F-waves of the facial muscles in healthy control subjects and in patients with peripheral facial nerve disturbance

F-waves were recorded from the mentalis muscles with surface electrodes following stimulation of the marginal mandibular branch of the facial nerve in healthy control subjects during wakefulness, non-REM (rapid eye movement) sleep and voluntary contraction and in patients with Bell's palsy and acoustic neurinoma. The F-wave of the facial muscles results from the backfiring of antidromically activated alpha motoneurons in the facial motonucleus. Therefore, first, the F-waves were not easily elicited in patients with any disturbance in the proximal segment of the facial nerve (Bell's palsy and acoustic neurinoma). Second, the F-waves were affected by excitability of the facial motonucleus; the F-waves were inhibited significantly during sleep and enhanced significantly during voluntary contraction compared with those at rest during wakefulness. When the stimulation strength was set submaximum for M-waves, F-waves were elicited but H-waves, which have lower threshold than M-waves, were not elicited in the facial muscles, unlike the case of the extremities. Measurement of the F-waves of facial muscles is a new method for estimating excitability of the facial motonucleus unless there is any disturbance of the proximal segment. Fundamental characteristics of the facial F-waves were shown in the present study and measuring facial F-waves is clinically applicable for investigation of both excitability of the facial motonucleus and facial peripheral nerve disturbance.     

Fine mapping of a gene responsible for regulating dietary cholesterol absorption; founder effects underlie cases of phytosterolaemia in multiple communities

Sitosterolaemia (also known as phytosterolaemia, MIM 210250) is a rare recessive autosomal inherited disorder, characterised by the presence of tendon and tuberous xanthomas, accelerated atherosclerosis and premature coronary artery disease. The defective gene is hypothesised to play an important role in regulating dietary sterol absorption and biliary secretion, thus defining a molecular mechanism whereby this physiological process is carried out. The disease locus was localised previously to chromosome 2p21, in a 15 cM interval between microsatellite markers D2S1788 and D2S1352 (based upon 10 families, maximum lodscore 4.49). In this study, we have extended these studies to include 30 families assembled from around the world. A maximum multipoint lodscore of 11.49 was obtained for marker D2S2998. Homozygosity and haplotype sharing was identified in probands from non-consanguineous marriages from a number of families, strongly supporting the existence of a founder effect among various populations. Additionally, based upon both genealogies, as well as genotyping, two Amish/Mennonite families, that were previously thought not to be related, appear to indicate a founder effect in this population as well. Using both homozygosity mapping, as well as informative recombination events, the sitosterolaemia gene is located at a region defined by markers D2S2294 and Afm210xe9, a distance of less than 2 cM.     

Eosinophilic neuronal inclusion bodies in the temporal lobe.

Intracytoplasmic neuronal inclusion bodies were found in the temporal lobe of an elderly woman. The oval or rod-shaped inclusion bodies were eosinophilic, showed bright red staining with azan, and were about half the size of the nucleus of a large neuron. They were non-argyrophilic and non-congophilic. Ultrastructurally, the inclusion bodies consisted of aggregates of filamentous materials showing partial periodicity. Among inclusion bodies reported up to now, the present ones resembled some described previously as "thalamic inclusions", but were different with regard to their partial filament periodicity, and unusual in that they were located in the deep layer of the temporal lobe and not in the thalamic nuclei.     

Aplastic anemia: lack of increase of in vitro colony formation after T cell depletion with monoclonal antibodies and complement

To detect suppressor T cells to hematopoietic stem cells, growth of granulocyte-macrophage colony-forming cells (CFU-GM) and burst-forming unit (BFU-E) was compared before and after treatment of bone marrow cells with anti-T monoclonal antibodies and complement in 29 patients with aplastic anemia. The anti-T monoclonal antibodies used were 35.1 (CD2), Tp120 (CD6) and ATL27 (not clustered). Treatment of normal bone marrow with anti-T monoclonal antibodies and complement resulted in complete (greater than 99%) lysis of T cells with negligible effects on colony growth. Preincubation of marrow samples with monoclonal antibodies and complement did not enhance CFU-GM or BFU-E colony growth in patients with aplastic anemia. Using this assay, there was no evidence of T cell-mediated inhibition of colony proliferation in any of 29 patients.     

Enhancement of an inhibitory input to the feeding central pattern generator in Lymnaea stagnalis during conditioned taste-aversion learning

To study the neuronal mechanism of a conditioned taste-aversion (CTA) learning in the pond snail Lymnaea stagnalis, we examined the synaptic connection between the neuron 1 medial (N1M) cell and the cerebral giant cell (CGC), the former is an interneuron in central pattern generator for the feeding response and the latter is a regulatory neuron to the central pattern generator. Inhibitory postsynaptic potential (IPSP) which was evoked in the N1M cell by activation of the CGC was larger and lasted longer in the conditioned animal than that in the control animal. The electrical properties of the cell body of CGC and the responses of the CGC to the chemosensory inputs were not changed during the CTA learning. These results, together with the previous report indicating the existence of excitatory projection from the N1M cell to the feeding motoneuron, suggest that enhanced IPSP in the N1M cell may underlie the suppression of feeding responses in the Lymnaea CTA learning.     

AN ELECTRON MICROSCOPIC STUDY ON THE RETICULOENDOTHELIAL CELLS IN THE LYMPH NODES

In an attempt to clarify the cytological characteristics of the RES cells in the lymph nodes and their embryological correlations, lymph nodes and lymph node anlages of germ-free rats, nude mice, and human fetuses were light and electron microscopically examined. On the basis of differences of intracellular organelles, their behaviors for reticulum fibers and of endogenous peroxidatic activity, histiocytes should be reasonably distinguished from the cells conventionally called reticulum cells. Reticulum cells and histiocytes respectively are destined to differentiate in different directions from the early stage of development of the lymph node anlage. Sinus endothelial cells are ontogenetically originated and differentiated from the endothelial lining cells of lymphatic vessels. Primitive reticular cells are differentiated into mature reticulum cells in the lymph nodes, they transform into the lympho-reticular cells, further into lymphoblasts, and finally develop into medium-sized lymphocytes.     

Dual Bar homeo box genes of Drosophila required in two photoreceptor cells, R1 and R6, and primary pigment cells for normal eye development.

In the Bar mutation of Drosophila, ommatidial differentiation is known to be suppressed in the anterior portion of the eye. Our structural analysis shows that the Bar region contains a pair of homeo box genes, BarH1 and BarH2. These genes encode polypeptides similar in size and sequence and share a common homeo domain that is identical in sequence except for putative trans-activator-binding sites. We also show, by mosaic analysis and immunostaining with anti-BarH1/BarH2 antibodies, that BarH1 and BarH2 are not only specifically coexpressed but also functionally required in R1/R6 prephotoreceptors and primary pigment cells in developing ommatidia. In R1/R6, the expression of BarH1 and BarH2 appears to be regulated by rough and glass gene products. BarH1 and BarH2 proteins are essential to normal lens formation, formation of three types of pigment cells, and elimination of excess cells from mature ommatidia. Taken together, our results suggest that Bar homeo domain proteins may play key roles in the fate-determination processes of pigment cells and cone cells.