Bacteriophage lambda cro mutations: effects on activity and intracellular degradation.

Following random mutagenesis of the bacteriophage lambda cro gene, we have isolated missense mutations that affect approximately half of the 66 residue positions of Cro. About two-thirds of the mutations change residues involved in the maintenance of Cro structure and stability. The corresponding mutant proteins are severely degraded in the cell but often have specific activities near that of wild-type Cro. The remaining mutations affect residues involved in DNA binding. These mutant proteins are present at moderately reduced intracellular levels, but their specific activities are much lower than that of wild type.     

Le DRESS syndrome, une réaction d''hypersensibilité aux médicaments, qui reste mal connue des pédiatres

The DRESS syndrome (Rash with Eosinophilia and Systemic Symptoms) is a drug hypersensitivity reaction poorly known by paediatricians. It occurs within 1 to 8 weeks of treatment. Clinical features associate in variable patterns, fever, rash, lymphadenopathies, arthritis and potentially life-threatening damage (hepatitis, nephritis, pneumonitis), hyperleucocytosis and eosinophilia. This condition must be early recognized in order to immediately stop suspect drugs. A 6.5 year old girl had a febrile rash, hyperleucocytosis, lymph nodes and cytolitic hepatitis probably due to phenobarbital. Diagnosis of DRESS syndrome was performed only 13 days after the beginning of the eruption. Evolution was favorable but characterized by the recurrence of the febrile eruption with pleuritis. DRESS syndrome is a well described disease that occurs during treatment with a number drugs, particularly anti-epileptic drugs. Steroid therapy and immunoglobulins are proposed for treatment but have not been evaluated.     

Role of nitric oxide in modulating neurotransmitter release from rat striatum

The effect of the nitric oxide synthase inhibitor N-nitro- -arginine methyl ester (L-NAME) on the basal and stimulation-evoked release of dopamine (DA) and acetylcholine (ACh) was investigated in rat striatum. The experiments were carried out in isolated superfused striatal slices, loaded with either [³H]-dopamine or [³H]-choline.We have found that L-NAME reduced the elecrical field stimulation-evoked release of DA, while its enantiomer N-nitro-D-arginine methyl ester (D-NAME) was ineffective. In the presence of the nitric oxide (NO) precursor -arginine L-NAME failed to influence DA release. Furthermore, treatment with the N-methyl- -aspartate (NMDA) receptor antagonist MK-801 completely reversed the effect of L-NAME on striatal DA release. In contrast, L-NAME had no effect on either the basal or the stimulation-evoked ACh release in any experimental conditions studied.Our data indicate that endogenously produced NO is involved in the modulation of striatal DA, but not in ACh release. Furthermore, it seems likely that the modulatory effect of NO is linked to activation of presynaptic NMDA receptors located on the striatal dopaminergic nerve terminals.     

Myocardial perfusion and function in dogs with moderate coronary stenosis

MRI studies of first-pass contrast enhancement with polylysine-Gd-DTPA and myocardial tagging using spatial modulation of magnetization (SPAMM) were performed to assess the feasibility of a combined regional myocardial blood flow and 2D deformation exam. Instrumented closed-chest dogs were imaged at a baseline control state (Cntl) followed by two interventions: moderate coronary stenosis (St) achieved by partial occlusion of the left anterior descending (LAD) and moderate coronary stenosis with dobutamine loading (StD). Hypoperfusion of the anterior region (ANT) of the myocardium (LAD distribution) relative to the posterior wall (POS) based on the upslope of the signal intensity time curve from the contrast-enhanced MR images was demonstrated only with dobutamine loading (ANT:POS Cntl=1.077 ± 0.15 versus ANT:POS StD=0.477 ± 0.11, P<0.03) and was confirmed with radio-labeled microspheres measurements (ANT:POS Cntl=1.18 ± 0.2 ml/min/g versus ANT:POS StD=0.44 ± 0.1 ml/min/g; P<0.002). Significant changes in regional myocardial shortening were only seen in the StD state (P<0.02); the anterior region showed impaired myocardial shortening with dobutamine loading (P=NS), whereas the nonaffected POS region showed a marked increase in shortening when compared with Cntl (Cntl=0.964 ± 0.02 versus StD=0.884 ± 0.03; P<0.001). These results demonstrate that an integrated quantitative assessment of regional myocardial function and semiquantitative assessment of myocardial blood flow can be performed noninvasively with ultrafast MRI.     

Chronic fibular ligament insufficiency at the upper ankle joint. Late results after modified Watson-Jones plastic surgery

The findings at clinical and roentgenological follow-up examination of 44 patients are reported to illustrate the long-term results of a modified Watson-Jones technique up to 90 months after the operation. The clinical results (86.3% of the patients without complaints and 88.6% with subjective stability of the ligaments) correspond with those given by a variety of sources in the literature. The roentgenological examination, on the other hand, showed signs of grade I or II arthrosis (Bargon scale) in 61.3% of cases, and arthrosis was worse than before the operation in nearly all cases. The patients in the group, that had received more conservative treatment with an average 6.3 years between lesion and surgical treatment (group 1), had the highest incidence of arthrosis, with 73.6%. In 10 cases the clinical examination revealed reduced supination and dorsiflexion attributable to the tenodesis effect associated with the Watson-Jones technique. In view of the high rate of arthrosis, younger patients and patients with a short tendon part of the peroneus brevis muscle should be treated by another, more "physiological" method.     

Functional analysis of the cag pathogenicity island in Helicobacter pylori isolates from patients with gastritis, peptic ulcer, and gastric cancer

Helicobacter pylori is the causative agent of a variety of gastric diseases, but the clinical relevance of bacterial virulence factors is still controversial. Virulent strains carrying the cag pathogenicity island (cagPAI) are thought to be key players in disease development. Here, we have compared cagPAI-dependent in vitro responses in H. pylori isolates obtained from 75 patients with gastritis, peptic ulcer, and gastric cancer (n = 25 in each group). AGS gastric epithelial cells were infected with each strain and assayed for (i) CagA expression, (ii) translocation and tyrosine phosphorylation of CagA, (iii) c-Src inactivation, (iv) cortactin dephosphorylation, (v) induction of actin cytoskeletal rearrangements associated with cell elongation, (vi) induction of cellular motility, and (vii) secretion of interleukin-8. Interestingly, we found high but similar prevalences of all of these cagPAI-dependent host cell responses (ranging from 56 to 80%) among the various groups of patients. This study revealed CagA proteins with unique features, CagA subspecies of various sizes, and new functional properties for the phenotypic outcomes. We further showed that induction of AGS cell motility and elongation are two independent processes. Our data corroborate epidemiological studies, which indicate a significant association of cagPAI presence and functionality with histopathological findings in gastritis, peptic ulcer, and gastric cancer patients, thus emphasizing the importance of the cagPAI for the pathogenicity of H. pylori. Nevertheless, we found no significant association of the specific H. pylori-induced responses with any particular patient group. This may indicate that the determination of disease development is highly complex and involves multiple bacterial and/or host factors.     

C-13-NMR-spektroskopische untersuchungen an polymerhomologen reihen von α,1→6- und α,1→4-glucanen

The ¹³C-NMR spectra of malto- and isomalto-oligosaccharides, amylose and dextrane were analysed. It was observed that in both series of oligosaccharides and polysaccharides the resonances of the central glucose units are independent of the chain length with the exception of the C-atoms 1 and 4 of amylose which show deviations of 0,4 and 0,5 ppm. These small effects can possibly be explained by a definite polysaccharide chain conformation in solution.     

Effects of increasing osmolality on rat ileal smooth muscle

The effects of changing bathing medium osmolality on tension generation in smooth muscle were studied on potassium-depolarized segments of rat ileum. Increasing the tonicity of the medium evokes a transient relaxation of the smooth muscle; restoration of isotonicity evokes a transient contraction of similar amplitude and time course. While immersed in hypertonic media of less than 1.3 times normal tonicity, the smooth muscle slowly increases its isometric tension; in media of nearly twice normal tonicity, the smooth muscle loses tension. All of these effects occur whether the medium is made hypertonic with added NaCl or sucrose.     

An extended association screen in multiple sclerosis using 202 microsatellite markers targeting apoptosis-related genes does not reveal new predisposing factors

Apoptosis, the programmed death of cells, plays a distinct role in the etiopathogenesis of Multiple sclerosis (MS), a common disease of the central nervous system with complex genetic background. Yet, it is not clear whether the impact of apoptosis is due to altered apoptotic behaviour caused by variations of apoptosis-related genes. Instead, apoptosis in MS may also represent a secondary response to cellular stress during acute inflammation in the central nervous system. Here, we screened 202 apoptosis-related genes for association by genotyping 202 microsatellite markers in initially 160 MS patients and 160 controls, both divided in 4 sets of pooled DNA samples, respectively. When applying Bonferroni correction, no significant differences in allele frequencies were detected between MS patients and controls. Nevertheless, we chose 7 markers for retyping in individual DNA samples, thereby eliminating 6 markers from the list of candidates. The remaining candidate, the ERBB3 gene microsatellite, was genotyped in additional 245 MS patients and controls. No association of the ERBB3 marker with the disease was detected in these additional cohorts. In consequence, we did not find further evidence for apoptosis-related genes as predisposition factors in MS.     

Mice with neonatally induced inactivation of the vascular cell adhesion molecule-1 fail to control the parasite in Toxoplasma encephalitis

Under various inflammatory conditions, cell adhesion molecules are up-regulated in the central nervous system (CNS) and may contribute to the recruitment of leukocytes to the brain. In the present study, the functional role of vascular cell adhesion molecule (VCAM)-1 in Toxoplasma encephalitis (TE) was addressed using VCAM(flox/flox MxCre) mice. Neonatal inactivation of the VCAM-1 gene resulted in a lack of induction of VCAM-1 on cerebral blood vessel endothelial cells, whereas the constitutive expression of VCAM-1 on choroid plexus epithelial cells and the ependyma was unaffected; in these animals, resistance to T. gondii was abolished, and VCAM(flox/flox MxCre) mice died of chronic TE caused by a failure to control parasites in the CNS. Although leukocyte recruitment to the CNS was unimpaired, the B cell response was significantly reduced as evidenced by reduced serum levels of anti-T. gondii-specific IgM and IgG antibodies. Furthermore, the frequency and activation state of intracerebral T. gondii-specific T cells were decreased, and microglial activation was markedly reduced. Taken together, these data demonstrate the crucial requirement of VCAM-1-mediated immune reactions for the control of an intracerebral infectious pathogen, whereas other cell adhesion molecules can efficiently compensate for VCAM-1-mediated homing across cerebral blood vessels.