The nucleus basalis magnocellularis: The origin of a cholinergic projection to the neocortex of the rat

The cells of origin of a neocortical cholinergic afferent projection have been identified by anterograde and retrograde methods in the rat. Horseradish peroxidase injected into neocortex labelled large, acetylcholinesterase-rich neurons in the ventromedial extremity of the globus pallidus. This same group of neurons underwent retrograde degeneration following cortical ablations. The region in which cell depletion occurred also showed significant decreases in the activities of choline acetyltransferase and acetylcholinesterase. Discrete electrolytic and kainic acid lesions restricted to the medial part of the globus pallidus each resulted in significant depletions of neocortical choline acetyltransferase and acetylcholinesterase. Hemitransections caudal to this cell group did not result in such depletions. Taken together these observations suggest that the acetylcholinesterase-rich neurons lying in the ventromedial extremity of the globus pallidus, as mapped in this study, constitute the origin of a major subcortical cholinergic projection to the neocortex. The utility of acetylcholinesterase histochemistry in animals pretreated with di-isopropylphosphorofluoridate in identifying cholinergic neurons is discussed in the light of this example; specifically, it is proposed that high acetylcholinesterase activity 4–8 h after this pretreatment is a necessary, but not sufficient, criterion for the identification of cholinergic perikarya.The neurons in question appear to be homologous to the nucleus basalis of the substantia innominata of primates, and are thus termed ‘nucleus basalis magnocellularis’ in the rat. No evidence was obtained to support the hypothesis that nucleus of the diagonal band projects to neocortex. However, striking similarities in size and acetylcholinesterase activity were observed among the putative cholinergic perikarya of the nucleus basalis magnocellularis, the nucleus of the diagonal band, and the medial septal nucleus.Kainic acid lesions of the neocortex produced uniform and complete destruction of neuronal perikarya. These lesions decreased neocortical glutamic acid decar?ylase activity, suggesting that there are GABAergic perikarya in the neocortex. However, the same lesions did not affect neocortical choline acetyltransferase. This observation suggests that there are no cholinergic perikarya in the neocortex, a conclusion that is consistent with the absence of intensely acetylcholinesterase-reactive neurons in the neocortex.     

Molecular interactions of fission yeast Skp1 and its role in the DNA damage checkpoint

Skp1 is a central component of the E3 ubiquitin ligase SCF (Skp1-Cullin-1-F-box). It forms an adapter bridge between Cullin-1 and the substrate-determining component, the F-box protein. In order to establish the role of Skp1, a temperature sensitive (ts) screen was carried out using mutagenic PCR (polymerase chain reaction) and 9 independent ts mutants were isolated. Mapping the mutated residues on the 3-D structure of human Skp1 suggested that the mutants would be compromised in binding to F-box proteins but not Cullin-1 (Pcu1). In order to assess the binding properties of ts Skp1, 12 F-box proteins and Pcu1 were epitope-tagged, and co-immunoprecipitation performed. This systematic analysis showed that ts Skp1 retains binding to Pcu1. However, binding to three specific F-box proteins, essential Pof1, Pof3 involved in maintaining genome integrity, and nonessential Pof10, was reduced. skp1ts cells exhibit a G2 cell cycle delay, which is attributable to activation of the DNA damage checkpoint. Intriguingly, contrary to pof3 mutants, in which this checkpoint is required for survival, checkpoint abrogation in skp1(ts) suppresses a G2 delay and furthermore almost rescues the ts phenotype. The activation mechanism of the DNA damage checkpoint therefore differs between pof3Delta and skp1(ts), implicating a novel role for Skp1 in the checkpoint-signalling cascade.     

Computerized Digital Imaging Techniques Provided by Digital X-ray Radiogrammetry as New Diagnostic Tool in Rheumatoid Arthritis

Purpose Our study evaluates digital x-ray radiogrammetry (DXR) and Radiogrammetry Kit (RK) as a new diagnostic method for the measurement of disease-related osteoporosis including quantification of joint space narrowing dependent on the severity of rheumatoid arthritis (RA). Materials and Methods A total of 172 unselected patients with RA underwent computerized measurements of bone mineral density (BMD) and metacarpal index (MCI) by DXR, as well as a semiautomated measurement of joint space distances at the metacarpal–phalangeal articulation (JSD-MCP 2–5), both were analyzed from plain radiographs of the nondominant hand. Results Correlations between DXR-BMD and DXR-MCI vs. parameters of RK were all significant (0.34 < R < 0.61; p < 0.01). An expected negative association was observed between RK parameters and the different scoring methods (−0.27 < R < −0.59). The maximum relative decrease in BMD vs. MCI as measured by DXR between the highest and lowest RA severity group was −27.7% vs. −27.5% (p < 0.01) for the modified Larsen Score, whereas the minimal value of relative DXR-BMD and DXR-MCI reduction could be documented for the Sharp Erosion Score (−20.8% vs. −26.8%; p < 0.01). The relative reduction of mean JSD-MCP using RK significantly varied from −25.0% (Sharp Erosion Score) to −41.2% (modified Larsen Score). In addition, an excellent reproducibility of DXR and RK could be verified. Conclusion DXR in combination with RK could be a promising, widely available diagnostic tool to supplement the different scoring methods of RA with quantitative data, allowing an earlier and improved diagnosis and more precision in determining disease progression.     

Grafting of fibroblasts isolated from the synovial membrane of rheumatoid arthritis (RA) patients induces chronic arthritis in SCID mice-A novel model for studying the arthritogenic role of RA fibroblasts in vivo

The objective of this study was to verify whether isolated rheumatoid arthritis (RA) synovial fibroblasts induce chronic arthritis in SCID mice, in analogy to whole tissue pieces. Fibroblasts were isolated from the synovial membrane of four RA patients (or controls) by out-growth and repeated-passage culture. Following flow-cytometry characterization, 2x10(6)cells were transferred into the left knee joint of SCID mice. The development of arthritis was assessed by joint swelling and histological changes. Human and murine cytokines were measured in vitro in co-cultures (or Transwelltrade mark systems) of human and murine cells. Purified RA synovial fibroblasts, but not healthy synovial or skin fibroblasts, induced hu/mu arthritis within 6 weeks. In-vitro secretion of murine and human interleukin(IL)-6, as well as murine tumour necrosis factor (TNF)-alpha, indicated cross-activation between murine macrophages and human RA fibroblasts. Soluble-factor mechanisms proved more effective than cell-contact mechanisms. Purified RA fibroblasts can, alone, induce hu/mu SCID arthritis. The cytokine profile suggests that xenogeneic interaction between human fibroblasts and murine macrophages may determine the sequence of events leading to hu/mu arthritis.     

Application of capillary electrophoresis in clinical chemistry: the clinical value of urinary modified nucleosides

Urinary modified nucleosides were determined by capillary electrophoresis using a 300 mM SDS-25 mM sodium tetraborate-50 mM sodium dihydrogenphosphate buffer. The nucleosides were extracted from urine by phenylboronate affinity gel chromatography. In cancer patients the levels of the modified nucleosides are generally elevated. By an artificial neural network method breast cancer patients were differentiated from normal individuals, which indicates that the modified nucleosides could be of clinical value as tumor markers.     

Factors influencing active avoidance behavior in rats with ventromedial hypothalamic lesions

Ventromedial hypothalamic lesioned rats maintained at preoperative body weight received an equal number of shocks while emitting significantly fewer responses than controls in a lever-pressing free-operant avoidance paradigm, and performed as well as unoperated animals in lever-pressing and shuttle box (both 1- and 2-way) discriminated avoidance tasks. The failure of VMH lesions to facilitate performance in the 2-way avoidance paradigm was probably the result of a ceiling effect. With the exception of the simple one-way avoidance task, obese lesioned rats were markedly impaired in the acquisition of all active avoidance behavior, but escape behavior was not affected. When tested in a free-operant paradigm, the avoidance performance of well trained lesioned animals varied inversely with body weight. As obese rats displayed lower flinch thresholds to shock than controls and similar levels of activity and responding as lean lesioned animals, it was concluded that their impaired avoidance behavior was not due to changes in sensitivity or mobility. The possible relation to other VMH lesion- and/or obesity-induced deficits is discussed.     

Linking: a dynamic electrophysiologic phenomenon in macroreentry circuits

The term "linking" has been used specifically to describe the mechanism for perpetuation of functional anterograde bundle branch block: namely, repetitive transseptal retrograde concealed penetration by impulses propagating along the contralateral bundle. We present selected examples that demonstrate tht linking-type phenomena actually have a wide spectrum of expression in human macroreentry circuits, particularly those incorporating either the bundle branches and His bundle or the normal pathway and Kent bundle. The examples presented are as follows: (1) persistent retrograde functional conduction delays in the His-Purkinje system during right ventricular pacing, (2) anterograde Kent bundle condution at rapid rates, dependent on prior block in the normal pathway, (3) persistent anterograde functional infra-His block of atrial impulses during rapid ventricular pacing in the presence of a retrogradely conducting accessory pathway, and (4) transient advancement of His activation with ventricular fusion complexes during overdrive ventricular pacing of bundle branch reentrant tachycardia. Based on these examples, we characterize linking as a generalized electrophysiologic phenomenon in which each successive impulse entering a macroreentry circuit propagates preferentially along one limb because of functional block in the contralateral limb resulting from the effects of the prior impulse. It is proposed that such functional block may be dynamically maintained either by repetitive impulse interference, which perpetuates local refractoriness (examples No. 1 to 3), or by repetitive impulse collision (example No. 4). The general conceptual scheme outlined can be applied to specific electrophysiologic phenomena associated with a wide variety of reentry circuits in man.     

Spironolactone as a source of interference in commercial digoxin immunoassays

Eight commercial digoxin immunoassay methods were tested in 17 subjects taking spironolactone (but not digoxin) to evaluate cross-reactivity from parent drug and/or metabolites. Four of these methods showed significant (up to 1.9 nmol/L) and variable "apparent digoxin" concentrations, despite the absence of digoxin in the drug regimen. The results suggest that clinical laboratories require a knowledge of their method with respect to spironolactone-related cross-reactivity and should exercise caution when interpreting digoxin results where spironolactone is coadministered. Further, the presence of concurrent renal and/or hepatic impairment could delay clearance of spironolactone metabolites (as well as digoxin metabolites and endogenous substances) and further distort a genuine digoxin result.     

Chest wall moulages for radiotherapy of resected breast cancer with fast electrons: comparative tests of different materials

Irradiation of the thoracic wall with high-speed electrons is one of the standard methods of prophylaxis and therapy of local recurrences and cutaneous metastases of an operated mammary carcinoma. The surface dose, however, is only 85% of the maximum dose, due to the depth dose curve of the electron beams with the preponderantly applied energy of 7MeV. This is a poor value, since most of all recurrences appear near to the surface and so the risk of giving an insufficient dose is involved. The dose distribution could be essentially improved by the use of moulages on the chest. These moulages were made of different materials which were tested and compared with respect to their suitability for radiotherapeutic purposes. The best materials proved to be "Urgo-Plastan" (manufacturer: Holphar, Sulzbach) and "Orthoplast" (manufacturer: Johnson & Johnson, Düsseldorf). Both materials are synthetic substances which after heating can easily be adapted to the body shape and which offer a good stability, little inconvenience for the patient and a relative easy handling. With these moulage materials, the surface dose is increased to 98% ("Urgo-Plastan") and 99% ("Orthoplast") of the maximum dose.