[The Würzburg questionnaire for assessing the quality of hearing in CI-children (WH-CIK)]

BACKGROUND

The goal of this study was to compare the auditory behaviour of bilaterally implanted children while using both CIs to their auditory behaviour during the time when they were using one CI.

METHODS

For this purpose a questionnaire looking at different aspects of hearing such as hearing in background noise, in complex listening situations and directional hearing was developed. The questionnaire was completed by the parents of 28 bilaterally implanted children. They were instructed to state their judgement on the behaviour of their children. The parents scaled their judgements using a method of extended category scaling similar to that applied in the loudness scaling with the Würzburg hearing field (WHF). Each of the five verbal categories was subdivided into 10 numerical subdivisions, so that the parents were able to express judgements lying between the different categories.

RESULTS

Eight out of eleven items showed that hearing with bilateral CIs was significantly better than with one CI (p < 0,003). The two items, which did not show a significant difference between the two conditions were those related to the interest in auditory rehabilitation and to aversion to noise.

CONCLUSIONS

The questionnaire has proven to be a useful instrument to assess the quality of hearing in children. The possibility of bilateral implantation should be considered during the decision process prior to implantation.

Lack of endothelial nitric oxide synthase aggravates murine pneumococcal meningitis

Nitric oxide (NO) plays a central role in the pathogenesis of bacterial meningitis. However, the role of NO produced by endothelial NO synthase (eNOS) in meningitis is still unclear. We investigated the influence of eNOS depletion on the inflammatory host response, intracranial complications, and outcome in experimental pneumococcal meningitis. Leukocyte accumulation in the cerebrospinal fluid was more pronounced in infected eNOS-deficient mice than in infected wild type mice. This effect could be attributed to an increased expression of P-selectin, macrophage inflammatory protein-2, keratinocyte-derived cytokine, and interleukin (IL)-1beta in the brain of infected eNOS-deficient mice. However, no differences in the cerebral expression of intercellular adhesion molecule-1, tumor necrosis factor-alpha, and IL-6 as well as of neuronal NOS and inducible NOS could be detected between infected wild type and mutant mice. In addition to enhanced leukocyte infiltration into the CSF, meningitis-associated intracranial complications including blood-brain barrier disruption and the rise in intracranial pressure were significantly augmented in infected eNOS-deficient mice. The aggravation of intracranial complications was paralleled by a worsening of the disease, as evidenced by a more pronounced hypothermia, an enhanced weight reduction, and an increased death rate. The current data indicate that eNOS deficiency is detrimental in bacterial meningitis. This effect seems to be related to an increased expression of (certain) cytokines/chemokines and adhesion molecules; thus leading to increased meningeal inflammation and, subsequently, to aggravated intracranial complications.

Superantigen overcomes resistance of IL-6-deficient mice towards MOG-induced EAE by a TNFR1 controlled pathway

Experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte glycoprotein peptide 35-55 (MOG) leads to a chronic form of disease characterized by demyelination, inflammation and gliosis in the central nervous system (CNS). Recently IL-6 and LT alpha were found to be required for induction of the disease. The main features associated with EAE resistance of IL-6(-/-) and LT alpha(-/-) mice were reduced T cell proliferation and endothelial activation. As shown here treatment of MOG-immunized IL-6(-/-) mice with staphylococcal enterotoxin B (SEB)reversed their resistance to MOG-induced EAE. SEB failed to restore susceptibility to EAE in LT alpha(-/-) mice. The effect of SEB to induce EAE in IL-6(-/-) mice depends on TNF receptor type 1 (TNFR1) signaling because IL-6/TNF/LT alpha(-/-) and IL-6/TNFR1(-/-) are refractory to SEB. TNFR1 is involved in SEB induced trafficking of T cells into the CNS as evidenced by the failure to up-regulate VCAM-1 on CNS endothelium and lack of accumulation of V beta 8(+) T cells in the CNS of IL-6/TNFR1(-/-) mice upon immunization with MOG and treatment with SEB. The course of SEB triggered EAE in MOG immunized IL-6(-/-) mice was characterized by reduced severity and duration of clinical manifestations, which were associated with a significant drop of CNS infiltrating neutrophils and MIP-2 expression after peak disease. Taken collectively the effect of SEB to overcome EAE resistance points to a transient IL-6 independent but TNFR1 dependent proinflamatory pathway in EAE pathogenesis and suggests a crucial function for IL-6 in disease perpetuation.

Differential Expression of Nitric Oxide Synthases in Bacterial Meningitis: Role of the Inducible Isoform for Blood‐Brain Barrier Breakdown

The aim of the study was to determine the differential expression of nitric oxide (NO) synthase (NOS) isoforms and the pathophysiologic relevance of inducible NOS (iNOS) in experimental pneumococcal meningitis. By use of reverse transcription-polymerase chain reaction analysis, immunohistochemistry, and Western blotting, increased brain mRNA and increased protein levels of endothelial NOS (eNOS) and iNOS were detected 24 h after intracisternal pneumococcal inoculation. In iNOS-deficient mice, disruption of the blood-brain barrier (BBB) was significantly reduced, compared with that in wild-type mice. This beneficial effect of iNOS deficiency was associated with a lack of nitrotyrosine immunoreactivity. Furthermore, brain protein levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha and brain mRNA levels of macrophage inflammatory protein (MIP)-1alpha and MIP-2 were significantly reduced in infected animals lacking iNOS. These findings suggest that (1) not only iNOS but also eNOS is up-regulated in the acute phase of experimental bacterial meningitis, and (2) iNOS-derived NO contributes to peroxynitrite formation and BBB breaching in this disease.

Acute severe spinal cord dysfunction in bacterial meningitis in adults: MRI findings suggest extensive myelitis

BACKGROUND

Bacterial meningitis is rarely complicated by acute spinal cord involvement (eg, myelitis, ischemic infarction, spinal abscess, or epidural hemorrhage). In spinal cord dysfunction, magnetic resonance imaging (MRI) is the imaging modality of choice. Still, MRI findings of myelitis due to bacterial meningitis in adults have not been reported.

METHODS

Spinal MRIs were obtained during the acute stage of meningitis and on follow-up in 3 adults with bacterial meningitis that was complicated by paraparesis or tetraparesis and bowel and bladder incontinence. The causative pathogens were Streptococcus pneumoniae and Neisseria meningitidis; in 1 patient, the pathogen was not identified.

RESULTS

In all cases, spinal MRI ruled out a compression of the cord by an extramedullary mass but demonstrated hyperintensities on T2-weighted images that predominantly involved the gray matter and extended from the cervical to the lumbar cord. Leptomeningeal and discrete nodular intramedullary enhancement on T1-weighted images was detected only in 1 patient. Follow-up examinations revealed that hyperintensities resolved completely in 1 patient, while a central cavitation developed in the cervical spinal cord of another, and the MRI findings were progressive during the first 4 weeks in the third patient. In all cases, severe paresis and bowel and bladder incontinence persisted.

CONCLUSION

We demonstrate for the first time the MRI findings of adults with acute spinal cord involvement during bacterial meningitis. Magnetic resonance imaging showed central intramedullary hyperintensities on T2-weighted images that extended from the cervical to the lumbar cord, indicating myelitis. Clinical follow-up examinations suggest that myelitis during bacterial meningitis has an unfavorable prognosis.

Comparison of the TEMPO+ ear-level speech processor and the cis pro+ body-worn processor in adult MED-EL cochlear implant users

A study was conducted to compare the new MED-EL TEMPO+ ear-level speech processor with the CIS PRO+ body-worn processor in the COMBI 40/COMBI 40+ implant system. Speech tests were performed in 46 experienced subjects in two test sessions approximately 4 weeks apart. Subjects were switched over from the CIS PRO+ to the TEMPO+ in the first session and used only the TEMPO+ in the time between the two sessions. Speech tests included monosyllabic word tests and sentence tests via the telephone. An adaptive noise method was used to adjust each subject's scores to approximately 50%. Additionally, subjects had to complete a questionnaire based on their 4 weeks of experience with the TEMPO+. The speech test results showed a statistically significant improvement in the monosyllabic word scores with the TEMPO+. In addition, in the second session, subjects showed a significant improvement when using the telephone with the TEMPO+, indicating some learning in this task. In the questionnaire, the vast majority of subjects found that the TEMPO+ allows equal or better speech understanding and rated the sound quality of the TEMPO+ higher. All these objective and subjective results indicate the superiority of the TEMPO+ and are mainly attributed to a new coding strategy called CIS+ and its implementation in the TEMPO+. In other words, based on the results of this study, it appears that after switching over from the CIS PRO+ to the TEMPO+, subjects are able to maintain or even improve their own speech understanding capability.

Reciprocal changes in endothelial and inducible nitric oxide synthase expression following carotid angioplasty in the pig

OBJECTIVE

Nitric oxide produced by nitric oxide synthase appears to have an important role in the regulation of arterial tone, platelet adhesion and smooth muscle cell proliferation. Our aim was to investigate the effects of balloon angioplasty on expression of endothelial NO synthase (cNOS) and inducible NO/synthase (iNOS) in the pig carotid artery and to relate any changes in expression to the processes of reendothelialisation and vascular repair.

METHODS

Pigs were sacrificed at various time points to follow NOS expression in the neointima, media and regenerated endothelium. Immunocytochemical staining was used to localize cNOS and iNOS expression in the vessel wall. Relative amounts of cNOS were measured using quantitative in vitro alitoradiography. cNOS mRNA and iNOS mRNA was quantified by competitive PCR based on the sequenced cDNA of porcine cNOS and iNOS.

RESULTS

Uninjured carotid arteries exhibited dense uniform luminal endothelial staining for cNOS. Balloon angioplasty caused denudation of cNOS immunoreactive cells and a marked reduction of cNOS gene expression but a complete recovery was noted by day 35. In normal uninjured carotid arteries no evidence of iNOS immunoreactivity was demonstrable but 24 h after injury, marked homogeneous iNOS immunoreactivity was detected in medial vascular smooth muscle cells. By 5 days, staining was evident in cells within the forming neointimal layer with no evidence of iNOS immunoreactivity in the media. iNOS immunoreactivity persisted in cells at the luminal surface at 7 days and iNOS gene expression appeared to be sustained in some animals with ruptured internal elastic lamina at 21 days.

CONCLUSION

Balloon injury is associated with de-endothelialisation and a marked reduction in cNOS gene expression and activity. iNOS is induced throughout the arterial media within VSMC soon after balloon injury and persists for up to 21 days. These observations imply an important regulatory role for locally generated NO in the pathophysiological response to balloon injury.

[Further contribution on glycogen in fetal intestinal epithelium]

In the first half of pregnancy the well-known occurrence of glycogen incorporation in the supra- and infranuclear cytoplasm of the villous enterocytes was verified. This enormous glycan store is evidently of very little functional importance. It seems to be an expression of a disordered glycogenolysis. These masses of glycogen are incorporated into impressive glycogenosomes, which are the predominante cytoplasmic inclusions for a short period of time. According to the present results it is not certain whether lysosomal glycogenolysis happens. There is no morphological or functional evidence for a utilization og glycogen.

[Further contribution on the fine structure of fetal goblet cells. Investigations on the small intestine of cattle]

Early in the fetal development, i.e. at the time both of the growth of intestinal villi and crypts and the epithelial cell differentiation the goblet cells also appear. The maturation of goblet cells progresses during their migration from the base of the villi respectively of the crypts to the villous top. As in the bovine large intestine there are vesicles and capsulated vacuoles, which contain vesicles, as single elements or as conglomerates in the immature goblet cells of the small intestine. These images deliver a scenario of the mechanism of secretory granule production and probably play a role in the formation of mucus.

Renin inhibition by substituted piperidines: a novel paradigm for the inhibition of monomeric aspartic proteinases?

BACKGROUND

The aspartic proteinase renin catalyses the first and rate-limiting step in the conversion of angiotensinogen to the hormone angiotensin II, and therefore plays an important physiological role in the regulation of blood pressure. Numerous potent peptidomimetic inhibitors of this important drug target have been developed, but none of these compounds have progressed past clinical phase II trials. Limited oral bioavailability or excessive production costs have prevented these inhibitors from becoming new antihypertensive drugs. We were interested in developing new nonpeptidomimetic renin inhibitors.

RESULTS

High-throughput screening of the Roche compound library identified a simple 3, 4-disubstituted piperidine lead compound. We determined the crystal structures of recombinant human renin complexed with two representatives of this new class. Binding of these substituted piperidine derivatives is accompanied by major induced-fit adaptations around the enzyme's active site.

CONCLUSIONS

The efficient optimisation of the piperidine inhibitors was facilitated by structural analysis of the renin active site in two renin-inhibitor complexes (some of the piperidine derivatives have picomolar affinities for renin). These structural changes provide the basis for a novel paradigm for inhibition of monomeric aspartic proteinases.

[Morphogenesis of the submucosal gland of cattle (Bos primigenius f. taurus)]

In the 10th week of gestation the development of duodenal glands in the bovine intestinum starts by circumscript epithelial proliferation. Their secretory channels are in contact with the crypts. Already in the early fetal stage ultrastructurally there are an inconspicuous equipment with organelles in the apical cytoplasm and single globular granules, which demonstrate the differentiation of epithelial cells into duodenal glandular cells. Until the mid-point of the pregnancy the granular endoplasmic reticulum strongly develops as a condition for the impressive increase in the formation of the prosecretory granules. Finally, in the second half of the pregnancy, granules varying in structure and electronic density, but mostly showing an intensively osmiophilic and fine granular material, are the predominant cytoplasmic structures. Like in goblet cells capsulated vacuoles seem to play a role in the formation of the secretory granules. Recent, extensive studies concerning our results have been discussed.

Comparative investigations of algorithms for the detection of breaths in newborns with disturbed respiratory signals

The correct detection of the beginning of inspiration and expiration in the respiratory signals is an essential prerequisite for accurate lung function testing in newborns. Five algorithms for breath detection using pneumotachographically measured flow and volume signals were investigated with regard to the error rate. To compare and to evaluate the reliability of these algorithms 12 minimally and 12 severely disturbed flow and volume signals from spontaneously breathing newborns were used. With the exception of an algorithm based on Walsh-transformed signals, all algorithms work reliably (error rate <1.1%) if disturbances are minimal. In severely disturbed signals there is a great difference between the algorithms. The most robust algorithm tested (trigger of the flow signal with an additional plausibility check of the recognized breath) resulted in an error rate of <3.4%. Not all algorithms tested are suitable for real-time applications because they differ considerably in delay time for breath detection.

[Prenatal development of the lamina epithelialis in the phase of vacuolization of villous epithelial cells. Investigations on the intestines of cattle (Bos primigenius taurus L., 1758)]

The development of the bovine small intestine was examined in 39 embryos and fetuses by light microscopic and transmission electron microscopic methods. Special reference was paid to the histogenesis of the ephithelium. In contrast to the duodenum the epithelium of jejunum and ileum undergoes a degeneration by vacuolation of its villous epithelial cells. The demonstration of the acid phosphatase activity of these vacuoles shows their lysosomal character. This degenerative process of the small intestinal epithelium is also known in large intestine where it leads to the destruction of the intestinal villi. Both seem to be part of a 'principle of construction of the intestine of the vertebrates' (Wille, 1984).

Structure-based design of beta-lactamase inhibitors. 1. Synthesis and evaluation of bridged monobactams

Bridged monobactams are novel, potent, mechanism-based inhibitors of class C beta-lactamases, designed using X-ray crystal structures of the enzymes. They stabilize the acyl-enzyme intermediate by blocking access of water to the enzyme-inhibitor ester bond. Bridged monobactams are selective class C beta-lactamase inhibitors, with half-inhibition constants as low as 10 nM, and are less effective against class A and class B enzymes (half-inhibition constants > 100 microM) because of the different hydrolysis mechanisms in these classes of beta-lactamases. The stability of the acyl-enzyme complexes formed with class C beta-lactamases (half-lives up to 2 days were observed) enabled determination of their crystal structures. The conformation of the inhibitor moiety was close to that predicted by molecular modeling, confirming a simple reaction mechanism, unlike those of known beta-lactamase inhibitors such as clavulanic acid and penam sulfones, which involve secondary rearrangements. Synergy between the bridged monobactams and beta-lactamase-labile antibiotics could be observed when such combinations were tested against strains of Enterobacteriaceae that produce large amounts of class C beta-lactamases. The minimal inhibitory concentration of the antibiotic of more than 64 mg/L could be decreased to 0.25 mg/L in a 1:4 combination with the inhibitor.

[Early fetal development of the small intestine mucosa in cattle (Bos primigenius taurus)]

The development of the bovine small intestine was examined in 24 embryos and fetuses by light microscopic, scanning and transmission electron microscopic methods. Special reference was paid to the genesis of the epithelium and particularly of the villi intestinales. The primitive intestine consists of one layer of epithelial cells surrounded by mesenchym and tunica serosa. The fetal intestine (up to the 24th week of gestation) shows all the morphologic structures of the adult. In small intestine the development of cryptae and villi intestinales starts before the 7th week of gestation and progresses with a proximo-distal gradient. Epithelial proliferation that gives rise to primary epithelial villi makes epithelium become temporarily stratified. Finger-like secondary villi develop by proliferation of the mesenchym. In addition to this process mucosal folds occur in duodenum giving rise to villi by segmentation. At the same time the differentiation of epithelium starts. The fetal small intestine, like many other fetal tissues displays masses of glycogen.

Digital pulse plethysmography as a non-invasive method for predicting drug-induced changes in left ventricular preload

OBJECTIVE

Changes in the contour of the plethysmographically recorded digital pulse curve after nitrate ingestion are well known, but it has not been fully established whether these changes reflect nitrate action on left ventricular (LV) preload or afterload. Therefore, we compared the pulse wave contour after administration of equieffective doses of nitroglycerin and nifedipine.

METHODS

In 20 patients with coronary artery disease we measured aortic blood pressure curve in the aorta ascendens, digital volume pulse curve with a photoelectric pulse pickup, Riva Rocci blood pressure and heart rate after administration of either 0.8 mg nitroglycerin or 10 mg nifedipine.

RESULTS

Peak plasma concentrations of nitroglycerin and nifedipine were achieved 5 min and 20 min after ingestion of the drugs. Systolic aortic blood pressure decreased after both nitroglycerin and nifedipine to 19.4 mmHg, but diastolic blood pressure decreased only after nifedipine by 10.5 mmHg (P < 0.05). Riva Rocci blood pressures showed a similar time course. Heart rate increased from 67.4 to 70.9 beats.min-1 after nitroglycerin and from 58.9 to 69.4 beats.min-1 after nifedipine. The calculated a/b ratio of the aortic pressure curve increased after both medications (nitroglycerin, from 1.66 to 1.99; nifedipine, from 1.66 to 1.93) and its time course mimicked that of the systolic blood pressure. The a/b ratio of the digital pulse curve did not change after nifedipine, but showed a pronounced rise after nitroglycerin from 1.29 to 1.84. With regard to pharmacological actions, nitroglycerin causes a reduction in LV preload and afterload, whereas nifedipine has only LV-afterload-reducing activity.

CONCLUSION

We conclude, that the reduction in afterload did not cause the typical changes in wave contour of the peripheral pulse curve which occur with organic nitrates. Most likely changes in the a/b ratio reflect changes in LV preload.

Crystallization of the complex of human IFN-gamma and the extracellular domain of the IFN-gamma receptor

A complex of human interferon-gamma (IFN-gamma) with the soluble extracellular domain of the IFN-gamma receptor alpha-chain (IFN-gamma-R) has been crystallised. Crystals of the complex were grown using PEG 4000 as the precipitating agent in the presence of beta-octyl glucoside. The receptor-ligand complex crystallizes in a monoclinic space group and diffracts to about 3.0 A resolution. Isomorphous crystals have been obtained with complex containing selenomethionine and cysteine mutants of IFN-gamma, which may facilitate the ongoing X-ray structure determination.

Topological similarities in TGF-beta 2, PDGF-BB and NGF define a superfamily of polypeptide growth factors

BACKGROUND

The development of functional diversity through gene duplication and subsequent divergent evolution can give rise to proteins that have little or no sequence similarity, but retain similar topologies.

RESULTS

The crystal structures of nerve growth factor, transforming growth factor-beta 2 and platelet-derived growth factor-BB show that all three are based on a cystine-knot plus beta-strands topology. There is very little sequence identity between the three proteins and the relationship between the structures had not been deduced from sequence comparisons. Each growth factor is usually active as a dimer; each exists as a dimer in the crystal, but the relative orientations of the protomers are different in each case.

CONCLUSION

The structural motif of disulphide bonds and hydrogen-bonded beta-strands unexpectedly found in these three growth factors acts as a stable framework for elaboration of loops of low sequence similarity that contain the specificity for receptor interaction.

Best for Britain?

Work in Oregon to develop a system for explicit rationing of healthcare has attracted worldwide attention. But, say Morton Warner and colleagues, it isn't a model the UK should follow.