ω-Transaminases for the amination of functionalised cyclic ketones.

The potential of a number of enantiocomplementary ω-transaminases (ω-TAms) in the amination of cyclic ketones has been investigated. After a preliminary screening of several compounds with increasing complexity, different approaches to shift the equilibrium of the reaction to the amine products were studied, and reaction conditions (temperature and pH) optimised. Interestingly, 2-propylamine as an amine donor was tolerated by all five selected ω-TAms, and therefore used in further experiments. Due to the higher conversions observed and interest in chiral amines studies then focused on the amination of α-tetralone and 2-methylcyclohexanone. Both ketones were aminated to give the corresponding amine with at least one of the employed enzymes. Moreover, the amination of 2-methylcyclohexanone was investigated in more detail due to the different stereoselectivities observed with TAms used. The highest yields and stereoselectivities were obtained using the ω-TAm from Chromobacterium violaceum (CV-TAm), producing 2-methylcyclohexylamine with complete stereoselectivity at the (1S)-amine position and up to 24 : 1 selectivity for the cis : trans [(1S,2R) : (1S,2S)] isomer.

[Testing of vaccines. The challenge of testing complex combination vaccines]. / Prüfung von Impfstoffen. Die Herausforderung der Prüfung komplexer Kombinationsimpfstoffe.

Vaccines are biologicals. This group of medicinal products is produced with a predefined variability based on the biological starting materials used. Vaccines are subject to official control authority batch release performed by the Paul-Ehrlich-Institut (PEI). To release batches to the market, experimental testing has to be conducted by an official medicines control laboratory as the PEI. It is the aim of this independent testing to demonstrate the conformity of quality criteria with conditions set in the marketing authorization for each lot produced. The testing is performed on the basis of vaccine specific batch release guideline and due to the difficult and time consuming testing procedures often run in parallel with manufacturers testing. If test results comply with the predefined criteria, the lot in question is released. This article describes the challenge of official control authority batch release testing of two complex combination vaccines.

DE-cadherin, a core component of the adherens junction complex modifies subcellular localization of the Drosophila gap junction protein innexin2.

The Drosophila innexin multigene family of gap junction encoding proteins consists of eight family members whose function in epithelial morphogenesis is mostly unknown. We have recently shown that innexin2 plays a crucial role in the organization of embryonic epithelia. Innexin2 protein accumulates in the epidermis in the apico-lateral membrane domain and colocalizes with core proteins of adherens junctions, such as DE-cadherin and Armadillo, the ss -catenin homolog. Innexin2 localization is altered in both armadillo and DE-cadherin mutants Biochemical interaction studies point to a direct interaction of DE-cadherin and Armadillo with innexin2 suggesting a close link between gap junction and adherens junction biogenesis. We have used the Drosophila Schneider cell tissue culture system to further study the interaction of innexin2 with DE-cadherin. Our results provide evidence that DE-cadherin may be a key component to control trafficking, and localization of Innexin2 to the plasma membrane.

Classical conditioning of feeding in Aplysia: I. Behavioral analysis.

A training protocol was developed to classically condition feeding behavior in Aplysia californica using tactile stimulation of the lips as the conditional stimulus (CS) and food as the unconditional stimulus (US). Paired training induced a greater increase in the number of bites to the CS than unpaired training or US-only stimulation. Memory for classical conditioning was retained for at least 24 hr. The organization of the reinforcement pathway that supports classical conditioning was analyzed in additional behavioral experiments. No evidence was found for the contribution to appetitive reinforcement of US-mediating pathways originating in the lips of the animals. Bilateral lesions of the anterior branch of the esophageal nerve, which innervates parts of the foregut, however, were found to attenuate classical conditioning. Thus, it appears likely that reinforcement during appetitive classical conditioning of feeding was mediated by afferent pathways that originate in the foregut. The companion paper () describes two neurophysiological correlates of the classical conditioning.

Classical conditioning of feeding in Aplysia: II. Neurophysiological correlates.

Feeding behavior in Aplysia californica can be classically conditioned using tactile stimulation of the lips as conditional stimulus (CS) and food as unconditional stimulus (US) [ (companion paper)]. Conditioning resulted in an increase in the number of CS-evoked bites that persisted for at least 24 hr after training. In this study, neurophysiological correlates of classical conditioning training were identified and characterized in an in vitro preparation of the cerebral and buccal ganglia. Stimulation of a lip nerve (AT(4)), which mediates mechanosensory information, resulted in a greater number of buccal motor patterns (BMPs) in ganglia isolated from animals that had received paired training than in ganglia from control animals. The majority of the evoked BMPs were classified as ingestion-like patterns. Intracellular recordings from pattern-initiating neuron B31/32 revealed that stimulation of AT(4) evoked greater excitatory input in B31/32 in preparations from animals that had received paired training than from control animals. In contrast, excitatory input to buccal neuron B4/5 in response to stimulation of AT(4) was not significantly increased by paired training. Moreover, correlates of classical conditioning were specific to stimulation of AT(4). The number of spontaneously occurring BMPs and the intrinsic properties of two buccal neurons (B4/5 and B31/32) did not differ between groups. These results suggest that appetitive classical conditioning of feeding resulted in the pairing-specific strengthening of the polysynaptic pathway between afferent fibers and pattern-initiating neurons of the buccal central pattern generator.

[Transpupillary thermotherapy (TTT) for uveal melanomas. Long term results of a single TTT with an adapter for a conventional infrared laser]. / Transpupillare Thermotherapie (TTT) von Aderhautmelanomen. Langzeitergebnisse einer alleinigen TTT mit einem Adapter für einen konventionellen Infrarotlaser.

BACKGROUND: An increasing number of orbital recurrences after TTT have been reported; the aim of our paper was to present our long-term results after a maximum follow-up of 8 years and 2 months. PATIENTS AND METHOD: Among 18 eyes, 10 tumors were classified as small, and 8 as medium sized (with a maximum prominence of 5.6 mm): 5 melanomas had a juxtapapillary location, 6 a macular (or juxtamacular) location, and 7 were located in the midperiphery of the fundus. RESULTS: After a median follow-up of 7 years in seven tumors a complete regression (scar formation) could be achieved, and in six a partial regression (with a maximum residual prominence of 2.9 mm) could be seen. In three patients a recurrence was treated either by another TTT or a Ruthenium-106 plaque; in another two recurrences, enucleation had to be performed. In none of the cases has an orbital recurrence occurred so far. CONCLUSION: To prevent recurrences, adequate technique and appropriate selection of patients are mandatory in our opinion (no tumors higher than 3 mm). The higher the tumor prominence, the greater the chance of recurrences. Amelanotic melanomas and macular melanomas seem to respond poorly to thermotherapy.

Magnetic resonance imaging cerebral abnormalities and neuropsychologic test performance in elderly hypertensive subjects. A case-control study.

OBJECTIVE: To search for a morphologic basis of cognitive impairment possibly associated with arterial hypertension using magnetic resonance imaging and a demanding neuropsychologic test battery. DESIGN: Case-control comparison with age, length of education, presence of diabetes, and presence of cardiac disease as matching criteria. SETTING: Austrian Stroke Prevention Study. SUBJECTS: A total of 89 hypertensive subjects and 89 control subjects from a subset of 272 volunteers with no neurologic symptoms undergoing extensive diagnostic workup in a large-scale stroke prevention study among randomly selected elderly community members. MAIN OUTCOME MEASURES: Focal brain abnormalities and size of ventricles and cortical sulci as assessed by magnetic resonance imaging and neuropsychological test scores. RESULTS: Hypertensive subjects more commonly showed areas of white matter hyperintensity and moderately severe ventricular enlargement compared with controls. While no differences were noted between the investigational groups in test results of memory capacity and conceptualization, hypertensive subjects tended to perform worse when assessed for attentional and visuopractical skills. These differences became significant when comparing the brain-damaged subsets of patients and controls with their counterparts without cerebral changes. The pattern and extent of neuropsychologic deficits was similar in hypertensive and normotensive subjects with abnormal magnetic resonance imaging scans. CONCLUSION: Our data strongly suggest the high rate of brain abnormalities among hypertensive subjects as the cause of their subtle neuropsychological dysfunction.

Magnetic resonance imaging signal hyperintensities in the deep and subcortical white matter. A comparative study between stroke patients and normal volunteers.

Mixed population studies suggest a relationship between deep and subcortical white matter hyperintensities on magnetic resonance imaging and cerebrovascular disease. To further clarify this issue we compared the prevalence and extent of such signal abnormalities between a group of 133 consecutive stroke patients (mean age, 54.7 +/- 16.7 years) and 101 normal volunteers (mean age, 54.7 +/- 13.1 years). Diabetes and cardiac disease were significantly more common in patients than in normal subjects. Prevalence rates of clinically silent lesions were 44% and 47.5%, respectively. Beginning confluent and confluent foci were seen in 19.5% of patients, but in only 7.5% of normal subjects. Significant univariate correlations were found for the presence and extent of lesions with age, diabetes, cardiac disease, severity of extracranial carotid arteriosclerosis, and arterial hypertension, but not with the diagnosis of stroke or the type of brain infarction. Multivariate regression analysis established age and diabetes mellitus as the only independent predictors of white matter damage. We conclude that more extensive white matter abnormalities in stroke patients stem from their higher rate of cerebrovascular risk factors but are unrelated to the occurrence of ischemic attacks per se.

Criteria for an increased specificity of MRI interpretation in elderly subjects with suspected multiple sclerosis.

We reviewed the MRIs of 49 asymptomatic volunteers (age range, 31 to 77 years) and of 50 MS patients (age range, 14 to 63) for areas of increased signal (AIS) and features discriminating MS lesions from lesions seen with normal aging. We obtained optimal specificity of MRI interpretation (100%) if we required at least two of the following three AIS features--size greater than or equal to 6 mm, abutting ventricular bodies, infratentorial location--for a positive MRI diagnosis of MS. Applying these criteria to the MRIs of elderly patients with suspected MS should significantly improve specificity (p less than 0.001) over current quantitative criteria (at least three AIS greater than or equal to 3 mm) without significantly decreasing sensitivity.

Assessment of MRI criteria for a diagnosis of MS.

To test the reliability of four previously proposed MRI criteria for the diagnosis of MS, we reviewed 1,500 consecutive brain scans for the presence, number, size, and location of areas of increased signal (AIS) on proton-density and T2-weighted images, unaware of the patients' clinical presentations and ages. This series included 134 subjects with a clinical diagnosis of MS. Relying exclusively on the presence of at least three or four AIS for a positive diagnosis of MS resulted in high sensitivity (90% for three AIS and 87% for four) but inadequate specificity (71% for three AIS and 74% for four) and positive predictive value (23% for three AIS and 25% for four). If one of these lesions was required to border the lateral ventricles, specificity was 92% and positive predictive value was 50% at a sensitivity of 87%. Using the Fazekas criteria (at least three AIS and two of the following features: abutting body of lateral ventricles, infratentorial lesion location, and size > 5 mm) led to a further highly significant improvement of specificity (96%; p = 0.0000) and increase of the positive predictive value (65%) at the expense of a less significant decrease in sensitivity (81%; p < 0.01).

Superficial siderosis of the spinal cord: a rare cause of myelopathy diagnosed by MRI.

Repeated bleeding into CSF spaces may cause superficial siderosis with progressive neurologic impairment. The unique physical properties of MRI provide a basis for the in vivo diagnosis of this entity.

Pathologic correlates of incidental MRI white matter signal hyperintensities.

We related the histopathologic changes associated with incidental white matter signal hyperintensities on MRIs from 11 elderly patients (age range, 52 to 82 years) to a descriptive classification for such abnormalities. Punctate, early confluent, and confluent white matter hyperintensities corresponded to increasing severity of ischemic tissue damage, ranging from mild perivascular alterations to large areas with variable loss of fibers, multiple small cavitations, and marked arteriolosclerosis. Microcystic infarcts and patchy rarefaction of myelin were also characteristic for irregular periventricular high signal intensity. Hyperintense periventricular caps and a smooth halo, however, were of nonischemic origin and constituted areas of demyelination associated with subependymal gliosis and discontinuity of the ependymal lining. Based on these findings, our classification appears to reflect both the different etiologies and severities of incidental MRI signal abnormalities, if it is modified to treat irregular periventricular and confluent deep white matter hyperintensities together.

The Mattis Dementia Rating Scale: normative data from 1,001 healthy volunteers.

We administered the Mattis Dementia Rating Scale (MDRS) to 1,001 healthy volunteers, aged 50 to 80 years, randomly selected from our community. Multivariate regression analysis revealed educational level (p = 0.000004) and age (p = 0.00001), but no other sociodemographic or risk factors for stroke, to be significantly associated with the MDRS score. The age- and education-specific lowest quintile cutoff scores ranged from 140 in subjects aged 50 to 59 years with at least college experience to 130 in subjects aged 70 to 80 years with only 4 to 9 years of schooling. These percentile distributions obtained for decades of age and different levels of education should be useful reference values for clinicians and investigators when applying the MDRS to assess cognitive functioning.

Brain magnetic resonance imaging in coronary artery bypass grafts: a pre- and postoperative assessment.

We undertook a study to determine (1) the frequency and prognostic significance of preexisting MRI brain abnormalities in patients undergoing coronary artery bypass grafts (CABG) and (2) whether MRI can detect surgery-related brain damage in 31 neurologically asymptomatic CABG patients (mean age, 61.0 +/- 6.6 years). MRIs were performed within 7 days before and 8 to 17 days after surgery. When we compared the preoperative images with those of 31 age- and risk factor-matched neurologically asymptomatic controls free of cardiac disease (mean age, 60.3 +/- 6.1 years), higher rates of thromboembolic infarcts (16% versus 0%), lacunes (58.1% versus 32.3%), and brainstem lesions (22.6% versus 3.8%) were noted. Subjective rating demonstrated significantly larger ventricles in patients than in controls (p = 0.002). CABG candidates also had significantly increased ventricular-to-intracranial cavity ratios (VICR) as determined by semiquantitative volumetric measurements (6.9 +/- 2.5% versus 4.9 +/- 1.6%; p = 0.0004). Eleven patients had postsurgical complications, with eight having symptoms consistent with diffuse encephalopathy. The only MRI finding that separated encephalopathic from complication-free patients was ventricular size (VICR 9.0 +/- 2.5% versus 4.9 +/- 1.6%; p = 0.006). This difference remained statistically significant after adjustment for the effects of age (p = 0.04). Postoperative MRI consistently failed to demonstrate surgery-related brain damage responsible for the encephalopathy.

Hyperthermia inhibits proliferation and stimulates the expression of differentiation markers in cultured thyroid carcinoma cells.

In the last two decades hyperthermia has increasingly been used as adjuvant therapy for the treatment of malignant tumours. The effects of heat were therefore analysed on cultured thyroid epithelial cells from patients with thyroid cancer and from non-malignant control thyroids. Purified thyroid cells were subjected to heat treatment (42.5 degrees C; 90 min). After 24 h [3H]thymidine incorporation was assessed and the expression of heat shock protein 72 (hsp72), thyroglobulin, CD54 (ICAM-I) and MHC class-Il were analysed by immunofluorescence staining. Additionally mRNA analysis was performed by Northern blotting. Whereas hyperthermia inhibited the proliferation of thyroid cells, it significantly increased the expression of hsp72, thyroglobulin, CD54 and HLA-DR (P < 0.05). Our results suggest that hyperthermia may suppress growth while supporting differentiation and immune recognition in thyroid cancer. It may therefore be beneficial as a treatment for patients with thyroid carcinoma.

Does cerebrovascular insufficiency contribute to Alzheimer's disease?

The differential diagnosis of vascular dementia (VD) and Alzheimer's disease (AD) based on clinical assessment and neuropsychologic testing is still associated with a relatively high degree of inaccuracy compared to neuropathology standards. This is especially true in the identification of mixed forms between AD and VD. The present study investigates the potential of neuroimaging methods in providing additional information in dealing with this problem. Magnetic resonance imaging (MRI) of the brain identified a relatively high percentage (39%) of patients with AD (with ischemia scores of 4 and less) with basal ganglia hyperintensities and also demonstrated basal ganglia lacunae and infarcts in some of these patients. These findings indicate that in these cases a vascular component, consistent with the mixed form of dementia, may contribute to the etiology of the disease. These findings also underscore the clinical usefulness of MRI in the further differentiation of the dementias.

MRI in tuberculous meningoencephalitis: report of four cases and review of the neuroimaging literature.

The contribution of MRI is reported in four adult patients with tuberculous meningoencephalitis (TbM) and with autopsy correlation in one. Contrast-enhanced T1-weighted MRI revealed the characteristic basal meningeal inflammation of TbM and its focal spreading into adjacent brain. Mixed and T2-weighted pulse sequences delineated a plethora of parenchymal abnormalities. Their relation to TbM was established by a close matching of the patient's neurological findings, contrast enhancement or a change in lesion size. The latter accurately reflected the clinical course in all patients. It remained difficult, however, to distinguish between ischaemic and inflammatory changes, which in some locations were intermixed even histologically. From our experience and that of other groups, MRI provides more diagnostic information in TbM than CT. Moreover, MRI promises to be a useful tool for monitoring treatment response.

The morphologic correlate of incidental punctate white matter hyperintensities on MR images.

Postmortem examinations were made of the brains of six patients, 52-63 years old, who exhibited incidental punctate white matter hyperintensities on MR images before death. Our aim was to unravel the morphologic correlate of such lesions. By repeating the MR study after fixation on four specimens, cutting the brain parallel to the MR imaging plane, and examining whole-hemisphere microscopic sections, we optimized lesion identification. The white matter signal abnormalities were better delineated on pre- than postmortem scans, and visual inspection of the brain slices was normal in all but one location. Histologically, we found areas of reduced myelination with atrophy of the neuropil around fibrohyalinotic arteries as well as different stages of perivenous damage. The latter ranged from spongiform transformation of the neuropil and scattered foci of demyelination to large perivenous areas with marked rarefaction of myelinated fibers. Edematous glial swelling in foci of ganglion cell heterotopia caused subcortical white matter hyperintensities in one case. Our results suggest minor perivascular damage but not infarction as the most likely substrate of punctate MR white matter hyperintensities in elderly brains. Histologic correlations with MR images obtained during life or with studies of unfixed material are necessary to analyze such small lesions.

Idiopathic sclerotic inflammation of the orbit with left optic nerve compression in a patient with multifocal fibrosclerosis.

We present the MR imaging findings in a 43-year-old male patient with bilateral idiopathic sclerosing inflammation of the orbit. Bilateral enhancing retrobulbar masses, with concentric compression of the retrobulbar segment of the left optic nerve, were seen. MR imaging proved to be the only means to distinguish between the different intraorbital structures and to determine the exact site of optic nerve compression. To our knowledge, this is the first documented case of MR imaging findings of this entity.

Extracorporeal fibrinogen and platelet precipitation as a new haemorheological treatment for acute stroke.

In thromboembolic brain infarctions high fibrinogen levels are associated with an increase of both plasma and whole blood viscosity as well as increased aggregability of blood cells. This decreases cerebral perfusion and might reduce blood flow in the penumbra surrounding infarction. An important goal in the treatment of acute cerebral infarction is to reduce fibrinogen and thereby improve the haemorheological state. Heparin-induced extracorporeal low-density lipoprotein/fibrinogen precipitation (HELP) appears to be successful in achieving this. Such treatment reduces lipid fractions, including total cholesterol, low-density lipoproteins (LDL) and triglycerides (p < 0.0001 each), as well as fibrinogen (p < 0.0001) in a safe and efficacious manner. Whole blood and plasma viscosity are also improved when measured by oscillo-rheometry. Furthermore, the number and aggregation tendency of blood cells is influenced positively as determined by Coulter counting and aggregometry. HELP improves the haemorheological profile to a degree which has not been achieved by haemorheologically active substances.