt. In comparison to retinoscopy the examination of children with the RM-A 7000 is difficult. An advantage of the Auto Refractometer is the fast and easy handling, so that measurements can be performed by medical staff.

Adolescent↗
PubMed2005

Muscarinic modulations of neuronal anticholinesterase responses.

Anticholinesterases (antiChEs) are increasingly used for treating patients with neurodegenerative diseases, but the dependence of their effects on the integrity of cholinergic functions has not yet been analyzed at the molecular level. Here, we report that manipulation of muscarinic neurotransmission confers drastic changes on antiChE responses in the rat brain. In the brains of naïve, un-stressed rats, the irreversible organophosphate antiChE, diisopropylfluorophosphonate (DFP) induced post-treatment accumulation of catalytically active G1 monomers of acetylcholinesterase (AChE). Pre-treatment with the selective M1 muscarinic antagonist, pirenzepine, but not the general muscarinic antagonist, scopolamine, attenuated this G1 increase. DFP-enhanced AChE gene expression was accompanied by diverted splicing from the primary AChE-S mRNA variant, encoding G4 synaptic membrane AChE-S tetramers, to "readthrough" AChE-R mRNA, which encodes soluble G1 monomers. Both the mRNA increase and the shifted splicing were long lasting (>24 h) and common to the parietal cortex and hippocampal CA1 and CA3 neurons. Importantly, the splicing shift was maximal under DFP alone, as compared with sham-injected rats, and virtually preventable by pre-treatment with pirenzepine. In contrast, induction of AChE transcription was less dependent on muscarinic function, resulting in AChE-S but not AChE-R increases. Our findings demonstrate distinct regulation of the enhanced transcription and the alternative splicing reactions to antiChE treatment and shed new light on the differential responses to antiChEs of demented patients with increasingly impaired cholinergic neurotransmission.

Acetylcholinesterase↗
PubMed2005

[Early Manifest Glaucoma Trial update 2004].

Elevated intraocular pressure (IOP) represents one of the most important risk factors for developing glaucomatous optic neuropathy. The "Early Manifest Glaucoma Trial" (EMGT) was initiated to answer the question of how immediate IOD-lowering therapy affects the progression of early manifest glaucoma and which clinically relevant factors are important. The study compares 129 patients undergoing treatment with 126 patients receiving no IOP-lowering therapy. IOP remained virtually constant in the untreated group, while a reduction of 25% was achieved in the treatment group. The results of the EMGT indicate that glaucoma progression is influenced by higher initial IOP, pseudoexfoliation or bilateral glaucoma, poorer MD value, higher age, and marginal papillary hemorrhage. No clear conclusions can be drawn regarding the significance of cardiovascular risk factors.

Aged↗
PubMed2005

[Perioperative evolution of the nutritional status in head and neck surgical patients. Prospective and descriptive case series].

AIM OF THE STUDY: To assess the perioperative evolution of the nutritional status of head and neck surgical patients. DESIGN: Prospective, descriptive case series. PATIENTS AND METHODS: Fifty-four patients candidates for total or partial laryngectomy for malignancy of the neck tract without a past of neck surgery. The nutritional status of all patients hospitalized for total pharyngolaryngectomy, total or partial laryngectomy was assessed by 1) clinical parameters including weight (W), weight variation (WV, percentage of loss), Body Mass Index (BMI), triceps skin fold measurement (T), midarm circumference (M), and 2) biological parameters such as serum albumin (SA), transthyretin (TTR), lymphocytes (Ly). These parameters were noted at the time of diagnostic laryngoscopy (T1), the day before surgery (T2), and 10 days afterward (T3) when patients were authorized to eat normally. All patients had enteral nutrition (EN) support (35 kcal/kg/day) starting at D1 and for 10 days afterward. Only complete data per patient were analyzed. RESULTS: 24 patients were excluded. During the 21 days [7-53] preoperative period (T1-T2), WV was (6.6% [-8,1-+20.0] [T2] vs. 4.7% [-12,9-+20.0] [T1], p<0.05) without difference in T and M. In the postoperative period (T2-T3), all parameters worsened, except T, with: WV (8.2% [-8,1-+20.0] [T3], p<0.05 vs T2), M (27.4 cm [20.0-37.0] [T3] vs 28.3 cm [20.5-39.0] [T2], p<0.05) et TTR (0.21 mg/l [0.09-0.36] [T3] vs. 0.27 mg/l [0.08-0.45] [T2], p<0.05). BMI was 22.9 [15.2-36.7] (T1) vs 22.9 [15.2-35.3] (T2), NS and 22.1 [15.0-34.9] (T3), p<0.05 vs (T2). CONCLUSION: The nutritional status in malignancy head and neck surgical patients seems to be best assessed by loss weight. It worsened mainly during the postoperative period even if a well-conducted EN was performed as defined by the French consensus conference.

Adult↗
PubMed2005

[Central and peripheral corneal pachymetry--standard evaluation with the Pentacam system].

BACKGROUND: Corneal thickness measurements are important in refractive surgery, for interpretation of IOP and in corneal diseases. The purpose of this study was to generate specific standard values for the Pentacam system and to investigate the influence of body size, body mass index, body weight, gender and refraction on central and peripheral corneal thickness for a more detailed characterization of the corneal anatomy. MATERIALS AND METHODS: The Pentacam system is based on a 180 degrees rotating computer-aided Scheimpflug camera, which generates reconstructions of the anterior segment from 12 to 50 single captures. The central corneal thickness was calculated from 25 single captures in both eyes of 182 normal Caucasian subjects (age: 18 - 83 years). The peripheral corneal thickness was measured within 3 mm distances at 0 degrees , 90 degrees , 180 degrees and 270 degrees . All subjects underwent an ophthalmological examination. Correlations between corneal thickness and body size, body mass index, body weight, gender and refraction were analyzed statistically by non-parametric tests. RESULTS: The mean central corneal thickness of all 364 eyes was 534 +/- 36 microm. Divided into sides it was the same, 534 +/- 36 microm, in the right and in the left eyes. The mean central corneal thickness for female subjects was 533 +/- 40 microm, for males it was 534 +/- 35 microm. Statistically there was no proof of any dependence of the central corneal thickness values on the sides, gender, age, height, body mass index (BMI) or refraction. However, there was a positive significant correlation between central corneal thickness and body weight. The peripheral corneal thickness values were lowest in the temporal and inferior areas and greatest in the superior and in the nasal areas. In the superior and in the nasal areas there was a statistically significant negative correlation between age and peripheral corneal thickness. CONCLUSIONS: The corneal thickness can be measured touchless with the Pentacam system. The central corneal thickness seems to be correlated with the body weight. Anatomical features lead to lower peripheral corneal thickness values in the temporal and inferior areas than in the nasal and superior areas. In the nasal and in the superior areas the corneal thickness seems to decrease with age. Further trials are necessary to confirm these findings and to evaluate the precision, reproducibilitiy and independence of investigators of the corneal pachymetry with the Pentacam system.

Adolescent↗
PubMed2005

[Differentiation between pupillary and ciliary block by means of the Orbscan II in a patient with angle block glaucoma].

BACKGROUND: A ciliary block is the rarer cause of angle block glaucoma. In order to choose the appropriate therapy, however, it is crucial to make the correct diagnosis. We report on a patient who suffered from recurrent increases of intraocular pressure while having renal dialysis. In his case the use of the Orbscan II made the differentiation between a pupillary and a ciliary block easier. CASE REPORT: In addition to basic ophthalmological examinations we performed a topographic analysis using Orbscan II before and after renal dialysis. Since intraocular pressure rise during renal dialysis had been proven, iridotomies on both eyes and an iridectomy on the left one had been performed before the patient was referred to us. In spite of these open shunts we measured an increase of intraocular pressure values of 10 to 12 mmHg directly after renal dialysis had been completed. The anterior chamber became shallower both at its centre and the periphery, thus its volume diminished analogously. Measurements by the Orbscan II showed that the lens swelled up and was displaced anteriorly as well, so that a ciliary block mechanism had to be assumed. CONCLUSIONS: Since the Orbscan II is capable of collecting topometric data of the cornea, anterior chamber and also lens, it is helpful in differentiating a pupillary from a ciliary block in angle block glaucoma.

Aged↗
PubMed2004

Central cholinergic functions in human amyloid precursor protein knock-in/presenilin-1 transgenic mice.

Alzheimer's disease is characterized by amyloid peptide formation and deposition, neurofibrillary tangles, central cholinergic dysfunction, and dementia; however, the relationship between these parameters is not well understood. We studied the effect of amyloid peptide formation and deposition on central cholinergic function in knock-in mice carrying the human amyloid precursor protein (APP) gene with the Swedish/London double mutation (APP-SL mice) which were crossbred with transgenic mice overexpressing normal (PS1wt) or mutated (M146L; PS1mut) human presenilin-1. APP-SLxPS1mut mice had increased levels of Abeta peptides at 10 months of age and amyloid plaques at 14 months of age while APP-SLxPS1wt mice did not have increased peptide levels and did not develop amyloid plaques. We used microdialysis in 15-27 months old mice to compare hippocampal acetylcholine (ACh) levels in the two mouse lines and found that extracellular ACh levels were slightly but significantly reduced in the APP-SLxPS1mut mice (-26%; P=0.044). Exploratory activity in the open field increased hippocampal ACh release by two-fold in both mouse lines; total and relative increases were not significantly different for the two strains under study. Similarly, infusion of scopolamine (1 microM) increased hippocampal ACh release to a similar extent (3-5-fold) in both groups. High-affinity choline uptake, a measure of the ACh turnover rate, was identical in both mouse lines. Neurons expressing choline acetyltransferase were increased in the septum of APP-SLxPS1mut mice (+26%; P=0.046). We conclude that amyloid peptide production causes a small decrease of extracellular ACh levels. The deposition of amyloid plaques, however, does not impair stimulated ACh release and proceeds without major changes of central cholinergic function.

Acetylcholine↗
PubMed2003

[Analysis of risk factors and comparison of heparin and hemodilution therapies for retinal artery occlusion].

No standards are available for the treatment of central retinal artery occlusion (CRAO). The aim of this study was to compare data about visual acuity development under heparin treatment with those from hemodilution. Data on 139 patients suffering from CRAO between 1991 and 2000 were examined retrospectively. Risk factors were listed. Therapies were compared in 38 of these patients, 23 of whom received full heparinization and 15 of whom received hemodilution. Many risk factors were shown. Neither therapy showed serious complications. Visual acuity improved significantly, by three or more lines, in five of 23 patients (21.7%) under full heparinization and six of 15 patients (40%) receiving hemodilution. Differences were not significant. For ethical reasons, the normal cause of disease in these patients cannot be studied and is still unknown. Because of many vascular risk factors, we recommend adapted therapies. Treatments should be examined in controlled studies.

Adolescent↗
PubMed2003

Comparison of remifentanil and alfentanil during anaesthesia for patients undergoing direct laryngoscopy without intubation.

BACKGROUND: Remifentanil and alfentanil are opioids often used during direct laryngoscopy (DL). This prospective, randomized study compared these agents with respect to haemodynamic and Bispectral Index (BIS) responses, glottic visualization, and rapidity of recovery (spontaneous ventilation, eye opening) in DL without intubation. METHODS: A total of 60 patients undergoing DL were randomized into two groups: remifentanil (R) and alfentanil (A). Anaesthesia was induced with propofol 2.5 mg kg(-1) and the opioid was administered 1 min later (R=2 microg kg(-1) or A=30 microg kg(-1) over 30 s). DL was commenced 1 min after (corresponding to 3 min after the beginning of induction). Glottic visualization, opioid and/or propofol re-injection, spontaneous ventilation recovery, and eye opening were recorded. RESULTS: During DL, mean arterial pressure (MAP) increased by 6% in the R group vs 20% in the A group (P<0.05) when compared with post-induction values without affecting heart rate or BIS. No significant difference was observed between groups with respect to glottic exposure, opioid and/or propofol re-injection, and spontaneous ventilation recovery (mean (SEM) 3.8 (0.6) min, R group vs 3.2 (0.7) min, A group, NS) or eye opening (7.1 (1.1) min, R group vs 7.4 (0.9) min, A group, NS). Thirty minutes after postanaesthesia care unit (PACU) admission, MAP returned to its pre-induction value in the R group (104 (3) vs 109 (3) at baseline, NS), whereas in the A group MAP remained significantly lower at this time point (96 (4) vs 106 (3) at baseline, P<0.05). CONCLUSION: This study showed that only remifentanil prevented MAP increase without adverse effects such as bradycardia during DL, and prevented MAP decrease 30 min after PACU admission.

Adult↗
PubMed2002

[Color vision defects in patients with arterial hypertension].

PURPOSE: In view of the generally impaired vascular condition in patients with arterial hypertension, we were interested in their colour perception. METHODS: Patients (n = 35, f:m = 14:21, mean age 52 +/- 11 years) with arterial hypertension without damage in end-organs and normal subjects (n = 62, :m = 28:34, mean age 49 +/- 9 years) as a control group were included in this study. Exclusion criteria were other systemic or ophthalmological diseases. In addition to the ophthalmological examinations (visual acuity, refraction, intraocular pressure, slit lamp and fundus examination) the colour vision was tested by the colour arrangement test Roth 28-hue (E) desaturated under standard conditions: The background used was black cardboard, illuminated by two Osram fluorescent lamps (L36 W/12LDL Daylight) providing 2000 lux at the test table. RESULTS: The ophthalmological examinations in the patients and in the control group were normal. The patients with arterial hypertension had a significantly higher mean error score (median +/- mean absolute deviation 150 +/- 56, Mann-Witney U-test: p < 0.001) in the colour arrangement test than the control group (median +/- mean absolute deviation 72 +/- 53.4). A particular colour axis (blue-yellow or red-green) was not found. CONCLUSION: Although the ophthalmological examinations were normal we found a disturbed colour vision in patients with arterial hypertension. This has to be taken into account in colour vision testing to avoid diagnostic interferences between specifically ocular diseases (e.g. glaucoma) and arterial hypertension.

Adult↗
PubMed2002

Neuronal overexpression of "readthrough" acetylcholinesterase is associated with antisense-suppressible behavioral impairments.

Molecular origin(s) of the diverse behavioral responses to anticholinesterases were explored in behaviorally impaired transgenic (Tg) FVB/N mice expressing synaptic human acetylcholinesterase (hAChE-S). Untreated hAChE-S Tg, unlike naïve FVB/N mice, presented variably intense neuronal overexpression of the alternatively spliced, stress-induced mouse "readthrough" mAChE-R mRNA. Both strains displayed similar diurnal patterns of locomotor activity that were impaired 3 days after a day-to-night switch. However, hAChE-S Tg, but not FVB/N mice responded to the circadian switch with irregular, diverse bursts of increased locomotor activity. In social recognition tests, controls displayed short-term recognition, reflected by decreased exploration of a familiar, compared to a novel juvenile conspecific as well as inverse correlation between social recognition and cortical and hippocampal AChE specific activities. In contrast, transgenics presented poor recognition, retrievable by tetrahydroaminoacridine (tacrine, 1.5 mg kg(-1)). Tacrine's effect was short-lived (24 h) suppression of the abnormal social recognition pattern in transgenics. Efficacy of antisense treatment was directly correlated with AChE-R levels and the severity of the impaired phenotype, being most apparent in transgenics presenting highly abnormal pre-treatment behavior. These findings demonstrate that neuronal AChE-R overproduction is involved in various behavioral impairments and anticholinesterase responses, and point to the antisense strategy as a potential approach for re-establishing cholinergic balance.

Acetylcholinesterase↗
PubMed2002

High occurrence rate of glaucoma among patients with Alzheimer's disease.

The purpose of the current study was to reveal the occurrence rate of glaucoma among patients with Alzheimer's disease (AD). All 112 patients of four nursing homes in Upper Bavaria, Germany, who met the diagnostic criteria of probable AD, were incorporated into the study. Visual field defects and/or optic disc cupping compatible with the diagnosis of glaucoma were found in 29 out of 112 patients with AD (25.9%). When compared to a control group (5.2%) and to the prevalence of glaucoma in western countries revealed in a number of glaucoma surveys (2.6-4.7%), patients with AD may have a significantly increased occurrence rate of glaucoma. In addition, ocular hypertension with normal visual fields and normal optic nerve heads was not found in patients with AD. The prevalence of ocular hypertension in the control group was 7.8% and parallels previous surveys. Therefore, we assume that the optic nerve seems to be less resistant to elevated intraocular pressure levels in AD patients.

Aged↗
PubMed2001

Compensatory mechanisms enhance hippocampal acetylcholine release in transgenic mice expressing human acetylcholinesterase.

Central cholinergic neurotransmission was studied in learning-impaired transgenic mice expressing human acetylcholinesterase (hAChE-Tg). Total catalytic activity of AChE was approximately twofold higher in synaptosomes from hippocampus, striatum and cortex of hAChE-Tg mice as compared with controls (FVB/N mice). Extracellular acetylcholine (ACh) levels in the hippocampus, monitored by microdialysis in the absence or presence of 10(-8)-10(-3) M neostigmine in the perfusion fluid, were indistinguishable in freely moving control and hAChE-Tg mice. Muscarinic receptor functions were unchanged as indicated by similar effects of scopolamine on ACh release and of carbachol on inositol phosphate formation. However, when the mice were anaesthetized with halothane (0.8 vol. %), hippocampal ACh reached significantly lower levels in AChE-Tg mice as compared with controls. Also, the high-affinity choline uptake (HACU) in hippocampal synaptosomes from awake hAChE-Tg mice was accelerated but was reduced by halothane anaesthesia. Moreover, hAChE-Tg mice displayed increased motor activity in novel but not in familiar environment and presented reduced anxiety in the elevated plus-maze test. Systemic application of a low dose of physostigmine (100 microgram/kg i.p.) normalized all of the enhanced parameters in hAChE-Tg mice: spontaneous motor activity, hippocampal ACh efflux and hippocampal HACU, attributing these parameters to the hypocholinergic state due to excessive AChE activity. We conclude that, in hAChE-Tg mice, hippocampal ACh release is up-regulated in response to external stimuli thereby facilitating cholinergic neurotransmission. Such compensatory phenomena most likely play important roles in counteracting functional deficits in mammals with central cholinergic dysfunctions.

Acetylcholine↗