A splicing factor that is inactivated during in vivo heat shock is functionally equivalent to the [U4/U6.U5] triple snRNP-specific proteins.

One of the consequences of the heat shock response is a shutdown of pre-mRNA splicing, a phenomenon that can be reproduced in extracts prepared from heat-shocked cells. The block in splicing occurs before the covalent modifications that generate spliced mRNA at the level of spliceosome formation. We have used extracts prepared from heat-shocked cells as a complementation system to characterize and partially purify a protein factor that is inactivated during the in vivo heat shock. The activity functions in the formation of the active spliceosome by assembling U4/U6 and U5 snRNPs into a triple snRNP particle. The factor appears to be different from previously isolated splicing factors and is functionally equivalent to several polypeptides that are specifically associated with the purified triple snRNP but not with individual U4/U6 or U5 snRNPs. Our data confirm the hypothesis that U4/U6 and U5 snRNPs enter the spliceosome as a triple snRNP complex and show for the first time a function of specific snRNP-associated polypeptides in the mammalian splicing pathway.     

Malignant effusions are sources of fibronectin and other promigratory and proinvasive components

Metastatic dissemination is the primary cause of death in ovarian cancer (OvCa) patients, and dissemination to pleural and peritoneal effusions is a common clinical event. Effusion samples were collected from 15 OvCa patients. Twenty-six samples were collected prospectively, two were archival, and eight were taken from patients with other malignancies. Twenty-nine samples were from malignant ascites, and seven specimens were pleural fluids. In addition, six ascites and two pleural fluids from noncancer patients were studied as effusion controls. Effusion supernatants were tested for migration-stimulation activity, using A2058 human melanoma cells as the index responder cell. Malignant samples induced a 400-1200% increase in migration. Sixty percent of the migration was inhibited by incubation of the malignant fluid with antifibronectin (FN) antibody, in contrast to 75% inhibition of control fluid-stimulated migration (P = 0.017). Gelatin zymography and Western blot analyses showed that latent and activated MMP-2 and MMP-9 collagenases, and tissue inhibitor of metalloproteinase-2 (TIMP-2) were present in all malignant fluids. Serial samples were taken from several patients, and a trend for correlation between MMPs and clinical behavior of the tumors was shown. Free TIMP-2 correlated with CA-125 levels in two patients for whom serial samples were available. The demonstration of promigratory and proinvasive activity in malignant effusions is consistent with their association with other metastatic disease in OvCa patients and their function as a haven for metastatic cells.     

Two unusual periosteal exotoses

After maceration of the skeleton of 2 persons we found 2 different solitary exostoses; one at the sciatic tuber, in the other at the sciatic tuber, in the other at the ventral side of the distal fibula. The exostoses reach a length of 2 cm. Prescher (1987) described a cartilaginous exostosis with a length of 2 cm at the proximal tibia. In our cases the exostoses belong to the periosteal form. We consider them to be bony origins of ligaments: at the sciatic tuber--the bony origin of the sacrotuberal ligament, at the distal fibula--the bony origin of the peroneal compartment of the retinaculum mm extensorum inferius.     

The amygdala is part of the behavioural reinforcement system modulating long-term potentiation in rat hippocampus

Long-term potentiation (LTP) in the dentate gyrus can be modulated and prolonged by emotional/motivational influences when concurrently activated. A similar effect on LTP can be obtained by stimulating the amygdala, suggesting that this limbic structure might be part of the neural system involved in behavioural reinforcement. To confirm this we have performed a series of experiments in which the basolateral amygdala was either temporary inactivated by injection of lidocaine or permanently lesioned electrolytically. Both manipulations completely blocked the reinforcing effect of a motivational stimulus (drinking after 24-h deprivation) on LTP at the perforant pathway-dentate gyrus synapses, whilst leaving intact the non-reinforced potentiation. These results demonstrate that the basolateral amygdala is a key structure within the system involved in the modulatory interaction between the affective status of the animal and the mechanisms of functional plasticity.     

Depression of Human Neutrophil Motility by Influenza Virus In Vitro

After in vitro treatment of human peripheral neutrophils for 60 min at 37°C with purified influenza A virus, their random locomotion (no chemoattractant), chemokinesis (migration in the presence of a chemoattractant without a gradient), and chemotaxis were depressed, as determined by a modification of the Boyden method. The inhibition was accentuated by the presence of human serum devoid of antibodies to the virus. A strain of influenza B virus did not depress neutrophil motility at the same concentration and agglutinated the neutrophils at higher concentrations. Antiserum treatment partly abolished the inhibitory activity of the influenza virus. Inactivation of the virus infectivity with Tween 80 and ether did not change the ability of the virus to inhibit neutrophil motility. Bacterial neuraminidase did not inhibit neutrophil motility. Pretreatment of neutrophils with amantadine hydrochloride, which has been reported to block viral replication in its early stages, did not modify the depression of neutrophil motility by influenza A virus. The results give additional support to the suggested mechanism of depressed neutrophil function as a cause of bacterial superinfection after influenza.     

HLA-DRB1* GENE SEQUENCES IN HLA-DR4 POSITIVE AND NEGATIVE PATIENTS WITH RHEUMATOID ARTHRITIS

The second exon of the DRB1 gene encoding for the first domain of the HLA-DR β-chain was sequenced in 16 patients (10 DR4/DR1 positive, 6 DR4/DR1 negative) with seropositive rheumatoid arthritis (RA). We could confirm the strong association of susceptibility to RA with functionally equivalent conformations on otherwise distinct MHC molecules. At least one HLA-DR allele in all of the analysed DR4 or DR1 positive patients showed such an epitope with a minimal variability limited to residue 71. However, in HLA-DR4 and -DR1 negative patients such a similar epitope could not be detected.     

gamma-Aminobutyric acid and taurine release in the striatum of the rat during hypoglycemic coma, studied by microdialysis

Extracellular levels of striatal gamma-aminobutyric acid (GABA) and taurine were monitored during insulin-induced hypoglycemia using microdialysis. At the onset of isoelectricity in the electroencephalogram (EEG), a transient 5-fold increase in the levels of GABA occurred. Taurine levels increased 5 min following the onset of isoelectricity and continued to increase during the entire isoelectric period. The results demonstrate that events associated with the onset of isoelectricity during hypoglycemia trigger an increase in extracellular concentrations of GABA and taurine. The discrepancy in time-course of these changes may reflect differences in compartmentation, function and metabolism of the two amino acids.     

Renovaskuläre Hypertonie

Zusammenfassung In der vorliegenden Untersuchung wurde das postoperative Blutdruckverhalten bei 35 Patienten mit renovaskulärer Hypertonie untersucht: 17 Patienten mit fibromuskulärer Dysplasie (FMD) und 18 mit arteriosklerotischen Gefäßwandveränderungen (ASS).Patienten mit FMD waren im Mittel jünger (31,8 Jahre), zeigten eine kürzere Hypertonieanamnese (1,8 Jahre) und waren prävalent weiblich (82%), während Patienten mit ASS deutlich älter waren (48,2 Jahre), eine längere Hypertoniedauer (2,6 Jahre) zeigten und bevorzugt männlich (78%) waren.In beiden Gruppen zeigte das intravenöse Pyelogramm einen vergleichbar hohen Anteil positiver Befunde (FMD=64%, ASS=61%).Postoperativ waren in der Gruppe mit FMD 47% (n=8) geheilt, 47% (n=8) gebessert und nur 6% (n=1) der Patienten geringgradig gebessert. Die vergleichbaren Werte für die Gruppe mit ASS betrugen 28, 55 und 17%. Für das Gesamtkollektiv war folglich ein guter Operationserfolg (geheilt und gebessert) in 88,5% der Fälle zu beobachten. Patienten mit ASS und postoperativ nur geringgradiger Besserung (n=3) zeigten eine auffallend lange Hypertonieanamnese (7,0±1,4 Jahre).Bei allen Patienten wurde präoperativ die seitengetrennte Bestimmung der Renin-Aktivität (PRA) im Nierenvenenblut durchgeführt und aus den Werten die PRA-Quotienten (PRA betroffene/nicht betroffene Seite) errechnet. Bei 27 Patienten wurde die Bestimmung 15 und 30 min nach intravenöser Stimulation mit 40 mg Furosemid wiederholt. PRA-Quotienten von 1,5 wurden als signifikant bezeichnet.Bei 31 Patienten mit einseitiger renovaskulärer Hypertonie wurde die Höhe des PRA-Quotienten zum postoperativen Blutdruckverhalten korreliert. Dabei zeigte sich zwischen der Gruppe der postoperativ Geheilten und der der postoperativ Gebesserten kein signifikanter Unterschied im mittleren PRA-Quotienten. Ferner ließen sich für das Gesamtkollektiv der 31 Patienten mit einseitiger renovaskulärer Hypertonie unter Ausgangs- und Stimulationsbedingungen keine signifikanten Korrelationen zwischen Höhe der PRA-Quotienten und postoperativem Blutdruckabfall ermitteln.Unsere Ergebnisse unterstützen nicht die weit verbreitete Ansicht, daß sich die seitengetrennte Bestimmung der PRA im Nierenvenenblut als Parameter für den zu erwartenden Operationserfolg bei Patienten mit einseitiger renovaskulärer Hypertonie eignet. Die Methode kann deshalb nach unserer Ansicht nicht mehr als obligater Bestandteile der präoperativen Diagnostik der renovaskulären Hypertonie empfohlen werden.     

Connective tissue growth factor in Alzheimer's disease

The chemical organization of excitatory axon terminals in the rat cerebellar cortex was examined by immunocytochemistry and in situ hybridization histochemistry of vesicular glutamate transporters 1 and 2 (VGluT1 and VGluT2). Chemical depletion of the inferior olivary complex neurons by 3-acetylpyridine treatment almost completely removed VGluT2 immunoreactivity from the molecular layer, leaving VGluT1 immunoreactivity apparently intact. On the other hand, neuronal deprivation of the cerebellar cortex by kainic acid injection induced a large loss of VGluT1 immunoreactivity in the molecular layer. In the cerebellar granular layer, both VGluT1 and VGluT2 immunoreactivities were found in mossy fiber terminals, and the two immunoreactivities were mostly colocalized in single-axon terminals. Signals for mRNA encoding VGluT2 were found in the inferior olivary complex, and those for VGluT1 and VGluT2 mRNAs were observed in most brainstem precerebellar nuclei sending mossy fibers, such as the pontine, pontine tegmental reticular, lateral reticular and external cuneate nuclei.These results indicate that climbing and parallel fibers selectively use VGluT2 and VGluT1, respectively, whereas mossy fibers apply both VGluT1 and VGluT2 together to accumulate glutamate into synaptic vesicles. Since climbing-fiber and parallel-fiber terminals are known to make depressing and facilitating synapses, respectively, VGluT1 and VGluT2 might have distinct properties associated with those synaptic characteristics. Thus, it would be the next interesting issue to determine whether mossy-fiber terminals co-expressing VGluT1 and VGluT2 show synaptic facilitation or depression.