Efficient removal of bacteria from aqueous media with kaolinite and diatomaceous earth products.

AIMS: To understand the relationships between physical and chemical parameters of kaolinite and diatomaceous earth, and their capacities to remove bacteria from aqueous media. To determine the optimal aqueous media parameters for use of these products in water disinfection processes. METHODS AND RESULTS: Seven kaolinite and three diatomaceous earth products were evaluated. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus megaterium were used as proxy for bacterial pathogens. Fully calcined kaolin and amorphous diatomaceous earth demonstrated the highest extent and consistency in removing all the bacteria. The removal depended on ionic strength and pH of aqueous media with 100 mmol l-1 pH 5 potassium hydrogen phthalate buffer revealing the highest (2 log per gram) extent of the removal. Al3+ cations enhanced sorption up to 4 log per gram. CONCLUSIONS: Calcined kaolin and amorphous diatomaceous earth are excellent sorbents for bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Fully calcined kaolin and amorphous diatomaceous earth are perspective tools for wastewater and water disinfection against waterborne bacterial pathogens.

[Concept of a pressure-controlled microstent for glaucoma therapy]. / Konzept eines druckgesteuerten Mikrostents für die Glaukomtherapie.

A pressure-controlled microstent could permanently normalise the intraocular pressure (IOP) for open-angle glaucoma therapy by drainage into the suprachoroidal space. The complex requirements demand new technical solutions as well as an improved understanding of specific cell biological processes at the implant's surface to develop effective local drug delivery (LDD) concepts and surface modifications. Fluid mechanical requirements were derived from physiological data and the analysis of commercial glaucoma implants. The technological basics for the production of suitable structures are refined ultra-short pulse laser technology and 2-photon polymerisation (2PP). All known glaucoma implants induce unwanted cell proliferation resulting in a loss of function. It is assumed that the activity of fibroblasts is low in the suprachoroidal space. However, it was seen that LDD concepts are required to control cell proliferation. Fibroblasts from sclera and choroidea were isolated und cultured as the most relevant cell types for in vitro investigation. Potential materials and drugs were investigated by cell viability tests for biocompatibility or suppression of cell viability. The fluid mechanical analysis leads to smallest stent lumina (ID = 50 µm) at anatomically suitable implant lengths (7 - 10 mm). Only pressure control can manage the individual conditions with changing IOP. Finite element analysis of valves showed the need for highly flexible structures. This can be achieved by combining basic structures with micromechanically active valves added by 2PP. The potential materials show perfect in vitro and in vivo biocompatibility. Ormocers which are best suited for 2PP are also highly biocompatible. The selected drugs paclitaxel and triamcinolon acetonide open a wide therapeutic window to impair fibroblast growth. The surgical procedure was established by implantation of prototypes in rabbit eyes, connecting the anterior chamber with the suprachoroidal space. Highly flexible implants are required for correct placement within the eye. The new concept of the microstent combines biomechanical approaches, technologies for microfabrication and current LDD concepts and opens new perspectives for glaucoma therapy.

Cross-linking of brain endothelial intercellular adhesion molecule (ICAM)-1 induces association of ICAM-1 with detergent-insoluble cytoskeletal fraction.

Intercellular adhesion molecule (ICAM)-1 plays a vital role in the process of leukocyte transmigration through endothelial cell (EC) barriers and has been shown to mediate signal transduction events in ECs induced either by its cross-linking or by the binding of T lymphocytes. Immunoblotting of ICAM-1 of Triton X-100 detergent fractions demonstrated that the majority of ICAM-1 was contained within the detergent-soluble fraction (noncytoskeletal associated) under basal conditions. After cross-linking of endothelial ICAM-1 with monoclonal antibody or coculture with T lymphocytes, EC ICAM-1 was observed to partition with a Triton X-100-insoluble (cytoskeletal associated) fraction in a dose- and time-dependent manner. Redistribution of ICAM-1 was specific, inasmuch as no association with the Triton X-100-insoluble fraction was observed after cross-linking of vascular cell adhesion molecule-1, nor did cross-linking of ICAM-1 result in a redistribution of the platelet and EC adhesion molecule. ICAM-1 association with the endothelial cytoskeleton after cross-linking was unaffected after treatment of the cells with cytochalasin D, C3-transferase, removal of extracellular calcium ions, or chelation of intracellular calcium ions. These data show that ICAM-1 colocalizes with the endothelial cytoskeleton and associates with a detergent-insoluble fraction after cross-linking.

Magnetic resonance angiography in 140 neuropediatric patients.

Three-dimensional magnetic resonance angiography (MRA) is a noninvasive technique that images the intracranial arterial vasculature without contrast agents. The suitability of MRA was evaluated for routine use and all children were prospectively studied with conventional MR imaging and time off flight MRA (FISP3D). All MR studies were performed on a 1.5 T-MRA system using a circularly polarized head coil. The study comprised 140 children, ages 3 weeks to 18 years, with different neuropediatric diseases. Major cervical and intracranial arteries were visualized in all age groups. Smaller branches of the supratentorial arteries were identified inconstantly and the number of arteries visualized increased up to the age of 6 years. Sixty-seven children (47%) had normal intracranial vasculature. MRA demonstrated anatomic variations in 21 patients (15%). Twenty-two of 32 children with congenital malformations demonstrated abnormalities of the intracranial vasculature. The diagnostic value of MRA was confirmed in 11 of 12 patients after neonatal stroke and in 3 of 10 children after stroke at older ages. Seven of 18 children with acute hemorrhage demonstrated arteriovenous malformations or an aneurysm on MRA. The correlation with digital subtraction angiographic findings was established in 13 patients. In 9 of 13 children with brain tumor, MRA proved to be diagnostically valuable. MRA proved to be of particular value in the evaluation of the carotid artery following extracorporeal membrane oxygenation therapy. MRA can be used in children of all age groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Development of a glaucoma microstent with drainage into the suprachoroidal space: fluid mechanical model approach]. / Entwicklung eines Glaukommikrostents mit Drainage in den suprachoroidalen Raum: Fluidmechanische Modellbetrachtungen.

BACKGROUND: The purpose of this study was to develop a microstent with valve function, which normalizes the intraocular pressure (IOP) and drains into the suprachoroidal space. In comparison to the subconjunctival space the suprachoroidal space is attributed with less fibroblast colonization and activity. METHODS: Different glaucoma drainage devices were idealized as tubes and the flow rates were calculated according to Hagen-Poiseuille. The dimensions of the ideal glaucoma implant were modified with respect to an aqueous humor production of 2 microl/min and the different outflow pathways. Specific components of glaucoma drainage devices at the inlet and outlet were not included. RESULTS: The volume flow calculation of the tested glaucoma implants showed that the dimensions of all lumina were too large to prevent postoperative hypotension. A maximum inner tube diameter of 53 microm was calculated for drainage into the suprachoroidal space based on an intra-ocular pressure (IOP) of 20 mmHg. CONCLUSION: The glaucoma microstent has to guarantee an aqueous humor flow for physiological IOP. An increase of IOP has to be regulated to physiological pressure conditions by the microvalve.

[Pyridoxine-dependent seizures. Remarks on clinical variability and pathogenesis]. / Pyridoxinabhängige Krampfanfälle. Bemerkungen zur klinischen Variabilität und pathogenese.

The clinical variability of pyridoxine dependent seizures is greater than mentioned in most textbooks. The seizures can start during the first days of life, or later during the first year. Frequently they are therapy-resistant, but seizure free periods of several weeks duration can be achieved with anticonvulsants in some patients. The response to the injection of pyridoxine can be delayed. A trial with daily oral administration of pyridoxine is often more suitable than a single injection.

[Unusual symptoms in brain tumors in childhood]. / Ungewöhnliche Symptome bei Hirntumoren im Kindesalter.

Headache, nausea, ataxia and diplopia are leading symptoms of brain tumors in children. We report of 3 children with unusual symptoms and findings. Patient 1 complained of occasional headaches. Clinical examination showed neurological deficits and uveitis. Lumbar puncture revealed a pleocytosis and the oligoclonal banding study was positive. Cranial MRI demonstrated an enlarged pons. Under treatment with cortisone a clinical improvement was seen, but no change of the abnormalities in MRI. Several weeks later a biopsy was performed, which verified an astrozytoma. The second child developed a torticollis, following an accident, and later a refractory constipation was noted. A clinical evaluation was within normal limits. Several weeks later the patient complained of bladder disturbances. Patient 3 had a lateralized tic disorder without any neurologic deficits. CT showed an infratentorial tumor above the 4th ventricle. The tic disorder vanished only after the tumor was completely resected in the second operation. The reported cases demonstrate the fact that in an individual patient a brain tumor can cause unusual symptoms and findings which do not make the diagnosis obvious.

Long-term follow up of children with head injuries-classified as "good recovery" using the Glasgow Outcome Scale: neurological, neuropsychological and magnetic resonance imaging results.

UNLABELLED: The primary issues addressed in this study were: (1) determination of the significance of the classification "good outcome" utilizing the Glasgow Outcome Scale (GOS) in children at least 1 year after brain injury; (2) detection of residual lesions of brain parenchyma in these children upon follow up MRI scans; and (3) detection of relationships between neuropsychological test performance and MRI results. Selection criteria included children 6-15 years of age at the time of testing who received an initial CT scan at the time of their head injury and who had been injured at least 12 months prior to the follow up test. Only children who did not demonstrate neurological disability at the time of follow up examination were selected. The children showed a status of "good outcome" as defined by the GOS. Neurological examination, neuropsychological tests and an MRI were done. The test results of 59 patients were compared to those of a matched control group. Children, after receiving head injuries, showed significantly poorer results with respect to cognitive, motor and fine motor skills. Of all MRI-scans 66% revealed pathological findings. Cortical lesions were detected on MRI in 14% of cases; subcortical injuries were detected in 12% and, deep white matter lesions in 31%. Furthermore, corpus callosum damage was observed in 26% of cases. Pathological MRI findings were also observed in children with mild head injuries. All of the children with normal MRI findings showed abilities comparable to those of children in the control group. Patients with cortical lesions exhibited only motor deficits, whereas motor and cognitive deficits were seen in patients with deep white matter lesions. Children with multiple lesions demonstrated test results in all variables 1 to 2 standard deviations below those of the control group. CONCLUSION: Children suffering a brain injury who 1 year later are classified within the "good outcome" group according to the Glasgow Outcome Scale often have significant morphological and functional brain deficits.

GM-2 gangliosidosis (Sandhoff's disease): two year follow-up by MRI.

Two children with GM-2 gangliosidosis type 0 (Sandhoff's disease) followed up by MRI at 1.5 Tesla for 1.8 years are reported. One was presymptomatic at the first MRI examination. As her neurological status deteriorated, MRI showed low signal in bilaterally, on T2-weighted images the white matter with involvement of the optic radiations. In the second, MRI correlated well with the clinical progression of the disease, showing in the different stages involvement of thalamus and basal ganglia. There was no contrast enhancement and the grey matter remained normal.

MRI of encephalitis in children: comparison of CT and MRI in the acute stage with long-term follow-up.

We examined 14 children aged 28 days to 12.7 years with encephalitis by CT or MRI. Of the patients examined by CT 58% had a normal first scan, whereas all MRI investigations demonstrated abnormalities. The clinical features correlated with several MRI investigations. On MRI herpes (HSV) encephalitis started in the medial temporal lobe and encephalomalacia developed within a few weeks. All patients had a follow-up examination 0.5 to 6.5 years after the acute phase. MRI revealed abnormalities in 13 of the 14 children; one boy, with lesions in only the white matter, had a normal follow-up MRI. Even with immediate, optimal therapy the children demonstrated severe parenchymal abnormalities. Signal abnormalities seen in the acute phase of the disease were likely to persist. In children with HSV encephalitis atypical lesions in different areas were seen.

Results of parenchymal and angiographic magnetic resonance imaging and neuropsychological testing of children after stroke as neonates.

We describe the long-term follow up of infants after neonatal stroke of the middle cerebral artery (MCA). Stroke was diagnosed by CT scan in eight full-term neonates. Three dimensional (volume) magnetic resonance angiography (MRA) is a noninvasive technique that images the arterial vessels without contrast agents. All patients, aged from 1.5 to 8.4 years, were investigated by MRI and MRA and by neuropsychological tests. Cognitive development was investigated by intelligence tests, tests of visual perception, motor and language development. Out of the eight patients, seven had a retarded mental and motor development, and 50% of the children were treated for epilepsy. Seven patients had a spastic hemiparesis. Seven out of eight children showed major cognitive deficits. In all patients, MRI revealed clear parenchymal defects with variable distribution patterns. MRA studies showed abnormalities corresponding to the expected vascular distribution. Children with complications at delivery, with seizures, and an interruption of the main stem of MCA as demonstrated on MRA had the least favourable long-term follow up prognosis with severe cognitive delays.

Neurological findings in newborn infants after extracorporeal membrane oxygenation, with special reference to the EEG.

Seventeen newborn infants were treated with extracorporeal membrane oxygenation (ECMO). Two died shortly after the start of ECMO due to the underlying disease, two died later in the course due to a lack of recovery of lung function and two others died weeks after ECMO from renal damage and a cardiac defect. Of the survivors, nine are developing normally (aged between one and four years) and two are severely disabled because of infarctions of the left hemisphere, acquired before and after ECMO. Intermittent-discontinuous EEGs did not indicate a poor prognosis if normalization of the EEG occurred within seven days. However, infarcted areas on ultrasonography, persistent EEG changes or deteriorating findings indicated disability or early death.

[Hemimegalencephaly. Therapy with hemispherectomy]. / Hemimegalenzephalie. Therapie mit Hemisphärektomie.

Hemimegalencephaly is associated with a poor clinical course characterized by intractable seizures and severe encephalopathy. We present a case report of a girl with hemimegalencephaly. At the age of 9 month hemispherectomy was undertaken to preserve function of the other hemisphere. MRI and histologic examinations showed characteristic dysplastic malformations. Follow-up and the complications are described.